10:27:11 - Iron - Iron Fe 2 – 4 g of iron present in the...

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Unformatted text preview: Iron - Fe 2 – 4 g of iron present in the human body 39 mg/kg female 50 mg/kg male >65% hemoglobin - Iron-containing oxygen-transport metalloprotein in the red blood cells. 10% myoglobin an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals 1-5% part of enzymes Remainder found in blood or storage Distribution Amount is dependent on body weight, gender, age, pregnancy, growth state. Types: Heme iron – or “animal source” is found in the hemoglobin and myoglobin of animal products in the diet. (50 – 60% of animal tissue protein) Nonheme iron – or “plant source” bound to components of food. (plant and some animal source, milk) Sources: Heme: animal tissue or meat poultry fish Nonheme: plants nuts fruits green leafy vegetables beans (lima, navy) grain tofu dairy – milk, cheese, eggs *not good sources DRI mg/day 1-3 7 4-8 10 Males 9-13 8 14 – 18 11 19 - >70 8 Females 9 -13 8 14 – 18 15 19 – 50 18 51 - >70 8 Fig. 12-2, p. 472 Digestion and Absorption • Heme iron: hydrolyzed by proteases in stomach and small intestine. It must be released from the porphyrin ring • Heme carrier protein is present in the proximal small intestine. • Heme iron absorption takes place throughout the small intestine but is most efficient in the proximal duodenum. • Iron can bind with ligands and chelating agents. If the bonds are strong and insoluble iron will not be absorbed. Structure Fig. 12-3, p. 473 Absorption enhanced by: acids - ascorbic, citric, lactic and tartaric acid mucin – acts as s chelate that aids iron absorption sugars (esp. fructose and sorbitol) meat, poultry and fish – cysteine and histidine Vitamin C - is especially helpful for iron absorption....
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This note was uploaded on 11/25/2011 for the course NTR 365 taught by Professor Sweltzer during the Fall '11 term at University of Texas.

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10:27:11 - Iron - Iron Fe 2 – 4 g of iron present in the...

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