Cancer Treatment Centers of America
Christina Shannon, ND, FABNO,

Multivitamins may not prevent cancer: Should you take one?

blog multivitamins

The headline in a leading medical journal, “Enough is Enough: Stop Wasting Money on Vitamin and Mineral Supplements,” caught my attention before the holidays. The editorial in Annals of Internal Medicine summarized research finding no clear evidence that vitamins and minerals prevent disease, including cancer.

While the debate it not new, media attention of the editorial left many people wondering if they should bother taking a daily multivitamin. The answer is not clear-cut but, as a naturopathic oncology provider, I can offer insight and advice on the topic.

First of all, some studies suggest multivitamins can prevent various diseases. Let’s focus on multivitamins and cancer. In fact, one of the studies the editorial discussed actually showed a 7 percent decrease in cancer incidence among men, but not women. Why did men benefit while women did not? Further research into this gender difference would be beneficial.

Other studies show multivitamins may reduce cancer risk:

  • The Physician’s Health Study II published in 2012 showed that men who took a multivitamin had a modest reduction in risk of cancer. Keep in mind that the men in this study derived a benefit even though many were smokers and overweight, which are two significant risk factors for cancer. 
  • A 2010 study found that past smokers benefited from eating large amounts of green leafy vegetables while taking a folate supplement and a multivitamin. The vegetables and supplements helped protect study participants from changes to genetic expression that put people at greater risk for lung cancer.
  • A 2002 study of women showed reduced colon cancer risk with the use of multivitamins.

However, some studies have shown the opposite:

  • A 2009 study suggests multivitamins do not reduce cancer risk.
  • A 2005 study found an association between multivitamin use and increased risk of prostate cancer in a small subgroup of study participants.

The take-home message is that the issue of multivitamin usage is complex. Several factors may have contributed to the mixed results of the studies above: individual risk factors, consistency of use, the quality of the multivitamin, forms of vitamins and minerals, the presence of contaminants, and certain medications study participants may have been taking.

However, there is a growing body of research suggesting an important role for nutritional supplements in health and in the prevention of cancer. The studies above show that some individuals may benefit from multivitamins, particularly smokers and moderate-to-heavy drinkers, who are at greater risk for nutrient deficiencies.

I believe the answer to whether someone should take a multivitamin depends on each individual’s situation, including health history, risk factors, diet, lifestyle, use of other nutrients and prevention goals. It is important to work with a qualified, experienced clinician to determine what supplements would be most beneficial. 

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