The Indian diet which is predominantly vegetarian contains large amounts of these inhibitors, e.g. phylates in bran, phosphates in egg yolk, tannin in tea and oxalates in vegetables. In some areas significant amounts of iron may be derived from cooking in iron vessels.
Benefits of Iron:
Iron is necessary for many functions in the body including formation of haemoglobin, brain development and function, regulation of body temperature, muscle activity and catecholamine metabolism. Lack of iron directly affects the immune system; it diminishes the number of T- cells and the production of antibodies. Besides haemoglobin, iron is a component of myoglobin, the cytochromes, catalase and certain enzyme systems.
Iron is essential for binding oxygen to the blood cells. The central function of the iron is oxygen transport and cell respiration.
Absorption: Iron is mostly absorbed from duodenum and upper small intestine in the ferrous state, according to body needs.
The rate of iron absorption is increased by many factors like iron reserves of the individual, the presence of inhibitors (e.g. phosphates) and promoters (e.g. ascorbic acid) of iron absorption and disorders of duodenum and jejunum.
Iron absorption is greater when there is an increased demand for iron, as for example during pregnancy.
The absorbed iron is transported as plasma ferritin and stored in liver, spleen, bone marrow and kidney. When red cells are broken down, the liberated iron is reutilized in the formation of new red cells.
Daily loss of iron from the body
The total daily iron loss of an adult is probably 1 mg and about 2 mg in menstruating women. Major routes of iron loss are:
- Through haemorrhages, that is wherever blood is lost, iron is lost, the causes of which may be physiological (e.g. menstruation, childbirth) or pathological (e.g. hookworms, malaria, haemorrhoids, peptic ulcer)
- Basal losses, such as excretion through urine, sweat and bile and desquamated surface cells.
- The recent widespread use of IUDs in the family planning programme is an additional cause of iron loss.
- Hormonal contraceptives on the other hand decrease menstrual blood loss by about 50 percent.
Three stages of iron deficiency have been described:
- First stage is characterized by decreased storage of iron without any other detectable abnormalities.
- An intermediate stage of latent iron deficiency that is iron stores are exhausted, but anemia has not occurred as yet. Its recognition depends upon measurement of serum ferritin levels. This stage is the most prevalent stage in India.
- The third stage is that of overt iron deficiency when there is a decrease in the concentration of circulating haemoglobin due to impaired haemoglobin synthesis.
The end result of iron deficiency is nutritional anaemia, which is not a disease. It is rather a syndrome caused by malnutrition. Besides anaemia there may be other functional disturbances such as impaired cell mediated immunity, reduced resistance to infection, increased morbidity and mortality and diminished work performance.
Daily requirement of iron
Because of the recycling of iron, only a small amount of iron is needed by the body. In general iron requirements are greater and there is rapid expansion of tissue and red cell mass, as for example during pregnancy, childhood and adolescence
Requirement of iron for different age groups is given below in the table:
Iron in mg that should be absorbed (daily needs)