5953053
Description
Flashcards by Lesley Howard, updated more than 1 year ago
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Created by Lesley Howard
over 8 years ago
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| Question | Answer |
| Heme iron | Usually found in meat Most bioavailable kind Heme shields iron from dietary chelators 5-35% absorbed |
| Non heme iron | Found in fruits, veggies, eggs Mostly Fe3 |
| Fe3 | Ferric iron Abundant but low bioavailability |
| Fe2 | Ferrous iron More soluble Less available Used in iron supplements |
| Fe | Elemental iron Insoluble at physiologic pH Used to fortify foods |
| Iron enhancers | Reducing molecules Amino acids Acidic foods |
| Iron inhibitors | Phytates Polyphenols Phosphates and phosphoproteins Oxalate Zn and Ca |
| Reducing molecules | Things like vitamin C that reduce Fe3 to Fe2 and form soluble complexes |
| Amino acids | Form soluble complexes with Fe2 Found in meat and fish |
| Acidic foods | Increased solubility of Fe and Fe3 |
| Phytates | Form insoluble complexes with Fe2 Cereal grains and legumes |
| Polyphenols | Form insoluble complexes with Fe2 Tannins in tea and coffee |
| Phosphates and phosphoproteins | Form insoluble complexes with Fe2 and Fe3 Egg yolk |
| Oxalate | Forms insoluble complexes with Fe2 and Fe3 Spinach |
| Zn + Ca | Compete with Fe Supplements |
| Fenton reaction | Unbound ferrous iron (Fe2) is toxic Non enzymatically catalyzes the formation of hydroxide radicals Fe2 + H2O2 = Fe3 + OH + OHdot |
| Transferrin | Binds ferric iron and solubilizes it Attenuates reactivity Delivers it to sites of use and storage |
| Transferrin receptor | Binds to the iron-transferrin complex Mediates endocytosis and the formation of an endosome Releases the iron-transferrin complex and is recycled to the cell surface |
| Ferritin | Intracellular iron storage protein 24 H or L subunits Homopolymers only found in pathologies Iron stored in ferritin cannot catalyze the Fenton reaction |
| Hemosiderin | A form of ferritin in lysosomes Stores insoluble iron Found in conditions of iron overload |
| Iron loss in toddlers | Nutritional deficiency |
| Iron loss in adults | Bleeding other than menstruation |
| I | Menstruation |
| Iron loss in pregnant women | Increased need |
| Serum transferrin test | Presented as total iron binding capacity (TIBC) Reflects total levels of transferrin |
| Serum ferritin test | Accurately reflects intracellular ferritin levels Inversely proportional to TF and TFR levels Low iron = low ferritin = high TF and TFR High iron = high ferritin = low TF and TFR Best test for iron deficiency anemia |
| Iron deficiency anemia | Caused by acute or chronic blood loss koilonychias, anisocytosis, poikilocytosis, target cells HGB < 10g /dL RBCs can be microcytic and hypochromic |
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