Taking a multivitamin may help prevent cancer in healthy middle-aged men, according to a new study published Wednesday in the Journal of the American Medical Association.

The study

Scientists at Brigham and Women's Hospital and Harvard Medical School recruited nearly 15,000 male physicians, 50 years or older, and followed them for more than a decade. Half took the daily multivitamin Centrum Silver; the others took a placebo.

Men in the vitamin group had a modest 8% reduction in cancer cases compared to the others.

"This study suggests, at least for men, that there might be benefits to taking multivitamins in terms of cancer,” study author Dr. John Michael Gaziano said in a press release. He is the chief of the Division of Aging at Brigham and Women’s Hospital.

"Overall the study provides the first very nice piece of evidence that well-balanced – not overdose, not mega dose – combination of vitamins and minerals seems to have an effect at preventing cancer," said Dr. Boris Pasche, director of the Division of Hematology/Oncology at the University of Alabama at Birmingham. "But more research is needed to validate this."

The researchers were not able to determine which types of cancers might be prevented when taking the vitamins.

They are also not sure that the results will be seen in other groups of people such as women or smokers. The men in this study were generally healthy physicians, not overweight or obese and most were non-smokers.

"It will be difficult to make generalizations to the broad public from this one study, but I was impressed by the data," said Dr. Ernest Hawk, vice president and division head for the Division of Cancer Prevention & Population Sciences at MD Anderson Center in Houston, Texas.

Vitamins: Friend or foe?

Back when the study began in 1997, most experts thought taking a vitamin would be beneficial to our health. But in the subsequent years, many scientists were alarmed by evidence suggesting potential harm from vitamin use. Newer studies found vitamin supplements didn't reduce the risk of cancer, and, in some cases, raised the risk of men and women developing cancer.

This latest study may once again lead experts to re-visit the issue. Pasche and Hawk, who did not participate in the research, said they are encouraged that after 10 years of study researchers did not see an increase in lung, colorectal, prostate and other cancers, but rather a modest decline in overall cancer cases.

Take home message

"I think this provides more data... that these sorts of supplements aren't associated with harm, so it removes the concern that many people had about the use of vitamin supplements drawing from recent data," explained Hawk.

Why might certain supplements offer protection again cancer? Experts aren't sure but said that the well-balanced formulation of nutrients in the multivitamin instead of mega doses may be part of the answer.

Pasche, who stopped taking vitamins back in the 2000s because of the cancer scare said, "This study will make me rethink this. You have a good rational to say from this study that it's not risky and could potentially help prevent a certain number of cancers."

Hawk is more cautious with his approach. He said that reducing cancer risk may not necessarily be garnered from a pill but rather by living healthy: eating right, getting plenty of exercise and not smoking.