Benefits and concerns regarding folic-acid fortification.

Folate, or its pharmaceutical form folic acid, is essential in amino acid metabolism and for the synthesis of DNA and RNA. Many fruits and vegetables, but also milk, bread and meat, are rich sources of dietary folates. The beneficial effect of folic-acid supplements on the prevalence of neural tube defects is well known. It is presumed that folic acid supplements also exert beneficial effects on the prevalence of other birth defects, cardiovascular disease, neuropsychiatric disease and cancer. A concern regarding folic acid supplementation is the masking of vitamin B12 deficiency, although this occurs only at high dosages. Other concerns might be an increased risk of progression of already existing, but still undiagnosed, cancer and, very unlikely, an increased risk of spontaneous abortions. There is, however, no evidence for these effects. Although consumption of folate-rich food increases blood folate levels, this increase remains insufficient, particularly for the prevention of neural tube defects. Much effort is made to stimulate women planning a pregnancy to take folic acid supplements, but most women still refrain from following this advice. By fortification of staple food with folic acid, analogous to the USA, Canada and some other countries, many birth defects can be prevented, while also the risk of cardiovascular disease may be favorably affected.