Normal human beings have stores of iron, folate, and vitamin B12 which are needed for the manufacture of red blood cells. If these stores are reduced, no clinical or biochemical abnormality may result, but the ability to meet increased demands for nutrients (for example, during pregnancy) is decreased. A further depletion of these stores may produce biochemical and/or clinical effects without anaemia. Iron deficiency anemia can be characterized by fatigue, headache, and poor concentration.
Women suffer more from anaemia than men. An adult woman needs three times as much iron as is required by an adult man but in many countries women's diets are frequently more deficient than men's. In certain societies food taboos, specially those that apply during pregnancy, aggravate malnutrition. About half of all women aged from 15 to 49 in developing countries, that is 230 out of 464 million, are anaemic, suffering from a deficiency of one or more essential nutrients, chiefly of iron, and less frequently of folate.