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BackgroundReturn to top

The name "carotene" was first coined in the early 19th Century by the scientist Wachenroder after he crystallized this compound from carrot roots. Beta-carotene is a member of the carotenoids, which are highly pigmented (red, orange, yellow), fat-soluble compounds naturally present in many fruits, grains, oils, and vegetables (green plants, carrots, sweet potatoes, squash, spinach, apricots, and green peppers). Alpha, beta, and gamma carotene are considered provitamins because they can be converted to active vitamin A.

The carotenes possess antioxidant properties. Vitamin A serves several biological functions including involvement in the synthesis of certain glycoproteins. Vitamin A deficiency leads to abnormal bone development, disorders of the reproductive system, xerophthalmia (a drying condition of the cornea of the eye), and ultimately death.

Commercially available beta-carotene is produced synthetically or from palm oil, algae, or fungi. Beta-carotene is converted to retinol, which is essential for vision and is subsequently converted to retinoic acid, which is used for processes involving growth and cell differentiation.

SynonymsReturn to top

A-beta-carotene, alpha carotene, beta carotene, beta-cryptoxanthin, carotene, carotenoids, dry beta carotene, eyebright, gamma carotene, green leafy vegetables, palm oil, provitamin A, red palm oil, sunflower oil, synthetic all-trans beta-carotene, retinol.

EvidenceReturn to top

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidenceGrade*
Erythropoietic protoporphyria

Erythropoietic protoporphyria is a rare inherited genetic disorder of porphyrin-heme metabolism that has skin and systemic manifestations, including photosensitivity (painful skin sensitivity to sunlight), as well as gallstones and liver dysfunction. It is usually recognized during childhood. The over-the-counter synthetic beta-carotene product Lumitene® is U.S. Food and Drug Administration (FDA)-approved for photoprotection in this disease. Antihistamines may also be used to reduce symptoms.
Cataract prevention

Study results of beta-carotene supplementation for cataract prevention are conflicting. Further well-designed clinical trials are needed before a conclusion can be drawn.
Carotenoid deficiency

Although consumption of provitamin A carotenoids (alpha-carotene, beta-carotene, and beta-cryptoxanthin) can prevent vitamin A deficiency, no overt deficiency symptoms have been identified in people consuming low-carotenoid diets if they consume adequate vitamin A. After reviewing the published scientific research, the Food and Nutrition Board of the Institute of Medicine (IOM) concluded that the existing evidence in 2000 was insufficient to establish a recommended dietary allowance (RDA) or adequate intake (AI) for carotenoids.
Chemotherapy toxicity

Observational research suggests that greater dietary intake of beta-carotene may lower the incidence of adverse effects in children undergoing chemotherapy for lymphoblastic leukemia. However, in theory high-dose antioxidants may interfere with the activity of some chemotherapy drugs or radiation therapy. Therefore, individuals undergoing cancer treatment should speak with their oncologist if they are taking or considering the use of high dose antioxidants. Additional evidence is needed in this area before a clear conclusion can be drawn.
Chronic obstructive pulmonary disease (COPD)

The prevalence of bronchitis and shortness of breath in male smokers with chronic obstructive pulmonary disorder (COPD) seems to be lower in those patients who consume a diet containing high amounts of beta-carotene. However, beta-carotene supplements have not been proven to benefit COPD and may actually increase cancer rates in smokers.
Cognitive performance

Antioxidants such as beta-carotene may be helpful for increasing cognition and memory. Long term, but not short-term, beta-carotene supplementation appears to benefit cognition.
Cystic fibrosis

Individuals with cystic fibrosis may be deficient in beta-carotene and vitamin E, and it has been suggested that they may be more susceptible to oxidative damage. Theoretically, these patients may benefit from beta-carotene supplementation. Further research is needed before a conclusion can be drawn.
Exercise-induced asthma prevention

Based on preliminary evidence, taking a mixture of beta-carotene isomers orally may prevent exercise-induced asthma. However, because synthetic beta-carotene has not been well tested for this indication, the difference between the activities of the two supplements cannot be deduced. Further research is needed before a strong recommendation can be made.
Immune system enhancement

Preliminary research of beta-carotene for immune system maintenance or stimulation shows mixed results. Further research is needed before a strong conclusion can be drawn.
Oral leukoplakia

Taking beta-carotene orally seems to induce remission in patients with oral leukoplakia. Further research is needed to confirm these results.

Beta-carotene supplementation does not appear to prevent osteoarthritis, but it might slow progression of the disease. Well-designed clinical trials are needed before a conclusion can be drawn.
Polymorphous light eruption (PLE)

Beta-carotene has been used for PLE. Additional study is needed in this area.
Pregnancy-related complications

All-trans beta-carotene (synthetic beta-carotene) taken weekly before, during, and after pregnancy may reduce pregnancy-related mortality, night blindness, post partum diarrhea and fever. A regular intake of a micronutrient supplement at a nutritional dose may be sufficient to improve micronutrient status of apparently healthy pregnant women and could prevent low birth weight in newborns. However, further research is necessary to consolidate the evidence in this area before a clear recommendation can be made.
UV-induced erythema prevention/sunburn

A combination of antioxidants may help protect the skin against irradiation. Long-term supplementation with beta-carotene may reduce UV-induced erythema, and appears to modestly reduce the risk of sunburn in individuals who are sensitive to sun exposure. However, beta-carotene is unlikely to have much effect on sunburn risk in most people.
Abdominal aortic aneurysm (AAA) prevention

Long-term supplementation with alpha-tocopherol or beta-carotene has been shown not to have a protective or preventive effect in male smokers with large AAAs.
Alzheimer's disease

Intake of dietary or supplemental beta-carotene has been shown not to have any effect on Alzheimer's disease risk.

There is some concern that when antioxidant vitamins, including beta-carotene, are used together they might have harmful effects in patients after angioplasty. Additional research is needed to determine the effect of beta-carotene specifically. Supplements containing these vitamins should be avoided immediately before and following angioplasty without the recommendation of a qualified healthcare professional.
Birthmark/mole (dysplastic nevi) prevention

Beta-carotene has been shown not to reduce the development of new moles in patients with numerous atypical moles.

While diets high in fruits and vegetables rich in beta-carotene have been shown to potentially reduce the incidence of certain cancers, results from randomized controlled trials with oral supplements do not support this claim. There is some concern that beta-carotene metabolites with pharmacological activity can accumulate and potentially have cancer-causing (carcinogenic) effects. A higher, statistically significant incidence of lung cancer in male smokers who took beta-carotene supplements has been discovered. Beta-carotene/vitamin A supplements may have an adverse effect on the incidence of lung cancer and on the risk of death in smokers and asbestos exposed people or in those who ingest significant amounts of alcohol. In addition, high-dose antioxidants theoretically may interfere with the activity of some chemotherapy drugs or radiation therapy. Therefore, individuals undergoing cancer treatment should speak with their oncologist if they are taking or considering the use of high dose antioxidants. Beta-carotene in the amounts normally found in food does not appear to have this adverse effect.
Cardiovascular disease

Although several studies suggest that diets high in fruits and vegetables containing beta-carotene appear to reduce the risk of cardiovascular disease, most randomized controlled trials with oral supplements of beta-carotene have not supported these claims. A Science Advisory from the American Heart Association states that the evidence does not justify the use of antioxidants such as beta-carotene for reducing the risk of cardiovascular disease.
Helicobacter pylori bacteria eradication

Infection with  Helicobacter pylori  bacteria in the gut can lead to gastric ulcers. Dietary supplementation with beta-carotene has not been found to be effective for this indication.
Macular degeneration

Taking beta-carotene and other antioxidants has been proposed to help prevent or delay progression of age-related macular degeneration. However, long-term studies have not shown strong evidence that beta-carotene supplementation can prevent age-related eye disorders.
Mortality reduction

Patients given beta-carotene supplements show no reduction in relative mortality rates from all causes based on most available data.
Postoperative tissue injury prevention

Study results conclude that peri-operative supplementation with antioxidant micronutrients has limited effects on strength and physical function following major elective surgery.

Taking all-trans beta-carotene (synthetic beta-carotene) orally has been reported to have no effect on the overall incidence of stroke in male smokers. Additionally, there is some evidence that beta-carotene actually increases the risk of intracerebral hemorrhage by 62% in patients who also drink alcohol.

*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.

Grading rationale

Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acute respiratory infections, anemia, angina pectoris (chest pain), asbestosis (chronic lung disease), benign breast diseases, bone marrow transplantation, bronchial asthma (exercise-induced bronchoconstriction symptoms in young athletes), bronchopulmonary dysplasia in premature infants, diabetes, gastritis (chronic atrophic), glioblastoma (supratentorial), Graves' disease, high cholesterol, HIV, infections (sepsis), iron deficiency (prevention), leukemia (chronic myeloid), low birth weight (prevention), lung function (improving), nasal polyposis, nutrition supplementation (during alcohol rehabilitation ), Streptococcal infections (group A), weight loss (HIV, post-partum).

DosingReturn to top

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Formulations: Beta-carotene supplements are available in both oil matrix gelatin capsules and water-miscible forms. Some clinical trials have used water-miscible beta-carotene (10%) beadlets. The water miscible form seems to produce a significantly higher response in plasma beta-carotene (approximately 47% to 50%) than oil matrix gelatin capsules. Oral dosage is available in capsules (United States and Canada), tablets (United States and Canada), and chewable tablets (Canada).

Dietary intake: Consuming 5 servings of fruit and vegetables daily provides 6-8 milligrams of beta-carotene. Beta-carotene requires some dietary fat for absorption, but supplemental beta-carotene is similarly absorbed when taken with high-fat or low-fat meals. 1,800 micrograms of beta-carotene has been reported to maintain adequate vitamin A levels.

Consensus recommendations: The American Heart Association recommends obtaining antioxidants, including beta-carotene, from a diet high in fruits, vegetables, and whole grains rather than through supplements, until more information is available from randomized clinical trials. Similar statements have been released by the American Cancer Society, the World Cancer Research Institute in association with the American Institute for Cancer Research, and the World Health Organization's International Agency for Research on Cancer. The Institute of Medicine has reviewed beta-carotene, but has not make recommendations for daily intake, citing lack of sufficient evidence. Routine use of beta-carotene supplements is not considered necessary in the general population.

Adults (18 years and older)
15-180 milligrams taken by mouth of supplemental beta-carotene has been studied for various indications.

Children (younger than 18 years)
There is insufficient available data to recommend high-dose oral (by mouth) supplementation in children.

SafetyReturn to top

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

People who are sensitive to beta-carotene, vitamin A, or any other ingredients in beta-carotene products should avoid supplemental use.

Side Effects and Warnings
Supplemental beta-carotene in children should be limited to specific medical indications. There is insufficient reliable information available about the safety of large doses of beta-carotene in pregnant or breastfeeding women.

Supplemental beta-carotene may increase the risk of lung cancer, prostate cancer, intracerebral hemorrhage, and cardiovascular and total mortality in people who smoke cigarettes or have a history of high-level exposure to asbestos. Beta-carotene from foods does not seem to have this effect.

In people who smoke, beta-carotene may increase cardiovascular mortality. In men who smoke and have had a prior myocardial infarction (MI or heart attack), the risk of fatal coronary heart disease increases by as much as 43% with low doses of beta-carotene. There is some evidence that beta-carotene in combination with selenium, vitamin C, and vitamin E might lower high-density lipoprotein 2 (HDL2) cholesterol levels. HDL levels are protective so this is considered to be a negative effect. Dizziness, reversible yellowing of palms, hands, or soles of feet and to a lesser extent the face (called carotenoderma) can occur with high doses of beta-carotene. Loose stools, diarrhea, unusual bleeding or bruising, and joint pain have been reported.

Pregnancy and Breastfeeding
U.S. Food and Drug Administration (FDA) Pregnancy Risk Factor C.

Insufficient data are available on larger oral doses of beta-carotene in pregnant and breastfeeding woman.

InteractionsReturn to top

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs
Preliminary studies in animals indicate that beta-carotene supplementation, when combined with heavy alcohol consumption, may increase liver toxicity and promote cancer.

Cigarette smoking decreases serum concentrations of beta-carotene and other carotenoids and depletes body stores of beta-carotene. However, oral beta-carotene supplementation should not be recommended in smokers because supplemental beta-carotene in certain doses is associated with a significantly higher risk of lung and prostate cancer in smokers. Smokers and people with a history of asbestos exposure should avoid taking beta-carotene supplements.

Cholestyramine (Questran®) and colestipol (Colestid®) can reduce the absorption of fat-soluble vitamins, including beta-carotene. Serum levels of beta-carotene can be reduced, but this is probably only in proportion to the lowering of cholesterol (on which beta-carotene is transported). Supplements are not usually necessary.

Colchicine can cause disruption of intestinal mucosal function, resulting in malabsorption of beta-carotene.

Taking beta-carotene in combination with selenium, vitamin C, and vitamin E appears to decrease the effectiveness of the combination of simvastatin (Zocor®) and niacin. Theoretically, beta-carotene could reduce the effectiveness of other HMG-CoA reductase inhibitors ("statins") such as atorvastatin (Lipitor®), fluvastatin (Lescol®), lovastatin (Mevacor®), and pravastatin (Pravachol®).

Mineral oil reduces absorption of fat-soluble vitamins, including beta-carotene.

Oral neomycin sulfate can reduce beta-carotene absorption, but short-term use is unlikely to have a significant effect.

Orlistat (Xenical®) can decrease the absorption of beta-carotene and other fat-soluble vitamins. It is recommended that patients take a multivitamin supplement, and separate the dosing time by at least two hours from orlistat.

Loss of stomach acid can reduce the absorption of a single dose of beta-carotene. Examples of proton pump inhibitors (PPIs) include esomeprazole (Nexium®), lansoprazole (Prevacid®), omeprazole (Prilosec®, Losec®), rabeprazole (Aciphex®), and pantoprazole (Protonix®, Pantoloc®).

Interactions with Herbs and Dietary Supplements
Consumption of a natural carotenoid mixture has been shown to lower the increase in oxidative stress induced by the fish oil. This carotenoid mixture may also enhance the plasma triglyceride-lowering effect of the fish oil.

Iron supplementation in infants with marginal vitamin A status has led to lower plasma vitamin A concentrations and greater vitamin A liver stores. Some researchers recommend that iron supplementation in infants should be accompanied by measures to improve vitamin A status.

Beta-carotene supplementation has been shown to lower serum lutein concentrations. Lutein from food sources does not seem to result in the decrease in beta-carotene concentrations that accompanies administration of lutein supplements.

Plant sterols have been shown to reduce beta-carotene bioavailability in some studies and not to have a significant effect in others. The effects on cholesterol levels are also unproven.

Supplementation of beta-carotene may decrease the vitamin E concentration in tissues.

Methodology Return to top

This information is based on a systematic review of scientific literature and consensus statements, peer-reviewed by contributors to the Natural Standard Research Collaboration ( Ethan Basch, MD, MSc, MPhil (Memorial Sloan-Kettering Cancer Center); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Natasha Tiffany, MD (Massachusetts General Hospital); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Christine Ulbricht, BS (University of Massachusetts); Wendy Weissner, BA (Natural Standard Research Collaboration).

Methodology details

Selected references Return to top

  1. Baron JA, Cole BF, Mott L, et al. Neoplastic and antineoplastic effects of beta-carotene on colorectal adenoma recurrence: results of a randomized trial. J Natl Cancer Inst 2003;95(10):717-722.
  2. Christen WG, Manson JE, Glynn RJ, et al. Beta carotene supplementation and age-related maculopathy in a randomized trial of US physicians. Arch Ophthalmol 2007 Mar;125(3):333-9.
  3. Darlington S, Williams G, Neale R, et al. A randomized controlled trial to assess sunscreen application and beta carotene supplementation in the prevention of solar keratoses. Arch Dermatol 2003;139(4):451-455.
  4. Grodstein F, Kang JH, Glynn RJ, et al. A randomized trial of beta carotene supplementation and cognitive function in men: the Physicians' Health Study II. Arch Intern Med 2007 Nov 12;167(20):2184-90.
  5. Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002;360(9326):23-33.
  6. Keefe KA, Schell MJ, Brewer C, et al. A randomized, double blind, Phase III trial using oral beta-carotene supplementation for women with high-grade cervical intraepithelial neoplasia. Cancer Epidemiol Biomarkers Prev 2001;10(10):1029-1035.
  7. Leppala JM, Virtamo J, Fogelholm R, et al. Vitamin E and beta carotene supplementation in high risk for stroke: a subgroup analysis of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Arch Neurol 2000;57(10):1503-1509.
  8. Ncube TN, Greiner T, Malaba LC, et al. Supplementing lactating women with pureed papaya and grated carrots improved vitamin A status in a placebo-controlled trial. J Nutr 2001;131(5):1497-1502.
  9. Rapola JM, Virtamo J, Haukka JK, et al. Effect of vitamin E and beta carotene on the incidence of angina pectoris. A randomized, double-blind, controlled trial. JAMA 1996;275(9):693-698.
  10. Rautalahti M, Virtamo J, Haukka J, et al. The effect of alpha-tocopherol and beta-carotene supplementation on COPD symptoms. Am J Respir Crit Care Med 1997;156(5):1447-1452.
  11. Schaumberg DA, Frieling UM, Rifai N, et al. No effect of beta-carotene supplementation on risk of nonmelanoma skin cancer among men with low baseline plasma beta-carotene. Cancer Epidemiol Biomarkers Prev 2004;13(6):1079-1080.
  12. Todd S, Woodward M, Tunstall-Pedoe H, et al. Dietary antioxidant vitamins and fiber in the etiology of cardiovascular disease and all-causes mortality: results from the Scottish Heart Health Study. Am J Epidemiol 1999;150(10):1073-1080.
  13. Toma S, Bonelli L, Sartoris A, et al. beta-carotene supplementation in patients radically treated for stage I-II head and neck cancer: results of a randomized trial. Oncol Rep 2003;10(6):1895-1901.
  14. Tornwall ME, Virtamo J, Haukka JK, et al. Alpha-tocopherol (vitamin E) and beta-carotene supplementation does not affect the risk for large abdominal aortic aneurysm in a controlled trial. Atherosclerosis 2001;157(1):167-173.
  15. West KP Jr, Katz J, Khatry SK, et al. Double blind, cluster randomised trial of low dose supplementation with vitamin A or beta carotene on mortality related to pregnancy in Nepal. The NNIPS-2 Study Group. BMJ 1999;318(7183):570-575.

February 01, 2008.

Natural Standard Logo This evidence-based monograph was prepared by the Natural Standard Research Collaboration. The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. Talk to your health care provider before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Copyright© 2008 Natural Standard ( All Rights Reserved.