Multivitamin Use May be Linked to Reduced Cancer Risk

This multivitamin was used in the randomized clinical research trial described below.

On NBC Nightly News (10/17, story 5, 1:50, Williams), NBC’s Chief Science Correspondent Robert Bazell said that for the clinical trial, “The Physicians Health Study,” researchers gave almost 15,000 male doctors  either a multivitamin or a placebo. Treatment with the multivitamin resulted in a small reduction in total cancer risk.

Bloomberg News (10/18, Flinn) reports, “The study’s authors couldn’t pinpoint any single reason for the reduction in cancer among those who took the supplements, though they speculated it may be due to the combination of several low-dose vitamins and minerals, where previous studies looked at the effect of high levels of individual nutrients.”

The Boston Globe (10/18, Kotz) “Daily Dose” blog reports, however, that according Dr. Albanes, “These are very encouraging results, but women weren’t included in this study, nor were younger men, nor those from a range of ethnicities.” Dr. Albanes added, “It’s one trial, and we’ve seen many cases where one trial doesn’t always give the final answer.

The AP (10/18, Marchione, Writer) reports that Dr. Ernest Hawk, formerly of the National Cancer Institute, said that “it’s a very mild effect and personally I’m not sure it’s significant enough to recommend to anyone,” but “at least this doesn’t suggest a harm.”

 Medical Commentary by Paul Goldfinger, MD, FACC

There have been many prior trials of multivitamins in the past, trying to prove a benefit in preventing chronic diseases, especially heart trouble and cancer. The National Institutes of Health’s most recent recommendations for good health do not include vitamins for protection. But, the fact is that 1/3-1/2 of the US population take vitamin supplements.

This trial is unique because it is a huge study over 14 years involving nearly 15,000 male physicians over the age of 50. The trial is considered kosher because of its size, long followup and the fact that it is randomized and placebo controlled. The multivitamin that was used was Pfizer’s Centrum Silver, which contains an array of vitamins and minerals.

The study did show a modest benefit with an 8% reduction in total cancer incidence, but the treatment did not result in any reduction in mortality. The most common cancer in the group was prostate, and that was not reduced by vitamins. Also, there is no answer here for women. Prior trials in women were inconclusive. Even the treated group here is a very special one consisting of mostly health minded, non-smoking doctors — not exactly reflecting the general population. This trial, the Physicians Health Study, is presented by the National Cancer Institute and the Brigham and Women’s Hospital in Boston.

The NIH will consider this result in planning for future recommendations, but so far they are not changing their guidelines. In the New York Times today, Dr. J. Michael Gaziano, a cardiologist from Boston, said that the benefit of the trial was “modest” but significant. He stressed that other measures are more important than taking vitamins, such as exercise, a nutritious diet and stopping smoking.

My own history over the years with vitamins has fluctuated with the tides of research trials that yielded conflicting results. My usual advice to patients was to skip the vitamin supplements unless they had a poor diet and needed nutritional augmentation. Certainly mega doses of vitamins, advocated by some, have no scientific support.

In the most recent (2011) edition of our book on preventing heart disease, this is what we say: “Vitamins used to be recommended as preventive therapy due to their anti-oxidant actions. In recent years, however, large trials have shown no benefit with vitamins, so these supplements can no longer be considered part of a prevention regimen. This conclusion does not apply to vitamins found in fruits and vegetables.”

But now, I think I’ll get some Centrum Silver. What the heck, it might help and it won’t hurt. Maybe I’ll change my mind with the next study.