Verlaging van homocysteïneconcentraties in plasma bij gezonde vrijwilligers door voedingsfolaat uit groenten en fruit en door lage doses synthetisch foliumzuur

To determine the effects of low doses of synthetic folic acid (study 1) and of natural dietary folate (study 2) on folate and homocysteine status in healthy volunteers.

Design

Randomised and blinded placebo-controlled study.

Method

Both studies had a parallel design with a 4-week intervention period. Study 1 investigated the effect of 500 μg of folic acid each day, 500 μg of folic acid every other day, or placebo each day, on homocysteine and folate concentrations in 144 women (age: 18-40 years). Study 2 was a dietary controlled trial with 67 men and women (age: 18-45 years) divided into 3 treatment groups. These groups consumed: (a) dietary folate group: a diet high in vegetables and citrus fruit (total folate content circa 560 μg/day) plus a placebo tablet; (b) folic acid group: a diet naturally low in folate (circa 210 μg/day) plus folic acid (500 μg folic acid and placebo tablet on alternate days, i.e. 250 μg folic acid/day); (c) placebo group: the same low folate diet plus a placebo tablet. Plasma total homocysteine and folate in plasma and red blood cells were measured in fasting blood samples at the start and the end of the study.

Results

Intervention with 500 μg each day and 500 μg every other day decreased homocysteine concentrations by respectively 2.5 μmol/l and 1.3 μmol/l. Homocysteine concentrations in the food folate group decreased by 1.5 μmol/l (95 confidence interval: 2.2-0.8). Folate concentrations increased by intake of folic acid as well as by intake of food folate.

Conclusion

Intake of low doses of synthetic folic acid as well as a high intake of folate from vegetables and citrus fruit for four weeks substantially improved plasma total homocysteine concentrations and the folate status of healthy persons.