One in two adults takes a daily vitamin pill, and Americans spend tens of billions of dollars each year on supplements. Now, a small coterie of physicians writing in a leading medical journal has offered this blunt advice: “Stop wasting money.”
In an unusually direct opinion piece, the five authors say that for healthy Americans worried about chronic disease, there’s no clear benefit to taking vitamin and mineral pills. And in some instances, they may even cause harm.
The authors make an exception for supplemental vitamin D, which they say needs further research. Even so, widespread use of vitamin D pills “is not based on solid evidence that benefits outweigh harms,” the authors wrote. For other vitamins and supplements, “the case is closed.”
“The message is simple,” the editorial continued. “Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.”
“We have so much information from so many studies,” Dr. Cynthia Mulrow, senior deputy editor of Annals of Internal Medicine and an author of the editorial, said in an interview. “We don’t need a lot more evidence to put this to bed.”
Officials with the Natural Products Association, a trade organization that represents supplement suppliers and retailers, said they were shocked by what they termed “an attack” on their industry, pointing to a study published last year that found a modest reduction in overall cancers in a long, randomized, controlled trial of 15,000 male doctors.
“Our members market and sell their products in order to assist people to achieve a healthier lifestyle,” said John Shaw, executive director of the association, adding that he could not understand why the industry was being criticized “for trying to promote health and wellness.”
Demand for vitamin and mineral supplements has grown markedly in recent years, with domestic sales totaling some $30 billion in 2011. More than half of Americans used at least one dietary supplement from 2003-06, up from 42 percent from 1988-94, according to national health surveys conducted by the Centers for Disease Control and Prevention. The most popular products are multivitamin and mineral supplements, which are consumed by some 40 percent of men and women in the United States, according to data from the National Health and Nutrition Examination Survey.
Whether regular long-term use can prevent heart disease and cancer has never been clearly established, and the authors of the editorial are not the first to point that out.
The Cochrane Collaboration, which publishes reviews of medical evidence, has also concluded that taking vitamins does not extend life. An updated review of the evidence by the United States Preventive Services Task Force, published online on Nov. 12, likewise concluded that there was limited evidence that vitamin and mineral supplementation could prevent cancer or cardiovascular disease.
The task force pointed out, however, that two clinical trials had found slight cancer reductions among men who took multivitamins. Yet other studies have found that beta-carotene supplements may actually increase the risk of lung cancer in smokers, the task force review noted, and that high doses of vitamins A and E cause harm and may increase the risk of death.
The editorial in the Annals is accompanied by two new studies reporting dismal results for multivitamins in helping preserve cognitive function and preventing heart attacks. In one study of nearly 6,000 male physicians 65 and older, participants who took a multivitamin for over a decade were no more likely to retain cognitive function as they aged than similar doctors who took a dummy pill.
But Dr. Francine Grodstein, one of the lead authors of that study, said that since physicians tend to have healthy diets and be well-nourished, the added nutrients may not have made a difference in their cases. “I do think there’s room for more research,” said Dr. Grodstein, who did not write or sign the editorial.
Demonstrating the prevention of chronic diseases can take decades and conducting long-term, randomized, controlled trials is both tricky and very costly. “We don’t and probably never will have randomized trial data over decades,” she said.
The results of another clinical trial published in the journal found that high-dose vitamins and minerals did not protect heart attack patients 50 and older from experiencing additional cardiovascular events, though the research was marred by a high dropout rate.
There have been few randomized clinical studies of the effects of multivitamins and minerals on heart disease, cancer and risk of death, said Dr. Stephen P. Fortmann, of the Kaiser Center of Health Research, who led the task force review. A draft of new task force recommendations, based on the updated review, said there was insufficient evidence to recommend taking or not taking vitamins.
But Dr. Fortmann, who also did not write or sign the editorial, suggested that those who buy vitamins may be “throwing their money away,” adding: “Don’t think it makes up for a bad diet, that you can eat a lot of fast food and then take a bunch of supplements. That’s not a good idea.”
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