Serum folate, total homocysteine levels and methylenetetrahydrofolate reductase 677C>T polymorphism in young healthy female Japanese.

Environmental and genetic factors influence serum total homocysteine (tHcy), a risk factor for vascular diseases. The gene polymorphism of methylenetetrahydrofolate reductase (MTHFR) is reported to be a genetic factor for influencing tHcy. However, it is not clear whether MTHFR polymorphism influences tHcy in the younger generation. To investigate the influence of MTHFR polymorphism on vascular disease risks in young Japanese females, we determined dietary intakes, serum folate and tHcy, and examined the influence of MTHFR 677C>T polymorphism in healthy junior and high school students (n=192, 12-18y). The relationships between MTHFR polymorphism and folate intake, serum folate or tHcy were investigated by dividing participants into CC, CT and TT types. Among individuals with the TT genotype, folate and tHcy levels were significantly lower (p<0.05) or higher (p<0.0001), respectively, than in those with the other genotypes; although there were no significant differences in the intake of folate among genotypes. In addition, a significant inverse correlation between folate and tHcy (p<0.05) was noted in all genotypes, even in young females, so far not examined in Asian populations. Therefore, MTHFR genotypes were proven to be a significant determinant for folate and tHcy concentrations. However, the association of increased folate intake with lower tHcy concentration, even in cases of the mutation TT type, indicates the importance of folate intake in young Japanese females for early detection of risk, as well as the prevention of vascular diseases.