Iron Flashcards
What are the 3 forms of Iron
Functional, Transport and Storage
What are Functional Iron forms
Hemoglobin, Myoglobin, Heme enzymes, Nonheme enzymes
What is the Transport Iron form
Transferrin
What are the Storage Iron forms
Ferritin and Hemosiderin
How much Storage Iron is common in Men
12mg/kg
How much Storage Iron is common in Women
4mg/kg
Why do women have so little Storage Iron
Menstruation
What is Functional Iron
Iron in molecules, doing something
What is Transport Iron
Iron in transit, available for use
What is Storage Iron
Iron bound to Protein (Ferritin), stored in liver and blood proportional
How much Hemoglobin is common in Men
31mg/kg
How much Hemoglobin is common in Women
28mg/kg
What are Iron containing enzymes
Monooxygenases and dioxygenases
Why is most Iron in body bound to protein
Highly reactive metal, bound to keep from oxidizing
What enzyme requires Copper as a cofactor
Hephaestin
What forms of Iron do we eat
Heme and nonheme
What is the first step in heme-iron digestion (Hemoglobin/Myoglobin)
Proteases (from pancreas) free heme from globin in lumen
What is the next step in heme-iron absorption after globin is cleaved off
Heme has own receptor on brush border
What is the next step in heme-iron absorption after heme receptor
Heme oxygenase frees Iron from heme as Iron2+: Ferrous iron
What is the next step in heme-iron absorption once in Fe2+ form
Ferroportin: Transport protein on basement membrane transports out into blood and oxidizes into Ferric form (Fe3+)- enzyme Hephaestin hen binds to Transferrin
What is the first step in nonheme-iron (Fe3+) absorption
Reductase at brush border reduces to Fe2+ form
What transports reduced nonheme-iron (Fe2+) at brush border
DMT1
What binds to iron, inhibiting absorption
Polyphenols and Phytic acid: tea, wine, chocolate and coffee
What is the RDA for Iron in Men
8mg
What is the RDA for Iron in Women
18mg
What is the UL for Iron
45mg
What are food sources of Iron
Beef liver, beef, dark meat poultry, oysters, leafy greens, fortified cereals, dark chocolate, tofu, walnuts
What is the absorption % for nonheme iron
8-10%
What is the absoprtion % for heme iron
15-18%
What nutrients Enhance absorption of Iron
Sugars (fructose, sorbitol), Acids (citric, lactic, ascorbic), meat (heme iron)
What nutrients Inhibit absorption of Iron
Calcium, Zinc, Magnesium: Competition in Multivitamins; Polyphenols, Phytates, Oxalic Acid
How much Iron is lost everyday
1-2mg
How much Iron must be absorbed everyday
1-2mg; replace what is lost
What are the stages of Iron deficiency
Normal - Early Negative Iron Balance - Iron Depletion - IronDeficient Erythropoiesis - IronDeficiency Anemia
At what stage of Iron deficiency would it be ideal to catch symptoms
Iron depletion
How is Iron status measured
Serum Ferritin
What is the first Iron function to deplete
Storage
What is Hematocrit (Hct)
% packed cell volume
What are symptoms for RBCs during Iron deficient anemia
Microcytic, Hypochromic
