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Beta-carotene is a member of the family of carotenoids, highly pigmented (red, orange, yellow) fat-soluble vitamins that are the precursors or provitamins of vitamin A. The principle provitamin A compounds include beta-carotene, alpha-carotene, and beta-cryptoxanthin. Carotenoids occur in high levels in many fruits and vegetables such as carrots, sweet potatoes, cantaloupe, and others. The most significant effect of these provitamins is their conversion to vitamin A, which plays a major role in vision as well as reproduction, embryonic growth, and immune function.
The highest levels of carotene can be found in the serum of individuals ingesting large amounts of vegetables, primarily carrots. These people may have a slight yellowish tinge of the skin but the sclera of the eye is not discolored. Decreased serum levels may be seen in individuals with nutritional deficiencies including anorexia nervosa, malabsorption, and steatorrhea.
Detection of excessive ingestion of carotene
Low beta-carotene concentrations in the serum are indicative of vitamin insufficiency. Elevated levels of beta-carotene may have clinical implications.
> or =18 years: 2.3-65.0 mcg/dL
<18 years: not established
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