Nutrients
Serum Folate and Plasma Homocysteine According to MTHFR C677T Genotype and Folic Acid Supplementation in Japanese Women Preparing for Pregnancy: A Cross-Sectional Study
By Koga Fumitoshi, Shogo Nakayama, Shigeki Kitagami and 3 others.
Abstract
Background
Periconceptional folic acid supplementation reduces the risk of neural tube defects. Serum folate primarily reflects recent folate exposure, whereas plasma homocysteine may provide complementary, although non-specific, information on folate-related one-carbon metabolism. We investigated the relationships among serum folate, plasma homocysteine, methylenetetrahydrofolate reductase (MTHFR) C677T genotype, and folic acid supplementation in Japanese women preparing for pregnancy.
Methods
This cross-sectional observational study included 359 Japanese women attending a fertility clinic who underwent MTHFR C677T genotyping and measurement of serum folate and plasma homocysteine. Participants were categorized according to reported supplemental folic acid intake (none, 400 µg/day, or 800 µg/day). Serum folate and plasma homocysteine concentrations were compared across supplementation categories within each genotype. Multivariable logistic regression was used to identify factors associated with plasma homocysteine concentrations ≥ 8.62 µmol/L, which was treated as an exploratory threshold rather than an established clinical cutoff.