2007 Annual Report 1a.Objectives (from AD-416) 1. To determine the impact of mandatory food folic acid fortification in the United States (U.S.). 2 Determine the interrelationships between B vitamin status, methionine intake, genetic polymorphism and plasma homocysteine (tHcy). 3. Determine the hereditary association of plasma homocysteine and vitamin status. 4. Determine the impact of aging on one-carbon metabolism in rats by measuring folate form distribution. 5. Determine the biochemical, pathological and functional impact of nutritional and genetic disruptions of one-carbon metabolism, in animal models of age-related vascular and neurological dysfunction, with emphasis on the roles of B vitamins, homocysteine and methionine in tissue-specific susceptibility to disease. 6. Determine the role of folate receptors in brain function and brain inflammation. 1b.Approach (from AD-416) Determine amount of folic acid in fortified foods using the affinity/HPLC method to modify the food folate tables and to estimate dietary folate equivalents. Use these values to determine folate intake and assess relationships to folate and homocysteine status in the Framingham Study. Relate folate, homocysteine, other B vitamins status, methionine intake and genetic polymorphism in the Framingham Study to the prevalence of age-related impairments such as cardiovascular disease, cognitive dysfunction and dementia. Measure homocysteine and B vitamins in Gen-3 in the Framingham Study and compare data with those in the Offspring Cohort of the Framingham Study to determine heritability of homocysteine and B12 status. Use animal models (mice and rats) which were made vitamin deficient or fed with excess methionine, to raise plasma homocysteine levels to determine effects on vascular system and brain function and assess mechanisms that underlie the association between homocysteine and age related dysfunctions. 4.Accomplishments 1) Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification One of our major area of interest is food folate fortification and its impact on the US population, especially the elderly. One of the major concerns is that increased intake of folic acid due supplement and fortified foods would have adverse effects on those with vitamin B12 deficiency. This concern originated from studies in the early fifties when patients with pernicious anemia caused by vitamin B12 deficiency were mistakenly treated with folic acid. Many of the patients appeared to have aggravated neuropathy which is typical to B12 deficiency. However, because this practice has been discontinued there has been a debate if intake of high doses of folic acid is indeed harmful. We have analyzed the data from the elderly population which participated in the NHANES1999-2002 surveys. These analyses demonstrated that the combination of high plasma folate and low vitamin B12 status is associated with increased prevalence of cognitive impairment and anemia. We estimate that close to 3% of the elderly may be prone to these adverse effects. This accomplishment is aligned with NP107 Human Nutrition Component 4-Nutrient Requirements. 2) The cognitive impact of nutritional homocysteinemia in Apolipoprotein-E deficient mice. Homocysteinemia is associated with a range of cognitive dysfunction in the elderly from subtle cognitive decline to dementia. Homocysteine is generated from methionine as a product of biological methylation reactions and is disposed of through reactions that require folate and vitamins B12 and B6 as cofactors. The relationship between cognitive dysfunction and nutritional imbalances in homocysteine metabolism is uncertain. Homocysteine is toxic in high doses and in vivo evidence suggests that it may potentiate, if not cause, brain damage. We have previously reported that excess dietary methionine can accelerate the atheromatous lesions in the aorta of ApoE-deficient mice, independently of homocysteinemia. We show here that in the same mice, nutritional homocysteinemia induces cognitive deficits independently of aortic pathology. Young ApoE-deficient mice were fed one of four diets with different methionine and B-vitamin contents. B-vitamin deficiency induced homocysteinemia and selectively impaired Morris Water Maze performance without affecting other behavioral measures. The cognitive deficits occurred in the absence of overt neurodegeneration but in association with moderate impairments of brain methylation potential. Furthermore, the diets that yielded cognitive deficits were different from those that exacerbated aortic pathology. These findings are inconsistent with a single overarching mechanism linking homocysteinemia to a broad range of vascular and neurological dysfunctions. Instead, they indicate that different “types” of homocysteinemia, or in other words different impairments of homocysteine metabolism, may lead to different diseases. This accomplishment is aligned with NP107 Human Nutrition Component 6-Prevention of Obesity and Disease: Relationship between Diet, Genetics, and Lifestyle. 5.Significant Activities that Support Special Target Populations None. 6.Technology Transfer Review Publications Wang, T.J., Gona, P., Larson, M.G., Toffler, G.H., Levy, D., Newton-Cheh, C., Jacques, P., Rifai, N., Selhub, J., Robins, S.J., Benjamin, E.J., D'Agostiono, R.B., Vasan, R.S. 2006. Multiple Biomarkers for the Prediction of First Major Cardiovascular Events and Death. New England Journal of Medicine. 355(25): 2631-9. Poo-Prieto, R., Haytowitz, D.B., Holden, J.M., Rogers, G., Choumenkovitch, S.F., Jacques, P.F., Selhub, J. 2006. Use of the affinity/HPLC method for quantitative estimation of folic acid enriched cereal grain products. Journal of Nutrition. 136:3079-3083. Troen, A.M., Shukitt Hale, B., Chao, W., Alburquerque, B., Smith, D.E., Selhub, J., Rosenberg, I. 2006. The cognitive impact of nutritional homocysteinemia in apolipoprotein-E deficient mice. Journal of Alzheimer's Disease. 9(4): 381-92. Troen, A.M., French, E.E., Roberts, J.F., Selhub, J., Ordovas, J.M., Parnell, L.D., Lai, C. 2006. Lifespan modification by glucose and methionine in Drosophila melanogaster fed a chemically defined diet. Age.29:29-39.