Among people with a history of cardiovascular disease, taking dietary supplements of B vitamins and/or omega-3 fatty acids does not appear to reduce the risk of cancer. These results were published in the Archives of Internal Medicine.
Dietary supplements are widely used by theU.S.population in the hope of preventing or treating common chronic diseases. The health effects of many of these supplements remain uncertain, and some supplements have been found to cause harm.
To explore whether supplementation with B vitamins or omega-3 fatty acids reduces the risk of cancer, researchers analyzed information from a large clinical trial of people who had survived cardiovascular disease. The study enrolled more than 2,500 people between the ages of 45 and 80 who had a history of heart attack, unstable angina, or ischemic stroke. Study participants were given supplements (B vitamins and/or omega-3 fatty acids) or placebos.
- Overall, the dietary supplements did not affect the risk of getting or dying from cancer.
- Among the female study participants, there was a suggestion that the dietary supplements may increase cancer risk. Because this result was based on fairly small numbers of people, however, it should not be considered definitive.
These results suggest that B vitamin and omega-3 fatty acid supplements are unlikely to be effective for cancer prevention. The possibility that these supplements could increase cancer risk in women requires additional research.
People who are considering taking dietary supplements are advised to discuss the decision with their doctor.
Reference: AndreevaVA, Touvier M, Kesse-Guyot E, Julia C, Galan P, Hercberg S. B Vitamin and/or omega-3 fatty acid supplementation and cancer. Archives of Internal Medicine. Early online publication February 13, 2012.