Beta carotene supplements are available in synthetic forms or from algae and palm oil, which may possess greater beneficial effects than synthetic forms. Vitamin A is fat-soluble and joins to fatty acids in the intestinal lining where it combines with other substances before being transferred to the liver, where 90 percent of the body s vitamin A is stored. Because vitamin A is fat-soluble and can be stored in the liver for long periods of time, there exists the possibility for toxicity. It would be difficult to intake toxic levels of vitamin A from diet alone, but vitamin A supplements do pose a potential risk. A toxicity include headaches, chapped lips, dry skin and joint and muscle pain.
Beta carotene is non toxic.
High doses of vitamin A complemented by doses of vitamin E administered to children in Bangladesh cured them of the bacterial disease, shinellosis, according to a report in the British Medical Journal . According to the researchers, vitamin A reduces the severity of acute shinellosis in children living in areas where vitamin A deficiency is a major health problem. 4 A puzzling story appearing in the Journal of the American Geriatrics Society indicated that zinc supplements improved some measures of immune function, while vitamin A supplements blunted others in a group of institutionalized but relatively healthy older adults. The researchers reported that they cannot explain the negative effects of vitamin A, especially since there is evidence that that the essential nutrient improved immune function. In a study published in International Journal of Vitamin and Nutrition Research , the inhibitory effects of beta carotene and vitamin A on precancerous lesions in rats was compared when administered early promotion of liver cancer.