Medscape Internal Medicine > Medicine Matters
Multivitamins: Time to Just Say No?
Sandra Adamson Fryhofer, MDDisclosures
April 08, 2014
Hello. I'm Dr. Sandra Fryhofer. Welcome to Medicine Matters. The topic: multivitamins, help or harm? There are 2 original studies,[1,2] a US Preventive Services Task Force (USPSTF) review,[3] and a provocative editorial,[4] all published in the Annals of Internal Medicine. Here is why it matters.
Vitamins and supplements: It's a growing industry, with sales of $28 billion in 2010 alone, but are they helpful or harmful? Are they a waste of precious healthcare resources that could be better spent on more beneficial therapies?
Let's start with the heart. The first study [discussed in the Annals editorial] was a multicenter, double-blind, placebo-controlled, randomized trial that included more than 1700 patients aged 50 years or older.[1] All had recently suffered a heart attack. Patients were given either a multivitamin, multimineral mix, or a placebo and were followed for nearly 3 years. The results: The extra vitamins didn't protect the heart. They did not seem to protect against secondary cardiovascular events.
Another study in the same Annals issue looked at the effect of vitamins on cognition.[2] This is from the Physicians' Health Study II and looked at nearly 6000 male physicians age 65 years and older and followed them for 12 years. Initial and intermittent cognitive assessments were conducted. The results: Vitamin use did not slow cognitive decline. There was no change in verbal memory scores or cognition between those who took them and those who didn't.
Also included in the Annals is the USPSTF review of 26 studies looking at the pros and cons of supplements and preventing heart disease, cancer, and death.[3] This blue-ribbon panel found insufficient evidence that vitamins were beneficial.
Now, the editorial.[4] Clear-spoken and direct: Enough is enough. Stop wasting money. Well-nourished adults don't need them. There is no clear benefit, and they might even be harmful. Don't use them to prevent chronic disease.
The editorial specifically mentions beta-carotene, vitamin E, and high doses of vitamin A as being harmful. Beta-carotene increases risk for lung cancer in those who smoke. Vitamin E supplements have been linked to increases in all-cause mortality.
There was one exception: vitamin D. The editorial acknowledges that the role of vitamin D supplementation is an open area of investigation, especially in those who are vitamin D deficient. More study is needed. But even with vitamin D, there is no solid evidence that the benefits outweigh the harms.
There is one group that does need vitamin supplementation: women of childbearing potential. For them, folic acid supplementation is important because it prevents neural tube defects in their babies. Now you know.