Beneficial Effects Of Vitamin A & Beta-Carotene

Article Highlights

Vitamin A is essential for normal metabolism, growth and general health.
Carotenoids such as beta-carotene are powerful antioxidants and may help prevent eye disease, heart disease and cancer.
Antioxidant properties of carotenoids are highest when obtained from foods rather than from dietary supplements.

Vitamin A is an essential vitamin necessary to maintain good health. It is most well known for its role in night vision, but has a number of other important functions as well. Vitamin A is necessary for growth of healthy bones and teeth, reproductive function, and normal immune system function. It also helps maintain the health of the lining of the eyes, intestinal, respiratory and urinary tracts and is required for normal gene expression and embryonic development.

Vitamin A precursors beta-carotene and other carotenoids are powerful antioxidants. Other antioxidants include selenium, zinc, manganese, and copper. They neutralize free radicals and singlet oxygen, both of which can damage DNA and contribute to age-related eye disease (macular degeneration), heart disease (coronary artery disease) and cancer. Some free radicals are made by the body while others are in our air and food. The antioxidant properties of beta-carotene and other carotenoids are highest when obtained from foods. There is less evidence for antioxidant benefit from high dose beta-carotene as a dietary supplement.^1,2 This difference between foods and dietary supplements actually may be due to other compounds in fresh fruits and vegetables called phytochemicals. One study, however, did show that 20,000 IU supplemental beta-carotene and several other antioxidants in doses typical of a good diet decreased the incidence of cancer by 31% and reduced death rates from all causes by 37%.³

¹Levin G, et al. Antioxidant activity of 9-cis compared to all-trans beta-carotene in vitro. Free Radic Biol Med. 1994;17(1):77-82.

²Levin G, et al. In vivo antiperoxidative effect of 9-cis beta-carotene compared with that of the all-trans isomer. Nutr Cancer. 1997;27(3):293-297.

³Hercberg S, et al. The SU.MAX Study: A Randomized, Placebo-Controlled Trial of the Health Effects of Antioxidant Vitamins and Minerals. Arch Intern Med. 2004;162(21):2335-2342.