Federal Register / Vol. 58, No. 3 / Wednesday, January 6, 1993 / Rules and Regulations DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 101 [Docket No. 91N - 0103] RIN 0905 - AB67 Food Labeling: Health Claims and Label Statements: Omega-3 Fatty Acids and Coronary Heart Disease AGENCY: Food and Drug Administration, HHS. ACTION: Final rule. SUMMARY: The Food and Drug Administration (FDA) is announcing its decision not to authorize the use on the label or labeling of foods of health claims relating to an association between omega-3 fatty acids and coronary heart disease (CHD).The agency has determined, based on: (1) The totality of the publicly available scientific evidence; and (2) the agency's review of comments received in response to its November 27, 1991, proposed rule on omega-3 fatty acids and CHD, including scientific information included in those comments, that there is not significant scientific agreement among experts that such evidence supports a health claim for omega-3 fatty acids and CHD. Further, FDA has determined that the new information does not change the conclusions that the agency reached on the basis of the information reviewed in its proposal. Therefore, FDA has concluded that such a claim is not justified. This action is in response to provisions of the Nutrition Labeling and Education Act of 1990 (ts, published elsewhere in this issue of the Federal Register. EFFECTIVE DATE: May 8, 1993. FOR FURTHER INFORMATION CONTACT: John C. Wallingford, Center for Food Safety and Applied Nutrition (HFS - 465), Food and Drug Administration, 200 C St. SW., Washington, DC 20204, 202 - 205 - 5461. SUPPLEMENTARY INFORMATION: I. Background In the Federal Register of November 27, 1991 (56 FR 60663), FDA proposed not to authorize a health claim relating diets high in omega-3 fatty acids to reduced risk of heart disease. The proposed rule was issued in response to provisions of the1990 amendments (Pub. L. 101 - 535) that bear on health claims and in accordance with the proposed general requirements for health claims for food (November 27, 1991, 56 FR 60537). As amended in 1990, the Federal Food, Drug, and Cosmetic Act (the act) provides that a food is misbranded if it bears a claim that characterizes the relationship of a nutrient to a disease or health-related condition unless the claim is made in accordance with section 403(r)(3) or (r)(5)(D) of the act (21 U.S.C. 343(r)(3) or(r)(5)(D)). Congress enacted the health claims provisions of the 1990 amendments to help U.S. consumers maintain good health through appropriate dietary patterns and to protect consumers from unfounded health claims. Section 3(b)(1)(A) of the 1990 amendments specifically requires the agency to determine whether health claims for 10 nutrient-disease relationships meet the requirements of section 403(r)(3) or (r)(5)(D) of the act. The relationship of omega-3 fatty acids and heart disease is one of the claims required to be evaluated. In the Federal Register of March 28, 1991 (56 FR 12932), FDA published a notice requesting scientific data and information on the 10 specific topic areas identified in the 1990 amendments. Relevant scientific studies and datareceived in response to this request were considered as part of the agency's review of the scientific literature on omega-3 fatty acids and CHD and were included in the proposed rule. In addition, on January 30 and 31, 1992, FDA held public hearings on all aspects of the proposed rules (57 FR 239). FDA requested in the Federal Register of November 27, 1991 (56 FR 60663), written comments in response to its proposed rule. FDA reviewed all of the comments it received, including new data submitted in the comments, and scientific articles referred to in the comments. FDA also reviewed additional scientific articles, reviews, and recommendations published from August 1991 through February 1992. The Dietary Supplement Act of 1992 (DS Act) established a moratorium on the implementation of the 1990 amendments with respect to dietary supplements. The DS Act says that FDA can grant health claims for food, including dietary supplements, under section 403(r)(3)(B)(i) of the act. However, it may not act on such claims under section 403(r)(5)(D) of the act until it establishes a standard to implement that section of the act, which the DS Act says may not occur until December 1993. Section 3(b)(1)(A)(x) of the 1990 amendments directs the agency to evaluate the omega-3 fatty acids/CHD claims based on the standard that FDA is establishing for determining the reliability of health claims under section 403(r)(5)(D) of the act. In the November 27, 1991, proposal on general requirements for health claims, FDA proposed to adopt the standard that the 1990 amendments provide for conventional foods, which is set forth in section 403(r)(3)(B)(i) of the act, as the standard for dietary supplements. Given this fact, and the fact that omega-3 fatty acids are found in numerous conventional foods as well as in dietary supplements, FDA broadened its inquiry to a determination as to whether it should grant a health claim on omega-3 fatty acids and CHD for any foods Because the DS Act provides that FDA may grant claims using the significant scientific agreement standard specified in section 403(r)(3)(B)(i) of the act, and given the breadth of FDA's November 1991, proposal on omega-3 fatty acids, FDA has decidedto move forward to determine whether it can authorize a claim under section 403(r)(3)(B)(i) for omega-3 fatty acids and CHD. However, this rule does not apply to dietary supplements. While a manufacturer of a dietary supplement can make a claim on omega-3 fatty acids and CHD without rendering its product misbranded under section 403(r)(1)(B) of the act, the manufacturer should assure itself that the making of the claim will not misbrand the product under section 403(a). II. Summary of Comments and the Agency's Response FDA received 80 letters, each containing one or more comments, from consumers, health care professionals, universities and research institutes, health profession associations, consumer advocacy organizations, State and local governments, foreign governments, trade organizations, industry, and professional organizations. In addition to these comments, the agency also considered statements made on omega-3 fatty acids and CHD at the January 30 and 31, 1992, public hearings. Some of the comments agreedwith one or more of the aspects of the proposed rule, without providing further grounds for support other than those provided by FDA in the preamble to the proposal. Other comments disagreed with one or more aspect of the proposal without providing specific grounds for the disagreement. A few comments addressed issues outside of the scope of this document and will not be discussed in this document. Most of the comments provided specific grounds in support of their positions concerning aspects of this health claim as proposed. The agency has summarized and addressed the issues raised in the sections of this document that follow. A. General Comments 1. Definition of omega-3 fatty acids and composition of omega-3 fatty acid supplements 1. One comment criticized the definition of omega-3 fatty acids used in the proposed rule, on the basis that omega-3 fatty acids were not distinguished from other polyunsaturated fatty acids (PUFA's). In the proposed rule, FDA limited the term omega-3 fatty acids to eicosapentaenoic acid ((EPA), 20 carbons, 5 double bonds) and docosahexaenoic acid ((DHA), 22 carbons, 6 double bonds) (56 FR 60663 at 60664). FDA noted that most of the relevant research has used fish or fish oils rich in these two fatty acids. FDA acknowledges that its statement defining omega-3 fatty acids did not explicitly refer to omega-3 fatty acids. The sentence: ``Their unique characteristic is the location of the first double bond, which occurs at the third carbon from the methyl (or omega) end of the fatty acid.'' (56 FR 60663 at 60664) was intended to refer to omega-3 fatty acids. This definition distinguishes omega-3 fatty acids from other PUFA's, which have their first unsaturation at the sixth or ninth carbon from the omega end of the fatty acid. 2. One comment argued that the definition of omega-3 fatty acids should include land-based (primarily plant) omega-3 fatty acids (i.e., linolenic acid). (For the purposes of this document, the term linolenic acid is used to indicate the omega-3 fatty acid, alpha linolenic acid. In contrast, gamma linolenic acid has its first double bond at the sixth carbon from the omega end of the fatty acid, and is not an omega-3 fatty acid.) FDA disagrees with this comment. FDA defined omega-3 fatty acids as EPA and DHA, primarily as a functional definition derived from the scientific literature. The hypothesis for a relationship between omega-3 fatty acids and CHD derived from correlations between low rates of CHD and high consumption of fish oils. Similarly, most of the intervention studies have used fish oil or fish as a source of EPA and DHA, not plant oils rich in linolenic acid. The comment provided no evidence that linolenic acidRef. 100). Therefore, FDA believes it has represented the potential nutrient-disease relationship appropriately by limiting its attention to EPA and DHA. 3. Two comments stated that FDA's position on fish as opposed to the omega-3 fatty acids in fish was a tautology, because: ``if polyunsaturated fatty acids have beneficial effects on CHD, and if fish oils are a member of this class of fatty acids, it should not be counted against their beneficial effects on CHD.'' FDA disagrees with this comment. FDA considers the claim for omega-3 fatty acids to reflect the unique biochemistry of these fatty acids. In particular, the prevailing theory about the mode of action of omega-3 fatty acids is that they compete with omega-6 fatty acids (fatty acids with their first double bond at the sixth carbon from the methyl end, and which comprise the largest amount of dietary PUFA's). Thus, a clear separation of effects of omega-3 fatty acids from effects of other (primarily omega-6) PUFA's is needed to support a claim. 4. One comment stated that FDA did not consider the importance of the ratio of omega-3 fatty acids to arachidonic acid (AA), a 20 carbon omega-6 PUFA with four double bonds, and stated that evidence exists for a relationship between the saturated fat:unsaturated fat ratio in the diet and the omega-6:omega-3 fatty acid ratio in the diet and the risk of CHD. FDA considers concerns about the ratio of AA to omega-3 fatty acids and the ratio of omega-6 fatty acids to omega-3 fatty acids to be reasonable in view of the competition between these classes of fatty acids in human biochemistry. FDA considered all types of foods and supplements used to provide omega-3 fatty acids in its evaluation of the claim. Although the AA content of the supplement was often reported, studies did not report data for total dietary AA. FDA is aware of only very limited data regarding the ratios of AA to omega-3 fatty acids, and of the omega-6 fatty acid:omega-3 fatty acid ratio in the diet and the risk of CHD. Therefore, it is not possible for FDA to draw any conclusions about these ratios and their possible modifying effectson the omega-3 fatty acids CHD health claim. However, because the fish oils used contained high concentrations of omega-3 fatty acids, FDA believes that the amounts of fish oils supplemented to the various test diets would have affected the AA:omega-3 fatty acid ratio and the omega-6:omega-3 fatty acid ratio of the diets to some extent. FDA advises that interested persons may petition FDA under 101.70 (21 CFR 101.70) to issue a regulation regarding a health claim that relates these ratios to the risk of CHD. 5. Another comment pointed out that supplements used currently have contained various amounts of short- and long-chain omega-3 fatty acids and that many supplements also contain saturated fat. The comment stated that some of the discrepancies in reported findings may be due to the type of supplement used. FDA agrees that numerous supplements varying in fatty acid composition have been used, and that the variation in the fatty acid composition of supplements may have influenced the outcome. FDA reexamined the studies cited in its proposal and the newdata submissions for evidence that the nature of the supplement used was related to the outcome. However, the agency found that the same results are observed regardless of the source of omega-3 fatty acids. For example, in eight well-designed studies cited in the proposal on the total serum cholesterol response among normal subjects (Refs. 6, 9, 14, 49, 54, 73, 156, and 166), six different sources of omega-3 fatty acids were used: Salmon oil, SuperEPA, MaxEPA, a fish oil triglyceride, Promega, and mackerel paste. None of these supplements produced a change in total serum cholesterol. Similarly, four different sources of omega-3 fatty acids (fresh water fish, salmon oil, purified EPA, MaxEPA) were shown in seven well-designed studies to reduce platelet a FDA did note that some differences in response have been produced by supplements that vary in ratio of EPA to DHA. For example, one fish oil (pollock oil) with a high EPA:DHA ratio increased low-density lipoprotein (LDL) cholesterol, LDL triglyceride and apoprotein B (apoB) (a protein component of LDL) in comparison to a butter-rich diet, but two fish oils with a low EPA:DHA ratio (tuna oil, salmon oil with added palmitic acid) reduced apoB and LDL cholesterol, and increased LDL triglyceride to a smaller extent than the pollock oil in comparison to the butter-rich diet (Ref. 17). However, the effects of the two major omega-3 fatty acids have not yet been systematically investigated. FDA recognizes that purified EPA and DHA are now available for research; such supplements will enable the study of the individual effects of these fatty acids. 6. One comment stated that conservation of omega-3 fatty acids in the body calls into question the importance of the amounts of omega-3 fatty acids used in scientific studies. However, the comment did not suggest any alternate method to describe intake. FDA recognizes that fish is not ordinarily consumed daily. However, the 1990 amendments require that health claims on foods be stated in such a way as to enable the public to understand the relative significance of such information in the context ofa total daily diet (section 403(r)(3)(B)(iii) of the act). Thus, a reasonable estimate of daily dietary intake of omega-3 fatty acids is needed when assessing the relationship between omega-3 fatty acids and the risk of CHD. Most of the studies reviewedby the agency used daily supplementation with a known amount of omega-3 fatty acids, but others estimated intake of omega-3 fatty acids from foods consumed in the daily diet. Both types of intake estimates are important. Daily supplementation is useful to relate changes to a carefully controlled amount of omega-3 fatty acids. The average daily intake of omega-3 fatty acids in nonintervention studies provides a basis upon which to determine whether the amounts of omega-3 fatty acids fed in supplementation studies are reasonable in the context of the total daily diet. 2. Criteria used in evaluating studies In the proposed rule, FDA listed some of the criteria used in evaluating epidemiological studies on the relationship of omega-3 fatty acids to CHD: (1) The reliability and accuracy of the methods used in food intake analysis and measurements of disease endpoints, (2) the choice of control subjects, (3) the representativeness of the subjects, (4) the control of confounding factors in data analysis, (5) the potential for misclassification of individuals with regard to dietary exposure or disease endpoints, (6) the presence of bias, and (7) the degree of compliance and how compliance was assessed (56 FR 60667). However, FDA stated that it considered randomized, double-blind, placebo-controlled trials to be more valuable than other types of human studies because they were less susceptible to bias, and because they allowed inference about the specific effects of omega-3 fatty acids. Studies in which the endpoint was CHD, by definition, provide the most persuasive type of evidence, but studies measuring CHD to date have not provided the specificity to show that the observed effects were due to omega-3 fatty acids. 7. Some comments expressed the concern that it was unlikely that additional clinical trials will be done due to their expense, and that, therefore, FDA should rely more heavily on epidemiologic studies, animal studies, and biochemical and physiological interventions that suggest an effect of omega-3 fatty acids on risk of CHD. FDA has no basis upon which to agree or disagree with the comments' assertion that further clinical trials are unlikely. FDA disagrees that its emphasis on clinical trials was misplaced. Because the 1990 amendments addressed nutrient-disease relationsdemonstrate that the effects are specifically due to omega-3 fatty acids. Human studies in which a surrogate marker for CHD risk was measured as the endpoint of the treatment were also considered carefully. The advantage of these studies is that they are able to demonstrate specificity of the effects due to omega-3 fatty acids. However, the relationships between many of these surrogate markers and risk of CHD are not well established, making it difficult to relate changes in these endpoints brought about by omega-3 fatty acids to the risk of disease. Biologic markers can serve as markers of a developing disease, but the relevance of such evidence depends directly on the strength of the association between the marker and the disease (Ref. 115). FDA agrees that there are considerable additional data in animal studies, in vitro studies, and biochemical and physiological interventions regarding the effects of omega-3 fatty acids. However, it is not clear that the results of such studies are relevant to the risk of human disease. Thus, FDA believes that these other types of data are of secondary importance compared to clinical data that measure either CHD per se or established surrogate markers for CHD. However, in response to the comments, FDA has provided a more thorough description of animal and in vitro studies that suggest a role for omega-3 fatty acids in reducing the risk of CHD, particularly with respect to the effects of omega-3 fatty acids on the development of atherosclerosis and with respect to the responsiveness of blood vessels to ischemia (see comments 38 and 49 and section II.C.3.a. of this document). 8. Many comments stated that the agency's position on omega-3 fatty acids and CHD was inconsistent with its position on other health claims, and argued that for each of the four claims proposed to be allowed by FDA, the data were no stronger than the data supporting the link between omega-3 fatty acids and CHD. The comments asserted that, by basing its decision on the relationship between the nutrient and a surrogate marker for the disease, or for a susceptible subpopulation, FDA held other claims to a less restrictive standard. One comment stated: ``The FDA statement is internally consistent in denying health claims for omega-3 fatty acids, but this is only in the context of holding these food components to essentially impossible standards not required for other, allowable, claims.'' Specific comparisons were made to the proposed claims on fat and CHD, fat and cancer, calcium and osteoporosis, and sodium and hypertension. Other comments indicated that qualified claims, such as that for calcium and osteoporosis, were appropriate models for the claim relating omega-3 fatty acids to CHD. FDA disagrees with these comments. FDA believes that for these other claims there is significant scientific agreement among qualified experts regarding the relationship between the nutrient and the disease, whereas there is not such agreement regarding the relationship between omega-3 fatty acids and CHD, or between omega-3 fatty acids and agreed surrogate markers for risk of CHD. For example, based on the totality of the publicly available scientific evidence, FDA determined that there is significant scientific agreement about the role of calcium in maintaining bone mineral density (the relationship of the nutrient to the intermediate marker for the disease), and about the relationship between peak (maximal) bone mass and the risk of developing osteoporosis and related bone fractures later in life (the relationship between the intermediate marker and the disease itself) (see 56 FR 60689; see also the final rule on calcium and osteoporosis published elsewhere in this issue of the Federal Register). Similarly, FDA relied on a long history of Federal Government and other consensus statements to conclude that there is significant scientific agreement about the role of sodium as a causal factor in hypertension for a segment of the population. (Srtension, published elsewhere in this issue of the Federal Register.) FDA also recognized the history of significant scientific agreement about the relationships between fat and cancer and between fat and CHD evidenced by statements in reports issued by Federal Government and other authoritative bodies. (See 56 FR 60764, 56 FR 60726; see also final rules on fat and cancer and fat and CHD, published elsewhere in this issue of the Federal Register.). Thus, these other nutrient-disease relationships have a history of being recognized in Federal Government and authoritative reports, indicating significant scientific agreement, whereas the relationship between omega-3 fatty acids and CHD has not been so recognized. For two of these other nutrient-disease relationships, the data relate to the disease itself, rather than to markers for the disease. In the other two, calcium and osteoporosis and fat and CHD, there is significant scientific agreement that the dietary factors are related to surrogate markers for the diseases, and that the surrogate markers are related to the diseases. There is significant scientific agreement that serum cholesterol and blood pressure are risk factors for CHD, as indicated by the emphasis on these factors in Federal Government and other authoritative documents (Refs. 34 through 36, 100, 115, and 169). Data regarding the effects of omega-3 fatty acids on these endpoints have been carefully reviewed. However, the other endpoints measured in studies of the effects of omega-3 fatty acids, e.g., in vitro platelet aggregation, various growth factors, fibrinogen, have not achieved the same extent of scientific agreement. Where authorized health claims include qualifications, the qualifications are intended to assure that the wording of allowed claims reflects those particular aspects of the substance-disease relationship for which there is significant scientific agreement, not to qualify the extent of agreement. 9. Some comments stated that FDA relied heavily on material published in the National Academy of Sciences 1989 report, ``Diet and Health: Implications for Reducing Chronic Disease Risk'' (Ref. 115) and the Surgeon General's 1988 report (Ref. 34), and did not place enough emphasis on information published since that time. FDA acknowledges that the two reports in question were important to its assessment of the scientific evidence. However, the agency does not agree that it failed to give appropriate weight to subsequently published research. The 1990 amendments required the agency to consider the totality of publicly available scientific evidence in assessing nutrient-disease relationships. Given the time constraints imposed by the 1990 amendments for developing and publishing proposed regulations, FDA depended on Federal Government reports and reports of authoritative bodies (e.g, the National Academy of Sciences) for assessment of the scientific evidence published before 1988. The reports were also used as a way of determining whether there was significant scientific agreement among qualified experts that the evidence supports a relationship between omega-3 fatty acids and CHD. The agency's reliance on these reports is consistent with the 1990 amendments, which require the agency to consider reports from authoritative scientific bodies of the United States in assessing health claim petitions and to justify any decision rejecting the conclusions of such reports (section 403(r)(4)(C) of the act). Recognizing, however, that considerable research had been published since these reports, and that these reports had not been updated, FDA also reviewed the available studies on humans published since 1988. FDA relied on its own review of individual studies rather than review articles, because review articles generally reflect the bias of the author and may not consider the totality of the evidence. FDA focused its independent review on primary papers published between January 1988 and August 1991. Sulished before 1988 and used to generate the hypothesis of a relationship between omega-3 fatty acids and CHD were also reexamined. Thus, by utilizing the two reports in question, supplemented with an independent review of the subsequently published research, FDA was able to assess the totality of the scientific evidence on omega-3 fatty acids and CHD in compliance with the statutory standard. 10. One comment suggested that FDA was inconsistent with the conclusions of the major reviews of this area, published after the Federal Government and other comprehensive reports. They stated that of the nine major reviews (excluding Kinsella, and Connor and Connor), eight concluded that omega-3 fatty acids played a beneficial role with factors affecting heart disease. Although FDA did not rely on review articles to assess the strength of association between omega-3 fatty acids and CHD, each review was read, and the agency interprets these reviews as supporting the hypothesis in concept. However, each review contained reservations about the extent to which the relationship between omega-3 fatty acids and CHD was established. The cautionary statements suggest general agreement that the area of omega-3 fatty acids and CHD holds promise for further research along a number of lines, but that, at present, there are not sufficient data to have certainty about the relationship between omega-3 fatty acids and CHD. Placed in chronological order, the concluding sections from the cited review articles exemplify the lack ofcertainty as to the relationship between omega-3 fatty acids and risk of CHD. The review of the relationship between omega-3 fatty acids and CHD by Leaf and Weber (Ref. 91) was considered in the National Academy of Sciences' ``Diet and Health: Implications for Reducing Chronic Disease Risk'' report (Ref. 115). FDA elected to include the Leaf and Weber review in its citations because it covered, in the most comprehensive manner of all available reviews, the state of scientific knowledge about omega-3 fatty acids in CHD at the time the Federal Government and other comprehensive reviews were published. Leaf and Weber wrote: ``Despite claims that n-3 fatty acids can help prevent atherosclerosis, recommendations to the public on diet have been conservative; people have been advised to increase their consumption of fish by replacing two or three meals a week containing red meat with meals containing fish.'' Their concluding sentence was: ``If prospective double-blind, placebo-controlled clinical trials were to show that n-3 fatty acids helped to prevent atherosclerosis, these agents apparently would represent one of the most benign interventions in our pharmacopeia.'' (Emphasis added.) Bonaa (Ref. 10) wrote in his conclusion that the data on blood pressure: * * * provide some support for the hypothesis that dietary marine lipids influence blood pressure in man. Supplementation of n-3 PUFAs [polyunsaturated fatty acids] to Western diets consistently lowered systolic blood pressure, while results fordiastolic blood pressure were conflicting * * *. There is no evidence of any substantial hypotensive response to marine lipids and further studies should be designed to detect small effects. Lands (Ref. 89) did not review the relationship between omega-3 fatty acids and any specific disease, but presented the hypothesis that the balance of omega-3 and omega-6 fatty acids in the diet may be related to diseases associated with overproduction of eicosanoids from AA. He indicates in the introduction that, ``We are now in an uncertain time of evaluating the benefits and risks of dietary n-6 and n-6 polyunsaturated fats.'' Weber (Ref. 161) concluded: The promise of n-3 fatty acids deduced from biochemical and functional effects will have to be evaluated in ongoing and future carefully designed and conducted studies. So far, published data of controlled clinical trials incorporating clinical enochemical and functional effects of dietary fatty acids assumed to be of clinical benefit in the prevention of atherothrombotic and allergic/inflammatory disorders is only beginning to be closed. (Emphasis added.) Connor and Connor (Ref. 21) wrote in their summary: The exact place of omega-3 fatty acids from fish and fish oil remains to be defined. However, this much seems certain. Fish provides an excellent substitute for meat in the diet. Fish is lower in fat, especially saturated fat, and contains the omega-3 fatty acids. Fish oil may have promise as a therapeutic agent in certain hyperlipidemic states, especially the chylomicronemia of type V hyperlipidemia. Fish oil has logical and well-defined antithrombotic and antiatherosclerotic activities since it depresses thromboxane A2 production and inhibits cellular proliferation responsible for the progression of atherosclerosis. As the years pass and more experiments are reported, it seems reasonable to place the omega-3 fatty acids from fish oil in a prominent position for specific hypolipidemic, antithrombotic and antiatherosclerotic activity. Kinsella et al. (Ref. 82) wrote: The cumulative findings concerning fish oils suggest that further amelioration of coronary heart disease may be feasible by dietary manipulation and by optimizing the intake of n-6 and n-3 PUFAs, not only to reduce plasma lipids but to ensure balanced eicosanoid metabolism--a prospect that deserves more research * * *. Overall, in view of the prevalence of coronary heart disease, consumption of n-3 PUFA oils should be considered as a useful complementary option for the amelioration of coronary vascular diseases. Knapp (Ref. 84) introduced his paper stating: ``The role of dietary polyunsaturated fats in the prevention of human vascular disease has not been defined, but population and intervention studies have suggested that w-3 fatty acids (FAs) from marine lipids may have a number of potentially beneficial effects.'' (Emphasis added.) And in conclusion he wrote: ``The proof of our hypotheses must be derived from increasingly ambitious clinical trials, which assess the potential benefits of dietary polyunsaturates in particular clinical settings; the recent demonstration that three helpings of oily fish per week prolongs survival after MI (Ref. 16) is an example of this.'' (Emphasis added.) Nestel (Ref. 111) concluded: ``More basic understanding of the actions of fish oils is necessary before fish oils can be recommended widely to the public.'' Nordoy and Goodnight (Ref. 112) cautioned that until additional data become available, ``clinicians should be advised to follow the dietary recommendations of the National Cholesterol Education Program's expert panel,'' which is silent on omega-3 fatty acids and limits the total polyunsaturated fat to 10 percent of calories. These reviewers added their own recommendation that omega-6/omega-3 ratio of the PUFA's be approximately 3/1, with the omega-3 fatty acids from marine sources. Weber and Leaf (Ref. 162) stated: Despite all the laboratory, human, animal, and epidemiologic studies suggesting an anti-atheromatous action of w3 fatty acids, we have been lacking adequate clinical trials which will determine in prospective, placebo-controlled, randomized studies, whether all the above experimental and epidemiologic evidence adds up to a demonstrable effect of fish oils to prevent atherosclerosis, e.g., coronary heart disease in humans at high risk for heart attacks. The Burr paper (Ref. 16) was described in Weber and Leaf's review, and thus was considered in the above summary statement. In summary, these reviews indicate that what is agreed is that there is a plausible biochemical basis for a relationship between omega-3 fatty acids and CHD, and that there are some data supporting some of the hypothesized mechanisms by which omega-3ding statements, is that such a relationship already has been established by the evidence. 11. A concern raised by many comments was that FDA's conclusions were different from the conclusions reached in the report from the Life Sciences Research Office (LSRO) of the Federation of American Societies for Experimental Biology (Ref. 100), themost recent comprehensive review, and that FDA did not explain why it reached a different conclusion from that reached in the LSRO report. The LSRO report was contracted for by FDA as an independent review of the scientific evidence about the relationship between omega-3 fatty acids and CHD. A draft of the tentative final report was received immediately prior to the publication of the proposed rule. Thus, there was insufficient time for the agency to prepare a detailed discussion of the report. The final report was submitted to FDA as a comment to the proposal. The LSRO report's conclusions on hypertension, thrombosis, the developmentof atherosclerotic plaque and intimal hyperplasia, plasma lipids and lipoproteins, diabetic and prediabetic patients, and epidemiologic observations are grouped with other comments on these topics and discussed in this document. 12. One comment considered FDA's caution against extrapolation of results from studies conducted in at-risk populations to the general population to be questionable, and possibly biased against hypertensives. The comment stated that the health claimshould be allowed, based on data showing that omega-3 fatty acids reduce blood pressure among hypertensives. FDA disagrees with this comment. FDA stated that, although it considered studies in the healthy population to be the most relevant, it also considered studies in a subpopulation with CHD or risk factors for CHD, in part because high risk populationsmay be more sensitive to showing a nutrient-disease relationship than the general population (56 FR 60663 at 60667). FDA stated that it extrapolated positive results from at-risk populations cautiously, and that comparable findings in the general population were needed to support a health claim. 13. Two comments discussed FDA's criteria for weighing various types of data. One comment stated that epidemiologic data are the ``most significant class of evidence,'' and that FDA should give priority to various types of data in the same order that various types of data were reviewed in the proposal. One comment stated that FDA should not have considered epidemiological studies separately from clinical trials. FDA considered the totality of publicly available scientific evidence in its assessment of the relationship of omega-3 fatty acids to CHD. However, some types of evidence were weighted more heavily than others because they were more useful in establishing whether or not the scientific basis of the claim was valid. In particular, the agency was concerned that both the substance (omega-3 fatty acids) and the disease (CHD) be carefully characterized. FDA also considered it important that the amount ofomega-3 fatty acids tested was reasonably related to normal dietary intake, and that the findings apply to the general population. FDA agrees that epidemiologic studies in which the endpoint was CHD provide persuasive evidence for a relationship betweenfish consumption and CHD, but these studies did not provide the specificity to show that the observed effects were due to omega-3 fatty acids. Intervention trials using fish oil supplements often showed that the effects were specific to omega-3 fatty acids (by controlling with other types of fatty acids) but typically did not measure the primary endpoint, CHD. Thus, these different types of data complement each other and must be considered together in assessing the totality of the scientific evidence. 14. One comment offered the services of the International Society for the Study of Fatty Acids and Lipids for the evaluation of the relationship between omega-3 fatty acids and CHD. FDA appreciates this offer. In the final rule on general requirements for health claims published elsewhere in this issue of the Federal Register, FDA advises that it welcomes the input of any professional organization that can provide expertise in reviewing data and in developing a thoughtful and well-organized petition for a health claim on a particular topic. In fact, FDA has added to 101.70(b) the provision that information submitted with petitions may include any findings, along withthe basis of the findings, of an outside panel with expertise in the subject area at issue. FDA, however, retains the authority to review such petitions and, through rulemaking, to decide whether or not to authorize the claim. 15. Two comments stated that it was contradictory for the U.S. Government to contract for research on the omega-3 fatty acids through the biologic test materials program but not to allow a health claim. Another comment pointed out that the Food and Agriculture Organization and the World Health Organization support research on omega-3 fatty acids. Other comments stated that the tone of FDA's proposed rule was unduly negative and that, by taking such a position, FDA may retard further research. FDA disagrees that Federal Government sponsorship of a program to provide test materials for research on the effects of omega-3 fatty acids and the denial of the omega-3 fatty acid-CHD health claim are contradictory actions. The purpose of the biologic test materials program is to develop and standardize a source of omega-3 fatty acids and enable carefully controlled research on the effects of particular omega-3 fatty acids. In the proposed rule, FDA's intent was to examine the total available scientificevidence, some of which was generated using omega-3 fatty acids from the biologic materials test program, and to state its conclusions about the relationship between omega-3 fatty acids and CHD. In its proposal and in this final rule, FDA has identified a number of areas where agreement is lacking that an observed effect of omega-3 fatty acids is related to the risk of CHD, or where there are ambiguities in the data that may be resolved by further research. Thus, FDA's analysis should provide guidance for additional research rather than inhibit it. B. Relationship Between Omega-3 Fatty Acids and CHD In the proposed rule, FDA tentatively concluded that the totality of the scientific evidence does not provide a basis upon which to authorize a claim that omega-3 fatty acids are associated with the risk of CHD (56 FR 60663). FDA noted that: the epidemiological research on this topic revealed that the available studies applied only to the consumption of fish, which contain omega-3 fatty acids, and * * * it was not possible to ascribe any effects specifically to the omega-3 fatty acids. Examination of data from clinical studies revealed that the effects on blood lipids of fish oils containing omega-3 fatty acids were primarily a reduction of blood triglycerides, a blood lipid variable not considered to be an independent risk factor for CHD, but they had no effect on serum cholesterol, low-density lipoprotein (LDL) cholesterol, or high density lipoprotein (HDL) cholesterol, the blood lipid variables most closely associated with risk of CHD. The scientific data are ambiguous on the effects of omega-3 fatty acids on blood pressure and other risk factors for CHD. (56 FR 60663.) A number of comments supported the agency's position on this health claim, but without any specific reasons for that support. One comment agreed with the agency's position in principle, but contested the agency's interpretation of the scientific information in some areas. Other comments disagreed with the agency's review of the scientific information and its conclusion regarding the strength of the evidence supporting the proposed health claim. Specific comments are summarized below. 1. Epidemiologic evidence In the proposed rule, FDA reviewed correlational and cross-sectional studies, prospective studies, and intervention studies available since 1988. (See 56 FR 60663 at 60667 through 60668). Except for the intervention studies (which were typically clinical trials) these studies used fish as a source of omega-3 fatty acids. FDA concluded that those studies that used fish as the source of omega-3 fatty acids were: ``ambiguous, because they are not capable of distinguishing the effects that are specificto omega-3 fatty acids from those that are related to fish consumption.'' (56 FR 60663 at 60668.) 16. A number of comments considered the evidence from epidemiologic studies that relates the consumption of fish inversely to CHD to be sufficient to support a health claim, but did not supply any new information or arguments to support their position. FDA disagrees with the comments. FDA found that: Only a few studies found an association between fish intake and CHD, while others have found no association. Thus there was not consistency of findings. None of the studies that reported a relationship distinguished fish consumption from other factors associated with fish consumption, and therefore they did not demonstrate specificity. Even in those studies reporting a relationship between fish consumption and CHD, it was not clear that the effects were because of the omega-3 fatty acids in fish. Also, the omega-3 fatty acid content of the fish diet associated with reduced CHD was so low that the importance of omega-3 fatty acids is questionable * * * (56 FR 60663 at 60672.) 17. One comment described the results of the Dolecek and Grandits analysis of multiple risk factor intervention trial (MRFIT) data (Ref. 38) as indicating a greater protective effect against CHD due to consumption of 0.6 gram (g) omega-3 fatty acidsthan all other conventional efforts combined (reducing saturated fat, cholesterol, cigarette smoking, and hypertension). FDA agrees with this comment that the association between omega-3 fatty acid consumption and CHD mortality reported in this study has the potential to make a very important public health impact. Notably, the results were obtained on data adjusted for age, race, smoking at entry to the study, diastolic blood pressure, and high-density lipoprotein (HDL) and LDL concentrations. Furthermore, the omega-3 fatty acids were obtained in the normal diet, providing evidence that the amount of omega-3 fatty acids consumed in a normal dietary intake is sufficient for the effect. The researchers' adjustments for lipoprotein measurements should control for some other dietary variables that have been associated with CHD through their effects on these lipoproteins, e.g., saturated fat, but other dietary variables associated with CHD were not controlled, e.g., alcohol. The association between omega-3 fatty acid consumption and CHD mortality described in this study is among the most provocative findings to date in this area, and merits additional study using a design that will document that the active dietary component is or is not the omega-3 fatty acids (i.e., specificity of the effect). 18. One comment pointed out that the Burr paper (Ref. 16) deserved close consideration, because, in contrast to trials on lipid lowering drugs, it showed that consumption of fish containing omega-3 fatty acids or dietary supplements of omega-3 fattyacids may reduce the risk of heart disease. One comment stated that it considered the Burr paper to be a positive finding, but gave no reason for this conclusion. The LSRO final report, submitted as a comment, also recognized the Burr paper as a very important trial. LSRO pointed out that, although separate results were not shown for those consuming fatty fish and those consuming supplemental fish oil, the results were dramatic, especially since all-cause mortality was reduced, in contrast to results from trials of plasma lipid-lowering drugs. LSRO concluded that ``future research will be needed to define the amount and duration of w-3 fatty acid supplementation required to produce the beneficial effects.'' FDA agrees that the Burr paper provides valuable evidence consistent with the hypothesized relationship between omega-3 fatty acids and CHD. However, FDA noted in its proposal (56 FR 60663 at 60668) that there are two specific shortcomings in this paper: the absence of separate data for subjects who consumed fish and those who consumed fish oil capsules, and the absence of dose-response data. These data would have provided evidence for a specific effect of omega-3 fatty acids. Ideally, other data regarding the subjects' diet would also show that there was no difference in consumption of other dietary factors related to CHD. The study design specifically included two such dietary factors, dietary fat and dietary fiber, and the lack of significant effects of these components argues against dietary factors other than omega-3 fatty acids as responsible for the association. FDA does not consider the Burr paper to have established a beneficial effect of omega-3 fatty acids, although its results are consistent with such an action. The LSRO conclusion indicates that neither the amount of omega-3 fatty acids necessary for beneficial effects nor the duration of their intake has been established. The specificity of the substance responsible for the beneficial effects, the quantitative amount needed to produce the effect and the duration of intake needed to produce the effect need to be established before FDA can authorize a claim linking omega-3 fatty acids to reduction of risk of CHD. 19. Some comments stated that the amount of fish in the Zutphen and Burr studies was so low that the association between fish consumption and reduced CHD mortality could not be explained by the displacement by fish of other atherogenic foods from the diet. FDA is not persuaded by these comments. The limitation in these studies is that they did not control for dietary factors associated with CHD, not that fish consumption displaced other atherogenic foods. FDA noted in its proposal that the Zutphen study found significant correlations between fish consumption and other dietary factors (i.e., alcohol, polyunsaturated fats) related to CHD. Comparable correlations were not addressed in the Burr paper because dietary intake data were not reported. Also, the design of the Burr paper was to encourage consumption of fish, which would likely have resulted in a reduction in the consumption of red meat (and, therefore, saturated fat). 20. Two comments discounted the Curb et al. study (Ref. 25), which showed no association between fish consumption and CHD mortality among subjects in Hawaii. The comments stated that the dietary source of fish was likely tropical fish, and since tropical fish feed on coral they have a high content of AA, which would counteract the effect of omega-3 fatty acids. FDA disagrees with the comments. No data regarding the AA content of the diet in this study, or in other correlational studies, have been reported. Indeed, most epidemiologic correlation studies have not quantified the intakes of omega-3 fatty acids, a fundamental measurement to establish an association between omega-3 fatty acids and CHD. Finally, there is an abstract reporting that the omega-3 fatty acid to omega-6 fatty acid ratio of tropical fish is comparable to or greater than that of fish inhigher latitudes (Ref. 237). Thus, the comments' explanation for a negative finding must be considered theoretical. 21. One comment argued that the lack of an association between fish consumption and CHD in two populations in Canada, a prairie province and a coastal province (Ref. 74), was because the prairie population consumed more alcohol and the coastal population smoked more. This comment criticized FDA for not pointing out the cautions raised by the authors about potential confounders like the difference in alcohol consumption. FDA believes it presented the results of this paper fairly. While the authors reported small differences in smoking (more in the coastal population) and alcohol consumption (more in the prairie population), they stated, ``It seems unlikely that theseto offset any strong effect of fish consumption.'' FDA is keenly aware that dietary and behavioral factors (e.g., smoking, alcohol) must be controlled before meaningful conclusions may be drawn about the effects of omega-3 fatty acids. FDA notes that alcohol consumption was also a confounding factor in a study that reported an association between fish consumption and CHD (Ref. 87). 22. A few comments stated that many of the reported effects come from studies on fish consumption, but that all measured biochemical changes related to CHD that are produced by fish have also been produced with fish oil concentrates. FDA agrees in part with this comment. The fact that the same biochemical results have been obtained using fish oils rather than fish provides strong evidence that particular biochemical markers are affected specifically by omega-3 fatty acids. Also,since most studies have used fish oils, these results add consistency to the effects reported for studies that used fish. However, FDA disagrees that the comparable findings in studies that used fish oils and fish are sufficient to support the health claim that omega-3 fatty acids reduce the risk of CHD, because the particular biochemical markers affected by both fish and fish oils are not recognized with significant scientific agreement as useful surrogate risk factors for CHD in the general population. 23. One comment argued that the fact that Greenland Eskimos ate diets with half the saturated fat and more polyunsaturated fat than Danes and had much less CHD than Danes strengthens the case for fish oil-derived omega-3 fatty acids. FDA agrees with the comment that diets lower in saturated fat are consistent with reduced CHD mortality (see the final rule on ``Dietary Lipids and Coronary Vascular Disease'' published elsewhere in this issue of the Federal Register). The differences in saturated fat intake, however, do not strengthen the case for omega-3 fatty acids, because they do not distinguish omega-3 fatty acids from polyunsaturated fats. Rather, the differences in dietary fat intakes strengthens the argument that saturated fat is associated with CHD mortality. The numerous dietary differences between the Greenland Eskimos and Danes make it difficult to ascribe to any single dietary factor the differences in CHD. 24. One comment pointed out that, of the ten prospective studies cited in the proposal (including three in Table 1 of the proposal), six support an inverse relationship between fish consumption and CHD. The comment noted that one study only showed arelationship in men under 45, and argued that this result is promising because one might expect to find positive effects of long-term fish consumption on CHD in younger, relatively healthy men rather than in older men. FDA agrees that some but not all reports find an inverse relationship between fish consumption and CHD. FDA does not agree, however, that this effect would more likely be noticed among younger, relatively healthy men. Older men would have had a greater duration of intake of omega-3 fatty acids and a greater incidence of CHD than younger men. Both these factors would favor finding an effect in older men rather than in younger men. 25. One comment noted that only two studies found a positive dose-response. Another comment stated that the studies that show no effect are those where the base group already consumed fish, whereas in studies that showed an effect, the base group did not consume fish. A third comment stated that there were data that described an inverse dose-response relationship between serum EPA and CHD deaths among Japanese, but did not identify a particular study. FDA disagrees that only two studies found a dose response correlation. Each study that reported a relationship between fish consumption (or, in one study, the calculated intake of omega-3 fatty acids) and CHD found a dose-response relationship. FDA agwho consume no fish at all and those who consume a small amount of fish, and that there appears to be little additional benefit from consumption of large amounts of fish (Ref. 88). An alternate way of describing these data is that those who consume no fish have an increased risk of CHD. These data merit followup, because a showing that the relationship is due to the omega-3 fatty acids may provide evidence that the long-chain omega-3 fatty acids are essential in the diet. In its proposal, FDA reviewed a study that described an inverse dose-response relationship between serum EPA and CHD mortality among two groups of Japanese (Ref. 78). FDA concluded that these cross-sectional, correlational data were useful in generating a hypothesis. Other notable dietary factors (including a difference in salt intake of 50 percent) and risk factors for CHD (prevalence of hypertension) also differed between the two groups, so it is not possible to conclude that differences in CHD mortality were due to differences in dietary omega-3 fatty acids. 26. Two comments stated that FDA had erred in stating that no biochemical data were reported in the Burr paper (Ref. 16). FDA agrees with this comment, and stands corrected. Burr et al. (Ref. 16) did report that the geometric mean percentages of EPA were 0.59 percent and 0.46 percent in men given advice to consume more fish and those not so advised, respectively, a highly significant difference (p <0.01). The fact that a geometric mean rather than an arithmetic mean was reported implies that there was substantial skewing of the data. It is not clear from the article whether these differences were for the 6-month time into the trial, or for the end of the trial. The authors did not correlate plasma EPA concentrations directly with myocardial infarction (MI) or CHD deaths. 27. One comment argued that it was highly misleading to state in Table 1 that Kromhout et al. (Ref. 87) reported that, ``lean fish, low in omega-3 fatty acids, had some protective effect against CHD,'' because Kromhout did not distinguish between the effects of lean and fatty fish. FDA disagrees with this comment. The authors made two statements about lean fish that imply that additional data analyses were conducted, although (as the comment correctly notes) results of these analyses were not included in the paper. The authorswrote, ``Lean fish was also inversely related to mortality from coronary heart disease,'' and ``Thus, the inverse relation between lean fish and coronary heart disease cannot be explained by eicosapentaenoic acid.'' FDA interprets these comments as a caution to the reader against assuming that EPA was the active component responsible for the observed reduction in CHD among fish-consuming subjects. 28. LSRO included in its report two studies that correlated plasma omega-3 fatty acids with dietary intake of these fatty acids (Refs. 213 and 225). Two other papers reviewed by LSRO but not included in the FDA proposal were correlation studies of mortality from different diseases among Greenlanders and Danes (Ref. 176) and diet-disease correlations in Japan (Ref. 284). FDA agrees with LSRO's descriptions of these studies. FDA notes that the authors of the studies that correlated intake and plasma levels of omega-3 fatty acids did not relate their data to CHD. The correlation studies of mortality did not provide any specific data regarding omega-3 fatty acids. 29. One comment provided new dose-response data from additional analyses of data of the Dart study, previously reported in part by Burr et al. (Ref. 16), that related the dietary intake of EPA at 6 months into the trial to the risk of CHD events (heart attacks, or MI's) or CHD mortality. The 947 subjects for whom dietary data were obtained were grouped according to EPA intake; 114 consumed less than 1 g per week (1 g/week), 373 consumed 1 to 2 g/week, and 460 consumed 2 or more g/week. The percentageietary EPA increased. For heart attacks the rates were 7.9 percent, 7.0 percent and 6.7 percent, for the less than 1 g/week, 1 to 2 g/week and 2 or more g/week groups, respectively. The percentages in each group who died were 6.1 percent, 5.1 percent, and 4.1 percent, respectively. There were no statistical analyses of these data reported. FDA notes some limitations in these data as reported that caution against strong conclusions. Most notably, the analysis excluded the events and deaths during the first 6 months of the trial, when about half of all events and deaths occurred. This clearly diminishes the sensitivity of the analysis, and may result in an underestimation of the true effect, since the difference in survival between the group advised to eat more fish and the group not advised to eat more fish was most pronounced during the first 6 months. Alternatively, if the healthiest subjects were also the most compliant subjects, the reduced death rate in the highest EPA-consumption subjects may reflect the underlying health of those subjects, and the importance of dietary EPA maybe overestimated. Also, the unequal group sizes for this analysis places a greater weight on each subject in the smallest group (less than 1 g/week) than in the other groups. This may be particularly important because the smallest group includes those who consume no fish, and who may differ from fish consumers in other dietary or behavioral factors associated with CHD risk. The sensitivity of the results to small changes in outcomes is shown by example: one fewer death (6/114 rather than the reported number, 7/114) makes the CHD death rate of the less than 1 g/week group equal to the rate in the 1 to 2 g/week group. Finally, although the dietary intake data at 6 months are useful, this study also assayed plasma fatty acids. Use of plasma EPA (or EPA plus DHA) in the dose-response analysis would have been a more powerful analysis, because it eliminates errors inthe diet record data, corrects for losses during food preparation and individual differences in bioavailability of the fatty acids, and integrates intake of omega-3 fatty acids over a longer period than the diet record data. Therefore, FDA finds these dose-response data to be consistent with the hypothesis that omega-3 fatty acids reduce the risk of CHD, but the shortcomings discussed above limit their usefulness in establishing a relationship between omega-3 fatty acids and risk of CHD. 2. Evidence relating omega-3 fatty acids to intermediateor surrogate markers of CHD In the proposed rule (56 FR 60663 at 60668), FDA stated that most information about the effects of omega-3 fatty acids on CHD has been derived from clinical trials using concentrated fish oils enriched in EPA and DHA, and in some cases purified methyl or ethyl esters of EPA and DHA. FDA concluded that: * * * there are a few established effects of omega-3 fatty acids from fish oils on thrombosis and hemostasis. Standardized bleeding times are increased, and platelet aggregation and function are reduced. However, direct relationships between thechanges in bleeding times or platelet function and risk of CHD have not been established. While there is an established relationship between blood pressure and CHD, it has not been shown that omega-3 fatty acids specifically affect blood pressure in normal subjects in a way that would provide a protective benefit toward the risk of CHD. Effects of omega-3 fatty acids on other markers linked with CHD, e.g., fibrinogen or lipoprotein (a) have not been established. (56 FR 60663 at 60671). a. Atherosclerosis i. Blood lipids 30. Numerous comments criticized FDA's focus on blood cholesterol as a surrogate marker for risk of CHD, although one comment noted that such an emphasis would be expected, given the importance of cholesterol in CHD. Another stated that the focus on c FDA disagrees with the comments that it overemphasized the importance of studies in which cholesterol was measured as a surrogate marker for CHD. The considerable attention given to blood cholesterol measurements (and measurements of other blood lipids and the protein components of blood lipoproteins) was the consequence of two factors: (1) There was a large number of studies on the effects of fish oils or fish containing omega-3 fatty acids on these blood lipid measures; and (2) there is general agreement that certain blood lipids are strongly associated with the risk of CHD. FDA undertook to evaluate findings in these studies whether or not fish or fish oils were used as the source of omega-3 fatty acids and whether or not the outcome measures were generally recognized as predictive of CHD. This approach allowed the identification of biologic activities of omega-3 fatty acids that may be related at some point to risk of CHD, and identified areas where additional research is needed. FDA included in the summary of its proposed rule (56 FR 60663) only measures of generally recognized risk factors. FDA did not intend to imply that data on alternate markers were not considered in its decision. FDA agrees that other factors contribute to blood lipid measures, but believes that randomization should control for these factors. In nonrandomized studies, these sources of potential bias limit the conclusions that can be inferred from the data. This is an important reason that data from correlation studies do not conclusively establish a relationship between omega-3 fatty acids and risk of CHD. 31. The LSRO report paid considerable attention to changes in blood lipids after increased consumption of omega-3 fatty acids, and reached some conclusions about effects of omega-3 fatty acids on blood lipids that differed from those reached by FDA.LSRO abstracted three studies from before the period covered by FDA review (Refs. 284a, 267, and 257). These studies were considered in Federal Government and other comprehensive reports reviewed in the proposed rule and not discussed further by FDA. LSRO also included three studies not reviewed by FDA in its proposal (Refs. 168, 226, and 301). Agren et al. (Ref. 168) studied healthy students randomly assigned to their normal diet (one fish meal per 2 weeks), a fish diet, or a fish diet low in saturated fat for 15 weeks. There was no change in total serum cholesterol on the control diet or fish diet, but the low-fat fish diet produced a reduction in total cholesterol. Jensen et al. (Ref. 226) studied 18 healthy subjects supplemented sequentially for 4-week periods with 4-week washouts between, with fish oils containing 1, 3, and 6 g EPA plus DHA, and found no change in total or LDL cholesterol. Wolmarans studied healthy subjects fed a meat diet or fish diet containing 6.1 g EPA plus DHA for 6 weeks each in a crossover design, and found reduced total cholesterol and LDL cholesterol during the fish diet phase. There was no difference in total fat of the two diets. However, there was significantly less saturated fat in the fish diet, so it is not certain that the omega-3 fatty acids were responsible for the decrease in the cholesterol measures. FDA is concerned that the studies abstracted by LSRO do not accurately represent the totality of publicly available scientific evidence. For example, in its proposal, FDA included five studies among normal subjects (Refs. 2, 6, 24, 73, and 143) and three studies among subjects with preexisting lipid or lipoprotein abnormalities (Refs. 18, 73, and 93) not included in the LSRO report that had data for effects of omega-3 fatty acids on plasma lipids or lipoproteins. FDA determined that seven studies that reported changes in total cholesterol had the most rigorous designs and the largest numbers of normal subjects. None of these seven studies (Refs. 6, 9, 14, 49, 54, 73, and 166) in normal subjects found a significant change in total cholesterol after f Only two of these seven strongest studies in normal subjects were abstracted in the LSRO text, and two others were not cited at all by this report. LSRO did not distinguish between normal and hyperlipidemic subjects in its summary or conclusions. LSRO summarized the evidence on total cholesterol by stating, ``Decreases in total cholesterol * * * have also been reported,'' (emphasis added), without mentioning that the predominant finding is that there is no effect on total cholesterol. Similarly, FDA stated that the strongest studies among normal subjects (Refs. 6, 9, 14, 49, 54, 73, and 166) found no change in LDL cholesterol, and one reported an increase in LDL cholesterol (Ref. 54). Indeed, most studies on hypertriglyceridemic or hypercholesterolemic subjects reported an increase in LDL cholesterol following fish oil supplementation (56 FR 60663 at 60669). Consequently, FDA disagrees strongly with the summary statements in the LSRO report: Effects of fish oil upon LDL have been variable, in part because of different doses. In normolipidemic individuals, LDL has generally declined significantly. In some patients with primary hypercholesterolemia, consumption of fish (sic) hasnot resulted in altered plasma cholesterol levels; other studies have shown decreased cholesterol and LDL levels. (Emphasis added.) 32. Two comments stated that FDA had not considered all relevant data on HDL2 cholesterol, and cited additional studies that reported increased HDL2 cholesterol after fish oil supplementation. One comment stated that overall HDL cholesterol tends to rise, and cited a review paper by Harris (Ref. 62). The LSRO report also concluded that HDL was increased by fish oil supplementation. FDA disagrees with the comment regarding the overall HDL cholesterol change after fish oil supplementation. The agency considered HDL changes separately for normal, healthy subjects and for hyperlipidemic subjects (56 FR 60663 at 60669). Nearly all studies on normal subjects found no significant change in HDL cholesterol level. Some investigators reported increased HDL2, but the data on HDL2 were equivocal. FDA also disagrees with the conclusions of the LSRO report regarding HDL cholesterol, because it does not represent the totality of publicly available scientific evidence. The LSRO summary states, ``In some studies HDL concentrations have actually increased with consumption of fish oil'' (emphasis added), not acknowledging that the balance of available scientific evidence on HDL indicates no change. In the review by Harris cited in the comment, the changes in HDL cholesterol in each study were weighted according to the number of subjects in the study, giving a per-subject change. This method of pooling data from different studies does not account for the variation of the response of subjects in each study, the amount of omega-3 fatty acids fed, the duration of feeding, or the source of the omega-3 fatty acids. Therefore, it must be considered only an estimate of the effects of omega-3 fatty acids on HDL cholesterol. Harris calculated the average HDL cholesterol change for normal subjects tobe an increase of approximately 3 percent, a net change smaller than the usual variability in the test used to measure HDL. The agency agrees with the comment that not all HDL2 data were considered in the proposed rule, although FDA noted (56 FR 60663 at 60669) that some studies among normal subjects found increases in the HDL2 fraction of HDL cholesterol, and that these reports were the most promising changes in blood lipids. Of the six references cited by the comments as not included among studies showing increased HDL cholesterol after omega-3 fatty acids, two were published after the time period covered in the proposed rule (Refs. 235 and 252). One other paper not cited by FDA in its proposal, although it was published during 1988 (Ref. 291), dealt with insulin-dependent diabetics. The other three papers were cited by FDA in other contexts, but data fese papers regarding HDL2 cholesterol levels were not discussed (Refs. 1, 32, and 148). FDA reexamined those papers that it cited but from which it did not present data regarding HDL2, together with the newer papers. When fractions of HDL cholesterol have been reported, an increase has generally been found in the HDL2 fraction (Refs. 1, 32, 148, 235, 251, and 291), with a comparable decrease in the HDL3 fraction (Refs. 1, 235, and 251). This represents a shift within the HDL fractions toward a lipid-rich lipoprotein, and away from a protein-rich lipoprotein, similar to that reported for LDL, below. This shift has been reported when there is (Refs. 32, 148, 235, and 291) or is not (Refs. 1 and 251) a change in total HDL cholesterol. This raises the possibility that a shift occurred in other studies where total HDL was reported as not changed. However, the importance of the shift in subfractions of HDL is not clear. FDA noted in its proposal (56 FR 60663 at 60669) that there is evidence that the HDL2 fraction is the one most closely linked to risk of CHD. However, the agency was unable to find evidence that there was significant scientific agreement that HDL2 was the fraction of HDL most closely associated with CHD. The National Institutes of Health's National Heart, Lung, and Blood Institute (NHLBI) consensus developmentconference on Triglyceride, High Density Lipoprotein and Coronary Heart Disease (Ref. 255), anticipated in the proposal (56 FR 60663 at 60664), concluded that, ``It is not known to what extent these alterations of HDL contribute to atherogenesis.'' Therefore, data on changes in HDL subfractions after increased consumption of omega-3 fatty acids do not provide a sufficient basis for a health claim, because there is not significant scientific agreement that HDL2 is directly related to risk of CHD. If the risk of CHD becomes linked with HDL2, these findings in normal subjects may be of great importance. 33. Many comments indicated that high triglycerides are causally related to decreased HDL, that triglycerides are an independent risk factor for CHD, or that statistical manipulations of data and imprecise measurements of triglycerides obscure the importance of triglycerides as a risk factor for CHD. One comment provided additional citations regarding the relationship between triglycerides and HDL, but these did not bear on risk of CHD. One comment stated that it was generally agreed that triglycerides were not independently associated with CHD. FDA disagrees with all but the last comment. FDA is aware that there has been, and still is, substantial interest in the potential role of triglycerides in the etiology of CHD (e.g., Ref. 208). Because of the continued interest, the relationship between triglycerides and CHD was the topic of a consensus development conference sponsored by NHLBI on February 26 through 28, 1992. NHLBI had previously addressed this topic in 1983 and concluded at that time that the relationship was controversial. The recent conference (Ref. 255) concluded, ``For triglyceride, the data are mixed; although strong associations are found in some studies, the evidence on a causal relation is still incomplete.'' FDA agrees that the statistical methods previously used to study the relationship between triglycerides and CHD have lessened the likelihood that triglycerides would be found to be a significant, independent predictor of CHD. Furthermore, the agencybelieves that study design and analytic measurement methods have contributed to variation in triglycerides that may have resulted in reducing the statistical association between triglycerides and CHD. FDA believes that these sources of variation in triglycerides can be reduced by careful study design and standardized analytical measurement techniques, and also that clinical studies designed to lower triglycerides could provide a basis upon which to reconsider the importance of triglycerides in CHD. 34. Some comments stated that some very recent evidence from the Helsinki Heart Study supports a protective effect of lowering triglycerides, at least for a selected subpopulation of people with a high ratio of LDL cholesterol/HDL cholesterol and very high triglycerides. FDA agrees that fish oils reduce plasma triglycerides. In its proposal FDA wrote, ``The predominant blood lipid effects of fish oils * * * are decreased plasma triglycerides and VLDL.'' (56 FR 60663 at 60669.) In this regard FDA and LSRO were in agreement. The LSRO summary states, ``The most striking effect is lowering of plasma triglyceride and VLDL concentrations.'' FDA disagrees, however, that triglycerides have been established as an independent risk factor for CHD. The recent results from the Helsinki Heart Study (Ref. 242) were discussed at length at the NHLBI consensus development conference (Ref. 255). While the reduction in CHD mortality following drug intervention was dramatic (i.e., approximately 7-fold) for a particular subgroup with both elevated triglycerides and elevated LDL to HDL ratio, this result was obtained by a post hoc analysis of earlier results. Because the combination of factors used to connote the high-risk group (i.e., high LDL cholesterol to HDL cholesterol ratio and high triglycerides) was determined after the data were collected, these results are not the results of the testing of a hypothesis, but are the origins of a new hypothesis. The authors indicate that the cut-off points for the ratio of LDL to HDL and triglycerides chosen were to some extent arbitrary. The actual number of cardiac events in the study was small (e.g., 18 events among 138 subjects in the highest risk subgroup), and the reduction in all-cause mortality due to the lipid-lowering drug, gemfibrozil, was not significant. Finally, independent of LDL to HDL ratio, increased triglycerides alone were not associated with an increased risk of heart attack. The dramatic reduction of triglycerides by omega-3 fatty acids has resulted in their use in the treatment of a rare genetic hypertriglyceridemia (type V) to prevent noncardiovascular effects of high triglycerides (i.e., pancreatitis), but the usefulness of lowering triglycerides as a general strategy in prevention of CHD is not generally agreed. Therefore, FDA believes that the triglyceride-lowering effect of fish oils for some at-risk persons does not provide a basis for a health claim at this time. 35. Numerous comments indicated that postprandial triglyceridemia is a mechanism of action in the development of atherosclerosis. Some comments indicated that the relationship of elevated triglycerides to risk of CHD would be discussed at the NHLBI consensus development conference (Ref. 255). Others pointed out that LSRO had concluded that elevated very low density lipoproteins (VLDL) and triglycerides were atherogenic. LSRO stated that the reduction of postprandial hyperlipidemia is a ``most important anti-atherogenic action.'' LSRO wrote in the summary that, ``Since postprandial lipemia has been identified as an atherogenic risk factor, its prevention by w-3 fatty acids would be a most desirable effect'' (emphasis added), and in its conclusions LSRO wrote: Fish oil has a generally accepted hypolipidemic effect without depressing HDL. This applies most to VLDL and triglyceride, lipids now believed to be atherogenic. There is little doubt that there is a reduction of postprandial hyperlipidemia following the ingestion of dietary fat if the background diet contains relatively small quantities of w-3 fatty acids. This may be a most important anti-atherogenic action. FDA agrees that fish oils do not generally lower HDL. FDA also agrees that major blood lipid effects of omega-3 fatty acids are reductions of triglyceride and VLDL. The role of omega-3 fatty acids in the reduction of postprandial triglycerides waspaper used only 5 g of fish oil, containing 1.7 g EPA plus DHA. These studies showed that the concentration of plasma chylomicrons after a high-fat test meal was significantly less if the subjects had been consuming a fish oil diet than if they had beenconsuming a saturated fat or olive oil supplemented diet. Thus, FDA agrees that fish oils reduce postprandial lipemia. However, FDA disagrees that there is significant scientific agreement that VLDL and triglycerides are atherogenic, or that the reduction in postprandial hyperlipemia is a most important anti-atherogenic action. Neither the Federal Government nor other authoritative reports have included these blood lipid measures among those they consider to be independent risk factors associated with CHD (Refs. 34 through 36, and 115). Furthermore, postprandial lipemia was discussed at the February 1992 NHLBI consensus development conference. The summary of that conference stated, ``Postprandial triglyceride may be more important than the fasting triglyceride levels [to CHD], but little is known about this at the present time.'' (Ref. 255). FDA notes that the only paper in the LSRO report cited in support of this hypothesized mechanism of action of omega-3 fatty acids in the prevention of CHD was a review paper published in 1979 (Ref. 305). Therefore, FDA believes that there is not significant scientific agreement at this time that postprandial triglycerides are related to the risk of CHD. ii. Vessel wall effects 36. One comment indicated that two new studies support the use of omega-3 fatty acids to prevent restenosis, the closing of a mechanically opened blood vessel (Refs. 172 and 259). This comment suggested that FDA discounted the findings of the Dehmerstudy (Ref. 30) on the basis that it employed simultaneous treatment with drugs and fish oils. FDA considered the use of omega-3 fatty acids to prevent restenosis to be a drug usage (56 FR 60663 at 60670), and notes that patients in these studies are under a physician's care. FDA's description of the Dehmer study points out a limitation of the data that is common in other reports of no effect of omega-3 fatty acids in restenosis (Refs. 56, 106, and 121), that the studies have not controlled for generalized effects of PUFA's that are not specific to omega-3 fatty acids. A better balanced experimental design would be comparison of drugs plus omega-3 fatty acids to drugs plus alternate PUFA's (e.g., corn oil). FDA agrees that the new studies provide some support for the role of omega-3 fatty acids in prevention of restenosis, although neither was designed to distinguish effects of omega-3 fatty acids from effects of omega-6 PUFA's. Nye et al. (Ref. 259) studied 79 men and 29 women who were referred for angina and underwent coronary percutaneous transluminal angioplasty (PCTA), i.e., a mechanical opening of a closed heart blood vessel. The subjects were randomly assigned to oneof three treatments: (1) A combination of aspirin plus dipyridamole (an anti-platelet combination of drugs), (2) olive oil placebo, or (3) 12 milliliters (mL) fish oil containing 3.2 g EPA plus DHA/day. Subjects were restudied 1 year later or before if symptoms recurred, and 93 percent of all subjects were followed for the year. Although there was no significant difference in angina among the groups, the rate of restenosis, defined in this study as a loss of 50 percent or more of the luminal diameter increased by PCTA, was significantly less in the fish oil group (11 percent) than in the placebo group (30 percent). The use of olive oil as the placebo did not control for effects due to PUFA's (omega-6). Also, it is notable that the restenosis rate in the aspirin group was somewhat higher (17 percent) than in the fish oil group, because aspirin is a much more pote The full ``Quebec study'' was published after the receipt of the comment, but because it was cited in the comment it will be discussed here. In this study, Bairati et al. (Ref. 172) conducted a double-blind, randomized intervention with either fish oil containing 4.5 g EPA plus DHA/day, or olive oil placebo in 205 patients undergoing first PCTA. The treatments were started 3 weeks before the procedure, and continued for 6 months after. Restenosis was assessed angiographically, using a quantitative computer analysis program. Restenosis was reduced in the fish oil group compared to the olive oil group according to 3 of 4 definitions of restenosis. It was not reduced according to the clinical definition used by Nye et al. (Ref. 259), above, of a lossof 50 percent or more of the luminal diameter increased by PCTA. This study also collected dietary data. The third of the subjects with the highest consumption of omega-3 fatty acids (0.15 g/day) and the third of the subjects with intermediate consumption of omega-3 fatty acids (0.033 to 0.15 g/day) had significantly lower rates of restenosis than the third consuming the least amount of omega-3 fatty acids. In fact, dietary omega-3 fatty acids (other than the supplement) were associated with a greater reduction in chance of restenosis than was the supplement. This result was somewhat surprising, since the supplement contained 30 times the amount of omega-3 fatty acids in the diet. No differences in rate of restenosis were found according to intake of total fat, polyunsaturated fat, monounsaturated fat, saturated fat, cholesterol, or total seafood consumption. These results suggest that chronic consumption of low amounts of omega-3 fatty acids may be as useful in preventing restenosis as much larger amounts consumed for a few weeks prior to and after PCTA. In general, the results of Bairati et al. (Ref. 172) and Nye et al. (Ref. 259) are consistent, even though they obtained different results according to one identical definition of restenosis. The Bairati et al. study, like Nye et al. 1990, used olive oil as the control. If the mechanism of action of omega-3 fatty acids in restenosis is through competition with AA, this control is suitable, and an omega-6 fatty acid oil would have made the difference due to omega-3 fatty acids even more pronounced. If, however, the mechanism of action is through nonspecific effects of highly unsaturated fatty acids, then a control of a PUFA (e.g., corn oil) might have reduced the apparent effect of omega-3 fatty acids. It is notable that the only study of restenosis that has used a polyunsaturated fat control (an olive oil-corn oil mix) did not find an effect (Ref. 56). 37. Five studies in humans relevant to the actions of omega-3 fatty acids on the vessel wall were referenced in comments (Refs. 200, 213, 259, 268, and 277), including two published since the time period covered by FDA's review in its proposed rule (Refs. 200 and 268). Hamakazi et al. (Ref. 213) found a slower aortic pulse wave velocity (an electro-physiologic measurement) in persons from a Japanese fishing village compared to those from a farming village. Other data showed the populations differedin their intake of omega-3 fatty acids. Rapp et al. (Ref. 268) measured the amount of omega-3 fatty acids in the atherosclerotic lesion after consumption of omega-3 fatty acids at a high level (6 percent of calories, 16 to 21 g EPA plus DHA/day) for 6 to 120 days prior to planned surgical intervention, and found that the amount of omega-3 fatty acids in the lesion continued to increase throughout the time of ingestion. Force et al. (Ref. 200) studied the effects of fish oils and aspirin on the production of urinary metabolites of AA and EPA. Fish oil feeding resulted in a slight decrease in the amount of thromboxane A2 made in the platelet, a decrease in the amount of AA-derived prostacyclin made in the endothelial cell, and an increase in the atudy is discussed in comment 36 of this document. FDA considers these studies to be observational, not clearly associating omega-3 fatty acids with risk of CHD. The correlation data of Hamakazi et al. do not indicate a specific role for omega-3 fatty acids. The Rapp et al. data verify that it is possible to incorporate omega-3 fatty acids into preexisting atherosclerotic plaque, but the relevance of incorporated omega-3 fatty acids has not been established. The studies of Force et al. and Schmidt et al. relate to a potential mechanism of action ofomega-3 fatty acids, but the importance of these actions in reducing risk of CHD has not been established. 38. Many comments stated that the biochemical and physiological actions of omega-3 fatty acids are anti-atherogenic because they favor vasodilatation and inhibit vasoconstriction. One comment by a manufacturer of omega-3 fatty acids considered theseactions have potential for future significance. Two comments cited a list of effects of omega-3 fatty acids, suggesting that each of the effects in the list was anti-atherogenic, and other comments referred to one or more of the components in the list. The listed changes were: decreased thromboxane; increased prostacyclin and leukotriene (LTB4); decreased fibrinogen; decreased platelet activating factor (PAF); decreased platelet-derived growth factor (PDGF); decreased superoxide; decreased interleukin-1 (TNF); increased endothelium-derived relaxation factor (EDRF); decreased lipoprotein (a) (Lp(a)); reduced inflammatory response; and increased fibrinolytic activity. The LSRO report stated that other mechanisms, such as cellular growth factors, interleukin-1 and cytokins, and EDRF may be important in the development of atherosclerosis, and be affected by omega-3 fatty acids. However, except for a single in vitrostudy on PDGF, no data are described in the report regarding these factors, nor is their relevance to human CHD discussed. FDA addresses fibrinogen, Lp(a), and fibrinolytic activity in comment 46 and in section II.C.2. of this document. FDA does not agree that omega-3 fatty acids produce changes in all of the listed parameters. FDA has determined that for some of these endpoints the changes have not been shown to be specific to omega-3 fatty acids, but may be due to polyunsaturated fats instead. FDA disagrees that the changes brought about by omega-3 fatty acids will prevent atherosclerosis. Most of the data regarding changes in these endpoints brought about by omega-3 fatty acids have been derived from tissue culture or animal experiments, and the relevance to human atherosclerosis has not been demonstrated. Thromboxanes and prostacyclins are compounds derived from omega-3 fatty acids and omega-6 fatty acids that affect the relaxed state of the blood vessels. Thromboxanes are produced primarily in platelets, and prostacyclins are produced primarily in the endothelial cells of the blood vessels. The thromboxane made from an omega-6 fatty acid called AA, thromboxane A2, is a potent vasoconstrictor. EPA competes with AA for the enzyme that makes thromboxane A2, and thereby diminishes the rate of production of thromboxane A2; the thromboxane made from EPA is a much less potent vasoconstrictor. The prostacyclins made from AA or EPA in the endothelial cells are vasodilators. Thus, the relative amounts of AA and EPA in platelets and endothelial cells play a role in determining the form and amounts of the prostaglandins and thromboxanes that affect the tension of the vessel wall. Excessive constriction may lead to an occlusion, resulting in a heart attack. While there is general recognition that these vasoactive compounds may play a role in the formation of clots and thereby in heart attacks, there is no agreement about the extent of changes needed in the concentrations of the vasoactive compounds in order to have an effect on heart diconsumption of fish oil, are only useful as marker for CHD only insofar as there is significant scientific agreement that the magnitude of the changes is related to CHD. FDA is not aware of any such agreement, nor did the comments provide any evidence of agreement that particular changes in the levels of these vasoactive compounds were related to a reduction in risk of disease. Furthermore, the amount of omega-3 fatty acids needed to produce these changes in humans is not known. For PDGF the evidence is confined to animal studies (Ref. 201), and the relevance to human disease has only been suggested, not demonstrated. The animal studies on PDGF also did not show that the effect was specific to omega-3 fatty acids. For example, the PDGF effect was observed also after polyunsaturated fats, and was abolished by anti-oxidants, suggesting that any highly unsaturated fatty acids prone to oxidation would have the effect. The experiments on EDRF (Ref. 181) also did not show that the effects were specific to omega-3 fatty acids, since the experiments were carried out in the presence of indomethacin, which blocks the eicosanoid effects of EPA. In fact, the authors consider changes in membrane fluidity to be a reasonable explanationfor the effects. In yet other cases, e.g., TNF, there are conflicting results depending on the species (Refs. 41 and 236), and the findings must be considered preliminary. FDA considered the effect of omega-3 fatty acids on chemotaxis, one aspect of inflammatory response (56 FR 60663 at 60670). A complete discussion of the role of fish oils in inhibition of the inflammatory process is outside of the scope of this rulemaking, but the relationship between omega-3 fatty acids and inflammatory response could be the subject of a petition for a health claim that includes the necessary information about this relationship. FDA agrees that the biochemistry of the products formed from the omega-3 fatty acids in vivo (i.e., eicosanoids) have been shown under experimental conditions, usually in vitro, to have pronounced effects on the vessel wall. However, demonstration of isolated biochemical effects is not a sufficient basis upon which to make a claim regarding the outcome of a multifactorial process. Intermediate markers of CHD are useful only insofar as there is significant scientific agreement that changes in these markers produced by omega-3 fatty acids are causally related to CHD. b. Thrombosis and hemostasis 39. A few comments stated that the mode of action of omega-3 fatty acids may be through stabilization of arrhythmia, and noted the reduced rate of death after heart attacks (MI's) in the Dart study (Ref. 16). This comment also stated that certain animal data were consistent with this hypothesis. The comments stated that the fibrillation mechanism suggested by DART was compelling, because 60 percent of sudden deaths are caused by ventricular fibrillation following reperfusion. Many commented that data from nonhuman primate models show that omega-3 fatty acids abolish arrhythmias, whereas polyunsaturated fat (safflower oil) had a lesser effect. FDA disagrees with these comments. FDA's review of the literature regarding the usefulness of omega-3 fatty acids in arrhythmia and ventricular fibrillation found only one study on arrhythmias in humans, and it reported no significant effect of omega-3 fatty acids (Ref. 58). A review in 1989 also concluded that, even among the animal studies, there was no significant difference between omega-3 fatty acids and other polyunsaturated fats on arrhythmias (Ref. 269). The data from the studies in nonhuman primates (i.e., the marmoset monkey) were published only as a nonpeer-reviewed paper in a book (Ref. 188). Two papers by the same author on the same topic were cited in 1990 as in press in a peer-reviewed journal,lement of DHA-rich fish oil at a level of 8 percent of the diet by weight. FDA calculates that this would provide 2.5 g of omega-3 fatty acids from fish oil/kilogram (kg), over 50 times the usual rate of supplementation in human studies (10 g fish oil or 3 g omega-3 fatty acids/day for a 70 kg subject), and over 300 times the amount of omega-3 fatty acids associated with reduced risk of CHD in the epidemiologic literature (Refs. 16, 38, and 87 report 300 to 660 milligrams (mg)/day). Thus, the relevanceof these studies to omega-3 fatty acids in the human diet is questionable. FDA is aware of in vitro data that show a specific protective effect of EPA against toxicity of heart muscle cells in culture. These results provide a biochemical basis for the hypothesized stabilization of cardiac arrhythmias by omega-3 fatty acids. Although this study (Ref. 212) was performed in vitro on heart cells from rats, it showed that the protective effect was specific to omega-3 fatty acids (EPA) because a similar effect was not obtained when a highly unsaturated omega-6 fatty acid (AA) was used instead. FDA also regards the evidence from the Burr study of reduced death following a heart attack among those men advised to increase fish consumption as consistent with a stabilization of arrhythmias (Ref. 16). FDA agrees that this postulated mechanism of action is of great potential public health significance. However, the agency finds the clinical data available at this time are not in agreement with animal and in vitro data. Because the clinical data are not in agreement with these other types of data and because of the limitations in the animal studies, FDA concludes that there is not sufficient basis for protective effect specific to omega-3 fatty acids on arrhythmias, and, therefore, CHD in humans. 40. One comment criticized the 6-week clinical study by Hardarson et al. that found no effect of omega-3 fatty acids on arrhythmias (Ref. 58), arguing that the time for incorporation of omega-3 fatty acids into heart phospholipids was too short for an effect to be observed. FDA agrees in part and disagrees in part with this comment. Generally, the time needed for incorporation of omega-3 fatty acids into cellular phospholipids is short; studies in animals show such incorporation in a period of weeks (Ref. 249). In the Hardarson study (Ref. 58), a substantial amount of cod liver oil was fed (20 mL/day) and a 230 percent increase in plasma phospholipid EPA was found. There was no trend toward reduced arrhythmias. Other data, however, show that although plasma phospholipids increase the omega-3 fatty acid content during the first few weeks of supplementation, the incorporation of omega-3 fatty acids in human atherosclerotic plaque continues to increase through 120 days (Ref. 268). Therefore, FDA agrees with the comment the supplementation period in the Hardarson study (Ref. 58) may have been too short to find an effect of fish oils on occurrence of arrhythmias. Also, the agency notes that the absence of a difference in CHD mortality during the first 6 weeks of the Burrstudy (Ref. 16) is consistent with the hypothesis that prolonged intake of omega-3 fatty acids (longer than 6 weeks) is needed to observe an effect on arrhythmias or other mechanisms that reduce CHD mortality. FDA agrees that effects of long-term consumption of omega-3 fatty acids on arrhythmias, other platelet or vessel wall functions, and even some blood lipid measures have not been sufficiently studied. i. Bleeding times 41. Two comments stated that there is no evidence of increased bleeding even among patients who had ingested 6 to 8 g of EPA plus DHA/day and underwent emergency surgery, coronary artery bypass surgery or angioplasty. The comments argued that increased bleeding has not a safety concern. FDA agrees that there are few reports of excessive bleeding after ingestion of omega-3 fatty acids. However, FDA notes that the cited reports are for subjects with CHD, and evidence of the lack of excessive bleeding complications in this population is not sufficient to assure safety of omega-3 fatty acids in the general population. FDA believes that changes in bleeding due to consumption of omega-3 fatty acids remains a valid safety concern (see comment 52 of this document). ii. Platelet aggregation In the proposal, FDA stated: The relationship between platelet aggregation and the risk of heart attacks or CHD death in the general population is an important line of evidence that would support drug claims and perhaps health claims for omega-3 fatty acids. Although there is some evidence that changes in platelet aggregation may help prevent second heart attacks * * * it has not been shown that changes in platelet aggregation in the general population will reduce the risk of CHD. (56 FR 60663 at 60670.) The agency added: ``What has not been established, however, is that platelet aggregation is a bona fide surrogate risk factor for CHD in the general population.'' (56 FR 60663 at 60672.) 42. Many comments argued that platelet aggregation is completely substantiated as a marker for risk of CHD, based on the results of the Physicians' Health Study (Ref. 66). One comment qualified this conclusion stating that the primary effect of omega-3 fatty acids in vivo was to reduce platelet deposition at sites of aortic lesions. FDA acknowledges that aspirin studies provide evidence that platelet aggregation is a risk factor for CHD. The effect of aspirin in inhibiting platelet function has been shown. Among persons who have already had an MI, aspirin is effective in preventing a second infarction. FDA has proposed that aspirin be used to reduce the risk of death and/or nonfatal heart attack in patients with previous infarction or unstable angina pectoris as a professional labeling indication (provided to health professionals, but not to the general public), in the tentative final monograph for over-the-counter internal analgesic, antipyretic, and antirheumatic drug products (November 16, 1988, 53 FR 46204 at 46259). However, FDA does not consider the effects of aspirin in the Physicians' Health Study sufficient to establish that dietary omega-3 fatty acids would have the same effect in the general population. The Physicians' Health Study did not evaluate omega-3 fatty acids. The study population was highly selected; therate of heart attacks was approximately 10-fold lower than in the general population, and cardiovascular mortality was only 15 percent of that expected for the general population of white men of the same age. Also, the results of the Physician's Health Study are not as straightforward as presented in the comments. The chairman of the Physicians' Health Study reported that there was a reduced risk of MI in the aspirin group, predominantly in nonfatal MI, but that there was no significant effect on overall cardiovascular mortality (a 2 percent reduction, not statistically significant) (Ref. 66). In addition, the aspirin group in this study had a greater number of sudden deaths (Ref. 282). In the other primary prevention trial (Ref. 265), aspirin did not have any significant effect on heart attacks, on stroke, or on total vascular mortality. There was a significant increase in disabling stroke in the group taking aspirin. On the basis of these studies there has not been an endorsement of the use of aspirin as a prophylactic measure against CHD by the general population by the American Heart Association or by the Canadian Medical Association (Ref. 187). Notably, ``1992 Heart and Stroke Facts'' published by the American Heart Association (Ref. 169) makes no reference to platelet aggregation as a risk factor for heart attacks (although sticky platelets are mentioned to be a consequence of cigarette smoking in the section on stroke), nor is aspirin discussed as an option for CHD prophylaxis, even though other drug and surgical treatments are discussed. Therefore, FDA concludes that there is not significant scientific agreement at this time that platelet aggregation is a surrogate marker for CHD in the general population. 43. The LSRO report, submitted as a comment, contained abstracts of 19 studies in humans that contained data regarding changes in platelet function following omega-3 fatty acid consumption. LSRO concluded that omega-3 fatty acids prevented platelet aggregation. In its proposal, FDA stated: ``Platelet aggregation is generally considered to be decreased by fish oil consumption.'' (56 FR 60663 at 60670.) The agency also stated: ``* * * platelet aggregation and function are reduced. However, direct relationships between the changes in * * * platelet function and risk or CHD have not been established.'' (56 FR 60633 at 60671.) Thus, FDA agrees with the conclusions of LSRO about effects of omega-3 fatty acids on platelet aggregation. Two of the studies described by LSRO were not considered by FDA in its review, because they were published before 1988, and had been considered by Federal Government and other authoritative reports. One study (Ref. 227) used a large amount of fish oil (50 mL/day) not reasonably related to normal dietary intake. The other study (Ref. 211) involved 13 insulin-dependent diabetics, and therefore is of questionable relevance for the general population. In its proposed rule, FDA considered 13 of the other 17 studies that were abstracted by LSRO. One of the four studies not addressed by FDA was a study on the effects of added vitamin E to fish oil on fibrinogen and fibrinolysis (Ref. 210). Two papers (Refs. 234 and 244) were published after the time period covered by FDA review. Marckmann et al. (Ref. 244) compared the effects of a fish diet and a lean meat diet on plasminogen activator (t-PA), plasminogen activator inhibitor (PAI - 1) and the activity of the inhibitor (PAI - 1 activity). Li and Steiner (Ref. 234) described changes in in vitro platelet adhesion after fish oil supplementation. The fourth paper was an uncontrolled observation study that found a high frequency of nosebleeds in adolescents supplemented with fish oils (Ref. 189). Six other papers on thrombosis were not described in the LSRO text, but were included in the table (Refs. 203, 204, 209, 226, 245, and 254). Of these six, one was not relevant to the nutrient-disease relationship (Ref. 245) because it did not study EPA and DHA. Jensen et al. (Ref. 226) found no significant change in bleeding times in normal subjects after 1, 3, or 6 g EPA plus DHA/day in healthy subjects. Green et al. (Ref. 209) found no change in platelet aggregation or platelet count in 27 hyperlipidemic subjects in a randomized double-blind placebo controlled crossover trial. The treatments were 15 g/day fish oil containing 4.3 g EPA plus DHA and a 50:50 mix of corn:olive oil, with each treatment lasting 8 weeks, and a 4-week washout between. Blood viscosity was decreased by fish oil. Gazso et al. (Ref. 204) found decreased platelet aggregation in healthy subjects after consumption of EFAmol-marine compared to olive oil in a double-blind randomized crossover study. These results of studies confirm others cited by FDA. The other studies (Refs. 203 and 254) pertained to regulators of bleeding and are discussed below. Eight papers on platelet function were reviewed by FDA but not by LSRO (Refs. 2, 6, 18, 24, 73, 93, 131, and 143). Three studies were uncontrolled (Refs. 18, 93, and 143), while two were randomized (Refs. 2 and 131). Three were randomized, double-blind, placebo-controlled trials that used saturated vegetable oil (Ref. 6), vitamin E (Ref. 24) or wheat germ oil (Ref. 73) as the placebos. The two studies that used vegetable oil or vitamin E as controls found a reduction in platelet aggregation after omega-3 fatty acids, where no difference was reported in the trial that used a wheat germ oil placebo, although the data were not provided in this paper. FDA and LSRO reached the same conclusions with regard to the effects of omega-3 fatty acids on platelet function. LSRO also concluded that platelet survival is also enhanced, but the only two studies published since 1987 that reported increased platelet survival (Refs. 94 and 144) were both uncontrolled, so the effect cannot be attributed specifically to omega-3 fatty acids. 44. One comment agreed in principle with the agency's assessment of the effects of omega-3 fatty acids on bleeding times, platelet aggregation, regulators of bleeding and blood pressure. The comment pointed out the extent of inhibition of platelet adhesion is as much as 60 percent, a marked reduction in adhesion. FDA agrees that the reported extent of reduction of platelet adhesion from omega-3 fatty acid intake is remarkable (Ref. 234). The agency notes that this effect appears specific to omega-3 fatty acids at reasonable intake levels. FDA notes that animal studies (Refs. 230 through 233) published since the proposed rule provide evidence of reduced platelet adhesion to blood vessel endothelium in vivo in response to agents that provoke such adhesion. Because of the magnitude of the effect of omega-3 fatty acids on platelet adhesion, FDA considers this action of omega-3 fatty acids on blood platelet function to have great potential with regard to the development of atherosclerosis and the risk of CHD. However, as for platelet aggregation, FDA does not believe that there currently is significant scientific agreement that platelet adhesion is an accepted risk factor for CHD in the general population. iii. Regulators of bleeding In its proposal (56 FR 60663 at 60670 through 60671), FDA reviewed data on the effects of omega-3 fatty acids on other factors that are involved in the regulation of bleeding--fibrinogen, fibrinolytic activity and Lp(a)--and that have been associated with CHD. 45. Some comments, including the LSRO report, stated that omega-3 fatty acids increase fibrinolysis. FDA disagrees with these comments. FDA found that there was no clear relationship between omega-3 fatty acids and factors involved in dissolving blood clots (56 FR 60663 at 60671). FDA noted that the data did not establish that omega-3 fatty acids reduced fibrinogen, because most studies did not control for other factors that might have reduced fibrinogen, e.g., other PUFA's. FDA has reviewed the relevant studies again, as well as studies brought to its attention in the LSRO report. LSRO cited three papers on fibrinogen or fibrinolysis not cited by FDA. One placebo (vitamin E) controlled study found no change in fibrinolytic activity (Ref. 210). Mullertz et al. (Ref. 254) supplemented seven healthy adults with 0.55 g EPA plus DHA/day for 21 days and found increased levels of PAI - 1, but no change in t-PA, suggesting that fish oil decreased fibrinolytic capability. Ganset al. (Ref. 203) reported no change in fibrinogen concentration after EFAmol-marine compared to corn oil, which is rich in polyunsaturated fat. These studies do not support the conclusion that omega-3 fatty acids reduce fibrinogen, or increase fibrinolysis. The selection of studies abstracted by LSRO may not have represented the publicly available scientific evidence. For example, five papers abstracted found either a decrease in fibrinogen or an increase in fibrinolytic activity (Refs. 57, 71, 98, 104, and 117). In contrast, two studies found no change in fibrinolytic activity (Refs. 150 and 166), and only one found increased fibrinogen (Ref. 144), leaving the impression that omega-3 fatty acids usually have been reported to enhance fibrinolysis. However, three other studies not abstracted by LSRO but included in their tables reported no effect of omega-3 fatty acids on fibrinogen compared to corn oil (Refs. 10, 118, and 203). One found a decrease compared to olive oil (Ref. 49) and one found a decrease compared to soybean oil only when 30 mL of fish oil were consumed, but not when 15 mL were consumed (Ref. 57). Additional well-designed studies not cited by LSRO, but considered in the FDA proposal, reported no change (Ref. 24) and an increase Therefore, FDA stands by its earlier conclusion that the publicly available scientific evidence does not support a relationship between omega-3 fatty acids and decreases in fibrinogen or increases in fibrinolysis. This conclusion is supported by findings that consumption of other PUFA's have effects comparable to those produced by consumption of omega-3 fatty acids. 46. Two comments cited unpublished data by Kostner and Herrmann, reporting reduced Lp(a) after fish oil consumption. FDA was unable to find the full paper by these authors showing the decrease in Lp(a). FDA did find a paper by these researchers published in 1991 (Ref. 241) that reported no effect of fish oils on Lp(a) and did not cite conflicting work from their laboratory. iv. Blood pressure In its proposal, FDA considered the relationship between omega-3 fatty acids and blood pressure, one of the recognized risk factors for CHD. FDA stated: These results for effects of omega-3 fatty acids on blood pressure of normal subjects are ambiguous. Some studies found a reduction in systolic blood pressure after consumption of fish oils containing omega-3 fatty acids, whereas others did not.None of the studies found a significant reduction in diastolic blood pressure. Therefore, it also remains to be established that the normal, healthy population will reduce their risk of CHD via a reduction in blood pressure following consumption of omega-3 fatty acids. (56 FR 60663 at 60671.) FDA also stated that it was not known whether or not the magnitude and duration of the effect would persist after longer term supplementation. FDA recognized that studies among hypertensives found an effect more consistently than studies among normal subjects, although sometimes large amounts of fish oils were used. 47. Some comments considered the effects of omega-3 fatty acids on hypertension as evidence of a reduction in CHD risk. Other comments called for FDA to reassess the studies on blood pressure. One of these comments argued that the results of studieson blood pressure are not ``completely'' ambiguous. One comment agreed in principle with the agency's assessment of the blood pressure studies. One comment considered a number of animal models to be relevant for hypertension. The LSRO report also considered the evidence relating omega-3 fatty acids to blood pressure to be important in relation to CHD. The LSRO report concluded that, ``Fish oil probably has a mild hypotensive effect, especially in high doses.'' FDA disagrees that the publicly available scientific evidence supports a relationship between omega-3 fatty acids and hypertension. At best, as stated in the proposal, the data are ambiguous. Qualifiers are needed to indicate that the reductions in blood pressure have not generally been shown to be specific to omega-3 fatty acids. Also, many valid studies have reported no effect. LSRO reported a total of 13 studies on hypertension. Four were published before 1988, and were not reviewed by FDA in the proposed rule. Three of these studies used fish as the source of omega-3 fatty acids and therefore did not show the effect specifically to be due to omega-3 fatty acids. In fact, in one study (Ref. 292), the control diet of meat produced a decrease in blood pressure comparable to that of the fish diet. The study that used fish oils (Ref. 271) used an olive oil control, rather than an oil high in PUFA's. This study is the only study to show an effect of omega-3 fatty acids on diastolic blood pressure in normal subjects. Of the other 10 studies on hypertension described in the LSRO report, 6 were also reviewed by FDA (Refs. 11, 57, 80, 85, 95, and 101). The LSRO and FDA interpretations of the results from these papers did not differ in any significant regard, exceptthat FDA specifically noted that two of these studies (Refs. 85 and 95) used very high amounts (50 mL) of fish oil to show the effect. In fact, FDA singled out the Bonaa et al. (Ref. 11) and Kestin et al. (Ref. 80) studies as well-designed studies that sh1). The LSRO report reviewed four papers not originally reviewed by FDA (Refs. 190, 285, and 299), including one study on linolenic acid outside of the scope of the definition of omega-3 fatty acids as used in this regulation (Ref. 262). Two other papers that appeared in the LSRO table but not in the text (Refs. 203 and 247) were also not reviewed by FDA in its proposal. FDA agrees with the LSRO interpretation of the Wing et al. study (Ref. 299), where subjects remained on blood pressure lowering medications and no effects of added fish oils were observed. FDA disagrees with the LSRO descriptions of the Singer and Cobiac studies. The placebo in the Singer study (Ref. 285) was olive oil, but this was not pointed out in the LSRO text. The reduction of blood pressure observed after fish oil, therefore, may have been due to a general unsaturated fatty acid effect not specific to omega-3 fatty acids. In the description of the Cobiac et al. study (Ref. 190), LSRO did not note that fish oil treatment alone (without simultaneous reduction of salt) had no effect on blood pressure. Two other studies were cited in the LSRO tables but not in the text and were not included in the FDA review. Neither of these found an effect on blood pressure. Gans et al. (Ref. 203) used a randomized double-blind, placebo-controlled design and found a reduction in diastolic blood pressure for both fish oil and corn oil (placebo). Meland et al. (Ref. 247) carried out a randomized, double-blind multicenter trial among 40 mildly hypertensive subjects, using 6.8 g EPA plus DHA/day, but found no difference in blood pressure compared to a 50:50 olive:corn oil control. Three other large and appropriately controlled studies not in the text of the LSRO report but included in its table were also reviewed by FDA. Two randomized studies on normal subjects (Refs. 9 and 49) and one controlled study among mildly hypertensive subjects (Ref. 20) reported no differences in blood pressure attributable to omega-3 fatty acids. FDA reviewed in its proposal three other randomized, double-blind, placebo-controlled studies among healthy subjects that were not included in the LSRO review. Two of these studies were on normal, healthy subjects (Refs. 6 and 24) and found a decrease in systolic blood pressure compared to a saturated vegetable oil or vitamin E, respectively. The third study (Ref. 73) found that omega-3 fatty acids did not affect blood pressure in hypertensives or normal men compared to wheat germ oil. Therefore, FDA concludes that the evidence of an effect of omega-3 fatty acids on blood pressure in normal subjects is ambiguous, because some studies reported a blood pressure lowering effect, whereas other equally well-designed studies found no specific effect. Studies among hypertensives found an effect more consistently than studies among normal subjects, although sometimes large amounts of fish oils were used, and many studies did not show that omega-3 fatty acids were more effective than other polyunsaturated fats. 48. Comments stated that other lines of evidence were not discussed in the proposal. Examples given were changes in plasma viscosity, increased vascular compliance, and reduced white blood cell (WBC) count. FDA disagrees with the comment with respect to plasma viscosity and vascular compliance. In its proposed rule, FDA acknowledged that plasma viscosity was decreased and red cell deformability was increased by omega-3 fatty acids, but that the importance of these effects on the risk of CHD had not been established (56 FR 60663 at 60670). The agency agrees that it did not systematically consider WBC count among the effects produced by omega-3 fatty acids. WBC count was not included among the actions of omega-3 fatty acids considered in major reviews. FDA notes that WBC count has only rter fish oil supplementation (Refs. 183 and 253). 3. Other relevant information a. Animal studies 49. Numerous comments asserted that animal studies did not receive an appropriate amount of discussion. One of these same comments stated that animal studies are not sufficient to support the claim, and that clinical trials on effects of omega-3 fatty acids directly on CHD are needed. One comment criticized FDA's review of animal studies because the negative findings have been in inappropriate models and should not have been discussed. Another comment stated that they did not believe that there is an appropriate animal model for human cardiovascular and CHD. The LSRO report considered animal studies to provide important evidence for an anti-atherogenic effect of fish oils, stating, ``Omega-3 fatty acids have been shown to retard the development ofthe atherosclerotic plaque in experimental animals including the pig and rhesus monkey.'' FDA agrees that the evidence from studies in animals warrants additional discussion. FDA has reviewed here those animal studies that were cited in its proposed rule and those that were cited in the LSRO report that were relevant to the development of atherosclerosis. Other animal studies relevant to the development of atherosclerosis, and animal studies on aspects of CHD other than atherosclerosis are reviewed under section II.C.3.a. of this document. In its proposal, FDA cited eight animal studies and one abstract on the development of atherosclerosis that were not included in the LSRO review (Refs. 19, 51, 65, 81, 97, 123, 126, and 151), seven of which reported either no beneficial effect or anadverse effect in fish oil supplemented animals. Only one animal study on the effects of omega-3 fatty acids on restenosis was abstracted by LSRO, although the others cited by FDA were described in the LSRO tables. Three studies in nonhuman primates have been reported (Refs. 27, 47, and 116). In the Davis et al. (Ref. 27) and Parks et al. (Ref. 116) studies, the polyunsaturated fat intake was higher in the fish oil groups, and polyunsaturated fat is known to lower total plasma cholesterol. Also, the control diet of the Davis et al. study had more saturated fat than the fish oil diet. Thus, the effects on atherosclerosis may not have been specific for omega-3 fatty acids. In these studies, the total cholesterol values for the fish oil groups were substantially lower than for the control group, which may explain the observed differences in atherosclerosis. In support of this interpretation, Parks et al. (Ref. 116) noted that one of monkeys fed the fish oil diet responded differently than the other 11 monkeys fed fish oil. This one monkey had a plasma cholesterol level comparable to that of the lard-fed control monkeys, and also had atherosclerosis comparable to the lard-fed monkeys. Changes in total cholesterol levels were noted by authors of another study in pigs that showed a reduction in atherosclerosis concomitant with a reduction in time-weighted total cholesterol (Ref. 81). Since cholesterol concentrations are not changedby fish oils in humans, animal studies where fish oil treatment lowered total cholesterol levels are of questionable relevance to the role of omega-3 fatty acids in the development of human atherosclerosis. A recent study (Ref. 47) in nonhuman primates (vervet) compared the effects of fish oil supplementation to sunflower oil supplementation in either an atherogenic diet (high fat, low polyunsaturated fat to saturated fat ratio, high cholesterol) or, following the atherogenic diet, in a therapeutic diet (low fat, high polyunsaturated fat to saturated fat ratio and low cholesterol). Animals in each diet group were matched for serum cholesterol. Sixteen separate measures of atherosclerosis were scored, inil fed animals. The LSRO report considered the amount of fish oil in the diets in this experiment (1.3 to 1.8 percent of calories) too low to observe an effect. In fact, FDA calculates a lower percent of calories from fish oil (1.0 to 1.5 percent) than calculated by LSRO. This level is about half the amount used in short-term human studies (i.e., 10 mL/day), and FDA agrees that the low level makes it less likely that an effect would be observed than if a higher amount had been used. However, diets were supplemented for a prolonged period of time (20 months) and in the therapeutic diet other dietary factors were also changed that might have made the effects of omega-3 fatty acids more noticeable (e.g., ratio of polyunsaturated to saturated fatty acids). Finally, the fact that there were differences between the fish oil-supplemented group and the polyunsaturated fat group while on either the atherogenic or therapeutic regimens suggests that there was sufficient sensitivity in the experimental design to detect protective effects of omega-3 fatty acids. In some animal studies that showed a protective effect of fish oils, an invasive procedure was used to accelerate atherosclerosis, either mechanical injury (Ref. 122) or vein grafts (Refs. 90 and 186). These studies may be most relevant to the late stages of atherosclerosis, and to CHD in humans following invasive procedures. All of the animal studies cited in the LSRO report except Kim et al. (Ref. 81) and Fincham et al. (Ref. 47) did not control for PUFA's, so the effects observed have not been shown to be specific to omega-3 fatty acids. Additionally, the level of use of fish oils has been high, e.g., 22 percent of calories in Parks et al. (Ref. 116) and 25 percent of the diet in Davis et al. (Ref. 27), which limits the extrapolation of findings in these studies to levels that might be reasonably consumed by humans. FDA disagrees with the summary of the literature in animals, as expressed in the LSRO report, because that report fails to mention important limitations in the data. FDA notes that most studies did not have an adequate design to show specificity of effects as due to omega-3 fatty acids. Furthermore, reductions in total cholesterol in the fish oil fed animals may explain the reported reductions in atherosclerosis. Since reasonable amounts of fish oils in human diets do not alter serum cholesterol concentrations, the results from these animal experiments are of questionable importance regarding human atherosclerosis. Finally, LSRO did not review numerous animal studies that found no effect or an adverse effect of supplementation with fish oils, and therefore the LSRO conclusion does not represent the totality of publicly available scientific information. With these qualifications in mind, FDA notes that some of the reported effects of the dietary interventions with fish oils on the development of atherosclerosis have been dramatic. Also, FDA recognized that animal studies are of great importance forstudy of long-term effects on chronic diseases of consumption of amounts of omega-3 fatty acids, particularly in amounts that might be obtained in a reasonable diet. Therefore, FDA encourages further research in this area using rigorous study designs and amounts of omega-3 fatty acids reasonably available in a normal diet to elucidate any effects specific to these fatty acids. After closer scrutiny of the animal studies cited in FDA's proposal and in the LSRO report, the agency has reached the same conclusion that it reached in its proposed rule: there are some data in studies from animals which suggest the possibility ofa beneficial effect of omega-3 fatty acids on CHD; however, the data are equivocal. (56 FR 60663 at 60671.) b. Safety considerations 50. One comment stated that the increases in LDL cholesterol observed were a chance occurrence, and another stated that increased LDL should not be considered an adverse finding in light of the results of the Burr study. FDA disagrees with this comment. FDA found that increased LDL cholesterol was ordinarily found when hyperlipidemics or diabetics were given fish oil supplements. This may be due in part to the fact that fairly large amounts of omega-3 fatty acids (i.e., 5 g EPA plus DHA/day or more) were used in these studies. Increased LDL is not ordinarily seen in the studies on normal subjects. FDA does not consider the Burr study (Ref. 16) to have established that omega-3 fatty acids reduce the risk of CHD, and therefore remains concerned that increases in LDL cholesterol could be adverse for some subjects. FDA notes that concern about increased LDL cholesterol was expressed in the report of the NHLBI consensus development conference (Ref. 255). 51. One comment stated that it was inappropriate to consider adverse effects in subpopulations without describing the advantages of omega-3 fatty acids in those same populations. FDA disagrees with this comment. As noted in the final rule on general requirements for health claims, published elsewhere in this issue of the Federal Register, it would be a violation of the agency's responsibility under the act to authorizea health claim about a substance without being satisfied that the use of the substance was safe. The agency attempted to examine all available scientific evidence regarding the effects of omega-3 fatty acids. FDA separated out the potential adverse effects discovered during its review, because it wanted to draw attention to these issues as impediments to a health claim for omega-3 fatty acids and CHD. Such potential adverse effects must be resolved, and may be important in setting the conditions under which FDA would allow a health claim to appear on the label and labeling of foods and food supplements. 52. Two comments stated that the safety issues raised in the Mitre Corp. report (Ref. 72) were outdated but did not indicate which issues, or suggest why they were outdated. FDA recognizes that there has been considerable debate regarding the clinical importance of bleeding times since the publication of the Mitre Corp. report (Ref. 72). However, the agency believes that the issues raised in that report have been restated in subsequent literature, and that all issues of safety are important in deciding whether or not to authorize a health claim. 53. A few comments recommended that FDA balance the benefits of reduced risk of CHD against the risk of reduced glycemic control among diabetics when deciding whether or not to authorize a health claim. One comment stated that physicians could adjust the dose of insulin if omega-3 fatty acids reduced their glycemic control, but another comment stated that glycemic control must be considered a real adverse effect. FDA agrees that limitations on the use of a substance by a subpopulation (e.g., diabetics) do not necessarily exclude a substance from bearing a health claim for the general population, because the claim may be appropriately restricted. However, FDAagrees that the loss of glycemic control is a potentially serious adverse effect that must be fully addressed before a health claim could be authorized. 54. Another comment stated that a major concern about omega-3 fatty acids not mentioned in the proposed rule is that they may be oxidized and, as oxidized products, may have adverse effects. FDA agrees that oxidation of omega-3 fatty acids is a concern. In fact, there are many studies that have been reported since the publication of the proposed rule, or that were not included in FDA's literature review, that indicate such a concern (Refs. 184, 210, 217, 229, 240, 248, 263, 283, and 290). Antioxidants have been successfully added to supplements and may be adequate to protect the omega-3 fatty acids in foods. It may be necessary to establish conditions that protect against oxidation of omega-3 fatty acids and incorporate those condition 55. A related comment indicated that the majority of the fish oil preparations that have been used are severely oxidized, including National Institutes of Health Fish Oil Test Materials. However, no data regarding the extent of oxidation, the natureof the oxidation products, or the physiologic action of these products was provided. FDA agrees with this comment. Many of the biologically active products of omega-3 fatty acids are oxidation products. Oxidation of test materials may explain some contradictory findings in the literature. 56. One comment pointed out that increased prothrombin times and possibility of increased stroke were not discussed. FDA agrees with this comment. FDA did not specifically review data on prothrombin times, although data on bleeding times as a measure of hemostasis were discussed for both normal subjects and for subjects with risk factors for CHD. The importance ofthe increase in bleeding time brought about by supplemental fish oils or increased fish consumption is not clear. FDA noted in the proposal that most reports suggest that serious bleeding is not an issue in patients supplemented with omega-3 fatty acids, and also that standardized bleeding times do not closely correlate with clinically significant bleeding. However, concerns about untoward bleeding after supplemental fish oils have been raised in the literature (Refs. 106, 120, and 189). FDA did not discuss the possibility of increased occurrence of stroke as a consequence of increased consumption of omega-3 fatty acids. The papers that reported a correlation between high consumption of omega-3 fatty acids from fish and other marineanimals and low rate of CHD mortality also noted an increase rate of stroke, particularly hemorrhagic stroke (Refs. 8 and 84). Also, the possibility of increased rates of stroke are raised by the data from studies on aspirin (Ref. 66). Thus, FDA considers these potential adverse reactions to be legitimate concerns, primarily in the context of very high intakes of omega-3 fatty acids. 57. One comment stated that even if adverse effects were only suspected in a medical disorder, pronounced warnings or contraindications would be required. As noted above, the agency must be satisfied that the use of a substance is safe before it will authorize a health claim about the substance. Thus, suspicions about potential adverse effects would need to be resolved prior to the authorization of a claim. Certain health claims may require appropriate qualification as a way of minimizing potential safety concerns. C. New Scientific Data To determine whether or not new scientific data published since the proposed rule provided a basis for modifying FDA's conclusions regarding the relationship between omega-3 fatty acids and risk of CHD, FDA conducted a search of the scientific literature for relevant studies. Reviews published since the period covered in the literature review in FDA's proposed rule were used to identify recently published studies. 1. Epidemiologic studies a. Cross-sectional studies and surveys (Table 1) Bulliyya et al. (Ref. 185) found lower total serum cholesterol and higher HDL cholesterol in a fish-consuming coastal village population than in a nonfish-consuming population from the interior of India. These correlational data are consistent with a beneficial effect of omega-3 fatty acids on blood lipids, but many possible confounding variables prevent strong conclusions regarding a specific role for omega-3 fatty acids. In a retrospective study, Popeski et al. (Ref. 266) found that women from communities with higher marine oil consumption had significantly lower diastolic pressure in the last 6 hours of pregnancy than women from communities with low fish oil consumption. Pregnancy associated hypertension was 2.6 times more common in communities with low fish consumption. These correlational data are consistent with an effect of omega-3 fatty acids on blood pressure in this particular situation. Again, many possible b. Prospective studies (other than intervention studies) (Table 1) Bjerregaard and Dyerberg (Ref. 176) reported age-standardized mortality rates per 10,000 person-years for CHD in men in Greenland settlements (5.3) as half of that reported for men in Denmark (10.0). There was an increasing rate of CHD from settlements to towns in Greenland. The difference in rates of CHD in women were less apparent, with lower rates in Denmark than in towns in Greenland. These studies do not have sufficient specificity to identify omega-3 fatty acids as causal in reducing CHD, butare consistent with the hypothesis that they are. Van Houwelingen et al. (Ref. 294) found that, while men from a high fish consumption group had higher concentrations of plasma phospholipid EPA and DHA than men from a low fish consumption group, there was no significant difference in collagen-induced platelet aggregation, cutaneous bleeding time, ATP-release in whole blood, or platelet number between the two groups. This study suggests that the outcome measures found commonly to be affected in clinical studies may not be related to consumption of omega-3 fatty acids in the free-living population. c. Intervention studies There were no new prospective intervention studies measuring occurrence of heart attacks or CHD mortality. 2. Evidence relating omega-3 fatty acids to intermediate or surrogate markers of CHD (Table 2) a. Atherosclerosis i. Blood lipids Through its own literature review, FDA has found another 34 studies not reviewed in the proposal that report data for serum cholesterol after consumption of fish containing omega-3 fatty acids or fish oil concentrated in omega-3 fatty acids. Among these, 25 found no change in blood cholesterol levels, 3 found an increase, and 6 found a decrease. Studies among normal healthy subjects generally reported no change in total cholesterol (Refs. 168, 196, 202, 210, 217, 220, 235, 241, 253, 254, and 277), although none of these studies was controlled for nonspecific effects of the omega-3 fatty acids as polyunsaturated fats. One study among normal subjects found that feeding a high fish diet did not change total cholesterol, unless combined with a low total fat and low saturated fat diet (Ref. 168). Another study (Ref. 301) reported decreased total cholesterol after switching from a meat diet to a fish diet, but the fish diet had significantly less saturated fat than the meat diet. One study (Ref. 283) found a slight increase after 5.4 g EPA plus DHA/day from MaxEPA (with 30 percent saturated fatty acids), and one study (Ref. 224) found a slight reduction in total cholesterol after 2.7 g purified EPA/day, but neither study was placebo controlled for effects of polyunsaturated and saturated fat contained in the supplements. Similarly, nearly all of the 17 studies on subjects in at-risk subpopulations, including all of the studies that controlled for PUFA's (Refs. 203, 209, 247, and 258), found no effect of supplemental omega-3 fatty acids on total cholesterol (except for a post hoc analysis of a subgroup in one study, (Ref. 209)). One study in diabetics (Ref. 252) found an increase in serum cholesterol, but the statistical significance of the result may have been due in part to a change in the opposite direction in the control group. One study among hyperlipidemics (Ref. 191) found decreased cholesterol after relatively high doses (4.6 to 6 g EPA plus DHA/day) but not after 3.6 g EPA plus DHA/day, and did not control for PUFA effects of the supplements. The other study that reported decreased cholesterol after supplemental omega-3 fatty acids (Ref. 268), similarly, found the effect after a high level (6 percent of calories, 16 to 21 g EPA plus DHA/day) and did not control for the polyunsaturated fat effects of the supplement. These studies support the conclusion reached in the proposed rule, that among normal, healthy subjects there is no significant effect of omega-3 fatty acids from fish or fish oils on total serum cholesterol. FDA concluded in the proposed rule that the best studies among normal subjects found no effect of fish oils on LDL cholesterol. All of the additional studies among normal healthy subjects obtained in FDA's updated literature search have reported no change in LDL cholesterol (Refs. 220, 253, 253, and 277). One study (Ref. 224) reported that purified EPA produced a significant decrease in a subfraction of large, light LDL cholesterol (LDL1), and a significant increase in small, dense LDL cholesterol (LDL2), but FDA calculates no change for the sum of these two fractions of LDL cholesterol. Some clinical studies reviewed in the proposed rule (Refs. 1, 43, 53, and 129) described changes in the composition of LDL particle after consumption of fish oil. The relative importance of various subfractions of LDL particles (and the associated composition of the particles), however, is still controversial. While Homma et al. (Ref. 224) suggest that large, light LDL are the fraction associated most closelywith atherosclerosis, Austin et al. (Ref. 171) report that the phenotype of small, dense LDL is the fraction most closely related to increased CHD risk. The February 1992 NHLBI consensus development conference (Ref. 255) included among its recommendations for further research the identification of the atherogenic and anti-atherogenic subfractions that may be present in VLDL and HDL; the uncertainty about the relevance of changes in the amounts of subfractions of these two lipoproteins similarly appliesto LDL. In at-risk populations, there have been some additional reports of increased LDL cholesterol after fish oil supplementation (Refs. 170, 191, and 251), a concern raised in the proposal. However, most studies have found LDL cholesterol not changed by fish oils (Refs. 174, 189, 205, 209, 219, 258, and 278). Moreover, each of the studies that used a polyunsaturated fat placebo control group found no change in LDL cholesterol (Refs. 203, 209, and 258). Therefore, FDA concludes that these most recently reviewed studies support the conclusion reached in the proposed rule, that for the general population, there is no significant effect of omega-3 fatty acids on LDL cholesterol. The results of recent studies among at-risk subjects, however, are not in complete agreement with the conclusions in the proposed rule, and suggest that omega-3 fatty acids may not uniformly increase LDL cholesterol. Additional study is needed to determine the conditions under which LDL cholesterol is increased by omega-3 fatty acids. Among more recent studies in normal healthy subjects found in FDA's updated literature review, about half have found no effect of fish oils or fish on HDL cholesterol (Refs. 202, 206, 217, 219 (after 1.25 and 2.5 g/day EPA plus DHA), 226 (after 1 and 3 g/day EPA plus DHA), 241, and 244), but about half have found increased HDL (Refs. 210, 219 (after 3.75 and 5 g/day EPA plus DHA), 220, 226 (after 6 g/day EPA plus DHA), 235, 253 (compared to baseline, significant compared to olive oil control), 278,283, and 301), including a metabolic ward study that very carefully controlled for total fat and saturated fat intake (Ref. 253). Weintraub et al. (Ref. 298) found decreased HDL after fish oil compared to a saturated fat diet. FDA attempted to ascertain how those studies that reported an increase in HDL cholesterol after increased intake of omega-3 fatty acids differed from those studies in which no effect was found. However, there was no apparent difference between the studies that reported that omega-3 fatty acids reduced HDL cholesterol and those that reported no change. Most of the studies that found a change used supplements containing substantial amounts (e.g., 30 percent) of saturated fatty acids, raising the possibility that the saturated fatty acids in the supplements were responsible for the increase in HDL (Ref. 17). However, some supplements had low amounts of saturated fatty acids (Ref. 278) or saturated fat in the diet was specifically controlled (Ref. 235),gnificantly more saturated fat than the fish diet (Ref. 301), so the saturated fat intake during omega-3 fatty acid supplementation cannot be the factor responsible for increased HDL. The amounts of omega-3 fatty acids used in those studies that reported increased HDL tended to be high (e.g., more than 5 g EPA plus DHA/day), but some studies that found a change used lower amounts (Ref. 278) and some studies that used high amountsfound no change (e.g., Ref. 241 (used 6.7 g EPA plus DHA/day) and 253 (used 8 g/day)). Some studies in which fish was fed, rather than fish oil, found an effect (Refs. 235 and 301), but others did not (Refs. 206 and 244). There was no systematic difference in sample sizes of the studies that found an effect and those that did not; seven of the negative studies reviewed in the proposed rule or in the present document had 30 or more subjects, compared to only one of the positive studies. Small studies (n= 10 or fewer) may not have observed a significant difference because of small sample size, but larger studies did not find a significant difference, even though some found a trend toward increased HDL after fish oil supplementation (Ref. 217). Finally, the enrichment of plasma phospholipids with EPA and DHA tended to be higher for subjects in studies where increased HDL was found than that for subjects in the studies where no change in HDL was found, reflecting the tendency of higher doses to produce increased HDL. In particular, all studies in which the plasma phospholipid EPA value was 3.9 percent or more found increased HDL. However, the studies that fed the highest amounts of EPA but that did not find an effect on HDL did not report data for phospholipid EPA, so it is not clear whether high phospholipid EPA is uniformly associated with increased HDL. Comparable results were found after inspection of data on phospholipid DHA after supplementation, however, because not all studies reported phospholipid fatty acid values, no conclusion can be drawn about the relationship between phospholipid DHA and HDL concentration. Notably, recent data suggest a direct correlation between plasma EPA and HDL, but an inverse relationship between plasma DHA and HDL (Refs. 177 and 178), underscoring the importance of reporting these data in future studies. Among subjects with risk factors for CHD fewer reports found increased HDL (Refs. 191 (for type IV on SuperEPA only), 195, 203, 209 (for type IIb), and 219) than found no change (Refs. 170, 174, 189, 191 (for type IIb and type IV on MaxEPA), 209 (type IV), 224, 258, 263, 277, and 299). Few studies have controlled for effects of PUFA's by giving a PUFA supplement. Two papers found no change in HDL in normal subjects fed fish oil as Promega (Ref. 73) or MaxEPA (Ref. 166) compared to wheat-germ oil or safflower oil (Refs. 73 and 166,respectively). Cobiac et al. (Ref. 20) reported increased HDL for mildly hypertensive subjects fed salmon and sardines in sild oil compared to those given a safflower-olive oil mix, but in comparable subjects, Meland et al. (Ref. 247) found no change inHDL cholesterol after MaxEPA fish oil compared to when the subjects were given a corn-olive oil mix. Very recent results, also for a mildly hypertensive population, found increased HDL after either, ethyl esters of EPA and DHA, or after corn oil (Ref. 177). Thus, for normal and hypertensive subjects, the change in HDL appears to not be a specific effect of omega-3 fatty acids, but may be related nonspecifically to increased PUFA's, either omega-3 fatty acids or omega-6 fatty acids. In contrast, there are two reports of increased HDL cholesterol in subjects with type Iib hyperlipidemia fed fish oil compared to safflower oil (Ref. 166) or a corn-olive oil mix (Ref. 209), and one report of increased HDL in type IIa hyperlipidemics Therefore, at this time, FDA concludes that there is some evidence that omega-3 fatty acids, in some form and amount and in some selected populations, may increase HDL cholesterol, but that current data are ambiguous because the conditions under which fish oils reliably increase (total) HDL cholesterol have not been established, either in a specific subpopulation, or in the general population. When fractions of HDL cholesterol have been reported, an increase has generally been found in the HDL2 fraction (Refs. 1, 9, 54, 148, 191, 202, 203, 220, 235, 251, and 286), with a comparable decrease in the HDL3 fraction (Refs. 202,235, 251, and 286). Interestingly, the two recent reports that failed to find increased HDL2 both used esterified omega-3 fatty acids rather than the fish oil triglyceride (Refs. 191 and 224), although others using ethyl esters have found increased HDL2 (Refs. 9 and 286). These studies suggest that fish oils produce a shift within the HDL fractions toward a lipid-rich, and away from a protein-rich lipoprotein, as well as within the LDL fractions. This shift may occur whether or not there is any change in total HDL cholesterol. FDA noted (56 FR 60663 at 60669) that some studies among normal subjects found increases in the HDL2 fraction of HDL cholesterol, and that these reports were the most promising changes in blood lipids. New studies published afterthe period covered in FDA's review of the literature, however, found that both HDL2, and HDL3 were correlated with reduced risk of MI (Refs. 185a and 287a), and the NHLBI consensus conference (Ref. 255) concluded that, ``The current studies of HDL2 and HDL3 levels have not shown consistent associations with CHD.'' Therefore, data on changes in HDL subfractions after increased consumption of omega-3 fatty acids do not provide a sufficient basis for a health claim, becausethere is not significant scientific agreement that the endpoints are directly related to risk of CHD. If the risk of CHD becomes linked with particular subfractions of these lipoproteins, these findings in normal subjects may be of great importance. However, FDA also notes that recently published data from a prospective study demonstrate an effect of aspirin consumption in reducing the incidence of first heart attacks among women (Ref. 243). Another study shows a relationship between spontaneous platelet aggregation in vitro and incidence of CHD (Ref. 288). Both studies were conducted in the general population and their results support the hypothesis that platelet aggregation is a useful marker for CHD risk in the general population. Additionally, preliminary data from the Caerphilly Collaborative Heart Disease Study (Ref. 302) supports a relationship between platelet aggregation and the incidence of ischemic heart disease; final data from this study will be available in the near future. These recently published and forthcoming studies may provide the basis for significant scientific agreement regarding the use of platelet function as a surrogate marker for CHD risk among the general population. ii. Vessel wall effects. New human studies on the effects of omega-3 fatty acids on vessel wall effects were discussed in response to comments 35 through 37 of this document. A recent meta-analysis of studies on use of fish oils in the prevention of restenosis concluded that the most plausible interpretation of the results was that there was a small to moderate beneficial effect of fish oils, but that chance could not be ruled out as a cause of the results (Ref. 260). The authors noted a significant heterogeneity in the findings and concluded that data from a large clinical study are necessary to confirm their interpretation. No study of restenosis to date has compared fish oil to an alternate polyunsaturated oil to control for nonspecific effects of PUFA's. b. Thrombosis and hemostasis i. Bleeding times A number of studies have reported data that show no significant effect of fish oils on standardized bleeding time tests (Refs. 179, 218, 253, 268, and 277). However, others have found a significant increase in bleeding time due to fish oil (Refs. 195, 219, 220, and 278) or salmon (Ref. 297) or have reported increased bleeding as a side effect of treatment (Refs. 189 and 295). ii. Platelet aggregation. Consistent with the literature previously reviewed, recent studies show that fish oil tends to decrease platelet aggregation to numerous stimuli including AA (Refs. 179 and 256), adenosine diphosphate (ADP) (Refs. 204, 256, and 297), collagen (Refs.218, 241, 251, and 297), thrombin (Ref. 241), and PAF (Ref. 251). Only one of these studies controlled for effects due to PUFA's (Ref. 204). The importance of the polyunsaturated fat control is less critical for studies on platelet function than for studies on blood lipids, because nonomega-3 PUFA's (i.e., omega-6 fatty acids derived from plant oils) produce effects in the opposite direction in platelets as omega-3 fatty acids (whereas many of the blood lipid effects of these two classes of fatty acidsare in the same direction). Thus, the effects of omega-3 fatty acids on platelet responsiveness are not likely to be produced by PUFA's in general. The only new study among healthy subjects that reported no difference in responsiveness to ADP used EPA ethyl esters as the source of omega-3 fatty acids (Ref. 179). Furthermore, the data were not shown in this brief report, so it is not clear if there was a trend toward an effect that might not have been statistically significant due to small number of subjects (eight per group). Those studies in healthy subjects reviewed in the proposed rule that did not find statistically significant differencesin platelet responsiveness to ADP did have trends in the direction of reduced responsiveness (Refs. 24 and 54). Other studies found no effect of fish oils on platelet aggregation in response to collagen (Refs. 179, 256 and 277). Each of these studies had a relatively small number of subjects, and there was a trend toward decreased sensitivity toward collagen at a high dose of omega-3 fatty acids in one study (Ref. 277). However, in the recent metabolic ward study (Ref. 256) there was no trend toward decreased sensitivity toward collagen or thrombin. These findings contrast with the results described above (Refs. 218, 241, 251, and 297) and with studies in healthy subjects described in the proposed rule (Refs. 2, 24, 54, 96, 143, and 166). Studies reporting no effect of fish oils on PAF or AA-induced platelet aggregation (Refs. 179 and 218) may not have had sufficient power to find a statistically significant difference; where the data were reported there was a trend toward decreased sensitivity for both agents (Ref. 218). iii. Platelet adhesion A provocative study by Li and Steiner (Ref. 234) showed a 60-percent decrease in the extent to which platelets prepared from subjects fed fish oils adhered to substrates in a laminar flow chamber. The high flow rates used in this experiment showed that the change in adhesiveness of the platelets was due to changes on the platelet surface, and not due to a difference in the amount of material released from platelets that subsequently caused adhesion (i.e., AA). Also, a dose-response relationship wasobserved, and the time to return to pre-fish oil adhesion values was related to the amount consumed. However, another study found no effect on fish oils on in vitro platelet adhesion to everted rabbit aorta, although there was a trend toward increased adhesion after 2 and 4 weeks of supplementation (Ref. 264). The reperfusion assay used in this study does not distinguish platelet membrane effects from effects mediated by substances released from platelets. Neither of these studies used a nonomega-3 PUFA control. iv. Regulators of bleeding Two recent studies in normal subjects have reported that omega-3 fatty acids have no effect on the clotting protein fibrinogen (Refs. 183 and 210), although in one of these studies a large supplement of vitamin E was associated with a decrease (Ref.210). An uncontrolled study in normal subjects found a decrease in fibrinogen after fish oil supplementation (Ref. 278). Studies on subjects at risk for CHD have reported no change (Ref. 203), a decrease (Refs. 276 and 277), and an increase in fibrinogen (Ref. 287). In agreement with its tentative conclusion in the proposed rule, FDA finds that the data on the effectsof omega-3 fatty acids on fibrinogen level are ambiguous, because they do not distinguish effects due to PUFA's from effects specific to omega-3 fatty acids. Plasminogen is an enzyme that dissolves clots. Plasminogen activator is a substance that increases clot dissolving; plasminogen activator is specifically inhibited by another substance, the PAI - 1. Thus, a high level of PAI - 1 decreases the capability to dissolve clots. Three recent studies reported increased concentrations of PAI - 1 after fish oil supplementation (Refs. 254, 278, and 287), which would appear inconsistent with a clot-dissolving effect of fish oil. Two of these investigators also found no change inthe amount of plasminogen activator (t-PA) after supplemental fish oil (Refs. 254 and 287) including one who used a very specific immunologic assay (Ref. 254), suggesting that fish oils do not increase clot dissolution by increasing the amount of this protein. The third group, however, found an increase in the activity of tissue plasminogen activator (Ref. 277), which suggests that fish oils might increase clot dissolution by a different mechanism than affecting the amount of activator. Another group found no effect of cod liver oil on t-PA activity or fibrinolysis measured directly (Ref. 216). These reports are in contradiction to a report of increased fibrinolytic activity after a fish or fish plus fish oil diet (Ref. 183). FDA has not been able to find a reason for this rather marked contradiction. Therefore, in agreement with the conclusion in its proposed rule, FDA finds there is no clear relationship between omega-3 fatty acids and factors involved in dissolving blood clots, or clot dissolutionactivity. Numerous investigators (Refs. 174, 191, 210, 220, 235, 241, and 279) have recently reported that fish oils do not affect the concentration of Lp(a), a lipoprotein correlated with the risk of CHD. One investigator reported that very high levels of fish oils (9 g EPA plus DHA/day) gave a trend toward lower values, but the response may have been due to the PUFA's (Ref. 279). One study reported no effect overall of fish oils on Lp(a) among hypertriglyceridemics, but Lp(a) was reduced in those whose initial values were high (Ref. 174). On the basis of these reports and those reviewed in the proposed rule, FDA concludes that omega-3 fatty acids do not affect the risk of CHD by lowering Lp(a). v. Blood pressure Most of the studies not reviewed in the proposed rule that report data on blood pressure after consumption of fish oils have not found a significant change. One study of 50 elderly, healthy subjects reported that fish oils in combination with a salt-restricted diet decreased both systolic and diastolic blood pressure, but that fish oil alone had no effect (Ref. 190). There was a reduction in blood pressure during the run-in period, when the polyunsaturated fat placebo, sunflower oil, was fed. Most studies on subjects with mild hypertension also have reported no change (Refs. 247, 277, and 289), including one large, randomized, placebo-controlled, multicenter trial of various behavioral changes and dietary supplements (Ref. 289). One study in hypertensives found reduced systolic and diastolic blood pressure comparable to reductions after the hypertension medication propranolol (Ref. 285), and in some cases the combined treatment of fish oil plus propranolol gave a greater decrease than eitdouble-blind randomized, placebo-controlled study in hypertensives whose blood pressures were maintained by medications found comparable blood pressure lowering compared to pretreatment values by fish oil or olive oil placebo (Ref. 299). One uncontrolled study among hyperlipidemics also found reduced systolic and diastolic blood pressure (Ref. 263), but no effect was found in uncontrolled trials in subjects with end-stage renal disease (Ref. 207) or diabetics (Ref. 215). In a polyunsaturated fat (corn oil) controlled study on subjects with stable claudication (Ref. 203) fish oil and corn oil both reduced diastolic blood pressure comparably, but systolic blood pressure was only reduced by the corn oil treatment. The results of these studies support the tentative conclusions reached in the proposed rule, that omega-3 fatty acids reduce blood pressure to a small degree in hypertensive people, but that it is not clear if there is any specific effect among normal subjects. 3. Other relevant information a. Animal studies Animal studies are especially important for studying effects of long-term consumption of omega-3 fatty acids, where there are few data from human intervention studies. The animal studies cited in the proposed rule related to the ability of omega-3 fatty acids to inhibit the development of atherosclerosis, an area not readily available for study in humans. A more complete discussion of the previously cited studies, with emphasis on those studies in nonhuman primates, is given in response to comment 47 of this document. Other recent animal studies cited in the comments or found during FDA's updated literature search that provide data on the development of atherosclerosis (where atherosclerosis is measured directly) are reviewed here. Also reviewed are studies on effects of omega-3 fatty acids during experimental ischemia, obviously not available for human study. i. Atherosclerosis One recent study in rabbits found less atherosclerosis in fish oil-supplemented animals, but there was no control for PUFA's, and the fish oil-treated animals also had reduced serum cholesterol (Ref. 192). Because humans do not have reduced serum cholesterol after fish oil consumption, these results are of questionable relevance to humans. Furthermore, the effect cannot be attributed specifically to omega-3 fatty acids rather than to polyunsaturated fats in general. Fish oil feeding has also been associated with reduced binding of LDL to the blood vessel endothelium in monkeys (Ref. 193), and purified EPA ethyl ester was reported to reduce susceptibility of LDL to oxidation (Ref. 273), but these studies did notcontrol for PUFA's. The antioxidant levels in the diets with respect to the amount of omega-3 fatty acids may be as important in determining whether or not there is any effect of omega-3 fatty acids on the oxidation of LDL. Three recent papers describe effects of fish oils fed before surgical grafting of a vein into an artery, a procedure associated with an accelerated development of atherosclerosis. Two papers (Refs. 275 and 303) each used a polyunsaturated fat control and studied fish oil effects after vein allografts in animals treated with the immunosuppressant cyclosporin. In one study (Ref. 303), six groups of rabbits received one of three amounts of fish oil (giving 29, 87 and 174 mg EPA plus DHA/kg, respectively, similar amounts to those used in most human studies) or comparable amounts of safflower oil. In this study, safflower oil was more effective at reducing cholesterol than fish oil, and there was a trend toward more protection from atherosclerosis in the safflower oil-fed group. In the other study (Ref. 275), rats received, in addition to cyclosporin, either fish oil (containing 210 mg EPA plus DHA/kg), or safflower oil with aspirin, or safflower oil only. The fish oil group had remarkably less atheroscression and the same polyunsaturated fat control, may be related to dose and species differences. A third study of vein allografts in dogs (Ref. 274) found significantly less atherosclerosis in fish oil-fed animals either fed the fish oil alone or in combination with aspirin or a thromboxane synthetase inhibitor. Other animals were treated with aspirin only or a thromboxane synthetase inhibitor only. There was no difference among groups for blood lipids, platelet function or eicosanoid metabolism. This study suggests that mechanisms of atherosclerosis other than those involving blood lipids andplatelet function may be affected by omega-3 fatty acids. These animal models are most relevant to comparable surgical procedures or other invasive procedures (e.g., angioplasty) that would be expected to activate platelets in humans. Use of omega-3 fatty acids in these settings is a drug usage, but provides information on the extent to which omega-3 fatty acids may modify platelet response in vivo. The very different results of omega-3 fatty acids in modifying the response to vein allografts in immune-suppressed animals indicates that the actions of omega-3 fatty acids in these settings are not yet well established. ii. Response to ischemia One major line of research on omega-3 fatty acids in animals is experimental ischemia (deficiency of blood flow to the heart). Force et al. (Ref. 199) found that rats fed a diet containing a high amount of fish oil (20 percent of the diet) for 6 to 12 weeks had much greater blood flow once the occlusion was removed than rats fed diets enriched in corn oil or lard. There were no differences among diet groups in the amount of tissue damaged by ischemia. Increased blood flow after ischemia has also been reported in a pig model (Ref. 221). This study did not control for polyunsaturated fat and used a lower amount of omega-3 fatty acids, and the differences in blood flow were not as pronounced as in the Force study. Another study found evidence of lesstissue damage during reperfusion when rats had been fed a diet with 12 percent fish oil compared to other rats fed the same level of corn oil (Ref. 223). Another study in yet a third animal species (Ref. 230) showed that the functional capillary densitywas preserved during reperfusion in hamsters fed 5 percent fish oil for 4 weeks prior to experimental ischemia. A reperfusion study in dogs determined the effects of fish oil on the duration of time needed for drug-induced reperfusion following an electrically induced blockage, and on the occurrence of spontaneous reocclusion in the reopened vessel (Ref. 182). High amounts of fish oil (one-third of total calories) for 3 weeks before the surgery resulted in a shorter time needed for the drug-induced reperfusion, but did not affect the time necessary for the electrically mediated occlusion to occur, the occurrence of second occlusion, or the time it took for the second occlusions to appear. This study did not have a polyunsaturated fat control, and even at the high intake only a modest effect of omega-3 fatty acids on platelet function was seen, that being primarily an enhancement of the effects of the fibrinolytic drug. Another possible consequence of ischemia is arrhythmia, when the heart fails to maintain its normal rhythmic beating. The effects of fish oils on arrhythmia in monkeys are discussed in response to comment 39 of this document. Similarly, data have been reported for experimental ischemia in rats that show that both fish oil and sunflower oil reduced the occurrence of arrhythmia during occlusion and reperfusion compared to a saturated fat diet (Ref. 246). Another study, done on isolated, cultured rat heart cells (myocytes) showed that EPA, but not AA, prevented a known toxin (ouabain) from disturbing the rhythmic contractions and killing the cells (Ref. 212). The effective amount of EPA was so low that the mode of action was proposed to be due to produ suggests a specific effect of EPA in stabilizing the heart myocytes during stress. Prevention of arrhythmia by stabilization of these heart cells has been proposed as a mechanism by which omega-3 fatty acids may increase the chances of survival following a heart attack as reported in the Dart study (Ref. 16). These studies indicate that, in various animal models, dietary fish oils promote greater reestablishment of blood flow in heart tissues following a transient block, as occurs in an acute heart attack. Importantly, the results are consistent across many animal species, and in some cases have been shown to be specific for omega-3 fatty acids rather than simply due to any PUFA. Finally, the experimental designs included coronary occlusions in otherwise healthy animals who were not suffering from heartdisease, a model relevant for use of omega-3 fatty acids in reducing the risk of CHD rather than in therapy for persons with preexisting heart disease. The studies remain limited in that ischemia was produced by an acute blockage produced by mechanical or electrical means rather than by chronic dietary means, and the response to these different types of block may not be the same. Other studies have attempted to learn the mechanism by which the platelet-vessel wall interactions are modified by omega-3 fatty acids. One study (Ref. 240) found that aortas from rats fed fish oil or corn oil did not contract as much in response toagents that cause contraction as aortas from rats fed beef tallow (saturated fat). This was true both before and after oxygen deprivation. The aortas from fish oil-fed rats were more responsive to one of three tested chemical relaxers than aortas from corn oil-fed or beef tallow-fed rats. Another study found that EPA potentiated the release of an EDRF (Ref. 181), but the effect was thought to be related to the unsaturation of the EPA, because the experiments were carried out in the presence of inhibitors of EPA metabolism. One research group has recently shown that leukotrienes, chemicals produced from AA, are important in the tissue injury that accompanies reperfusion (Refs. 230 and 232). Since EPA competes with AA for the enzyme that makes leukotrienes from AA, EPA could potentially reduce the amount of leukotriene formed from AA. This same group has shown that leukotrienes promote the adhesion of leukocytes to the vessel wall (Ref. 231), and that feeding hamsters fish oil at 5 percent of the diet for 4 weeks greatly reduced (over 60 percent) the adhesion of leukocytes to the vessel wall (Ref. 233). The reduced adhesion could be relevant for both the conditions during which atherosclerosis develops (indeed, the stimulus used to elicit leukocyte adhesion was oxidized LDL, a candidate for promoting atherosclerosis in humans), and the acute response to coronary ischemia. These animal data suggest mechanisms by which omega-3 fatty acids could affect the development of atherosclerosis or the response of heart tissue after a transient occlusion of its blood flow. Both modes of action could make important contributions to the risk of CHD and, therefore, merit additional study. The reperfusion studies and the myocyte toxicity study have demonstrated specificity of the effect as to omega-3 fatty acids. However, the increase in reperfusion volume is not sufficient to ensure a reduced risk of CHD death. Omega-3 fatty acids may not affect the extent of tissue damaged during an occlusion, or the tendency for a second, spontaneous occlusion. Additionally, omega-3 fatty acids may not affect tissue vulnerability during reperfusion. Those studies where CHD deaths or second occlusions have been recorded used large amounts of fish oils, and do not indicate whether amounts of omega-3 fatty acids found in the diet would have the same effects. Thus, there are many possible avenues suom these data about the importance of omega-3 fatty acids in reducing the risk of human CHD. b. Safety concerns i. Diabetes Three additional papers (Refs. 170, 222, and 304) and one major review (Ref. 238) on the effects of fish oils in diabetics were published after the time period reviewed in the proposal. All three new studies found increased LDL cholesterol after fish oil consumption in type II diabetics. However, effects on fasting glucose varied, with no change (Ref. 170), a transient increase (Ref. 222) or an increase (Ref. 304) reported. Although fasting insulin concentration was unchanged after fish oil (Refs. 170 and 304), postprandial insulin response usually, but not always (Ref. 170), has been reported as reduced (Refs. 238 and 304). These effects of fish oils on blood glucose appear to depend on the amount of fish oils fed. One study found no change in fasting blood glucose levels among type II diabetics treated with 3.0 g/day EPA plus DHA for 2 weeks (Ref. 170). Two other studies that used 3 or 2.7 g/day EPA plus DHA for 6 and 8 weeks (Refs. 222 and 79) only found transient increases in blood glucose halfway through their respective supplementation periods. A fifth study (Ref. 12) that used 3.0 g/day EPA plus DHA for 3 weeks found comparable increases in fasting blood glucose when either fish oil or safflower oil was fed, so the increase cannot be attributed specifically to the omega-3 fatty acids. Similarly, Vessby and Boberg (Ref. 157) fed 3 g/day EPA plus DHA and did not find a difference in fasting glucose or glycosylated hemoglobin after fish oil supplementation compared to baseline; they did find a significant difference compared to the olive oil treatment that produced changes in the opposite direction from fish oil.Studies on type II diabetics that reported increased glucose used higher amounts (4.5 to 8 g/day) of omega-3 fatty acids (Refs. 52, 55, 128, and 304). Thus, FDA concludes that glycemic control among diabetics remains a valid safety concern, but notes that restriction of the amount of supplemental omega-3 fatty acids may suitably address this concern. ii. Increase in LDL cholesterol Many studies published after 1987 with data for LDL or apoB report increased LDL cholesterol or apoB after fish oils, in hypercholesterolemic or hypertriglyceridemic subjects (Refs. 1, 26, 32, 55, 60, 61, 63, 73, 75, 94, 114, 119, 120, 129, 146, and166). Virtually all the studies with 10 or more subjects supplemented with 5 g/day EPA plus DHA or more found increased LDL. Some studies on normal subjects (all of which were reviewed in the proposed rule) also report increased LDL or apoB after fish oil consumption (Refs. 54, 127, and 156). Many studies that found no effect may not have had sufficient sample size to detect a difference due to treatment. FDA concludes that increased LDL cholesterol among some populations already at increased risk of CHD remains a valid safety concern, but because most reports of increased LDL are in studies where large amounts of fish oils are given, it is possible that restriction of the amount of supplemental omega-3 fatty acids and/or changes in the fatty acid composition of omega-3 fatty acid supplements may suitably address this concern. III. Overall Summary and Conclusions FDA concludes that there is some evidence that supports a relationship between omega-3 fatty acids and CHD, but that the totality of scientific evidence available at this time does not provide an adequate basis for a health claim. In some cases, there is not significant scientific agreement that the changes that are specific to omega-3 fatty acids will reduce the risk of CHD. In other cases, the data do not demonstrate that the effect is specifically due to the omega-3 fatty acids and not due to other dietary variables. For yet other cases, the data are ambiguous because effects of omega-3 fatty acids are not consistently observed, which suggests that other variables are important in determining whether or not an effect is seen. Therefore, the agenc consider the evidence sufficiently strong to draw a firm conclusion about the relationship between omega-3 fatty acids and risk of CHD, and therefore is not authorizing the claim at this time. In the course of developing this regulation, FDA has identified some areas where greater agreement is needed that the effects produced by omega-3 fatty acids are directly related to the risk of CHD. Many surrogate markers have been hypothesized, on the basis of limited evidence, to be related to specific diseases, including CHD, but few have withstood the continued scrutiny of scientific investigation. Also, some markers may have scientific validity, but may not be applicable for use in the generalpopulation, because of technical limitations. Thus, FDA asserts that only when a surrogate marker for a disease has been accepted as a risk factor for the general population, as indicated by a statement by an unbiased, nationally representative authoritative scientific or medical body, can the agency authorize a health claim based on the relationship of a nutrient to the surrogate marker of the disease. Examples of potential surrogate measures for which validation is needed are in vitro platelet aggregation, in vitro platelet adhesion, elevated fasting triglycerides postprandial triglycerides (recently considered at the NHLBI consensus development conference, Ref. 255), and subfractions of LDL and/or HDL. In some cases additional research is needed to determine whether hypothesized subpopulations, e.g., those with high LDL:HDL ratio and high triglycerides, are at increased risk of disease. The pronounced triglyceride lowering effects of omega-3 fattyacids might well have a protective effect against CHD in such a subpopulation. There are other areas where additional research is needed to show, for agreed endpoints, that the effects are consistently produced, or are specifically due to omega-3 fatty acids. These areas require additional data to establish that the effect of omega-3 fatty acids is specific, or to further define the conditions under which omega-3 fatty acids have their effects. For example, data are needed to show a reduction in MI or CHD mortality among individuals fed supplemental omega-3 fatty acids (specifically) compared to a group fed omega-6 PUFA's. The critical failing of some recent studies associating omega-3 fatty acids and CHD is that specificity was not obtained. Future studies should carefully control for known confounders, particularly dietaryvariables. Finally, the available data suggest that some set of conditions or population may exist for which omega-3 fatty acids will increase HDL. Additional research should be able to define the conditions under which omega-3 fatty acids have this effect. Interested parties may choose to petition the agency for approval of other health claims about omega-3 fatty acids. For example, additional data may be developed to support an omega-3 fatty acids/hypertension health claim petition. Because the bloodpressure-lowering effect of omega-3 fatty acids appears most marked against a background of very low dietary intakes of omega-3 fatty acids, the role of omega-3 fatty acids in the total diet would need clarification before such a petition could be adequately supported. Similarly, limitations of the effects of omega-3 fatty acids on the magnitude and duration of change in blood pressure, the quantitative amounts of omega-3 fatty acids required for the effects, and characterization of the sensitive subpopulation would require discussion in a petition. A petition should also address apparent conflicting pieces of information, e.g., high blood pressure among populations that have high intakes of omega-3 fatty acids. Safety concerns raised in this final rule will, of course, require resolution prior to the authorization of any petitioned claim. IV. Decision Not to Authorize a Health Claim Relating Ingestion of Omega-3 Fatty Acids to Reduced Risk of CHD In evaluating the scientific evidence, FDA considered: (1) The strength of the association of omega-3 fatty acids with CHD or surrogate markers for CHD, (2) the consistency of findings among the many studies, (3) the specificity of the outcome to omega-3 fatty acids, (4) the presence or absence of a dose-response relationship, and (5) the biologic plausibility of an association. FDA has determined that there is inadequate evidence to show that increased consumption of omega-3 fatty acids will reduce the risk of CHD. FDA sought to determine whether there was significant scientific agreement among qualified experts that the totality of publicly available scientific evidence supported the claim that omega-3 fatty acids reduce the risk of heart disease. FDA reviewed the position taken in numerous Federal Government reports and other authoritative scientific reports and evaluated the publicly available scientific evidence that has become available since those reports were written. The decision to deny a health claim is based on the conclusions reached following review of the following sources of information: (1) ``The Surgeon General's Report on Nutrition and Health;'' (2) the National Research Council's ``Diet and Health: Implications for Reducing Chronic DiseaseRisk,'' and (3) the National Cholesterol Education Program's Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults. Each of these reports concluded that there was inadequate evidence of a relationship between consumption of omega-3 fatty acids and CHD. FDA has reviewed again all of the relevant cross-sectional data from which the hypothesized relationship between omega-3 fatty acids and CHD originated, and all clinical intervention data published since these Federal Government and other authoritative reports were issued to determine whether the additional evidence is adequate to support a health claim for omega-3 fatty acids. The LSRO report reached a different conclusion from the other authoritative reports by finding a relationship between omega-3 fatty acids and CHD. The report used only selected evidence, and often did not distinguish effects specifically due to omega-3 fatty acids from effects due to PUFA's in general. The description of international epidemiologic findings of a relationship between fish consumption and CHD, similarly, was not shown to be specific to omega-3 fatty acids. In some instances, FDA disagreed with the interpretation of the studies reviewed by LSRO, or with LSRO's conclusions. Finally, the LSRO report also based its conclusions about the usefulness of omega-3 fatty acids, in part, on changes in blood lipid parameters that are not generally agreed to be risk factors for CHD. Therefore, FDA finds numerous reasons for not accepting all of the findings of the LSRO report. FDA's conclusions regarding the relationship between omega-3 fatty acids and CHD rely instead on FDA's independent review of the publicly available scientific information, and are consistent with the Federal Government and other comprehensive and authoritative reports except for the LSRO report. The surveys, cross-sectional studies, and nonintervention prospective studies do not provide adequate support for a relationship between consumption of omega-3 fatty acids and CHD. Only a few studies found an association between fish intake and CHD,while others have found no association; thus, there was no consistency of findings. None of the studies that reported a relationship distinguished fish consumption from other factors associated with fish consumption, and therefore none demonstrates specificity. Even in those studies that reported a relationship between fish consumption and CHD, it is not clear that the observed effects were due to the omega-3 fatty acids in fish. Also, the omega-3 fatty acid content of the fish diet associated with reduced CHD in these studies was so low that the importance of omega-3 fatty acids is questionable, thus weakening the biologic plausibility of the relationship. The data from intervention studies also do not establish a relationship between omega-3 fatty acids and risk of CHD. The most compelling type of evidence to support a diet-disease relationship is a prospective, double-blind, placebo-controlled intervention study, with CHD morbidity and mortality as endpoints. To date, there is only one such trial (Ref. 16). The results of that study showed that increased consumption of fish does not reduce the risk of a second heart attack but may reduce the risk that the attack will be fatal. This study provides evidence for a protective effect of fish consumption against second heart attacks. However, as with the nonintervention study data, this study did not provide evidence to attribute the benefit to omega-3 fatty acid intake rather than some other factor associated with fish consumption (specificity). Less persuasive than prospective studies in which CHD per se is measured, but still very useful, are prospective clinical trials in which surrogate markers for CHD are measured. Recent studies have not found beneficial effects from omega-3 fatty acids on total cholesterol or LDL cholesterol in normal, healthy persons, or among persons at risk for CHD. Numerous studies, including some large or multicenter studies, have reported these results, demonstrating consistency in the findings and providing the agency confidence that they were not spurious. The data on HDL cholesterol are ambiguous. There appear to be other factors in the dietary interventions besides the omega-3 fatty acids that determine whether or not supplementation with fish or fish oils raises HDL. An increase in bleeding times and a decrease in platelet aggregation have been observed frequently, but not always, after supplemental omega-3 fatty acids in normal healthy individuals as well as in diseased persons. Additionally, there is evidence that platelet adhesion is reduced by omega-3 fatty acids. The effects of decreased platelet aggregation and platelet adhesion appear to be related to the intake of omega-3 fatty acids in a dose-response relationship. What has not been established, however, is that in vitro platelet aggregation or platelet adhesion are bona fide surrogate risk factors for CHD in the general population. Omega-3 fatty acids have been shown to reduce blood pressure in hypertensive people to a small degree, which may bear on a relationship between omega-3 fatty acids and CHD. This effect was not of large magnitude, but it is specific to omega-3 fatty acids, it has been reported by a number of investigators, a dose response was found, and the effect is biologically plausible through at least two mechanisms. However, it has not been established that omega-3 fatty acids reduce blood pressure in normal subjects (lack of consistency, weak effect, absence of dose-response relationship). Additionally, it has not been demonstrated that the magnitude and duration of changes in blood pressure observed in short-term studies will persist during long-term consumption of omega-3 fatty acids, or that these changes result in a reduced risk of CHD. Finally, the potential that omega-3 fatty acids may increase LDL cholesterol and/or apoB among diabetics and hyperlipidemics, and the potential that omega-3 fatty acids may worsen control of blood glucose in diabetics are significant safety concernsthat must be addressed before a claim may be made that consumption of omega-3 fatty acids by the general population will reduce the risk of CHD. In conclusion, there are numerous effects of omega-3 fatty acids that may be related to the risk of CHD, e.g., reduction in fasting and postprandial triglycerides, reductions in platelet aggregation and adhesion, changes in the composition of lipoproteins. However, at this time these endpoints are not generally agreed to be closely related to the risk of CHD. In other areas, additional data are needed to show that effects related to fish consumption are specifically due to the omega-3 fatty acids intion for a health claim relating omega-3 fatty acids to the risk of CHD. V. Environmental Impact The agency has determined under 21 CFR 25.24(a)(11) that this action is of a type that does not individually or cumulatively have a significant effect on the human environment. Therefore, neither an environmental assessment nor an environmental impact statement is required. VI. Economic Impact In its food labeling proposals of November 27, 1991 (56 FR 60366 et seq.), FDA stated that the food labeling reform initiative, taken as a whole, would have associated costs in excess of the $100 million threshold that defines a major rule. Thus, inaccordance with Executive Order 12291 and the Regulatory Flexibility Act (Pub. L. 96 - 354), FDA developed one comprehensive regulatory impact analysis (RIA) that presented the costs and benefits of all of the food labeling provisions taken together. That RIA was published in the Federal Register of November 27, 1991 (56 FR 60856), and along with the food labeling proposals, the agency requested comments on the RIA. FDA has evaluated more than 300 comments that it received in response to the November 1991 RIA. FDA's discussion of these comments is contained in the agency's final RIA published elsewhere in this issue of the Federal Register. In addition, FDA will prepare a final regulatory flexibility analysis (RFA) subsequent to the publication of the food labeling final rules. The final RFA will be placed on file with the Dockets Management Branch (HFA - 305), Food and Drug Administration, rm. 1 - 23, 12420 Parklawn Dr., Rockville, MD 20857, and a notice will be published in the Federal Register announcing its availability. In the final RIA, FDA has concluded, based on its review of available data and comments, that the overall food labeling reform initiative constitutes a major rule as defined by Executive Order 12291. Further, the agency has concluded that although the costs of complying with the new food labeling requirements are substantial, such costs are outweighed by the public health benefits that will be realized through the use of improved nutrition information provided by food labeling. VII. References The following references have been placed on display in the Dockets Management Branch (address above) and may be seen by interested persons between 9 a.m. and 4 p.m., Monday through Friday. 1. Abbey, M., P. Clifton, M. Kestin, B. Belling., P. Nestel, ``Effect of Fish Oil on Lipoproteins, Lecithin: Cholesterol, Acyltransferase, and Lipid Transfer Protein Activity in Humans,'' Arteriosclerosis, 10:85 - 94, 1990. 2. Agren, J. J., O. Hanninen, A. Hanninen, K. Seppanen, ``Dose Responses in Platelet Fatty Acid Composition, Aggregation, and Prostanoid Metabolism During Moderate Freshwater Fish Diet,'' Thrombosis Research, 57:231 - 28, 1990. 3. Al-Mahtaseb, N., N. Hayat, M. Al-Khafaji, ``Lipoproteins and Apolipoproteins in Young Male Survivors of Myocardial Infarction,'' Atherosclerosis, 77:131 - 138, 1989. 4. Austin, M. A., ``Plasma Triglyceride and Coronary Heart Disease,'' Arteriosclerosis and Thrombosis, 11:1 - 14, 1991. 5. Azar, R., F. Dequiedt, J. Awada, P. Dequiedt, A. Tacquet, ``Effects of Fish Oil Rich in Polyunsaturated Fatty Acids on Hyperlipidemia of Hemodialysis Patients,'' Kidney International, 36:26 - 27, 1989. 6. Bach, R., U. Schmidt, F. Jung,H. Kiesewetter, ``Effects of Fish Oil Capsules in Two Dosages on Blood Pressure, PlateletFunctions, Haemorrheological, and Clinical Chemistry Parameters in Apparently Healthy Subjects,'' Annals Nutrition Metabolism, 33:359 - 367, 1989. 7. Bagdade, J. D., W. E. Buchanan, R. A. Levy, P. A. 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The authority citation for 21 CFR part 101 continues to read as follows: Authority: Secs. 4, 5, 6 of the Fair Packaging and Labeling Act (15 U.S.C. 1453, 1454, 1455); secs. 201, 301, 402, 403, 409, 701 of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 321, 331, 342, 343, 348, 371). 2. Section 101.71 is amended by adding new paragraph (f) to read as follows: 101.71 Health claims: claims not authorized. * * * * * (f) Omega-3 fatty acids and coronary heart disease. Dated: October 30, 1992. David A. Kessler, Commissioner of Food and Drugs. Louis W. Sullivan, Secretary of Health and Human Services. Note: The following tables will not appear in the annual Code of Federal Regulations. BILLING CODE 4160 - 01 - F [FR Doc. 92 - 31518 Filed 12 - 28 - 92; 8:45 am] BILLING CODE 4160 - 01 - C