Connie Crawley, MS, RD, LD Over the past decade, several studies have indicated that supplementing the diets of women with folic acid significantly reduces their risk for having babies with neural tube defects. The original studies only supplemented the diets of women who had already had a baby with spina bifida (incomplete or improper closing of the spinal cord) or anencephaly (incomplete development of the brain and skull). Later studies supplemented women with no previous history of children with neural tube defects. The questions have been how much folic acid is needed, when is it needed and whether foods eaten by the general public should be fortified. Neural tube defects are more common in certain parts of the country. The highest incidence is in the Appalachian region but they are also common in the Northeast and along the Atlantic seaboard. Researchers hypothesize that some women have a genetic defect that does not allow them to absorb or metabolize folic acid normally. Higher doses of the vitamin seem to overcome the defect. Early studies done in Atlanta and England found a reduction in risk of 30-70 percent when a women took supplements with folic acid before pregnancy and during the first two to three months after conception. A large British prospective study used a daily supplement of 4 milligrams. This amount is ten times higher than the current Recommended Dietary Allowance (R.D.A.). Experts in the United States were concerned about the long term effects of taking such a high dose of folate since some women might continue the supplement even between pregnancies. A recent study done in the eastern part of the United States and Canada found that only 0.4 milligrams or 400 micrograms was sufficient to reduce risk by 60 percent. This is good news since 400 micrograms is the amount most commonly used in over-the-counter multivitamin preparation and is the current R.D.A. for folate. This study also found that a high dietary intake was protective. Foods high in folic acid include liver, green leafy vegetables, legumes, wheat germ, egg yolks, beets, whole wheat bread, fortified breakfast cereals and citrus fruits. Unfortunately folic acid is easily destroyed by poor storage, improper processing or extended heating. Even in the raw product, folic acid content varies a great deal. Many pregnant women have low folate stores. This is due to poor intake, poor absorption often due to alcohol abuse, and increased need due to cigarette smoking, previous oral contraceptive use and pregnancy. While low levels frequently are associated with low socio- economic status, folate levels do not always increase with income especially in women who are chronic dieters. The Food and Drug Administration does allow foods and nutrition supplements that are good sources of folic acid to claim that folic acid in the diet may reduce risk for neural tube defects. The main concern about allowing a health claim for folate has been that high doses of folic acid can correct the megaloblastic anemia associated with B12 deficiency while allowing the neurologic damage to continue. There is also potential risk for people on medications that interfere with folate metabolism and concern about the possible interactions of high doses of folate and other nutrients like zinc. There is even uncertainty about any possible negative effects of high levels of folate on the embryo during gestation since folate is so important in DNA replication. Because of these concerns, claims on the label about folate will have to state that "folate consumption should be limited to 1,000 micrograms per day from all sources." Even though supplementation for pregnant women seems warranted, increasing folic acid intake for the general population is controversial and may in some cases even be harmful.
2. Intake through food or supplements of 400 micrograms of folate per day is enough. 3. Foods high in folate are liver, green leafy vegetables, legumes, wheat germ, egg yolks, beets, whole wheat bread, fortified breakfast cereals and citrus fruits. 4. Vitamin supplements that contain at least 40 micrograms of folate may have a health claim on their labels about folate and neural tube defects. 5. Folate intakes under 1000 micrograms per day are considered safe.
Sources: 1) Weler, M. et al. Periconceptional folic acid exposure and risk of occurrent neural tube defects. JAMA Vol. 269, No. 10: 1257-1261. 2) Wagner, W.E and Levine, B. Folic Acid and Neural Tube Defects. Monograph, Nutrition Information Center, Vol 3, No. 1, January, 1993. 3) Hotline: folic and neural tube defects. Nutrition Perspectives, September/October, 1991. 4) E-mail transmission on folic acid and neural tube defects from Jan Singleton, Mon. Jan. 31, 1994. 5) Federal Register, January 4, 1994: 433-437. The Cooperative Extension Service, The University of Georgia College of Agriculture offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or handicap status. AN EQUAL OPPORTUNITY EMPLOYER Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agriculture and the U.S. Department of Agriculture cooperating. Gail A. Buchanan, Dean and Director
Document use: Permission is granted to reproduce these materials in whole or in part for educational purposes only (not for profit beyond the cost of reproduction) provided that the author and the University of Georgia receive acknowledgement and the notice is included:
Reprinted with permission from the University of Georgia. Available from: In Georgia: Contact your local County Extension Office. Out of state: Distribution Center Cooperative Extension Service University of Georgia 305 Riverbend Road Athens, GA 30602 Fax: (706) 542-2162 Phone: (706) 542-8946 Email: eruark@arches.uga.edu Content Person Contact: Connie Crawley, MS, RD, LD ccrawley@uga.edu Copyright Permission: (706) 542-4860 Document Review: level 2: Department Peer Review Document Size: 7k Publication Date: 1994-01-01 Entry Date: 1997-07-01 Pull Date: 1999-07-01 Pub #: FDNS-E-14
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