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,


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,


3

Iron balance4

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,


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,


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,


7

Iron-

containing

foods

Sunday, May 22,


8

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,


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,


10

Iron metabolism11

Iron absorption

Sunday, May 22,


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,


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,


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

Iron transport

Sunday, May 22,

2016

15

Sunday, May 22,

2016

16

iron metabolism

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