March 8, 2009

Vitamin E and Vitamin C Supplementation Do Not Appear to Prevent Cancer


Vitamin E and Vitamin C Supplementation Do Not Appear to Prevent Cancer

Long-term supplementation with vitamin E and vitamin C may not prevent cancer, according to data from the Physician’s Health Study II that was presented at the American Association for Cancer Research’s Seventh Annual International Conference in Washington, D.C. on November 16, 2008.[1]

The role of diet in cancer incidence remains a major focus among researchers, as it is becoming more evident that diet may reduce the risk of developing certain types of cancers. For example, vitamin D appears to have a protective effect against pancreatic cancer and also colorectal adenomas.[2][3] In addition, several studies have linked vitamin E, selenium, and lycopene with a reduction in prostate cancer. However, it has also been discovered that supplementation with specific vitamins and minerals often does not have the same protective role as obtaining the nutrients from foods. In other words, there is still much to be learned about the role of nutrients in the prevention of cancer.

The Physician’s Health Study II is a large-scale, long-term, randomized clinical trial involving over 14,000 physicians over the age of 50. The physicians were given either a) 400 IU of vitamin E every other day or placebo or b) 500 mg of vitamin C daily or placebo and were then followed for up to 10 years. The primary endpoint of the vitamin C group was the development of cancer. The primary endpoint of the vitamin E group was the development of prostate cancer, with a secondary endpoint being the development of any type of cancer.

After nearly 10 years of supplementation, there was no evidence that vitamin E or vitamin C played a protective role against cancer. Thus far, there have been 1,929 cancer cases in the group, including 1,013 cases of prostate cancer. The researchers concluded that neither vitamin E nor vitamin C offers any beneficial effect against cancer.

Research in this field is ongoing; however, the results from this study indicate that vitamin supplements may not provide the same benefits as vitamins included as part of a healthy, balanced diet.


[1] Buring JE, Sesso HD, Gaziano JM, et al. A randomized factorial trial of vitamins E and C in the prevention of cancer in men: the Physicians’ Health Study II. Proceedings from American Association for Cancer Research Annual Meeting. Abstract #PR-1.

[2] Skinner HG, Michaud DS, Giovannucci E, Willett WC, Colditz GA, Fuchs CS. Vitamin D Intake and the Risk for Pancreatic Cancer in Two Cohort Studies. Cancer Epidemiology, Biomarkers, and Prevention. 2006;15:1688-95.

[3] Wei MY, Garland CF, Gorham ED. Vitamin D and prevention of colorectal adenoma: A meta-analysis. Cancer Epidemiology, Biomarkers and Prevention. 2008;17(11):2958-2969.

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