A new study making headlines finds finds older men who took a daily multivitamin had a lower overall risk for cancer occurrence. The new data, from the Physicians’ Health Study II, is published in the Journal of the American Medical Association (JAMA) and was presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research.
Researchers led by J. Michael Gaziano, M.D., M.P.H., of Brigham and Women’s Hospital and Harvard Medical School, Boston, analyzed data from the only large-scale, randomized, double-blind, placebo-controlled trial testing the long-term effects of a common multivitamin in the prevention of chronic disease. In the study, 14,641 male U.S. physicians, ages 50 years or older received a daily multivitamin or a placebo for an average of 11 years. After analyzing the data, the researchers concluded that men taking a multivitamin had a modest 8 percent reduction in total cancer incidence.
We asked Susan M. Gapstur, PhD, MPH, vice president, Epidemiology Research Program, for her comments on the study.
“Results of previous trials of vitamin and or mineral supplementation for cancer prevention have been mixed, and some studies of individual nutrients have shown evidence of possible harm. A daily multivitamin, as used in the current study, contains more nutrients and usually in smaller doses than those studied in trials of individual nutrients.
“This well-designed randomized clinical trial suggests that a daily multivitamin was associated with a modest reduction in cancer risk in older non-smoking men. But it’s important to remember that this study, as credible as it is, is still just one trial. Typically, we like to see these kinds of findings replicated by other studies, and in other populations, before coming to solid conclusions.
“Probably the most important limitation of this study is the fact that it was done in older men, the great majority of whom were non-smokers. Whether this protective association will be found in women or in high risk populations, such as smokers, is unclear. We’ll need further studies to help sort through these issues.
“For years, the American Cancer Society has recommended getting nutrients from a healthy diet, and has recommended that for people who choose to take supplements, the best choice is a balanced multivitamin/mineral supplement containing no more than 100% of the Daily Value of most nutrients. This study is an important addition to the body of evidence the Society reviews in establishing its guidelines.”
For some information about how and if individual supplements can affect cancer risk, see this blog post by Marji McCullough, ScD, RD, strategic director of nutritional epidemiology at the American Cancer Society: “Will a vitamin a day keep cancer away?”