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United States Department of Agriculture

Agricultural Research Service

Folic Acid Helps Fight Disease
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By Eric Uthus

About a year ago I wrote on how the intake of folate relates inversely to the production in your body of homocysteine, a compound associated with increased risk of heart disease and cancer. Although folate is important in fighting such diseases, it is most commonly associated with preventing neural tube defects in newborns. In fact, in 1998 it became law to fortify cereal-grain products with folic acid (the synthetic version of folate) in hopes of decreasing the risk that women will have children with neural tube defects. Also at that time, the Institute of Medicine recommended that women capable of becoming pregnant consume enough folate through supplements, fortified foods, or both in addition to consuming food folate to achieve the recommended daily allowance of 400 micrograms.

A recent study, published in the American Journal of Clinical Nutrition, reports on the effectiveness of this mandatory fortification and the recommendation of the Institute of Medicine. The authors reported that the prevalence of low serum folate concentrations decreased from 16% before, to 0.5% after, fortification; folate is a form of folic acid in your body. In elderly, who tend to have poorer nutrition habits, the prevalence of high serum folate increased from 7% before, to 38% after, fortification. The authors conclude that every segment of the U.S. population appears to benefit from the folic acid fortification. Other studies have shown that folic acid fortification has resulted in an approximate 15-50% reduction in the prevalence of neural tube defects in the U.S., Canada and Western Australia thus fulfilling the main goal of fortification.

Besides reducing the risk of neural tube defects, heart disease, and some cancers, there are other benefits of folic acid. A recently published study suggests the intakes of folic acid at or above the recommended daily allowance by older adults significantly reduces the risk of developing Alzheimer's disease. In this study, part of the Baltimore Longitudinal Study of Aging, 579 men and women aged 60 and over were followed for up to 14 years. The authors carefully studied the diets of these volunteers and found that a high dietary intake of folic acid was significantly linked to lower rates of the disease. The authors note, however, that it is possible that other dietary factors could play a role in reduction of risk because people with high intakes of one nutrient generally have higher intakes of other nutrients. Furthermore, they may have healthier lifestyles. For example, smoking is associated with reduced concentrations of serum folate. Also, it is known that patients with Alzheimer's disease, who are smokers, have serum levels of folate that are known to be associated with increased risk for vascular brain damage and impaired cognitive function.

Although there is considerable evidence suggesting that high intakes of folic acid are beneficial, there is concern. While folic acid is almost free of toxicity, high intakes can mask symptoms of vitamin B12 deficiency, especially in the elderly. Thus, the best advice is to eat well balanced meals that contain plenty of fruits and vegetables (green leafy vegetables, dry beans and peas, and fortified cereals and grain products are good sources of folic acid). This diet will ensure that you receive the nutrients you need. Not smoking, a good diet, and regular exercise, is the best advice to offer and the best advice to follow.

For further information see the National Council on Folic Acid at

A personalized nutrient intake assessment, which includes a folate-intake audit, is available free from USDA. Log on to and key-in the foods you've eaten in a day, preferably for at least two or more days, up to a year's worth. This will generate your daily folate intake amount ingested from dietary food, and compare that with your recommended or acceptable range based on height, weight, sex, and age.

Last Modified: 10/23/2006
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