6pp Zinc lecture Sp2011

6pp Zinc lecture Sp2011 - 3/19/11 In 1961, Prasad...

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3/19/11 1 HUN 4221 Spring 2011 In 1961, Prasad discovered a disorder of delayed growth and maturation in young men and boys. Iranian farmer presented with a syndrome of anemia, hypogonadism, and dwarfism A similar syndrome in Egyptian boys responsive to diet containing meat Later studies defined Zn deficiency as the source of the syndrome Bioavailable zinc portion that is absorbed and used Phytic acid in plants decreases Zn bioavailability. Zn-phytic acid insoluble in GI tract Leavening of bread with yeast allows phytase to reduce phytate content Most zinc in food is bound to proteins and nucleic acids require digestive release Pepsin and HCl Areas at risk for zinc deficiency National risk of zinc deficiency based on combined information regarding the prevalence of childhood growth stunting and the percent of individuals at risk of inadequate zinc intake. www. IZiNCG.org Pren;ce et al. J. Clin. Invest. 2008 Type of Food Zinc (mg/100g) Oysters 17-91 Tuna 0.5-0.8 Ground beef 3.9-4.1 Eggs 1.1 Milk 0.4 Whole-wheat bread 1.0 Vegetables 0.1-0.7
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3/19/11 2 Dietary Zinc Metabolism Func4on Regulatory Structural Cataly4c Intes;ne Pancreas Fecal Kidney Renal Skin Integumental Diet Lacta;onal Breast Bone Hepatocytes Prostate Thymus Lymphocytes Monocytes→Macrophages Bone Marrow Zn RBC Zn Tissue Macrophage RE System Spleen Absorption mainly in small intestine Carrier-mediated: saturable Apical and basolateral membrane transport Passive: non-saturable Paracellular transport Regulation of absorption efficiency Primary mechanism of maintaining homeostasis Diet Zn = absorption = fecal loss Fecal loss dietary Zn and endogenous secretion Lichten, LA and Cousins, R.J. Ann Rev Nutr 2009: 29± 153 Tissue Specific Expression Usually affects Young infants: Severe dermatitis Impaired growth Treatment: 30-50 mg zinc/day
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3/19/11 3 Acrodermatitis enteropathica (AE) A dz of zinc malabsorption Zinc-responsive inborn error of metabolism Symptoms include: Dermatits Impaired immunity Impaired wound healing Hair loss Anorexia Impaired taste acuity (From Thyres on, Acta Dermatovener 54:383, 1974) Varies with dietary intake and Zn status Fecal excretion (~90%) 1 - 5 mg/day Urinary excretion (~10%) excretion not sig influenced by Zn intake responds to changes in muscle catabolism may markedly in diseases that result in
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This note was uploaded on 12/09/2011 for the course HUN 4445 taught by Professor Sitren during the Spring '08 term at University of Florida.

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6pp Zinc lecture Sp2011 - 3/19/11 In 1961, Prasad...

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