December 16th, 2013
Case Closed: Multivitamins Should Not be Used
The editorialists are fed up: “Enough is enough.” Writing about three new papers in the Annals of Internal Medicine that find no benefits for the use of multivitamins — only the latest in a long line of negative findings — Eliseo Guallar and colleagues write:
…we believe that the case is closed — supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough.”
In the first paper, Stephen Fortmann and colleagues performed an updated systematic evidence review of vitamin and mineral supplements for the U.S. Preventive Services Task Force (USPSTF). They found “no evidence of an effect of nutritional doses on CVD, cancer, or mortality in healthy individuals without known nutritional deficiencies for most supplements we examined.” However, they were unable to rule out a benefit for vitamin D, and they called for improved studies to better assess both potential harms and potential benefits.
In the second paper, investigators from the Physicians Health Study II randomized nearly 6,000 physicians 65 years of age or older to a multivitamin or a placebo. Over 12 years the physicians underwent as many as four assessments of global cognition, verbal memory, and category fluency. There were no significant differences between the groups in any of the test scores at any time.
In the third paper, Gervasio Lamas and his fellow investigators in the NIH’s Trial to Assess Chelation Therapy (TACT) randomized 1,708 patients who had had a heart attack to a multivitamin supplement or placebo. They found no significant difference in outcomes between the two groups after 4.6 years of followup. The results were less robust because the nonadherence rate was much higher than anticipated.
It should be noted that patients in TACT were also randomized to chelation therapy or placebo. Last year the results of that arm of the trial sparked an enormous controversy by suggesting that chelation therapy might be beneficial. Last month the TACT investigators reported that all the benefits observed in the main trial occurred in the large subgroup of patients who also had diabetes. At the American Heart Association meeting last month they also presented results showing that, although multivitamins did not have an independent effect, when added to chelation there was an additional 10% reduction in events. These findings have not yet been published.