Download - Iron metabolism
Department of Biochemistry, Nepalgunj Medical College
Sunday, May 22,
2016Rajesh Chaudhary
1
For MBBS I
Biomedical importance of iron in our
body
For hematopoiesis to make hemoglobin.
Involved in conversion of blood sugar to energy.
Helps in production of enzymes and hormones.
Aiding immunity.
Sunday, May 22,
2016Rajesh Chaudhary
2
Why is Iron required by our body?
Central ion in heme, cytochrome,
and non-protein component of
hemoglobin.
Iron deficiency leads to anemia
and thus tissue hypoxia.
But, since, free iron is cytotoxic, it
has to be in the protein-bound
form.
Sunday, May 22,
2016Rajesh Chaudhary
3
Iron physiology and biochemistry
Iron level is controlled by regulating its uptake, since there is no mechanism for controlling its excretion.
Dietary intake of iron is about 0.35 mmol (20 mg) per day.
Total amount of iron in the body: 50-70 mmol (3-4 gm) of iron in the body.
In body, it exists in two forms: Soluble and insoluble form.
Soluble: proteins ferritin
Insoluble: Haemosiderin.
Sunday, May 22,
2016Rajesh Chaudhary
5
Iron physiology and biochemistry
1% of body iron in the plasma is associated with the iron
binding glycoprotein, transferrin, each molecule of which
binds two Fe2+ ions.
Serum iron concentration differ with age and sex.
Normal adult: 10-40 mmol/L
Circulation rhythm is marked – varies by 50% over 24
hours.
Peaks in the morning, lowest in the evening.
Sunday, May 22,
2016Rajesh Chaudhary
6
Requirement and Sources
Dried beans.
Dried fruits.
Eggs (especially egg yolks)
Iron-fortified cereals.
Liver.
Lean red meat (especially beef)
Oysters.
Poultry, dark red meat.
Sunday, May 22,
2016Rajesh Chaudhary
7
Consequences of iron deficiency
anemia
Heart problem – rapid or irregular heartbeat.
Problems during pregnancy: lower birth weight, premature
delivery.
Growth problem – delayed growth and development.
Susceptible to bacterial infections.
Restless legs syndrome.
Sunday, May 22,
2016Rajesh Chaudhary
9
Iron deficiency can lead to severe
consequences
Iron deficiency anemia.
Principal cause: chronic blood loss, poor dietary intake of bio-
available iron.
Uptake can be decreased by number of dietary constituents, such as
phytic acid, malabsorptive condition such as coeliac disease.
Intestinal parasite leading to chronic blood loss.
In pregnant mother because of higher iron requirement for
developing baby.
Sunday, May 22,
2016Rajesh Chaudhary
10
Iron absorption
Sunday, May 22,
2016Rajesh Chaudhary
12
DMT 1: Divalent
Metal Transporter 1
HT: Heme
Transporter
FP: Ferroportin 1
HP: Hephaestin
Both DMT1 and Ferroportin 1 are widely distributed throughout the body and are
involved in iron transport in other tissues as well.
Factors affecting non-heme iron
absorption
Polyphenols.
Oxalate
Phytates
Soy protein
Dietary fibers
Calcium
Sunday, May 22,
2016Rajesh Chaudhary
13
Ascorbic acid enhances iron absorption by keeping iron in its ferrous
form. This is due to reducing property of Vitamin C.
Factors affecting non-heme iron
absorption
Sunday, May 22,
2016Rajesh Chaudhary
14
Improve absorption Inhibit absorption
Meat, fish and poultry Tannins in tea, coffee and cocoa
Citrus fruit (Vitamin C) Phytates in wholegrains
Kiwifruit Soy protein
Tomatoes Dietary fibers
Capsicum
Broccoli, Cauliflower