Most people would unhesitatingly declare their health is more important than wealth, but almost no one would wish to waste money on products falsely marketed as a benefit to health. Yet an editorial based on three studies published in the Annals of Internal Medicine suggests that many Americans may be doing exactly that each time they purchase vitamins and supplements.
“With respect to multivitamins, the studies published in this issue and previous trials indicate no substantial health benefit,” write the authors of an editorial appearing in the Annals of Internal Medicine. This evidence, combined with biological considerations, suggests that any effect, either beneficial or harmful, is probably small.” Is it really time to throw out your favorite bottle of horse pills?
Along with citing a large body of previous evidence, the editorialists focus on three published articles on vitamin and mineral supplementation appearing in Annals of Internal Medicine. In one study, a team of researchers associated with Kaiser Permanente Center for Health Research reviewed evidence to determine the efficacy of vitamin supplements in adults with no nutritional deficiencies for the primary prevention of cardiovascular disease and cancer. After reviewing the three trials of multivitamin supplements and 24 trials of single or paired vitamins that were randomly assigned to more than 450,000 participants, the authors concluded that no clear evidence existed of a beneficial effect of supplements with regard to cardiovascular disease, cancer, or mortality from any cause.
A second study evaluated the efficacy of a daily multivitamin to prevent cognitive decline among 5,947 men aged 65 years or older, all participants in the Physicians’ Health Study II, a Harvard study begun in 1997, created to examine the benefits and risks of three supplements for the primary prevention of cardiovascular disease, cancer, age-related eye disease, and cognitive decline: vitamin E, vitamin C, and a multivitamin. Researchers followed-up participants after 12 years and discovered no differences between the multivitamin and placebo groups in overall cognitive performance or verbal memory.
The researchers — funded by the National Institutes of Health and chemical giant BASF (with additional support from Pfizer and DSM Nutritional Product) — noted high adherence rates and a large sample size, both of which contribute to precise estimates. The team of researchers suggest that the “findings are compatible with a recent review of 12 fair- to good-quality trials that evaluated dietary supplements, including multivitamins, B vitamins, vitamins E and C, and omega-3 fatty acids, in persons with mild cognitive impairment or mild to moderate dementia. None of the supplements improved cognitive function.
Finally, the editorialists cite a third study, one admittedly limited by high rates of non-adherence and dropouts. In this case, researchers assessed the potential benefits of a high-dose, 28-component multivitamin supplement in 1,708 men and women with a previous myocardial infarction participating in TACT (Trial to Assess Chelation Therapy, a trial sponsored by the Mount Sinai Medical Center in Miami). Upon follow-up, the researchers found no significant difference in recurrent cardiovascular events when comparing participants who took a multivitamin and those who took a placebo.
“Although available evidence does not rule out small benefits or harms or large benefits or harms in a small subgroup of the population,” the editorialists noted, “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.”
Sources: Grodstein F, O’Brien J, Kang JH, et al. Long-Term Multivitamin Supplementation and Cognitive Function in Men. A Randomized Trial. Annals of Internal Medicine. 2013.
Lamas GA, Boineau R, Goertz C, et al. Oral High-Dose Multivitamins and Minerals After Myocardial Infarction: A Randomized, Controlled Trial. Annals of Internal Medicine. 2013.
Fortmann SP, Burda BU, Senger CA, et al. Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: an updated systematic evidence review for the U.S. Preventive Services Task Force. Annals of Internal Medicine. 2013.
Guallar E, Strange S, Mulrow C, et al. Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements. Annals of Internal Medicine. 2013.