Three common ingredients of multivitamin supplements - folic acid, vitamin B6, and vitamin B12 - have no significant effect on cancer risk in women, according to a study published in the November 5, 2008 issue of the Journal of the American Medical Association.

Researchers from Harvard Medical School analyzed data from the Women's Antioxidant and Folic Acid Cardiovascular Study, a randomized trial of 5442 female health professionals with an average age of 62.8 years in order to evaluate the effect of combined folic acid, vitamin B6, and vitamin B12 treatment on cancer risk in women at high risk for cardiovascular disease. During an average follow-up period of over 7 years, the researchers found that usage of these three nutritional supplements did not appear to be an effective way to prevent cancer in women.

Women aged 65 years and older did demonstrate a significantly reduced risk for overall cancer and breast cancer, but the researchers caution that these results may be due to chance and need to be further substantiated.