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FOLIC ACID AND THE PREVENTION OF NEURAL TUBE DEFECTS

 WASHINGTON, Dec. 23 /PRNewswire/ -- The Council for Responsible Nutrition issued the following backgrounder:
 Scientific evidence shows that it is possible to reduce the incidence of some birth defects by 60 to 85 percent by the simple means of giving women a nutritional supplement providing the U.S. Recommended Daily Allowance (U.S. RDA) of a B vitamin. The vitamin is folic acid, and the birth defects that can be prevented are "neural tube defects" (NTD) including spina bifida and anencephaly.
 This week, a study in the New England Journal of Medicine (NEJM) adds to the already-impressive data showing this effect. The new study is a report from a nationwide Hungarian family planning program, in which women planning a pregnancy were given multivitamin supplements containing folic acid, or a placebo. There were over 2,000 pregnancies in the vitamin group and over 2,000 in the placebo group. The number of neural tube defects in the offspring were zero in the vitamin group and six in the placebo group. This showed a significant protective effect of the folic acid supplement. The amount of folic acid contained in the Hungarian supplement was 0.8 mg (800 mcg), which is twice the U.S. RDA.
 The authors of the Hungarian study conclude, "Given the results of this study, we think that all women planning pregnancy should receive a vitamin supplement containing folic acid."
 Even before publication of the Hungarian study, similar conclusions were reached by the governments of the United Kingdom and the United States.
 On Dec. 17 of this year, the chief medical officer of the United Kingdom wrote a letter to all doctors in England, Scotland, Wales and Northern Ireland. The letter recommended that, in order to help prevent the occurrence of neural tube defects, "all women planning a pregnancy should consume additional folate/folic acid prior to conception and during the first 12 weeks of pregnancy by eating more folate rich foods including those fortified with folic acid, and by taking a daily dietary supplement of 0.4 milligrams of folic acid." The chief medical officer added the comment, "We are in no doubt that the main recommendations should be introduced without delay."
 In September of this year, the U.S. Public Health Service (PHS) recommended, "All women of child bearing-age in the United States who are capable of becoming pregnant should consume 0.4 mg of folic acid per day for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other NTDs."
 The U.S. Food and Drug Administration has recently convened an advisory committee on folic acid to provide guidance on how best to implement this recommendation. The committee recommended that more foods be fortified with folic acid, and that an educational campaign be undertaken.
 The FDA advisory committee's failure to include a recommendation for supplement use is striking, since virtually all of the evidence for a protective effect is based on a history of supplement use in epidemiological surveys or the provision of a supplement containing folic acid in intervention studies.
 In a September report on the PHS recommendation, the Centers for Disease Control reviewed the available data. There were at the time four published intervention trials, in which folic acid supplements were provided at doses ranging from 0.36 mg (approximately the U.S. RDA) to 4 mg (10 times the U.S. RDA). The supplements reduced the incidence of neural tube defects by 60 to 86 percent, compared to the incidence in unsupplemented women. Also, there were four epidemiological studies. Three of them showed a protective effect of 60 to 75 percent from supplement use. Only one study, conducted in areas of low incidence of NTD, failed to show a protective effect.
 The governments of the United States and the United Kingdom had decided that the weight of the evidence justified a recommendation for increasing folic acid intake, even before publication of the Hungarian results. The new results only strengthen that position. In an editorial accompanying the NEJM article, Dr. Irwin Rosenberg of Tufts University points out some of the public policy issues that must be considered in implementing the U.S. and U.K. recommendations. He recognizes that "we can now prevent some of the serious congenital abnormalities associated with the neural tube," but points out that the minimum effective intake has not been absolutely defined. Nevertheless, public health officials have reached the conclusion that action should be taken on the basis of the evidence at hand.
 Subar, Block and James calculated dietary intakes of folate in the United States, based on the NHANES II national survey (AJCN 1989; 50: 508-516). They concluded that 93 percent of black women and 91 percent of white women consumed less than the 1980 Recommended Dietary Allowance (400 mcg) of folate. The median intake was only 165 mcg for white women and 142 mcg for black women. Even these intakes overestimate the amount of folate actually available from U.S. diets.
 The terms "folic acid" and "folate" are sometimes used interchangeably, but there are important differences between the two. Folic acid is the "free" compound added to foods when they are fortified, and used in dietary supplements. Folate is the complex compound which occurs naturally in foods. Folate in foods has a chain of glutamate residues, which must be cleaved off in the body before the vitamin can be absorbed. Only about half of food folate is absorbed. Therefore, a given quantity of folate in foods cannot be equated to a similar quantity of folic acid consumed in fortified foods or supplements. A dietary supplement providing 400 mcg (0.4 mg) of folic acid is delivering considerably more of this B vitamin to the body than a diet providing 400 mcg of dietary folate.
 The available scientific studies show that dietary supplements containing folic acid can substantially reduce the incidence of neural tube defects, if those supplements are taken at least one month before conception and are continued for the first trimester of pregnancy. The supplements must be taken before most women are aware of their pregnancy, since the fetus' neural tube closes (or forever fails to close) in the first 28 days of gestation. It is this necessity for early use that raises the public health issue of the need to provide additional folate for all women of childbearing age -- not just for women who are planning pregnancy. Less than half of all pregnancies are planned, and for young women the vast majority of pregnancies are unplanned.
 We know of no public health intervention which provides greater promise.
 -0- 12/23/92
 /CONTACT: Susan Fitzgerald of the Council for Responsible Nutrition, 202-872-1488/


CO: Council for Responsible Nutrition ST: District of Columbia IN: HEA SU:

DC -- DC016 -- 9708 12/23/92 16:48 EST
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