Vitamin B and Cancer Risk in Women

That folate and vitamins B₆ and B₁₂ are important in DNA stability and regulation is thought to explain the results of observational studies that showed a lower risk for colorectal and breast cancer with higher intake of these vitamins. However, results of randomized trials have been inconsistent, and women have been underrepresented in such studies. Boston researchers used data from a previous study of vitamin B supplementation and risk for cardiovascular disease (CVD) to assess cancer risk.

They randomized 5442 women (age, ≥40; mean age, 63) with CVD or important CVD risk factors to daily supplementation with folate plus B₆ plus B₁₂ or placebo. During about 7 years of follow-up, 379 women developed invasive cancer, mostly of the breast, co…