Vitamin Supplementation Fails to Reduce Cancer Risk
In women at high risk for heart disease, folic acid, B6 and B12 are neither helpful nor harmful
TUESDAY, Nov. 4 (HealthDay News) -- In women with a high risk for cardiovascular disease, supplementation with combined folic acid, vitamin B6 and vitamin B12 has neither a beneficial nor harmful effect on cancer risk, researchers report in the Nov. 5 issue of the Journal of the American Medical Association.
Shumin M. Zhang, M.D., of Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues from the Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS) randomly assigned 5,442 female health professionals aged 42 and older with pre-existing cardiovascular disease or three or more coronary risk factors to receive either a daily combination of folic acid, vitamin B6 and vitamin B12, or placebo, for 7.3 years.
The researchers found no significant differences between the active-treatment group and placebo group in the risk of invasive cancer (hazard ratio, 0.97), breast cancer (HR, 0.83) or any cancer death (HR, 0.82).
"The WAFACS participants were female health professionals who tended to be health conscious, have well-balanced diets, and greater access to health care and screening, which may have led to lower occurrences of cancer," the authors write. "However, more than two-thirds of participants also were overweight or obese, and thus were at elevated risk for cardiovascular disease and cancer. Therefore, the findings may not be directly generalizable to the entire U.S. population. However, it seems unlikely that the exposure-disease relationships observed among women in the WAFACS differ from women in general."
Several of the study authors report financial relationships with pharmaceutical companies and vitamin companies.