No Easy Way: B Vitamins Don’t Prevent Cancer in Everyone

Women have been underrepresented in clinical trials of B vitamins. In the Women’s Antioxidant and Folic Acid Cardiovascular Study (WAFACS), 5442 women (age, ≥40) at high risk for or with coronary artery disease were randomized to combined folic acid (2.5 mg), vitamin B₆ (50 mg), and vitamin B₁₂ (1 mg) or to placebo.

At a follow-up of 7.3 years, no significant differences were noted between the intervention and control groups in risk for any specific cancer, all cancers, or deaths from any cancer or any cause. In a subgroup analysis, however, older women (age, ≥65) who took supplements were 25% and 40% less likely to develop invasive cancer (of any sort) or breast cancer, respectively, than were middle-aged women (age range, 40–64). Interesti…