Alpha Carotene and Beta Carotene
Beta carotene is one of about 500 similar compounds called carotenoids, which are present in many fruits and vegetables. The body changes beta carotene into vitamin A, which is important in strengthening the immune system and promoting healthy cell growth. However, beta carotene is much more than the precursor for vitamin A. Only so much beta carotene can be changed into vitamin A, and that which is not changed contributes to boosting the immune system and is also a potent antioxidant. Antioxidants fight free radicals and help prevent them from causing membrane damage, DNA mutation, and lipid (fat) oxidation, all of which may lead to many of the diseases that we consider "degenerative."
Beta carotene is not the only carotenoid. Often overlooked, and also found in carrots, is alpha carotene. According to an article in NCI Cancer Weekly (Nov. 13, 1989), Michiaki Murakoshi, who leads a team of biochemists at Japan's Kyoto Prefectural University of Medicine, contends that alpha carotene may be more powerful than beta carotene in inhibiting processes that may lead to tumor growth. Murakoshi indicates that neuroblastoma (cancer) cells coated with carotenoids experience a drop in N-myc activity compared to untreated cells. N-myc is a gene that codes for cell growth-stimulating proteins and can contribute to cancer formation and growth. Alpha carotene was found to be about ten times more inhibitory toward N-myc activity than beta carotene. Murakoshi concludes that all types of carotenoids should be studied for possible health benefits.
In sum, alpha carotene and beta carotene, like all nutrients found in vegetables and fruits, have health benefits. Indeed, The 1995 Dietary Guidelines for Americans, released by the U.S. government, states that "The antioxidant nutrients found in plant foods (vitamin C, carotene, vitamin E, and the mineral selenium) are presently of great interest to scientists and the public because of their potentially beneficial role in reducing the risk of cancer and certain other chronic diseases."