Beta-carotene is a precursor of vitamin A (provitamin A), and is a conditionally essential nutrient. It is essential only when the dietary intake of vitamin A is inadequate. Beta-carotene is a natural fat-soluble pigment found principally in plants, algae, and photosynthetic bacteria. It is claimed to have immuno-mudulatory and anti-carcinogenic activities. Carotenoids are the principal pigments responsible for the red, orange, yellow and green colors of vegetables and fruits (beta-carotene is responsible for the color of carrots). Rich sources are carrots, cantaloupe, broccoli, spinach, collard greens, and palm oil. Supplemental intake of beta-carotene ranges from 3-15 milligrams/day. (For more detailed information, please visit ISM’s searchable database: Nutraceutical Search.)

Consuming beta-carotene in vegetables (three or more servings a week) could reduce the risk of stomach cancer by between 35 and 57 per cent.

o        L. Larsson, Cancer Epidemiology Biomarkers & Prevention Vol. 15, pp. 1998 -2001.

People with the highest intake of the carotenoids, lutein and zeaxanthin, were associated with a 46 per cent lower risk of non-Hodgkin lymphoma, compared to people in the lowest intake group, while zinc intake was also linked to a lower risk (42 per cent) (epidemiological study). The researchers propose that the mechanism is the antioxidant effects of the carotenoids. One of the risk factors for NHL is said to be DNA damage caused by oxidative stress from reactive oxygen species (ROS), and this is reduced by an antioxidant-rich diet. Non-Hodgkin Lymphoma is a cancer that starts in the lymphatic system and encompasses about 29 different forms of lymphoma. According to the American Cancer Society, over 50,000 new cases are diagnosed in the US every year.

o        Kelemen, American Journal of Clinical Nutrition Vol. 83, pp. 1401-1410.

Various natural carotenoids were proven to have anticarcinogenic activity. Multi-carotenoids (mixture of natural carotenoids) seems to be of interest in human cancer prevention.

o        Biofactors. 2000; 13(1-4): 89-94.

Population of 25,000 showed beta-carotene protected against cancers of lung, stomach, colon, prostate & cervix.

o        Hughes, Nutr. Rep (1992) 10(1):1-8.

Major review found “carotenoids exert an important influence in modulating the actions of carcinogens”.

o        Krinsky, Amer. J. of Clinical Nutr. (1991) vol 53, p 238s.

A diet rich in carotenoids, including beta-carotene can decrease the risk of ovarian cancer in postmenopausal women.

o        Cramer, Int J Cancer 94:128-34.

Breast Cancer:

A low intake of carotenoids, through poor diet and/or lack of vitamin supplementation, may be associated with increased risk of breast cancer.

o        Am J Epidemiol. 2001 Jun 15; 153(12): 1142-7.

Women with cancer of the breast or of other sites might have low intake of carotenoids such as beta-carotene and zeaxanthin & lutein.

o        J Epidemiol. 1999 Nov; 9(5): 306-14.

Inhibit the growth of colon cancer cells and reduces colon cell proliferation of adenomatous polyps. The suppression of COX-2 may represent a molecular mechanism by which beta-carotene acts as an anti-tumor agent in colon carcinogenesis.

o        J Nutr. 2005 Jan; 135(1): 129-36.

Increasing dietary beta-carotene can decrease the incidence of colorectal cancer.

o        Levi, Eur J Cancer 2000;36:2115-9.

Prostate Cancer:

Beta-carotene supplementation associated with reduced risk.

o        J Natl Cancer Inst. 2006 Feb 15; 98(4): 245-54.