Antioxidants and Cancer Prevention – Part 1

Most scientists now believe that antioxidants help to protect cells from the damage caused by unstable molecules, also known as free radicals. Researchers do know that free radicals cause damage to cells that later lead to cancer, Alzheimer’s disease, Parkinson’s disease and cardiovascular disease. (1)

There are actually a variety of different antioxidants which are found in nature. Some examples of antioxidants include Beta-Carotene, Lycopene, Vitamin C, Vitamin E, and Vitamin A. While proponents of antioxidant therapy have theorized that the way in which these substances fight free radicals will have a positive effect on the prevention of cancer or the treatment of cancer, they also believe that it may reverse cell aging. At this time there are no studies to indicate that antioxidants will have an effect on cell aging.

There has also been considerable evidence from a variety of research studies that antioxidants can slow or prevent the development of cancer cells in the petri dish. However, in clinical trials the evidence is less clear and the more recent larger clinical trials all reach inconsistent conclusions.

In the 1990s there were five large-scale clinical trials which were published, all of which reached different conclusions about the effects of antioxidants on cancer cells. These studies examine the effects of Beta-Carotene and other antioxidant chemicals on different patient groups.

In one study published in 1993 researchers in the Chinese Cancer Prevention Study investigated the effect of a combination of three different antioxidants- Beta-Carotene, Vitamin C and Selenium-on cancer in healthy Chinese men and women who were already at high risk for getting gastric cancer. This particular study showed that the combination of these three antioxidants were able to significantly reduce the incidence of gastric cancer in this population. (2)

References:

(1) National Cancer Institute: Antioxidants and Cancer Prevention

http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants

(2) National Cancer Institute: Stomach Cancer Prevention

http://www.cancer.gov/cancertopics/pdq/prevention/gastric/HealthProfessional/page1/AllPages/Print

(3) The New England Journal of Medicine: The Effect of Vitamin E and Beta Carotene on the Incidence of Lung Cancer and Other Cancers in Male Smokers

http://www.nejm.org/doi/full/10.1056/NEJM199404143301501

(4) Harvard University: Physician Health Study I

http://phs.bwh.harvard.edu/phs1.htm