Beta carotene is well known as a precursor to vitamin A. Beta carotene has been used as an antioxidant, to treat conditions of the eyes, and to support immune function. It comes from a large class of compounds called carotenoids, which include beta carotene, alpha carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene. Carotenoids are plant pigments of the yellow, orange and red fruits and vegetables. Beta carotene and some of the other carotenes are precursor to vitamin A. The carotenoids lutein, zeaxanthin, and lycopene have no vitamin A activity.
The immune system benefits a great deal from beta carotene and other vitamin A related compounds. Placebo-controlled research has shown positive benefits of beta-carotene supplements in increasing numbers of some white blood cells, especially when beta carotene is taken with vitamin E. Beta carotene has been thought to enhance cellular maturation and differentiation of the thymus gland, and to prevent thymic involution that can happen as humans age. The thymus gland is primarily responsible for the maturation of white blood cells called T-lymphocytes, which are involved in helping other white blood cells secrete specific antibodies in response to infection.
As an antioxidant, beta carotene was one of the main ingredients in formulations to prevent cancer. However, most of the supplements sold are synthetic beta carotene. Unfortunately, there is a great deal of difference between natural and synthetic beta carotene. The synthetic form consists of only one molecule called all trans beta-carotene. Natural beta-carotene, found in food, is made of two molecules-all trans beta-carotene and 9-cis beta-carotene. Many of the medical studies have used synthetic beta carotene. We now know that synthetic beta carotene may cause an increased risk of lung cancer in people who smoke, and if taken alone, may increase cardiovascular disease. It is for that reason that many doctors are recommending that people supplement only with natural beta-carotene. And until more research is known, smokers should avoid all beta-carotene supplements.
In supplements, the natural form can be identified by the phrases “from D. salina,””from an algal source,””from a palm source,” or as “natural beta-carotene” on the label. The synthetic form is identified as “beta-carotene” and it may not say what the source is.
Occasionally hypercarotenemia, a yellowish discoloration of the skin of the palms on the hands and souls of the feet, will occur if too much beta carotene is ingested (especially from fresh carrot juice, and has been known to happen from tomato soup; rarely does it occur on supplementation alone). While this is not a serious issues, except perhaps for being confused with jaundice (which can indicate liver problems) it does show the beta carotene is building up in the tissues and not being utilized. However, high levels of vitamin A can be a serious condition, and may present with nausea and vomiting, with dry peeling skin. If you are interested in bringing the positive effects of beta carotene into your health plan, consultation with a medical is important, and should be done before adding any new supplement into your diet.