Folate is an essential B vitamin found naturally in a variety of foods such as leafy vegetables, citrus fruits, liver, and lentils. There are many forms of folate, and folic acid is the form used in folate supplements and food fortification. Folate is involved in many reactions requiring the transfer of 1-carbon units, being essential for both DNA and RNA synthesis. Although folate was first demonstrated to be important for human health more than 70 years ago, only recently have health professionals begun to understand the full range of its physiological functions. For example, several controlled clinical trials have shown that increased consumption of folic acid may decrease the risk of neural tube defects. Other observational studies suggest inverse relationships between folate and risk for a variety of chronic diseases such as cancer and cardiovascular disease; controlled clinical trials to confirm these associations, however, are either in process or have tended not to support a simple cause-and-effect relationship. Assessment of folate status can involve both biochemical and dietary data, and it is important that clinicians understand the appropriate uses and limitations of these assessment tools. Because of the potential public health benefit of higher folate intakes on decreasing risk of neural tube defects, the Food and Drug Administration launched a national folic acid food fortification program that became fully effective in 1998. Dietary and biochemical analysis suggests that folate status has increased since the initiation of this program, although there is concern that folate intake now may be too high in some individuals. Still others argue that folate intake remains too low to achieve the original intended effect. Clearly, continued monitoring of this program is warranted. Although much has been learned about folate during the past 80 years, there is still much to ascertain about the mechanisms by which it exerts its numerous effects on human health
The latest news on folic acid from four experts on the topic
Mary Frances Picciano, PhD, is a senior nutrition research scientist at the National Institutes of Health's Office of Dietary Supplements (ODS), where she is involved in overseeing training and career development programs for nutrition and dietary supplement researchers.
Elizabeth A. Yetley, PhD, is a senior nutrition research scientist in the ODS, where her focus is on the development of a research and science-based strategy for the role of dietary supplements in health promotion and disease prevention.
Paul M. Coates, PhD, is the director of the ODS.
Michelle Kay McGuire, PhD, is an associate professor in nutrition at Washington State University, where she teaches a variety of courses and conducts research on nutritional control of lactational amenorrhea and the effect of dietary lipids on human milk composition.
Source of Support: National Institutes of Health's Office of Dietary Supplements.
Corresponding author: Mary Frances Picciano, PhD, Office of Dietary Supplements, National Institutes of Health, 6100 Executive Blvd, 3B01, Bethesda, MD 20892-7517 (PiccianoMF@od.nih.gov).