Contact: Debbie Burke (212)614-5149
BACKGROUNDER: Folic Acid
In recent years, one of the most talked about nutrients has been the B-complex vitamin, folic acid, which helps the body build red blood cells and is essential for normal metabolism. Although folic acid has been mostly recognized for its ability to help prevent neural tube birth defects, recent studies now suggest folic acid may have a range of other potential health benefits, including reducing the risk of heart disease and some types of cancer. The Making of a Potential Wonder Nutrient
First identified in spinach and other green leafy vegetables in 1941, folic acid was synthesized four years later as a supplement by Lederle Laboratories. In the 1950s scientists initially hypothesized that diet had something to do with neural tube birth defects. From early on, the incidence of these defects has always been higher in areas with low socioeconomic populations in which women presumably have poorer diets. 1, 3, 4, 5
Beginning in the early 1980s, significant research in the United Kingdom linked low dietary folate levels in women of childbearing age and recurrent neural tube birth defects. In 1991, a significant study by the British Medical Research Council found a 72 percent reduction in incidences of recurrent defects when high levels of folic acid were consumed.1, 2, 3
Studies in the U.S. sought to confirm these findings and determine if folic acid could help prevent first-time incidences of neural tube birth defects (as opposed to its effectiveness in women who had already given birth to a baby with neural tube birth defects and were planning more children).1, 2, 3 Today, folic acid and its role in helping to prevent neural tube birth defects has become one of only two nutrient health claims allowed by the U.S. Food and Drug Administration (FDA). Neural Tube Birth Defects: The Details
Neural tube birth defects are a group of related abnormalities of development of the brain and spinal cord, the most well-known of which is spina bifida. These defects are a primary cause of stillbirth and infant death and remain a severe handicap of survivors.1 Studies indicate that women taking folic acid supplements before and during the first six weeks of pregnancy can reduce the risk of neural tube birth defects by more than 50 percent. 4
With this benefit having been scientifically established, education of the general population has become the top priority. In August 1991, the Centers for Disease Control (CDC) took the first step and issued a guideline for women who had a prior pregnancy affected by neural tube birth defects and who were planning to start a new pregnancy. The guideline called for the consumption of a 4.0 milligram (mg) daily dose of folic acid at least one month before conception and continuing through the first three months of pregnancy.2, 6
A year later, in 1992, the U.S. Public Health Service (PHS) strengthened the folic acid recommendation to include all women of childbearing age, recommending that all women consume 400 micrograms (mcg) of folic acid daily. The PHS estimated that if the recommendation was heeded, the incidence of neural tube birth defects would decrease by 50 percent.2, 4 However, as of 1994, the U.S. Department of Agriculture (USDA) estimates that most women age 19 to 50 still consume only 200 mcg or less of folic acid per day.3
In 1995, the March of Dimes Birth Defects Foundation (MOD), through a grant from the CDC, conducted and released survey results highlighting womenÃs lack of knowledge about folic acid -- nearly half of the more than 2,000 women surveyed had never heard of folic acid and only 15 percent were aware of the PHS recommendation.7 These results strengthened the commitment by both the MOD and CDC to educate women of childbearing age on the importance of folic acid. Through various programs, MOD urges women to eat a well-balanced diet and to take a complete daily multivitamin supplement that contains 400 mcg of folic acid before and during their pregnancy.
As the latest effort to reduce neural tube birth defects, the FDA now has promulgated a regulation requiring food manufacturers to add folic acid to most grains including enriched breads, flours, corn meals, rice, noodles and macaroni.3, 6 While not a complete solution, this ruling will help women of childbearing age meet the PHS goal of 400 mcg/day of folic acid. Manufacturers may begin fortification immediately, but compliance is not required until January 1, 1998. Maintaining high folate intake among all young women is particularly important because in the United States at present, over 50% of all pregnancies are unplanned.2 Benefits on the Horizon
The prevention of neural tube birth defects has been a driving force in the recommendation of the PHS and the CDC as well as the recent regulations authorizing food fortification. However, new studies continue to demonstrate other potential benefits of folic acid, including the potential for reduction in cardiovascular disease and cancer. Cardiovascular Disease
There is a substantial body of research supporting the role of folic acid in helping to prevent various forms of cardiovascular disease, such as heart attack -- the link lies in homocysteine. High blood levels of a naturally occurring compound, homocysteine, have been associated with an increased risk of cardiovascular disease. 8, 9, 10, 11, 12, 13, 14 Moreover, several studies have indicated an inverse correlation between folic acid intake and serum homocysteine levels. 16, 17, 18
The reason that folic acid is important is that scientists believe it helps the body convert homocysteine, which is a byproduct of metabolism, to a less harmful substance. Without adequate folic acid and other B vitamins, homocysteine levels may build up and damage the cells lining the heart and blood vessels. The damage makes it more likely that plaque will form inside blood vessels causing a blockage in blood flow, thus inviting unwanted blood clots which may induce heart attacks.10
A study published in the Journal of the American Medical Association reported a 69% increased risk of fatal heart disease among men and women with the lowest levels of folic acid in their bloodstream compared to those with higher levels of folic acid.12 Cancer
Epidemiological research also suggests that low intake of folic acid may be associated with an increased risk of colon cancer. Researchers believe that this relationship may be linked to the role of folic acid in cell replication and DNA production.20 A study examining individuals with ulcerative colitis -- a condition that puts them at high risk of developing colon cancer -- showed that precancerous changes in the colon were found less often in those individuals who took folic acid supplements.20 Preliminary research also suggests that low blood levels of folic acid may be correlated with the early development of cervical cancer.20 Folic Acid in High Risk Populations
Consuming sufficient levels of folic acid may be of greater importance for certain high risk populations, such as smokers of all ages and the elderly. Smoking, already established as a risk factor for both heart disease and cancer, may also impact the blood levels of folic acid. A recent study has indicated that smokers may require up to three times the intake of folic acid to achieve the same plasma folate concentration as non-smokers.21
Another high risk population is the elderly. As people age, their risk for heart disease and cancer increases. This risk is further compounded by the tendency of elderly people to decrease their overall food intake and consequently consume lower levels of folic acid.
Safety of Folic Acid
Folic acid is considered non-toxic in doses up to several times the U.S. RDI (Reference Daily Intake). Occasional reports have suggested that regular high doses of folic acid greater than 1000 mcg/day can mask the diagnosis of pernicious anemia in the elderly, a form of vitamin B-12 deficiency that can lead to permanent nerve damage.6 This complication, however, is unlikely to occur with the amount of folic acid found in over-the-counter dietary supplements. In fact, according to the FDA, consuming fortified grains, fruits and vegetables as recommended by the USDAÃs Food Guide Pyramid and also taking a multivitamin containing 400 mcg of folic acid would still achieve a daily folic acid intake under 1000 mcg.3 In addition, new methods of diagnosing pernicious anemia have markedly reduced this possible complication. Dietary Sources of Folic Acid
Even after the regulation to fortify certain food groups takes effect in 1998, it will not guarantee that everyone will consume 400 mcg of folic acid daily (the RDI of folic acid for all adults). However, there are steps that people can take to help ensure that the recommended dietary levels are achieved. Folic acid can be obtained by eating a wide variety of foods such as liver, dark-green leafy vegetables (such as spinach), asparagus, beans, citrus fruits and juices, and whole wheat bread.
Even with the abundance of foods rich in folic acid, the National Center for Health Statistics has found that at least 50 percent of all American adults consume less than the RDI for folic acid on any given day.22 In addition, while it is important to get all your nutrients from food, the form of folic acid found in foods is not always utilized or absorbed optimally; 50 to 95 percent of the folic acid found in foods may be destroyed by cooking or other processing, such as canning.23, 24 Research shows that folic acid from supplements may be more easily absorbed by the body than folic acid found naturally in foods.25, 26 It should also be noted that the major clinical studies which have demonstrated the benefits of folic acid were conducted with supplements.
Since many adults consume less than the RDI of folic acid, a complete multivitamin/multimineral supplement offers a safe, effective dose, and a convenient means of attaining 100 percent of the RDI of this important nutrient. ###
See folic.bm for news release on recent findings that re-confirm most Americans aren't getting the message about folic acid
1 Seller MJ. An achievement in prevention: neural tube defects. Medical and Health Annual 1985;64-70. 2 Centers for Disease Control and Prevention; Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. JAMA 1993;263:1233-1238. 3 Williams RD. FDA proposes folic acid fortification; in foods to reduce neural tube birth defects. U.S. Department of Health & Human Services FDA Consumer 1994. 4 Milunsky A, Jick H, Jick SS, et al. Multivitamin/folic acid supplementation in early pregnancy reduces the prevalence of neural tube defects. JAMA 1989;262:2847-2852. 5 MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council vitamin study. Lancet 1991;338:131-137. 6 U.S. Food & Drug Administration. Folic acid fortification. FDA/CFSAN Folic Acid Fact Sheet 1996. 7 March of Dimes, 1995. 8 Stampfer MJ, Malinow MR, Willett WC, et al. A prospective study of plasma homocyst(e)ine and risk of myocardial infarction in US physicians. JAMA 1992;268:877-881. 9 Ueland PM, Refsum HJ, Brattstrom L. Plasma homocysteine and cardiovascular disease. In: Francis BR ed. Athersclerotic cardiovascular disease, homeostasis, and endothelial function. New York: Marcel Dekker. 1992;183-235. 10 Kang S, Wong PWK, Malinow MR. Hyperhomocyst(e)inemia as a risk factor for occlusive vascular disease. Annu Rev Nutr 1992;12:279-298. 11 Clarke R, Daly L, Robinson K, et al. Hyperhomocysteinemia: an independent risk factor for vascular disease. N Eng J Med 1991;324:1149-1155. 12 Morrison H, et al. Serum folate and risk of fatal coronary heart disease. JAMA 1996;275(24):1893-1896. 13 Butterworth CE, Bendich A. Folic acid and the prevention of birth defects. Annu Rev Nutr 1996;16:73-97. 14 Stampfer MJ, Willett WC. Homocysteine and marginal vitamin deficiency. JAMA 1993;270:22:2726-2727. 15 Morbidity and Mortality Weekly Report 1991;40:30:513-516. 16 Ubbink JB. Vitamin nutrition status and homocysteine: an atherogenic risk factor. Nutrition Reviews 1994;383-387. 17 Ubbink JB, Vermaak WJH, van der Merwe A, Becker PJ, Delport R, Potgieter HC. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr 1994;124:1927-1933. 18 Boushey CJ, Beresford SAA, Omenn GS, Motulsky AG. A quantitative assessment of plasma homocysteine as a risk factor for vascular disease. JAMA 1995;274:1049-1057. 19 Giovannuci E, Stampfer MJ, Colditz GA, Rimm EB, et al. Folate, methionine, and alcohol intake and risk of colorectal adenoma. J Natl Cancer Inst 1993;85:875-884. 20 Glynn SA, Albanes D. Folate and cancer: a review of the literature. Nutr Cancer 1994;22:101-119. 21 Pryathilake CJ, Macaluso M, Jean Hine R, Richards EW, Krumdieck CL. Local and systematic effects of cigarette smoking on folate and vitamin B-12. Am J Clin Nutr 1994;60:559-566. 22 Alaimo K, McDowell MA, Briefel RR, et al. Dietary intake of vitamins, minerals, and fiber of persons age 2 months and over in the United States: Third National Health and Nutrition Examination Survey, Phase I, 1988-91. Advance data from vital and health statistics; no 258. Hyattsville, Maryland: National Center for Health Statistics. 1994. 23 Davis RE, Nicol DJ. Folic acid. Int J Biochem 1988;20:133-139. 24 Shils ME, Olson JA, Shike, eds. Modern Nutrition in Health and Disease 1994;412. 25 Halsted CH. Intestinal absorption of dietary folates. In: Picciano MJ, Stokstad ER, Gregory JF, eds. Folic acid metabolism in health and disease. New York: Wiley-Liss; 1990;24-25. 26 Darcy-Vrillan B, Selhub J, Rosenberg IH. Analysis of sequential events in intestinal absorption of folypolyglutamate. Am J Physiol 1988;225:361-366.
RSS