Inadequate iron intake: Inadequate consumption of iron rich food. The average cereal legume based diets as consumed in most developing countries would appear adequate in iron content (20-22mg) for an adult. But, the availability of iron from such diets is very poor.
Poor absorption and transport of iron in the body.
Various factors inhibit iron absorption of which phytates and tannins present in plant foods are most important.
Deficiencies of ascorbic acid, calcium and protein commonly found in the diets tend to lower iron absorption.
Poor iron stores of the body: Most of our population have negligible iron stores as indicated by poor bone marrow haemosiderin levels and low levels of liver iron.
Most women enter pregnancy with little or no iron reserve. Repeated and closely spaced pregnancies and prolonged periods of lactation as noticed in poor socio-economic groups, deplete iron stores with each successive pregnancy and this is reflected in the high incidence of anemia with higher parity.
Inadequate utilization: Defective release of iron from iron stores in to the body and defective iron utilization.
Chronic diseases such as tuberculosis, ulcers or intestinal disorders or excessive blood donation or due to blood loss in hookworm infestation.
Excessive loss of blood during menstruation and child birth increases the requirement for iron. In rural areas post partum hemorrhage on account of poor obstetric care leads to iron depletion to a considerable extent. In women, using intrauterine contraceptive device, menorrhagia (increased blood loss) may result in further depression of already poor store of iron.
Increased demand for iron
Demand for iron substantially increases during pregnancy and growth failure to provide iron through diet or medication would lead to anaemia.
Rapid growth during infancy and childhood increases iron requirement.
Infants often born with poor reserves & solely breast fed for prolonged periods of time , aggravate anemia.
Deficiency of folic acid and B12 vitamins: Folic acid and B12 are essential for the formation and normal growth of red cells along with iron.
Diet poor in folic acid and Vit B12 , low dietary folate absorption, infestations and infections, mal absorption of vitamins in tropical sprue, causes megaloblastic anemia.