This stage is also called pre-latent iron deficiency. The second stage in iron deficiency involves impaired erythrocyte production and is called iron-deficient erythropoiesis. When iron is not available to bind with protoporphyrin, protoporphyrin will increase in the blood - this is used then as an indicator of depressed erythrocyte production. As the inability to produce erythrocytes continues, Hb formation will be impaired. This third and final stage is called iron-deficiency anaemia.
Iron deficiency is arguably the most common nutritional deficiency in the world.
In fact, there is evidence to suggest that the incidence of the problem with athletes is no greater than with the general population. Iron intake is likely to be lower than normal when caloric intake is restricted and when energy is gained from processed food. Women will have greater loss of iron than men due to menstruation and the fact that they generally eat less food. Vegetarians will have lower uptake of iron due to lower bioavailability of iron in non-animal foods. Meat, seafoods and poultry contain both forms while cereals, legumes, vegetables and eggs contain only the non-haem form.