Chapter Six, vitamins

Chapter Six, vitamins - Chapter Six The Vitamins Vitamins...

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Chapter Six - The Vitamins •Vitamins –Micronutrients –Contain carbon –Essential in regulating body processes –May be fat-soluble vitamins –May be water-soluble vitamins •Fat-Soluble Vitamins •Are soluble in fat –Absorbed in the intestine with dietary fat –Found in fat-containing foods •Can be stored in the body - Don’t have to be consumed daily - Because they are stored they can build up to toxic levels •Include vitamins A, D, E, and K •Vitamin A Needed everywhere. - Three active forms are: - Retinol - Retinal - Retinoic acid •Functions of vitamin A - Essential to proper vision o Cell differentiation- the process by which the cells mature and specialize o Epithelial tissue o Development of T lymphocytes of the immune system o Sperm production and fertilization o Bone growth •Recommended intake –RDA is 900 micrograms/day for men; –700 micrograms/day for women –Expressed as retinol activity equivalents (RAE) •Sources of vitamin A –Obtained from animal sources (liver, eggs) and plant sources (dark green, orange, and deep yellow fruits and vegetables) •Beta Carotene -Vitamin A is readily created in the body by conversion of its precursor form, beta-carotene -You can’t OD on bet-carotene, although it will turn you yellow -Populations with adequate beta-carotene intake have lower rates of macular degeneration **Beta-carotene is the precursor of retinol
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•Deficiency Diseases - Xerosis and zerophthamia - Infections - Weak bones, poor teeth - Keratinization •Vitamin A Deficiency and Toxicity •Beta-carotene is a carotenoid •Carotenoids in general are known to: –Protect cell membranes against damage –Enhance the immune system –Protect skin from damage by UV light –Protect eyes from damage **Provitamins are inactive precursors that must be converted to active forms in the body. •Vitamin D –Fat-soluble vitamin –Can be synthesized by the body with exposure to UV light from the sun –Is a hormone since it is synthesized in one location and acts in another location •Functions of vitamin D –Required for calcium and phosphorus absorption –Regulates blood calcium levels - Promotes increase absorption from small intestine - Promotes resorption from bone - Promotes retention in kidneys –Necessary for bone calcification -Recent research and preliminary findings - Promote cell differentiation o Prevent cancer- breast and colon o Prevent reoccurrence- breast •Recommended intake –There is no RDA for vitamin D. –AI values range from 5 to 15 µg/day depending on age and gender.
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This note was uploaded on 05/05/2010 for the course MCB 181R taught by Professor Leonard during the Spring '08 term at Arizona.

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Chapter Six, vitamins - Chapter Six The Vitamins Vitamins...

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