SOC 103 Chapter Notes - Chapter all: Yolk, Hydroxylapatite, Vitamin A
6 Feb 2018
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Alpha-carotene a-carotene-carrots, leafy greens beta-cryptoxanthin b-carotene- mangoes, papayas, winter squash, red peppers. Carotenoids and preformed vitamin a are absorbed at 70- Bound to proteins in foods they are released by pepsin and bile acids and then form micelles which facilitate diffusion into mucosal cells. Once inside mucosal cells b-carotene is converted into retinoids, chylomicrons deliver to body tissues. Pro-vitamin carotenoids are less absorbed and absorption decreases with excess intake. A diet low in fat will reduce absorption. In the body retinol and retinal can be interconverted. B-carotene from plant foods can be converted into retinal in the intestinal mucosa and the liver. It takes 12 mg of dietary b-carotene to yield 1mg of retinol. Vitamin a remains fairly stable when heated but is destroyed by exposure to light and oxygen. Egg yolk, liver, fish, oils, tuna, salmon, fortified milk, synthesis from sunlight. Absorption of calcium and phosphorous, maintenance of bone. Calcium deposits in soft tissues, growth retardation, kidney damage.
