Alpha-Tocopherol & Beta-Carotene Supplementation: A Post-Intervention Follow-Up
According to an article recently published in the Journal of the American Medical Association, alpha-tocopherol appears to significantly reduce the risk of prostate cancer, while beta-carotene increases risk of lung cancer and total mortality.
Alpha-tocopherol and beta-carotene are specific forms of fat-soluble vitamins. Alpha-tocopherol is one of eight forms of Vitamin E. According to research, alpha-tocopherol appears to be the most active form of Vitamin E in the human body. Food abundant in alpha-tocopherol includes vegetable oils, nuts, leafy green vegetables, and fortified cereals. Beta-carotene is a carotenoid, which are substances that contain pigments responsible for color in foods, such as orange in carrots. Beta-carotene is converted by the body into retinol, the most bioavailable form of Vitamin A. Dark green and orange-yellow vegetables are good sources of beta-carotene.
Both alpha-tocopherol and beta-carotene are anti-oxidants, substances that deactivate free radicals. Free radicals are by-products of metabolism consisting of single oxygen molecules. Free radicals are highly reactive, causing them to damage cell walls, certain cell structures, and genetic material (such as DNA) within cells through a process known as oxidation. Oxidative damage can become irreversible over long periods of time, leading to various degenerative diseases such as cancer. Commonly included in multi-vitamin supplements, numerous studies are exploring whether these anti-oxidants may prevent cancer.
The National Public Health Institute of Finland conducted the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. In the ATBC study, 29,133 healthy men between the ages of 50 and 69 years were randomly assigned to one of four groups. For five to eight years, each patient consumed daily: 1) alpha-tocopherol (50 mg), 2) beta-carotene (20 mg), 3) both agents, or 4) placebo (an inert substance). The current study followed 25,563 men between six and eight years after completion of the original trial.
Researchers reported that recipients of beta-carotene were significantly more likely to develop lung cancer or to die than non-recipients. In contrast, participants receiving alpha-tocopherol were significantly less likely to develop prostate cancer. No late preventive effects on other cancers were observed for either supplement. In addition, the increased risk associated with beta carotene was no longer evident four and six years after the end of the study.
The authors suggested that additional research is needed to confirm the potential cancer preventative effect of alpha-tocopherol against prostrate cancer. They also cautioned smokers to avoid beta-carotene. Patients with cancer may wish to speak with their physician about the risks and benefits of CAM or about participation in a clinical trial further evaluating CAM therapies. Three sources of information regarding ongoing clinical trials include the National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine at , the National Center for Complementary and Alternative Medicine at ,and eCancerTrials.com. Personalized clinical trial searches on behalf of patients are also provided at eCancerTrials.com.
Reference: Virtamo J, Pietinen P, Huttunen JK, et al. Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up.
Journal of the American Medical Association. 2003;290:476-85.
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