Beta Carotene

Beta-carotene is one of a group of natural chemicals known as carotenes or carotenoids. Carotenes are responsible for the orange colour of many fruits and vegetables such as carrots, pumpkins, and sweet potatoes.
Beta carotene is converted in the body to vitamin A. It is an antioxidant, like vitamins E and C, and it is fat-soluble.
Good food sources of beta-carotene include dark green and orange-yellow vegetables, such as carrots, sweet potatoes, squash, spinach, broccoli, romaine lettuce, apricots, and green peppers.
Beta-carotene is not an essential nutrient, although vitamin A is. This makes beta-carotene conditionally essential; if there is no source of pre-formed vitamin A in the diet (this applies to those with very poor diets, or vegans) then beta-carotene becomes essential as it is the only source of vitamin A.

Beta-carotene is useful for: Prevention against cancer and heart disease; To slow the progression of cataracts; To prevent macular degeneration; To boost immunity; To protect the skin against sunburn; Asthma; Depression; Infertility; Parkinson's disease; Psoriasis; Arthritis; High blood pressure; Cervical dysplasia; Intermittent claudication.
Beta carotene is useful in most of these problems because it is a strong antioxidant; in the rest it is because it is a source of vitamin A.
Beta carotene is relatively safe. There is some concern that high doses of beta-carotene can cause a slight increase in the risk of heart disease and cancer, especially in people who smoke cigarettes and who consume excessive alcohol. However, the studies showing this effect were done with synthetic beta-carotene on its own, without the other carotenoids that usually accompany beta carotene in food and in the better supplements.

Other side effects include diarrhoea and a yellowish tinge to the skin, both of which subside then the intake of beta-carotene is lowered. The yellow tinge occurs because the body has to find somewhere to put the beta carotene that is surplus to requirements.