Methylenetetrahydrofolate reductase mutation (677C-->T) negatively influences plasma homocysteine response to marginal folate intake in elderly women.

Individuals who are homozygous for the methylenetetrahydrofolate reductase (MTHFR) 677C --> T mutation have depressed serum folate (SF) and elevated plasma total homocysteine (tHcy) concentrations, which may affect folate requirements and increase the risk for coronary artery disease. A controlled metabolic study (14 weeks) using a depletion/repletion protocol was performed in women (aged 60 to 85 years, N = 33) to provide age-specific data on the effects of the MTHFR mutation on SF and tHcy status. Subjects consumed a moderately folate-deplete diet (118 microg/d) for 7 weeks, followed by 7 weeks of folate repletion with 200 or 415 microg/d provided as two different treatments.

Folate status of elderly women following moderate folate depletion responds only to a higher folate intake.

Dietary Reference Intakes (DRI) for folate for elderly women have been based primarily on data extrapolated from studies in younger women. This study was conducted to provide the first age-specific data in elderly women (60-85 y) from a controlled metabolic study on which to base folate intake recommendations. Subjects (n = 33) consumed a moderately folate-deplete (118 microg/d) diet for 7 wk, followed by repletion diets providing either 200 or 415 microg folate/d as diet plus folic acid (FA) or a combination of FA and orange juice (OJ) for 7 wk (n = 30).