A study out today in the Journal of the American Medical Association suggests that multivitamins might help prevent cancer. Does that mean you should start popping the pills? Not so fast, say our medical experts.
The study is a good one, a randomized trial of nearly 15,000 male physicians 50 or older, led by researchers at Brigham and Women's Hospital and the Harvard Medical School. After an average of about 11 years, 1,290 men who took the multivitamin (in this case, Centrum Silver) were diagnosed with cancer, compared with 1,379 men who took the placebo.
That's promising, but as the researchers who led the study point out, it represents only a modest 8 percent reduction in risk. More important, this one study has to be put into the context of years of other research into the effect of supplemental vitamins and minerals, including multis, on health.
And that research is murky at best. As we reported in our September report 10 Surprising Dangers of Vitamins and Supplements, other large clinical trials have repeatedly found that multivitamins don't improve the health of the average person. For example, researchers from the Women's Health Initiative, who tracked more than 161,000 women, concluded that women who took the pills had no lower risk of cancer, cardiovascular disease, or death from any cause over an eight-year period than those who didn't. And some studies hint that multivitamins may even increase the risk of certain health problems. For example, a Swedish study that tracked some 35,000 women over 10 years found that those who took multivitamins were slightly more likely to be diagnosed with breast cancer than those who didn't take the supplements.
"The only end point that reached statistical significance, and that barely, was in the occurrence of cancer in general," says Marvin Lipman, M.D., Consumer Reports' Chief Medical Adviser. "The use of multivitamins did not affect site-specific cancers, such as colon cancer, nor did their use decrease the death rate from cancer," he says. "This study would not persuade me to tell my patients to take multivitamins."
Instead, we continue to recommend that when possible you get your nutrients from foods, many of which contain their own potent cancer-protective properties. If you do need more of certain nutrients, like calcium and vitamin D, we think it's usually better to get that from specific supplements rather than from a multi.
People who might need a multivitamin include women who are pregnant, breast-feeding, or trying to conceive; dieters consuming fewer than 1,200 calories a day or cutting out an entire food group (carbs, for example); strict vegetarians; and those with medical conditions that affect digestion and food absorption. For more detailed advice, see our Ratings of multivitamins.
Note that our Ratings found that most of the multis we tested contained what they claimed, so we advise that if you do opt for the pills you choose by price, not brand. Centrum Silver was near the middle of the pack in price. Kirkland Signature Daily Multi (Costco) and Equate Complete Multivitamin (Walmart) were the least expensive.
Multivitamins in the prevention of cancer in men [JAMA]