Exam - Iron Flashcards
supplement label
helps prevent iron deficiency
where is iron found
lots of foods at low levels - liver, meats, plant sources
2 forms that iron can be found as in the body
heme (animals)
non-heme (plants)
where is heme found
within porphyrin ring of hemoglobin and myoglobin
what are the only 2 states of iron that are stable in the aqueous environment of the body and food:
ferric and serous
functions of iron in the body
oxygen transport
redox reactions
iron metalloenzymes
what are metalloenzymes
enzymes that need a metal ion as cofactor
what percentage of iron ingested gets absorbed
10-18%
2 fates of Fe2+ (ferrous)
either used in intestinal cells, stored in intestinal cells or transported to blood
what are chelators
small organic compounds that form a complex with a metal ion
what do chelators affect
iron absorption
what happens if the iron-chelate is soluble
iron absorption is enhanced
what happens if iron-chelate is insoluble
iron absorption is inhibited
examples of enhancers
vitamin C (reducing agent)
pectin
examples of inhibitors
polyphenols
oxalic acid
insoluble fibres
what does coffee after a meal reduce
iron absorption by 50%
how does oxalic acid inhibit
binds with iron, preventing its absorption
how does iron get transported in the blood
in its ferric form, bound to transferrin
why is it important that iron is bound to a carrier
unbound ferrous iron has a high redox activity and can readily lose an electron, increasing radical production
what is ferritin
iron storage protein
where is iron readily available from
ferritin
what is hemosiderin
a complex of ferritins and denatured proteins found mostly in macrophages that engulfed red blood cells
where is iron poorly available from
hemosiderin
what is necessary for iron to attach to transferrin
oxidation of Fe2+ by ceruloplasmin
examples of hemmed-dependent enzymes
catalase
thyroid peroxidase
what does catalase do
converts H2O2 into H2O
what does thyroid peroxidase do
addition of iodides to thyroglobulin protein
4 groups where iron deficiencies are most seen
infants/young children
adolescents in early growth spurts
females during childbearing years
pregnant women
general symptoms of iron deficiency
fatigue
pallor
weakness
hair loss/brittle nails
irritability
impaired immune system
what percentage of people worldwide have iron deficiency
30%
short term consequences of iron deficiency in fetal development/early childhood
lower test scores on mental development
lower test scores on motor development
what does iron toxicity eventually cause
liver failure
what is hemochromatosis
increased iron absorption
what is hemosiderosis
iron deposition in tissues
