Vitamin A

Vitamin A is a fat-soluble vitamin that occurs in two forms: retinol and provitamin A (carotene). Vitamin A is essential for an efficient immune system and is important in maintaining the quality of health of your eyes, skin, teeth, bones, and mucous membranes. Beta carotene is a provitamin A carotenoid that is more efficiently converted to an active form of vitamin A than other carotenoids. Because it is a "provitamin", the body can also regulate its conversion in a manner that will prevent vitamin A toxicity, which can occur when taking vitamin A in the form of retinol. High intake of retinol has also been associated with an increased risk of hip fractures in both men and women (Journal of the American Medical Association, 2002, and New England Journal of Medicine, 2003). Most people get enough of this vitamin through food; therefore, the preferred form of this vitamin is beta carotene or the natural mixed carotenoids.

Beta carotene, as well as the other members of the carotenoid family, are precursors to Vitamin A (transformed into the vitamin after entering the body). Beta carotene has been linked to a lower risk of cataracts, heart disease, and cancers, such as rectal cancer, melanoma, and bladder cancer. In the November 4,1994 issue of the Journal of the American Medical Association, stated that the natural carotenoids, including beta carotene (5000 IU) but also lutein and zeaxanthin, have been shown to be effective in decreasing the risk and even reversing the development of age-related macular degeneration, the leading cause of blindness in Americans over 65 years of age.

Two studies published in the New England Journal of Medicine in April 1994 suggest an increased risk for lung cancer and heart disease in smokers when taking mega doses of beta carotene, but there are still unanswered questions.