Iron absorption is increased in all except (PGI May 2008)
|D||Alkaline pH of stomach|
|E||Ferrous iron salts|
Alkaline pH of stomach
Physiology of Iron Metabolism
Hb is 0.34% iron by weight.
Acid medium favors formation of soluble macromolecular complexes of iron with vitamin C, sugar, amino acid or bile in the duodenum.
Only 10% of the ingested iron is absorbed.
Normal serum iron level is 50 to 150 μg/dl.
Factors which influences iron absorption
Factor which increase iron absorption
Factor which decrease absorption.
A. Dietary factor
1. Increase Haema iron
2. Increase animal food
3. Ferrous salt
1. Decrease Haem iron
2. Decrease Animal food
3. Ferric salt
B. Luminal factor
1. Acidic pH
2. Food like
a. Vit C
c. Amino acid d. Citric acid
1. Alkaline pH (Pancreatic secretion)
2. Decrease iron absorption by
a. Phytates b. Tannic acid in tea
c. Carbonate d. Oxalate e. Phosphate
f. High phosphorous diet (Bread, mild, bran)
C. Systemic factor
1. Iron Def state
2. Increased erythropoiesis
3. Pregnancy 4. Hypoxia
1. Iron overload state
2. Decrease erythropoiesis
3. Inflammatory conditions.
Extra Edge: Iron absorption NOT increased in all types of anemia (it depends on iron store & in some anaemia iron stores are not depleted. e.g Aplastic anaemia, Fanconi Anaemia)
Extra Edge: Normally 1 mg of elemental iron is lost from shedding of senescent cells of GIT and genitourinary tract, and from desquamation of skin.
Iron requirement in males 1 mg per day
Iron requirement in females 2 mg per day
Iron requirement in pregnancy 3 mg per day
Causes of Iron Deficiency (Ref. Hari- 18th ed., Pg. 846, table 103.2)
1. Increased demand for iron and/or hematopoiesis
a. Rapid growth in infancy or adolescence
c. Erythropoietin therapy
2. Increased iron loss
a. Acute & Chronic blood loss
c. Hookworm infestation
3. Decreased iron intake or absorption
a. Inadequate diet
b. Malabsorption (sprue, Crohn's disease, post-gastrectomy)