More than 11 million Americans had cancer in 2007, according to the American Cancer Society, or ACS. Cancer can start when cells make mistakes, and replicate out of control. Folic acid is a key player in the appropriate production and repair of your cells. Low blood levels of this vitamin have been linked to higher rates of some types of cancer, says the ACS.
Folic Acid
Folic acid is the synthetic form of the water-soluble B vitamin in supplements and fortified foods, according to the U.S. Government's Office of Dietary Supplements. In 1998, the FDA mandated that enriched breads, cereals and other grains be fortified with folic acid. The term folate refers to the form occurring naturally in foods, such as leafy green vegetables, beans, nuts and fruits, as well as the form in your body.
Functions
DNA, the molecule that carries your genetic information, depends on folate for its construction. The B vitamin is also necessary for normal red blood cell production, and prevention of anemia. Folate plays a critical role in amino acid metabolism, most notably, the synthesis of methionine from homocysteine. Folate deficiency causes a buildup of homocysteine, and a subsequent increased risk for cardiovascular disease, states Oregon State University's Linus Pauling Institute.
Sources
Folic acid is more bioavailable than the natural form of folate found in some foods. This means that more of its active components enter the bloodstream and reach the target site, states the Linus Pauling Institute. Most vitamin and mineral supplements contain the recommended daily value of 400 mcg. Doses greater than 1,000 mcg require a prescription. Foods fortified with folic acid include rice, pasta, bread, cereals, flour and corn meal.
Significance
According to the American Cancer Society, folate levels may affect the ability of your cells to repair and replicate properly. Low blood levels may be responsible for DNA damage that can lead to cancer. Intake of folate-rich fruits and vegetables is associated with lower cancer risk.
Research
Women in the Nurses' Health Study who took folic acid-containing multivitamins for 15 years had a lower risk of colon cancer, as published in the "Annals of Internal Medicine" in 1998. Colon cancer risk was also lower for men who consumed adequate folate, but did not consume alcohol, over a 20-year period, reports a 2001 issue of the "Annals of Epidemiology." A 1999 study in the "Journal of the American Medical Association" reported that, for women who had more than one alcoholic drink daily, at least 600 mcg of folic acid a day cut breast cancer risk in half, compared to women who took less than 300 mcg a day.
Caveats
The American Cancer Society calls folic acid "a safe and necessary nutrient," but too much of a good thing may not be good for you. The Linus Pauling Institute warns that high doses of supplemental folic acid may accelerate tumor growth in cancer patients. Indeed, men who supplemented with folic acid had a higher risk of being diagnosed with prostate cancer than those who took a placebo, reported the "Journal of the National Cancer Institute," in 2009. The Institute of Medicine's Food and Nutrition Board recommends that you consume no more than 1,000 mcg of folic acid from supplements or fortified foods. There is no evidence that excess folate from food has any adverse effects.
References
- Office of Dietary Supplements: Folate
- Oregon State University Linus Pauling Institute: Folic Acid
- American Cancer Society: Folic Acid
- E. Giovannucci, M. Stampfer, G. Colditz, D.Hunter, C. Fuchs, B. Rosner, F. Speizer, W. Willett; Multivitamin Use, Folate and Colon Cancer in Women in the Nurses' Health Study; Ann Intern Med; Oct. 1998
- L. Su, L. Arab; Nutritional Status of Folate and Colon Cancer Risk: Evidence from NHANES I Epidemiologic Follow-Up Study; Ann Epidemiol; Jan. 2001
- S. Zhang, D. Hunter, S. Hankinson, et al; A Prospective Study of Folate Intake and the Risk of Breast Cancer; JAMA; May 1999
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