Folic Acid Prevents Heart Defects in Babies
Since 1993, the U.S. Public Health Service has advised women who are capable of becoming pregnant to take 0.4 mg of folic acid per day to reduce the risk of having a child with spina bifida or other neural-tube defects. Recent research, as described in Family Practice News (2003;33:10) suggests that supplementing with folic acid during the early weeks of pregnancy may also reduce the probability that a child will have a congenital heart defect.
Congenital heart defects are among the more common birth defects. One group of defects is collectively referred to as conotruncal defects; these include various malformations of the large arteries that exit the heart. Another frequently occurring defect is a ventricular septal defect, in which a hole is present in the wall between the two ventricles, allowing blood to move in the wrong direction, from the left ventricle back into the right ventricle. Some congenital heart defects are tolerated well by the affected individual, whereas others can be fatal if not corrected by open-heart surgery.
In the new study, pregnancy outcomes were assessed in 1,884 women. After adjustment for potentially confounding factors such as maternal age, race, and smoking and alcohol consumption, women who took a daily folic acid supplement during the first six weeks of pregnancy (the period during which the heart develops) were 54% less likely to have a baby with a ventricular septal defect or a conotruncal defect, compared with women who did not take a daily folic acid supplement. The protective effect of folic acid increased with larger daily doses of the vitamin, and it appeared that at least 400 mcg per day of supplemental folic acid was necessary to achieve a reduction in risk. No benefit was associated with starting the supplement after the first six weeks of pregnancy, or with taking folic acid before, but not during, pregnancy.
Good food sources of folic acid include leafy green vegetables, whole grains, folic acid-fortified grains, citrus fruits, and meats. The consumption of folic acid-rich foods, however, does not guarantee that a woman will obtain enough of this nutrient to prevent birth defects. Studies have shown that genetic factors determine in part how the body handles folic acid, and that some women have a higher requirement for this vitamin than others. Other research has demonstrated that some women manufacture antibodies that bind to the folic acid receptors on the placenta, an effect that could prevent the fetus from receiving an adequate supply of folic acid. In one study, these antibodies were present in the blood of 75% of women who had given birth to a child with a neural-tube defect, compared with only 10% of women who had given birth to a normal infant. Presumably, the inhibitory effect of these antibodies on folic acid utilization can be overcome by increasing the amount of the vitamin consumed. Thus, some women appear to have a higher-than-normal requirement for folic acid, and a failure to meet this increased requirement may contribute to the risk of certain birth defects.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
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