One in two American adults takes a daily vitamin pill, and North 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.”

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In an unusually direct opinion piece, the five authors said that for healthy people worried about chronic disease, there is no clear benefit to taking vitamin and mineral pills. In some instances, they may even cause harm.

The authors made an exception for supplemental vitamin D, which they said needed 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 at the Natural Products Association, a U.S. trade organization that represents supplement suppliers and retailers, said they were shocked by what they called “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 he could not understand why the industry was being criticized “for trying to promote health and wellness.”

Whether regular, long-term use prevents heart disease and cancer has never been clearly established, and the editorial authors were 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 U.S. Preventive Services Task Force 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 to preserve cognitive function and prevent 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.

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However, 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 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.

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