Do Multivitamins Fight Cancer?

Multivitamins Cancer

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Approximately one-third of Americans take a daily multivitamin for various reasons, but to date no major medical organization has come out in support of this practice. In addition, the 2010 Dietary Guidelines for Americans states that there is “no evidence to support a recommendation for the use of multivitamin/mineral supplements in the primary prevention of chronic disease.” But will a new study, just released in the Journal of the American Medical Association, change all this?

What the New Research Says

Researchers followed over 14,000 healthy male physicians 50 and older for an average of 11.2 years. Half the participants took a daily multivitamin; half took a placebo. The study was double-blind, meaning that neither the participants nor the investigators knew who was taking which. At the end of the study period, here’s what the researchers discovered:

  • There were a total of 2,669 cases of cancer. The most common, not surprisingly, was prostate cancer.
  • In the group that took a daily multivitamin, there was a statistically significant decrease in the number of overall cancer cases. How significant? There was a decrease of approximately 1 case of cancer for every 100 men who took a daily multivitamin for 10 years. This effect, while modest, is not the result of random chance.
  • There was no significant difference in the rate of death between the two groups. In other words, although the incidence of cancer declined, this finding didn’t translate into better outcomes. Perhaps the sample size and duration of the study was too short to demonstrate a reduction in deaths, or else the major impact of vitamin consumption was primarily on nonfatal cancer cases.
  • The group of men who took a daily multivitamin didn’t suffer an increase in serious side effects.

What We Know So Far

A plethora of previous studies have examined vitamins in various combinations in various populations and come to conflicting conclusions. Some showed a benefit in cancer reduction, others showed no benefit, and even others showed possible harm (some studies examining particular combinations of nutrients have actually found an increased rate of cancer). So what does this new study tell us? At best, we can say that this new data shows a modest benefit in cancer reduction in middle-aged to elderly men. Beyond that, there isn’t enough information to say for certain whether taking a daily multivitamin is beneficial as a preventive step against cancer for any other group.

Should You Take a Daily Multivitamin?

If you’re a man who’s 50 or older, you might consider making it a part of your morning ritual, but with the understanding that a daily multivitamin is not a magic bullet that will protect against cancer. Remember, based on what we know from the current data, only 1 out of 100 men taking a daily multivitamin for 10 years would benefit. Furthermore, that benefit doesn’t (as of yet) translate into a reduction in mortality. If you don’t fall into the demographic of this latest study, this new information may not to be particularly pertinent to you, but if you choose to take a daily multivitamin, there appears to be no obvious harm.

Of course, if you really want to reduce your risk of cancer–regardless of your age and sex–first and foremost, don’t smoke; eat a healthy diet; get enough rest; use sunscreen; and exercise regularly.

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The One Medical blog is published by One Medical, an innovative primary care practice with offices in Boston, Chicago, Los Angeles, New York, Phoenix, the San Francisco Bay Area, Seattle, and Washington, DC.

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