BIOS 12114 Chapter Notes - Chapter 9: Retinol, Chylomicron, Retinoid
11 Nov 2016
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Vitamin a carrots high in vitamin a, vitamin a important for vision. Vitamin a also interacts with genes to regulate growth and cell differentiation. Preformed vitamin a found in animal foods aka retinoids (consists of retinol, retinal, and retinoic acid) Provitamin a found in plants aka carotenoids (pigments synthesized by plants and many microorganisms. They give yellow, orange, and red fruits/veggies their color) Vitamin a in foods can be destroyed when exposed to light and oxygen. Preformed and carotenoids are bound to proteins in foods they must be released from the protein by pepsin and other protein-enzymes to be absorbed. In small intestines, combine with bile acid to form micelles, facilitate their diffusion into mucosal cells fat content of diet can affect absorption of vitamin a low fat diet = reduced vitamin a absorption. Absorbed vitamin a transported from small intestine in chylomicrons, these lipoproteins are delivered to body tissues preformed vitamin a and carotenoids stored in liver.
