Vitamin B

Research suggests that high intake of supplemental vitamin B12 may be associated with increased risk of cancer, with some evidence that this association may vary by gender and smoking status. This investigation evaluates if similar patterns in association are observed for data for 11,757 adults from the National Health and Nutrition Examination Survey (1999–2006). Survey-weighted multivariable-adjusted linear regression was used to evaluate the association between regular B12 supplement use and log-transformed serum B12 levels. Persons taking vitamin B12 through a multivitamin/multimineral (MVMM) had a median supplemental intake of 12 mcg/day (Q1: 6, Q3: 25), compared to 100 mcg/day (Q1: 22, Q3: 500) for persons reporting supplemental B12 intake through a MVMM-exclusive source. MVMM users had a geometric mean serum B12 26% (95% CI: 23%−30%) higher than non-users, whereas MVMM-exclusive users’ geometric mean was 61% (95% CI: 53%−70%) higher than non-users (p-trend