Dietary Folate in a Changing Environment: Bioavailability, Fortification, and Requirements

Abstract

ABSTRACT: The US and several other countries have instituted mandatory inclusion of folic acid in many enriched cereal grain products, and certain other countries allow optional addition. Nutritional surveys in the US now indicate that folate deficiency is infrequent, and vitamin B12 status is often a primary determinant of plasma homocysteine concentration. Thus, the current situation in the US is markedly different from that of the pre‐fortification era and from countries that do not allow the addition of folic acid to foods. Recent analytical studies have indicated that food composition databases may underestimate naturally occurring folate, although folate intakes calculated from database values have allowed accurate ranking of intakes among population groups in many epidemiological studies. Published analyses of cereal grain foods in the US indicate that added folic acid exceeds intended ranges. Studies comparing folate nutritional status in the US before and after fortification indicate that the fortification program has contributed about 200 micrograms of folic acid to the average person per day. This increment is twice that predicted due, in part, to a greater than anticipated intake as well as the higher bioavailability of folic acid than most naturally occurring forms of food folate. More precise information is needed regarding the actual difference in bioavailability between natural folate and added folic acid.