Folic acid is one of the B vitamins essential for proper body functioning and overall health. Adequate folic acid intake can protect against neural tube defects in newborns and possibly reduce the risk of certain cancers. However, if you already have cancer, you may or may not benefit from folic acid supplementation, depending on the type of cancer and treatment as well as your overall health and nutritional status.
Folic Acid Forms and Sources
Folic acid is a synthetic form of folate, or vitamin B-9, naturally found in green leafy vegetables, such as spinach, kale and lettuce, and also broccoli, asparagus, beans and mushrooms. This form is widely used in the United States to fortify grains and cereals as well as in supplements. The current recommended daily intake of folic acid for adults is 400 micrograms per day. Folinic acid, or leucovorin, is another form of the vitamin that is normally used in conjunction with certain cancer treatments and available only by prescription.
Folic Acid and Cancer Prevention
Low levels of folic acid in the blood may increase the risk for several cancers, including colon, breast, ovarian and pancreatic, especially among drinkers of the alcohol. According to the November 1, 2007 issue of the "International Journal of Cancer," low folate intake can further increase risk for colon cancer in people drinking alcoholic beverages daily.
Folic Acid During Cancer Treatment
Some cancer treatments can interfere with folate absorption in the body. For example, a common chemotherapy drug for treatment of leukemia and lymphoma called methotrexate is a folate antagonist. This means that the body absorbs methotrexate and folic acid in the same manner, and they may compete for absorption. If you undergo treatment with methotrexate, your oncologist can prescribe folic acid supplements to help prevent folic acid deficiency before, during or after treatment, depending on the disease state, dose of methotrexate and length of the treatment. Folinic acid, or leucovorin, is the preferred form of folate for use with chemotherapy and is usually prescribed 24 hours after the methotrexate treatment to protect healthy cells from toxicity without cancelling the effects of chemotherapy. In addition, leucovorin has the potential to increase the anti-tumor activity of another chemotherapy agent called 5-FU, which is standard treatment for colon and esophageal cancers.
Concerns
While folate from food sources may protect from certain cancers, some investigations point out that if you already have cancer, large amounts of folic acid from supplements may potentially promote cancer cell growth. According to the July 19, 2011 issue of the "British Journal of Urology International," high levels of folic acid can increase prostate cancer growth. To be on the safe side, eat plenty of folate-containing foods and consult your oncologist before starting folic acid supplementation.
References
- Linus Pauling Institute: Folic Acid
- American Cancer Society: Leucovorin
- Office of Dietary Supplements: Folate
- "International Journal of Cancer"; Lifetime and Baseline Alcohol Intake and Risk of Colon and Rectal Cancers in the European Prospective Investigation Into Cancer and Nutrition (EPIC); Ferrani P, et al.; November, 2007
- "British Journal of Urology International"; Elevated Physiological Levels of Folic Acid Can Increase in Vitro Growth and Invasiveness of Prostate Cancer Cells; Petersen LF, et al.; July 19, 2011
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