Folic acid: are current fortification levels adequate?
Beginning on January 1, 1998, all cereal and grain products in the United States were fortified with folic acid to reduce the occurrence of the very common congenital malformations known as neural-tube defects. Three years have passed since the fortification program began, and it is time to evaluate whether the current fortification levels have met their intended objective. We offer an overview of folate and its potential role in the etiology of neural-tube defects, review some of the highlights of the deliberations that led to the decision by the Food and Drug Administration to fortify the food supply, and offer a perspective on how to measure whether current fortification levels are adequate. There is no national system in the United States that monitors neural-tube and other birth defects over time, and no postmarketing surveillance was mandated to monitor the safety of the fortification program. Therefore, we must evaluate the program in other ways. Blood biomarkers of folate status such as the levels of folate in red blood cells and homocysteine in plasma provided the best evidence of the effectiveness of the folic-acid-fortification program because of their relatively high sensitivities in relation to their specificities as markers of folate status. In addition, these biomarkers might provide information about the risks of other diseases related to folate status such as vascular disease. Federal agencies should coordinate efforts to gather and evaluate markers of folate status at the population level. These measures can be used to evaluate the safety and efficacy of folic-acid fortification and whether changes are warranted in fortification levels.