Daily vitamin and mineral supplements do not prevent or limit the progression of chronic disease, according to an editorial in the December issue of Annals of Internal Medicine.
“We believe that the case is closed,” the editors wrote. “Supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful.”
The editorial summarized the results of three meta-analyses published in the same issue, and garnered national media attention.
The first study analyzed the health benefits of multivitamin or single supplement use in more than 400,000 participants across 27 separate trials. The authors found no clear evidence to suggest that any form of nutritional supplementation reduced subjects’ risk of all-cause mortality, cardiovascular disease or cancer.
The second study evaluated the protective effect of daily multivitamin supplementation on 5,947 men aged 65 years or older who were at an increased risk for cognitive decline. After 12 years of follow-up, the researchers observed no differences in cognitive performance or verbal memory between subjects who used multivitamins and those who received a placebo.
In the third study, researchers examined the potential benefits of a high-dose, 28-component multivitamin in 1,708 men and women with a history of myocardial infarction. After 4.6 years of follow-up, no significant reduction in recurrent cardiovascular events was observed in those who received the supplement.
After reviewing these data, as well as the results from several other multivitamin trials, the editorial’s authors concluded: “Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.”
So, should eye care professionals be seriously concerned by these findings? Probably not.
Ocular Nutrition Society Science Committee Director A. Paul Chous, MS, OD, of Tacoma, Wash., suggests that health care providers and the lay public should be very wary whenever such blanket claims are made. “Many supplement studies are relatively short term and use high doses of a single micronutrient that often depend on a host of additional cofactors,” he says. “This means that the benefits and harms of supplementation may not be observed properly, and that any nutritional imbalance may exert pro-oxidant, disease-promoting effects.”
In specific regard to eye care, Dr. Chous believes that optometrists who currently recommend nutritional supplements to their patients should continue to do so with confidence. “The AREDS studies prove that a combination of antioxidants and zinc––plus xanthophylls in AREDS2––reduces the risk of advanced AMD in high-risk patients,” he says. “Further, there are now numerous interventional trials showing improved visual function in early AMD and diabetic eye disease patients following vitamin supplementation.”
Guallar E, Stranges S, Mulrow C, et al. Enough is enough: Stop wasting money on vitamin and mineral supplements. Ann Intern Med. 2013 Dec;159(12):850-1.