A new medical report is claiming that a daily intake of multivitamins can help reduce the risk of cancer in older men.
The claim is based on the results of a decade-plus-long clinical trial of nearly 15,000 older male physicians who took a multivitamin each day, and had eight percent fewer occurrences of cancer than test subjects who ingested placebos. Conducted in an extremely rigorous manner, the trial was one of the largest and longest experiments regarding vitamin usage.
The newsworthy findings were presented last week at an American Association for Cancer Research conference on cancer prevention in Anaheim, California, and they were published online in The Journal of the American Medical Association.
While the percentage of cancer reduction was technically small, it is considered statistically significant, according to the study’s lead author, Dr. J. Michael Gaziano, a cardiologist at Brigham and Women’s Hospital and the VA Boston Healthcare System. Acknowledging that a multivitamin’s primary purpose is to prevent nutritional deficiencies, Dr. Gaziano stated, “It certainly appears there is a modest reduction in the risk of cancer from a typical multivitamin.”
Dr. Graziano also agreed that the daily ingestion of multivitamins would not be as effective a preventative against cancer as other commonly accepted methods. “It would be a big mistake for people to go out and take a multivitamin instead of quitting smoking or doing other things that we have a higher suspicion play a bigger role, like eating a good diet and getting exercise,” the physician said. “You’ve got to keep wearing your sunscreen.” A balanced diet, exercise and abstaining from smoking can each decrease one’s cancer risk by 20 percent to 30 percent, according to cancer experts.
The study was financed by the National Institutes of Health and a grant from the chemical company BASF, and Pfizer supplied the multivitamins. The sponsors had no influence over the trial’s study design, data analysis or manuscript preparation, the authors said.
Studies show that approximately one-half of all Americans take a vitamin supplement in some variation, and at least one-third take a multivitamin. In contrast to the latest report, many recent vitamin studies have demonstrated no health benefit – and even some possible harm – from taking large doses of multivitamin supplements. The 2010 dietary guidelines for Americans deny any solid evidence that the daily intake of multivitamins or mineral supplements can serve to prevent chronic disease.
According to the American Cancer Society, people should maintain a balanced diet, but those who wish to take nutritional supplements should select a balanced multivitamin that contains an absolute maximum of 100 percent of the daily value of most nutrients.
Dr. E. Robert Greenberg, an affiliate at Fred Hutchinson Cancer Research Center in Seattle, reacted positively to the study results. “It is a small overall effect, but from a public health standpoint, it could be of great importance,” Greenberg noted. “Other than quitting smoking, there’s not much else out there that has shown it will reduce your cancer risk by nearly 10 percent.”
Multivitamins did not impact the incidence of prostate cancer, the most common cancer diagnosed in the clinical trial’s participants. However, researchers discovered a 12 percent reduction in occurrence of all other types of cancer.
Sounding a cautionary note about the study’s results, Marji McCullough, a nutritional epidemiologist with the American Cancer Society, pointed out that it only encompassed male doctors, who were especially healthy, and had extremely low smoking rates. “We still need to find out whether these findings can be applied to others in the population,” McCullough said.
Dr. David Chapin, a 73-year-old gynecologist at Beth Israel Deaconess Medical Center in Boston who took part in the experiment, remarked that while he had “never believed” in vitamins, he is now thinking of beginning a daily multivitamin regimen, despite the moderate benefit.
“A lot of studies make big news, but when you look at the nitty-gritty, they don’t show all that much,” Dr. Chapin said. “This was a very reliable study, it was very well designed and administered, and it went on and on and on.”
Dr. Ernest Hawk, vice president of cancer prevention at the University of Texas MD Anderson Cancer Center and formerly of the National Cancer Institute, was somewhat less impressed by the study results. “It’s a very mild effect and personally I’m not sure it’s significant enough to recommend to anyone, although it is promising,” he commented. “At least this doesn’t suggest a harm.”