The hemoglobin content of the red blood cells is made up of certain proteins and iron. In a normal healthy adult, there is about 15 g of hemoglobin per 100 ml of blood. Each gram of hemoglobin contains about 3.5 mg of iron.
The normal body of an adult contains about 4 to 5 g of iron. About 60 to 70 per cent of this iron is present in the hemoglobin. Iron stores in the liver, spleen, and bone marrow account for the next largest concentration of iron – that is, about 30 to 35 per cent.
Small amounts of iron are found in the muscles as myoglobin, as also in the blood serum and in every cell as a constituent of certain enzymes. Iron is present in the body in combination with other body constituents.
All healthy persons absorb about 2 to 10 per cent of iron from food, depending on its nature. But in persons who are deficient in iron, the amount absorbed increases up to 50 per cent from ingested foods.
The main sites of absorption are the stomach and the upper part of the small intestine.
Absorption of iron is enhanced when there is a deficiency of iron in the body or there is a need for increased blood formation.
Iron is stored in the liver, spleen, and intestinal mucosa. The store of iron as well as the iron released from the disintegration of red blood cells is available to the body for the synthesis of hemoglobin. Hence the iron in our bodies is used very efficiently, and is not normally used up or destroyed but converted and utilized again and again.
Iron is excreted along with the bile, stools, scaling of the skin, and sweating. It is, therefore, advisable to take an extra quantity of iron-rich foods during summer to compensate the loss of iron.
How Does Copper Converts Iron Into Hemoglobin?
- Copper is an essential element for the formation of hemoglobin. There is approximately 75 to 150 mg of copper in the adult human body. Newborn infants have higher concentrations of copper than adults. The liver, brain, kidneys, heart, and hair contain relatively high concentrations. The average serum copper levels are higher in adult females than in males. The serum copper levels also increase significantly in women during pregnancy and when taking oral contraceptives.
- In the human body, copper is a constituent of several enzymes and is found in combination with sexual proteins in the blood.
- Ceruloplasmin, a copper-containing plasma enzyme, catalyzes the oxidation of the ferrous ion to ferric ion, and thereby enables iron to be trapped by transferring (a protein transporting iron in the blood). It is then transported to tissues for the synthesis of iron-containing compounds, especially hemoglobin.
- Copper is mostly absorbed at the level of the duodenum in the intestine. Approximately 3:2 per cent of the copper in the diet is absorbed. Excess copper is excreted in the bile.