EHS 150 Lecture Notes - Lecture 6: Vitamin A Deficiency, Cholecalciferol, Cryptoxanthin

• School: UMass Boston
• Department: Exercise and Health Science
• Course: EHS 150
• Professor: Ivanov Milko

Document Summary

Retinal and the visual cycle: vitamin a is involved in the perception of light, vitamin a deficiency can cause light blindness. Retinoic acid and gene expression: vitamin a affects cell differentiation through its effect on gene expression. Maintenance of epithelial tissue, normal reproduction, growth, and immune function. Beta-carotene: a vitamin a precursor and an antioxidant: beta-carotene can be converted to vitamin a in the intestinal mucosa and liver, unconverted carotenoids may function as antioxidants in the body, other provitamin a carotenoids: Vitamin a toxicity: preformed vitamin a can be highly toxic (both acutely and chronically) Ul: 3000 g/day for adults: excess vitamin a intake during pregnancy may contribute to birth defect, carotenoids are not toxic, but large dose can lead to hypercarotenemia, carotenoid supplements may be harmful to cigarette smokers. Vitamin d the sunshine vitamin: only a few foods naturally contain cholecalciferol (vitamin d3, fortified foods contain vitamin d3 and d2. Functions of vitamin d: regulates blood calcium.