February 24th, 2014

Vitamin Supplements Come Up Short Once Again

Once again, the U.S. Preventive Services Task Force (USPSTF) has concluded that there is no good evidence to support the routine use of multivitamins or most individual or combination vitamins by healthy adults to prevent cardiovascular disease or cancer.

The USPSTF also recommended against the use of two specific vitamins — beta-carotene and vitamin E. Beta-carotene has been linked to a significant increase in the risk for lung cancer among smokers, while “a large and consistent body of evidence has demonstrated that vitamin E supplementation has no effect on cardiovascular disease, cancer, or all-cause mortality.”

For other vitamins or multivitamins, the task force found few significant harms, though they said the evidence was insufficient to allow definitive assessments of the risks and benefits.

The recommendation statement, published in Annals of Internal Medicine, updates the USPSTF’s previous 2003 recommendations and incorporates new evidence about vitamin D, calcium, selenium, and folic acid. An initial draft of the recommendation statement was published last December. The USPSTF statement is broadly consistent with similar statements from the National Institutes of Health, the Academy of Nutrition and Dietetics, the American Cancer Society, the American Institute for Cancer Research, the American Heart Association, and the American Academy of Family Physicians, all of which found no evidence that vitamins could help prevent cardiovascular disease or cancer.

The USPSTF states that vitamins and minerals are essential to overall health and notes that “a diet rich in fruits, vegetables, whole grains, fat-free and low-fat dairy products, and seafood has been associated with a reduced risk for cardiovascular disease and cancer.” The group also acknowledges that some people with well-defined conditions may benefit from specific nutrients. Folic acid, for instance, when taken by pregnant women can help prevent neural tube defects, and vitamin D  may be beneficial in older people to prevent damage from falling.

Nearly half (40%) of  U.S. adults take at least one dietary supplement, and nearly a third (32%) take a multivitamin supplement. In 2010, people in the U.S. spent more than $28 billion on dietary supplements.

One Response to “Vitamin Supplements Come Up Short Once Again”

  1. Please show me one study that shows a benefit from whole grains. Please show me one study that demonstrates a benefit from fat free and low fat dairy products or benefit from a low fat diet. So we are promoting a diet that lacks evidence of benefit while in the same breath disparaging supplements where the evidence does not meet our standards for “evidence”.

    The fact that there are no studies demonstrating benefit does not mean that there is no benefit, especially when few meaningful studies have been performed. Vitamin E is well studied but only with synthetic alpha tocopherol. Natural source vitamin E has never been studied despite biochemical evidence that the synthetic vitamin E might create a pseudo deficiency state.

    Vitamin E has been shown to reduce the progression of Alzheimer’s disease. Is this no benefit?

    Making sweeping statements about subjects of which we are mostly ignorant strikes me as foolish. But then, that is not inconsistent with the SOP of many of our august medical bodies.