The iron mineral is the part of the structure of many important body constituents e.g. hemoglobin, myoglobin, enzymes like cytochromes, catalases, xanthine oxidase, mitochondrial glycerophosphate oxidase etc. The iron content of hemoglobin is 0.34%. The adult human being contains about 2-4gtam of iron of which 60-70% is present in the blood as circulating iron and the rest as storage iron. Recommended daily intake of iron in adults in 0.9 mg
There are two forms of irons
- Heme iron
- Non-heme iron
- Animal sources: Animal sources of food rich in heme iron are liver, red meat, poultry and egg yolk. Milk is very low in iron. These are not only rich sources of iron but also readily increase non-heme iron absorption in plant foods eaten at the same time.
- Plant sources: Foods containing non-heme iron are of plant origin and are rich in vegetables and include spinach and leafy vegetables, nuts, legumes, oilseeds, and jaggery. Dried fruits also contain appreciable amounts of iron.
Cooking in iron utensils increases the iron content of foods. Food which decreases iron absorptions is milk, eggs, and tea.
Iron is necessary for many functions in the body including formation of hemoglobin, brain development and function regulation of body temperature, muscle activity, and catecholamine metabolism. It is important for our immune system also. Lack of it directly affects the immune system; it diminished the number of T-cells and the production of antibodies. Beside hemoglobin, iron is component of myoglobin, the cytochromes, catalase, and certain other enzyme systems. Iron is essential for binding oxygen to the blood cells. The central function of iron is oxygen transport and cell respiration.
The total daily iron loss of an adult is probably 1mg and about 2 mg in menstruating women. Major routes of iron loss are
Hemorrhage: The cause of which may be psychological or pathological.
Basal Losses: These include excretion through urine, sweat, bile and desquamated surface cells. The recent use of an intrauterine device is also an additional cause of iron loss.
There are three stages of iron deficiency which have been categorized.
- The first stage characterized by decreased storage of iron without any other detectable abnormalities
- An intermediate stage of latent iron deficiency which means iron stores are exhausted but anemia has not occurred as yet.
- The third stage is overt iron deficiency when there is a decrease in the concentration of circulating hemoglobin due to impaired hemoglobin synthesis
This is of hypochromic, microcytic type and is the most common type of anemia being especially present in women of childbearing age and infants below 1 year of age.
- These include derangement of the epithelial surface such as abnormal nails growth that becomes spoon-shaped, other include glossitis, fissures around the mouth, pale skin, weakness, and fatigue. Thickening of the mucous lining of esophagus also occurs with the resultant effect of difficulty in eating and swallowing.
- Besides anemia, there may arise many other functional disturbances due to iron deficiency and these are impaired cell-mediated immunity; reduced resistance to infection; increased morbidity and mortality; diminished work performance.
Increase in iron levels in the body results in a condition called hemosiderosis and it is seen in some people who eat food cooked in iron utensils.