Iron Flashcards
Where does iron absorption mainly occur?
Duodenum
What enhances iron absorption?
Haem iron
Ascorbic acid reduces iron to Fe2+
Alcohol
What inhibits iron absorption?
Tannins - tea
Phytates - cereal, nuts, seeds
Calcium - dairy
Describe the absorption of Iron into the enterocyte
Haem iron is absorbed by its dedicated transporter
Non-haem iron is absorbed by DMT1
What enzyme converts Fe3+ to Fe2+?
Duodenal cytochrome B
What protein facilitates iron export?
Ferroportin
What protein controls iron absorption?
Hepcidin
Describe hepcidin
Produced in the liver in response to increased iron and inflammation - binds to ferroportin and causes it to degrade. Iron is trapped in duodenal cells and macrophages
State three ways to assess iron status
Functional iron - Hb concentration
Transport - % saturation of transferrin
Storage iron - serum ferritin
How many binding sites does transferrin have?
Two
Name the two variations of transferrin
Holtransferrin
Apotransferrin
When does ferritin rise?
Increased iron
Inflammation - acute phase protein
What can cause iron deficiency?
Insufficient intake
Bleeding
Malabsorption
Name the two types of iron overload
Primary - haemochromatosis
Secondary - transfusions
Which gene is mutated in haemochromatosis?
HFE leading to decreased hepcidin synthesis
