NTR 401 Study Guide - Midterm Guide: Vitamin K Deficiency, Vitamin Deficiency, Alpha-Carotene
15 May 2016
School
Department
Course
Professor
Document Summary
Yield no energy, but facilitate energy-yielding chemical reactions. If absent from a diet, it will produce deficiency signs and symptoms. If absorption mechanism is defective, deficiency is likely. Fat malabsorption, alcohol abuse, intestinal diseases (cystic fibrosis, celiac disease, crohn"s disease) affects absorption. Pre-formed: retinoids (retinal, retinol, retinoic acid, found in animal products. Pro-formed: carotenoids (beta-carotene, alpha carotene, must be converted to retinoid form, found in plant products, conversion of carotenoids to retinoids enzymes in the small intestine or liver cells. Retinal oxidation retinoic acid: absorption of vitamin a. Intestinal cells can convert carotenoids to retinoids: transport and storage of vitamin a. Liver stores 90% of vitamin a in the body. Transported from the liver as retinol via retinol-binding protein to target tissues: functions of vitamin a (night vision) Needed for night and color vision: the visual cycle. Cones in the retina: responsible for vision under bright lights, translate objects to color vision.
