Dietary folate from vegetables and citrus fruit decreases plasma homocysteine concentrations in humans in a dietary controlled trial

Elevated total plasma homocysteine (tHcy) concentrations are considered a risk factor for neural tube defects (NTD) and cardiovascular disease. Supplementation with folic acid decreases the risk of women having children with NTD. In both sexes, it decreases tHcy levels, We investigated the efficacy of natural dietary folate in improving folate and homocysteine status. We performed a 4-wk dietary controlled, parallel design intervention trial with 66 healthy subjects (18-45 y) divided into 3 treatment groups: the dietary folate group, the folic acid group and the placebo group. Each day each group was fed a different diet. The dietary folate group received a diet high in vegetables and citrus fruit (total folate content similar to 560 mu g) plus a placebo tablet. The folic acid group received a diet naturally low in folate (similar to 210 mu g) plus 500 mu g folic acid and placebo tablet on alternate days, i.e., 250 mu g folic acid/d. And the placebo group received the same low-folate diet as the folic acid group plus a placebo tablet. After 4 wk of intervention, folate status improved, and tHcy concentrations decreased in both the dietary folate and the folio acid groups. From the amount of additional folate (350 mu g/d) and folic acid (250 mu g/d) consumed, the relative bioavailability of dietary folate compared to folio acid was calculated to be 60-98%, depending on the endpoint used. In conclusion, increasing the consumption of vegetables and citrus fruit, both good sources of folate, will improve folate status and decrease tHcy concentrations. This may contribute to the prevention of cardiovascular disease and NTD in the general population.