Folate Status in Mexican-American Men Is Dependent On Genetics

Previous studies have indicated that individuals with the methylenetetrahydrofolate reductase (MTHFR) 677C to T gene variant might have an insufficient folate status, as the aforementioned enzyme is responsible for converting folic acid to the active form, 5-methyltetrahydrofolate (5MTHF). These individuals therefore have depleted methylation capabilities and elevated serum homocysteine. This study looked at the prevalence of this genetic variance in a Mexican-American population and discussed whether or not their folate needs were being met with the current Recommended Daily Allowance of 400 mcg folate per day. The researchers also examined whether choline supplementation would be an adequate substitute for lowering homocysteine in the absence of adequate folic acid.

With 12-week supplementation of folate (438 mcg/day) and varying levels of choline, (300, 500, 1100, or 2200 mg/d) subjects with the TT homozygous MTHFR 677C to T variant had a decrease in serum folate (SF) of 66% while "wildtype" or CC variant decreased SF by 62%. Consequently, plasma homocysteine increased 170% in the 677TT variant group while the 677CC group increased 18%. This study demonstrated that the current RDA for folate may be inadequate for the Mexican-American population, and in particularly for those with the 677TT gene variant. Choline was proven to not adequately influence folate status makers in the subjects of this study.

Solis C, Veenema K, Ivanov AA, et al. Folate intake at RDA levels is inadequate for Mexican-American men with the methylenetetrahydrofolate reductase 677TT genotype. J Nutr 2008;138:67-72.