The daily multivitamin, America’s most popular dietary supplement, has shown that it modestly prevents cancer in some older men, according to a US clinical study that was published Wednesday in The Journal of the American Medical Association.
The long-running study, the first to look at multivitamins, found they reduced the chance of developing cancer by eight percent among men aged 50 and over.
“Our main message is that the main reason to take a multivitamin is to prevent deficiencies, but there appears that there may be a modest effect in terms of preventing cancer in men over the age of 50,” said Dr. J. Michael Gaziano, a cardiologist at Brigham and Women’s Hospital in Boston and the study’s lead author.
"It's a very mild effect and personally I'm not sure it's significant enough to recommend to anyone," Dr. Ernest Hawk, vice president of cancer prevention at the University of Texas MD Anderson Cancer Center, told the Associated Press.
He added, “At least this doesn’t suggest a harm.”
The results of the new study are in contrast to previous tests of some individual vitamins, such as vitamins A and E, which were found to not prevent chronic illnesses and, in higher doses, may even cause problems.
About half of all Americans take vitamin supplements, and at least one-third take a multivitamin.
Multivitamin intake is still less effective than a good diet, exercise and not smoking, each of which can lower cancer risk by 20 to 30 percent, according to cancer experts who spoke with the AP.
Still, this latest study somewhat contradicts the 2010 Dietary Guidelines for Americans that said “there is no evidence to support a recommendation for the use of multivitamin/mineral supplements in the primary prevention of chronic disease.”
In the clinical trial, conducted by Brigham and Women’s Hospital, nearly 15,000 male doctors who were 50 and older and cancer-free were given monthly packets of Centrum Silver multivitamins or fake multivitamins without knowing which type they received.
After nearly 11 years, there were 2,669 new cancers, and some of the men had cancer more than once. For every 1,000 men per year in the study, there were 17 cancers among multivitamin users and 18 among those taking the placebos.
That came to an eight percent lower risk of cancer in the group taking multivitamins.
The study also found that multivitamins cut site-specific cancers, except for prostate cancer, by 12 percent.