Functions on the Body: Iron is generally absorbed from the whole of the gastro intestinal tract but most of it comes from the upper part of the small intestine mainly the duodenum. Dietary Iron is absorbed through the mucosal cells in ferrous form. Iron in diet is present in ferric state which is reduced to ferrous during absorption, with the help of Vitamin C, glutathione and amino acid –SH groups. After entering the mucosal cell in ferrous form, the iron molecules are soon reconverted into ferric state, which combine with a protein, apoferritin of the mucosal cells to form ferritin. Such ferritin is one of the storage forms of iron in the tissues, which passes into the blood. This ferritn iron gets reduced into ferrous from with the help of Vitamin C and enters the blood stream. After entering the blood stream this ferrous iron is re-oxidised into ferric from unde the catalytic action of copper-binding protein ceruloplasmin, and combines with iron binding globulin transferrin or iderophilin of the plasma. Thus the Transferrin iron complex is the transport form of iron of the plasma and is carried to the different tissues of the body. The protein-bound iron in the plasma per 100 ml is about 120-140 mcg in males, and 90-120 mcg in females. The total iron-binding capacity is about 300-360 mcg per 100 ml in both sexes.
The absorption of iron depends upon
1) Iron requirement of the individual e. g.increased during growth, anaemias, menstruation pregnancy, haemorrhage, etc.
2) Form of iron compound e. g. the inorganic form of ferric available in food is to be first converted into organic ferrous form for best absorption.
3) Reaction of the gastro intestinal tract e. g. , the acidity of gastric juice helps liberation of iron from organic compounds of diet, and reduction from ferric to ferrous form of iron. Thus absorption is retarded by low gastric acidity, excessive mucus, administration of alkalies.
4) Vitamin C and Calcium e. g. , Vitamin C helps in reducing the ferric to ferrous state for absorption of iron form food. Small amount of Calcium decreases the formation of insoluble iron phosphates and thus promote absorption, but large amounts of Calcium inhibit assimilation.
5) Pigments i. e. , Chlorophyll and bile pigments increase the absorption of iron.
The rate of absorption of iron depends on the iron requirement for haemoglobin synthesis. After a single dose of iron, serum iron rises in 30 mts reaching to maximum in 3-5 hrs (0.35 mg %) compared to normal 0.10 mg %), returning to normal in 12 hours, and completing the maximum absorption in 18 hrs. Haemoglobin in the blood falls when iron loss exceeds that of iorn absorption and anaemia develops.
The functions of Iorn consist of
1) Formation of haemoglobin (Hb) by synthesis which is its primary function.
2) Development of red cells by their formation and maturation.
3) Carrying of Oxygen in blood in the form of Hb; 1 gm of Hb carries about 1.34 ml of oxygen.
4) Tissue oxidation as cytochrome and indophenol oxidase is iron-containing compounds concerned with the oxidation of metabolites in the cells.
5) Supply of Oxygen to the muscle, as the myoglobin of muscle is an iron-containing chromoprotein like haeemoglomin, which combines will oxygen and acts as an oxygen store for muscle.
6) Cell nucleus function, the chromatin of the nucleus contains iron which takes an active part (may be oxidative) in the functions of nuclei,
7) Oxidation in nerve cells, as nissl granules in the cytoplasm of the nerve cells contain organically combined iron, which serves an essential role in oxidation. Their granules disappear during activity of the nerve cells, and reappear during rest.
8) Prevents fatigue and aids growth. Iron increases resistance to stress and disease.
Deficiency Indicators: Nutrients like iron, folic acid, and vitamin B-12 are required to avoid nutritional anaemia. About 80% of the total anaemic cases are due to lack of iron. Iron deficiency anaemia is a neglect tragedy. Also, unlike other nutrition deficiencies, anaemia is not visible. Iron deficiency causes secondary anaemia (hypochromic), as the haemoglobin content of the red cells is lowered. The size and volume of the red cells get reduced. Milk anaemia does not even send out warning signals.
However when it gets worse you may feel fatigued, lethargic, vulnerable to infections and irritable. The deficiency of iron results in lowered resistance to disease, general run out, pale complexion, shortness of breath on exertion, loss of interest in sex, mental depression, and irritability. The iron status can be evaluated by measurement of serum ferritin. The normal value of haemoglobin levels is 12 gm/dl for women and 13 gm/dl for men. (1 dl=100ml)
Iron deficiency is commonly seen among growing children, menstruating and pregnant women, and anyone suffering from parasitic diseases such as hookworms, and malaria. Excessive physical activity or exercise can also make a person anaemic as the body uses up more iron. With iron deficiency you might feel colder than others and take time to warm up, as in this condition your body may produce low thyroid hormone (which is one of its heat regulators). Know more about Iron- Functions and its deficiency
Dr John Anne
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