Nutrition Science Update - Carotenoids (Part Three of
Ten)
This special Nutrition Science Update takes the guess work out of keeping up-to-date on important nutritional breakthroughs by presenting the following summations of all the most important research released over the past year.
Key concepts in Carotenoid Research:
Beta-carotene made headlines early last year when researchers from the Beta Carotene and Retinol Efficacy Trial (CARET) announced the termination of their study, after four years of beta-carotene supplements showed no health benefit, and may have actually increased the risk of lung cancer. Some carotenoid experts theorize that the synthetic form of beta-carotene utilized in this study may have contributed to these unexpected results. Natural forms of beta-carotene are better utilized by the body.
Nonetheless, CARET's interim results are cause for alarm; it may be prudent for smokers to avoid synthetic beta-carotene until more is known. Or better yet quit smoking. There is no evidence to suggest that non-smokers are harmed by any type of beta-carotene.
But not all of the recent beta-carotene news is bad. For instance, researchers at the Human Nutrition Research Center on Aging at Tufts University, Boston, report that "long term beta-carotene supplementation enhances NK [natural killer] cell activity in elderly men, which may be beneficial for viral and tumoral surveillance." (Santos, M.S., et al., American Journal of Clinical Nutrition, 1996;64:772-777.)
Another study of 5,182 individuals 55-95 years old found that beta-carotene rich foods "may protect against cognitive impairment in older people." (Launer, L.J., et al., American Journal of Epidemiology, 1996;144(3):275-280.)
Beta-carotene is only one of hundreds of different carotenoids with potentially health-enhancing effects. An article in the Journal of Nutrition (Jyonouchi, H., et al., 1995;125:2483-2492) reports that astaxanthin boosts immune function. Canthaxanthin, at the same concentration as beta-carotene, exerts greater antioxidant protection in laboratory dishes of cells exposed to carcinogens. (Palozza, P., et al., Archives of Biochemistry and Biophysics January 15, 1996;325(2):145-151).
Although beta-carotene has been tied to the prevention of prostate cancer, research involving the other carotenoids has been few and far between. That is, until a large prospective study was initiated by Harvard researchers to determine the effect of various carotenoids on the risk of prostate cancer. In this study of 47,894 healthy men, a diet rich in lycopene reduced the risk of prostate cancer by 45%. (Giovannucci, E., et al., Journal of the National Cancer Institute, December 6, 1995;87(23):1767-1776.)
Vitamin Retailer - February 1997
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Don't miss Part four - Herbs in this Ten Part series
