iron metabolism

Question 1

Site of most iron absorption

Answer 1

upper small intestine especially the duodenum

Fe2+ (ferrous iron) much better absorbed than Fe3+ (ferric iron)
absorption is regulated according to body’s need
increased by vitamin C, gastric acid
decreased by proton pump inhibitors, tetracycline, gastric achlorhydria, tannin (found in tea)

Question 2

What percentage of dietary iron is absorbed?

Answer 2

about 10% of dietary iron absorbed

Question 3

Which is better absorbed, Fe2+ or Fe3+?

Answer 3

Fe2+

Question 4

What is the total body iron?

Answer 4

4g

Question 5

Where is most iron distributed in the body?

Answer 5

haemoglobin = 70%
ferritin and haemosiderin = 25%
myoglobin = 4%
plasma iron = 0.1%

Question 6

how is iron transported around the body?

Answer 6

carried in plasma as Fe3+ bound to transferrin

Question 7

How is iron stored?

Answer 7

stored as ferritin in tissues

Question 8

how is iron excreted?

Answer 8

lost via intestinal tract following desquamation