In the News
More than one-third of Americans take multivitamin supplements, despite inconsistent evidence of their benefits. Two new studies do not support the use of multivitamins for the prevention of chronic disease.
In one, 1,708 men and women ages 50 years and older who'd had a myocardial infarction (MI) at least six weeks before were randomly assigned to a high-dose, 28-component oral vitamin-and-mineral supplement or placebo daily. In each group, 76% of the patients completed at least one year of vitamin therapy. However, 46% of patients in both groups discontinued the study regimen early.
During a median 55 months of follow-up, the incidence of the primary composite end point—time to death from any cause, recurrent MI, stroke, coronary revascularization, or hospitalization for angina—was similar between the two groups: 27% in the vitamin group and 30% in the placebo group. No evidence of adverse effects from vitamin therapy was found. But the researchers caution that the high rate of nonadherence makes it difficult to draw firm conclusions from the findings.
In the other study, 5,947 male physicians ages 65 years and older were randomized to a daily multivitamin or placebo. Cognitive function was assessed up to four times over 12 years. After 8.5 years of follow-up, no significant differences between the two groups were found in a composite score of global cognition or in verbal memory scores.
An accompanying editorial concludes that evidence from these and other trials indicate that most supplements don't protect against chronic disease or death in well-nourished adults and should be avoided.—Karen Rosenberg
Lamas GA, et al. Ann Intern Med. 2013;159(12):797–804
Grodstein F, et al. Ann Intern Med. 2013;159(12):806–14
Guallar E, et al. Ann Intern Med. 2013;159(12):850–1