In their recent study of the effects of folic acid on reduction in homocysteine concentrations, Wald et al1 randomized 151 patients with ischemic heart disease to dosages of folic acid of 0.2 to 0.8 mg/d or placebo and measured serum homocysteine levels at baseline, after 3 months of supplementation, and 3 months after folic acid use was discontinued. Median serum homocysteine levels decreased with increasing folic acid dosage to a maximum of 0.8 mg/d of folic acid, at which point a 23% reduction in homocysteine level was observed. Wald et al1 concluded that a dosage of 0.8 mg/d of folic acid was necessary to achieve the maximum reduction in serum homocysteine level. Wald et al further stated that current US food fortification levels (0.14 mg of folic acid/100 g of cereal-grain product) will achieve only a small proportion of the achievable homocysteine-lowering effect and that the higher level of fortification recommended in England (0.24 mg of folic acid/100 g of flour) will likewise have only a partial effect in lowering serum homocysteine levels. Wald et al inappropriately generalize their study results regarding folic acid fortification levels in enriched cereal-grain products to the United States, which warrants our response.
Rader JI, Yetley EA. Nationwide Folate Fortification Has Complex Ramifications and Requires Careful Monitoring Over Time. Arch Intern Med. 2002;162(5):608-609. doi: