Iron gotten richly from Heme sources including Fish, meat and chicken and non-Heme which includes vegetables, grains and cereals is an essential mineral and important part of protein.
Iron is involved in the formation of hemoglobin (about 65% to 68%) of total iron in the body and it is an important factor for the transport of oxygen in the blood. The total quantity of iron in the body is about 4g. It is distributed thus (I) 65% to 68% (ii) 4% as myoglobin in muscle. 1% is combined with the protein transferrin in the blood plasma. About 15 to 30 percent is stored in the liver and reticuloendothelial system for future use.
Absorption from The GIT
After ingestion and churning of the ingested food materials by the stomach, the small intestine absorb iron through the intestinal cells (enterocytes) by pinocytosis and transport it into the blood. The liver plays a major role in the absorption process by secreting moderate amounts of apotransferrin into the bile (usually flow through the bile duct into the duodenum) which is attracted to and binds with receptors in the membrane of the intestinal epithelial cells. Then by pinocytosis, transferrin molecule (a combination of apotransferrin and free iron) is absorbed from the intestine daily with the rate of absorption being regulated by feedback mechanism.
FACT: about 1mg of iron is lost daily in male through feces but it is higher in female about 1.3mg/day due to menstrual loss of blood.
Formation of Hemoglobin
Heme-Iron, Globin-protein. Heme is synthesized in mitochondria and globin is synthesized in ribosomes. When the quantity of iron in plasma falls low, some of the iron in the ferritin storage pools is removed and easily transported in the form of transferrin in the plasma to areas its needed in the body. The transferrin molecule binds strongly with receptors in the cell membranes of erythroblasts in the bone marrow. Then it binds with iron and ingested in the erythroblasts by endocytosis. There transferrin delivers iron directly into the mitochondria where is synthesized.
Succinly-COA binds with glycine to form a pyrrole molecule, in turn four pyrroles combine to form protoporphyrin IX, combining with iron to form Heme molecule. Then, each Heme molecule combines with a long polypeptide chain, a globin synthesized by ribosomes, forming a subunit of hemoglobin called a HEMOGLOBIN CHAIN.
Transport of Oxygen
The primary function of Hb is the transport of oxygen and it does that by combining (loosely) with oxygen in the lungs and releases readily with one molecules of O2, a total of 4 molecules of O2. It is bounded loosely so the combination is only reversible.
Daily requirement of Iron: Men (10mg/day) and 15mg/day in women.
Iron helps in the building of the RBC, part of the hemoglobin and myoglobin muscle.
It also helps in the conversion of hydrogen peroxide to oxygen and water.
Deficiency symptoms: reduced resistance to infection, productivity, physical fitness, anemia in children and women; paled eyes.
Major sources of iron include: Red meat, fish, eggs, legumes, dried fruits.
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