Evaluation of vitamin A toxicity.

摘要: Toxicity has been associated with abuse of vitamin A supplements and diets extremely high in preformed A. Consumption 25,000-50,000 IU/d for periods several months or more can produce multiple adverse effects. The lowest reported intakes causing toxicity have occurred persons liver function compromised by drugs, viral hepatitis, protein-energy malnutrition. Certain drugs other chemicals may markedly potentiate animals. Especially vulnerable groups include children, effects occurring as low 1,500 IU.kg-1.d-1, pregnant women, birth defects being maternal approximately 25,000 IU/d. dose threshold cannot be identified from present data. An identifiable fraction the population surveyed consumes at a few individuals consume much more. beta-Carotene is less toxic than