The intimate relationship between the plant pigment carotene and the indispensable accessory food factor known as vitamin A is well founded. Carotene is absorbed from the intestinal tract and is changed into vitamin A in the body. The vitamin A potency of plant material is largely due to carotene, whereas that of animal products is to a greater or less extent accounted for by vitamin A itself. Chemically it is reasonably well established that the molecule of the hydrocarbon beta-carotene gives rise to two molecules of the primary alcohol vitamin A. The two compounds exhibit definite differences in chemical and physical properties, yet their effect in the organism is so similar that the accepted international standard for vitamin A is 0.6 microgram of beta-carotene.
Although both these compounds are soluble in fats and in the so-called fat solvents, an increasing mass of evidence indicates that the extent of absorption is
UTILIZATION OF VITAMIN A AND CAROTENE. JAMA. 1937;109(13):1045–1046. doi:10.1001/jama.1937.02780390047019
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