The Benefits of Beta Carotene:
In the 1970's, researchers found that beta-carotene can protect the skin from the damaging effects of erythropoietic protoporphyria, an inherited disease in which the skin becomes red and swollen when exposed to sunlight. This use of beta-carotene followed the discovery that carotenoids protect plants from free radicals that are generated during photosynthesis. Studies also indicate that it may help to protect the eyes from the damage that can lead to cataracts.
The fat-soluble beta-carotene is converted to vitamin A in the body as it is needed. For the most part, this conversion takes place in the small intestine. Any remaining beta-carotene in the blood will be converted by the liver. Unlike vitamin A, which has potentially toxic effects if taken in excess, beta-carotene threatens no such toxicity. If you consume amounts in excess of the body's immediate needs, the extra beta-carotene may be stored in fat tissues or it may circulate in the blood.
In a 1985 study, people who took beta-carotene had an increased number of T-helper cells, which assist in critical aspects of the host immune response. Similarly, a recent study of older adults found that beta-carotene supplements of 30 mg or more a day significantly increased the number of T helper cells and natural killer cells. In this case, the levels of retinol (vitamin A) did not increase along with beta-carotene in the plasma. This finding suggests that beta-carotene enhances the immune system independently of its pro-vitamin A function. The researchers concluded: "These results support the role of immunostimulation as a potential mechanism of action of beta-carotene with cancer prevention potential."
Beta-carotene's most powerful role is to quench singlet oxygen, the reactive oxygen species that can generate free radicals by unloading its excess energy onto other molecules. Beta-carotene may put singlet oxygen out of business before it can initiate skin and lung cancer. In fact, beta-carotene is in a class by itself when it comes to combating singlet oxygen. Unlike vitamin E, which is destroyed in the process of returning singlet oxygen to its normal state, beta-carotene can come through the battle unharmed.
As if quenching singlet oxygen were not enough, beta-carotene also acts as a direct scavenger of free radicals. It comes on the scene after free radicals are formed to trap the maverick molecules and break the chain reaction. Vitamin E, by contrast, can prevent free radicals from being formed in the first place.
Another interesting footnote on beta-carotene: It seems to do its best antioxidant work in areas of the body that have low concentrations of oxygen, such as the capillary beds. Meanwhile, antioxidants such as vitamins C and E, glutathione peroxidase and catalase are not especially effective in these low-oxygen areas. As a result, beta carotene's actions may be complementary to those of other nutrients.
Beta-carotene complements the antioxidant action of vitamin E, with beta-carotene working well at low oxygen concentrations and vitamin E excelling at higher oxygen concentrations.
There may even be a synergistic effect between beta-carotene and vitamin A (retinal). In one study, women with severe premenstrual breast pain were treated with both nutrients for six months. They showed a marked reduction in the pain and, in some cases, a recovery from the condition.
The government has not established a recommended level for beta-carotene. As a precursor to vitamin A, beta-carotene itself is not considered to be an essential nutrient. The National Academy of Sciences suggests that adults need 500 to 600 micrograms of retinol (vitamin A) or twice as much beta-carotene to prevent deficiency and to achieve the beneficial effects of storing beta-carotene in the liver. |