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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #208393
Title: Beta-Carotene

Author
item MERNITZ, HEATHER - HNRCA AT TUFTS
item Wang, Xiang-Dong

Submitted to: Encyclopedia of Cancer and Society
Publication Type: Book / Chapter
Publication Acceptance Date: 6/2/2007
Publication Date: 9/12/2007
Citation: Mernitz, H., Wang, X. 2007. Beta-Carotene. In: Golson, J.G., Colditz, G.A. Encyclopedia of Cancer and Society. Sage Publications. p. 94-99.

Interpretive Summary:

Technical Abstract: Beta-carotene is a pigment that occurs naturally in many photosynthetic plants and organisms and one of the most abundant carotenoids found in human blood. The richest dietary sources of beta-carotene are yellow, orange, and leafy green fruits and vegetables, such as carrots, spinach, sweet potatoes, and cantaloupe. There are several mechanisms by which beta-carotene may be able to offer protection against cancer. Beta-carotene acts as a fat-soluble antioxidant to protect plants and animals against free radical-induced oxidative damage to DNA, lipids, and other molecules. Beta-carotene also serves as a precursor to vitamin A and represents the major dietary source of vitamin A for much of the world's population. Through vitamin A action, beta-carotene can exert effects on cellular proliferation and differentiation, immune function, and cell-cell communication. Epidemiological studies suggest that a higher dietary intake of carotenoids, including beta-carotene, may offer protection against the development of certain cancers (e.g., lung, prostate, cervix, bladder, gastrointestinal tract, breast), as well as other health conditions linked to oxidative damage (e.g., heart disease, macular degeneration, cataracts). However, two large, double-blind clinical trials have shown that supplementation with high doses of beta-carotene do not reduce the risk of lung cancer and may even increase that risk in smokers. These findings have led to an increased effort over the last decade to better understand the mechanisms behind the conversion of beta-carotene to vitamin A and the role of beta-carotene and its metabolites in the process of carcinogenesis.