PROSPECTS FOR PREVENTION OF NEURAL-TUBE DEFECTS BY VITAMIN SUPPLEMENTATION

Recent studies have resolved the debate over the role of vitamins in p reventing neural tube defects. The British Medical Research Council tr ial demonstrated that 4 mg of folate daily, but not other vitamins, pr evented 72% of recurrences. The Hungarian trial prevented neural tube defects in women who had not previously had affected children by givin g multivitamins containing 0.8 mg of folate. The US Public Health Serv ice currently recommends that women at risk for becoming pregnant take 0.4 mg of folate daily. Unfortunately, most pregnancies are unplanned , and women not planning to become pregnant may not follow this recomm endation. Therefore, the US Food and Drug Administration is exploring methods of food fortification. Because large doses of folate have been reported to ameliorate B-12 deficiency anemia while allowing neurolog ic damage to progress, and to cause electroencephalogram abnormalities in epileptics, it is important to plan fortification carefully and to monitor both toxicity and benefits.