Vitamins don’t confer benefit – evidence seems conclusive

The vitamin industry is big business (some other posts on vitamins are here, here and here). A recent editorial in Annals of Internal Medicine notes that vitamins sell $28 billion per year. This editorial also looks at the science behind vitamins, including three new, well-conducted studies published in this journal (see below). Looking at this research as well as the volumes of other past studies, the editorial notes that vitamins don’t produce benefits, meaning in essence that they are placebos. And with sales of $28 billion, well, that’s a lot to spend on placebos.

Touching briefly on the three articles, the first study evaluated 1,708 patients to assess whether taking multivitamins could cut the risk of heart attack, stroke or death. The answer: vitamins confer no benefit.

The second study assessed whether multivitamins would prevent cognitive decline. This study included 5,947 male physicians age over 65 as participants. The answer: vitamins confer no benefit.

Finally, the U.S. Preventative Services Task Force performed a comprehensive review of available medical literature to evaluate the totality of science amassed to date on this topic. They conclude the following:

We found no consistent evidence that the included supplements affected [cardiovascular disease], cancer, or all-cause mortality in healthy individuals without known nutritional deficiencies. Other systematic reviews have arrived at this same conclusion.

The five physicians who wrote the editorial mentioned at the outset of this post assert that vitamins have no clear benefit and that some might even cause harm (namely B-carotene, vitamin E, and possibly vitamin A). Vitamins, they say, should not be used by well-nourished people to prevent chronic disease. I agree.

I find it frustrating to observe that some people cling to a belief that vitamins are helpful. There’s a deeply rooted belief that ‘natural’ substances must somehow be beneficial. The evidence (mountains of it) simply does not support this.

Someone could argue that by taking vitamins they aren’t doing any harm, and there’s the potential for a benefit, so why not? Wrong. There is no potential for benefit. The verdict is in. In fact, why not avoid vitamins because of the converse finding that there is actually a potential for harm? There was a higher risk of hip fracture for women taking vitamin A in the Nurses Health Study, and a review of established science suggested Beta-carotene and vitamin E supplements seem to increase the risk of death. (I personally think these signals of harm are spurious, and vitamins are no more likely to be deleterious than they are to produce a benefit.) But in another light, giving away money to buy misplaced hope . . .  that’s harmful. If you must do something to generate a hope of producing some kind of benefit, consider sending a dollar per day to charity and hoping that good karma from the universe will come back to you. At least in that case, even if it doesn’t make you healthier, some good has been accomplished.

As Einstein said, “The definition of insanity is doing the same experiment over and over and expecting a different result.” But I accept that some parties might want to do more research investigating vitamins (even though I personally would allocate research dollars elsewhere). Regardless, until they show a benefit, I applaud the very thoughtful authors of the editorial and hope people won’t waste their money.


sources: 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);  JAMA – Vitamin A intake and hip fractures among postmenopausal women; Oral High-Dose Multivitamins and Minerals After Myocardial Infarction: A Randomized Trial (Annals of Internal Medicine); Long-Term Multivitamin Supplementation and Cognitive Function in Men: A Randomized Trial (Annals of Internal Medicine); Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements (Annals of Internal Medicine); Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases (Cochrane Database of Systematic Reviews)


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1 comment for “Vitamins don’t confer benefit – evidence seems conclusive

  1. steve chiu
    December 29, 2013 at 8:33 pm

    thanks for your advice

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