Antioxidants and Cancer Prevention – Part 2

In another study published in 1994 men from Finland who smoked were given both Beta-Carotene and Vitamin E. This study demonstrated that lung cancer rates increased dramatically in individuals who smoked and took Beta-Carotene but were not affected by the combination of smoke and Vitamin E. (3) Another study also published in 1994 also demonstrated the same increase in lung cancer in individuals who had higher levels of Beta-Carotene.

In another study published in 1996, Physicians Health Study I, actually found no change in cancer rates associated with Beta-Carotene and aspirin which were taken by male physicians in the United States. (4) In a 1999 research study, women were tested for the effects of Vitamin E and Beta-Carotene in the prevention of both cancer and cardiovascular disease. In this study researchers found no benefit or harm from Beta-Carotene supplementation and the investigation on the effect of Vitamin E is still ongoing.

These large clinical trials demonstrate the inconsistency in the results found in individuals who were supplementing with Beta-Carotene, Vitamin E and/or aspirin. Because of this degree of inconsistency, further clinical trials are needed in order to ascertain results which can be used for clinical recommendations.

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