NUTR 1010 Chapter Notes -Nyctalopia, Margarine, Vitamin
30 Sep 2014
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Absorbed in the body same way as fat in the micelles with fat. Measured in retinal activity equivalents (rae) or international units (iu) > 1 rae = 1 microgram of retinol or 12 micrograms of beta carotene. In canada, half of our dietary v. a comes from preformed v. a. Sources from beta carotene (will be made into v. a in body) Works in the retina of the eye. Retinal attaches to opsin (protein) and when exposed to light it changes shape and allows us to see. Once used up it cannot be used again. Young cells = undifferentiated they could become several different types of cells (ie. liver, Fat soulble vitamins a + beta carotene, & e brain, heart, etc) V. a makes sure this process happens properly. Needed for epithelial tissue (tissue exposed to environment/on surface of body skin, linnings of the eyes, digestive tract, lungs, etc. ) V. a makes sure that epithelial cells differentiate properly. Makes sure you replace these cells properly.
