The risk of hyperhomocysteinemia in subjects with the TT genotype of MTHFR C677T was successfully corrected by taking 400 μg/day of folate (Hiraoka et al. 2004), which is identical to the FAO/WHO and US recommended dietary allowance (RDA) of folate (Joint FAO/WHO Expert Consultation on Human Vitamin and Mineral Requirements 1998). This evidence concerns the gene MTHFR and hyperhomocysteinemia.