Renato Faillace, MD., Hematology Specialistby the Brazilian Medical Association.

Alternative name: hypoferric anemia

Iron, for being part of a molecule, is indispensable to hemoglobin production, the pigment of the red blood cells that allows the transportation of oxygen, and whose deficiency is called anemia.

Iron deficiency is the most common cause of anemia (hypoferric anemia).

Reasons precede history. The primitive man presumably had a diet similar to that of his counterparts on the top of the zoological scale: wild fruits, palatable herbs, avidly sought after eggs and animal preys, from larvae to sizeable mammals. Cannibalism perhaps was an ordinary event.

This natural diet supplied him with iron associated to animal proteins and vitamin C from fruits, a suitable combination for iron absorption in the human digestive tract. In times of scarceness, the primitive man must have experienced undernourishment, famine, but rarely iron deficiency.

The last name “sapiens”, which differentiated him from the anthropoids, led the homo to the invention of agriculture: the crop fixed him to the soil, the predictable source of foods gave rise to demographic expansion. Thousands became millions, now six billion. There aren’t animal proteins for so many, and, unfortunately, the human digestive tract hasn’t evolved for the new times: it poorly absorbs iron from grains, tubercles and green plants. 20% of the world population is believed to lack, in their organism, enough iron stores to replenish hemoglobin: any excessive demand triggers iron deficiency anemia. This has become a public health problem of startling prevalence.

In Brazil, a deficient diet is per se the triggering factor for iron deficiency anemia only in the following cases:

In breastfeeding age infants, when fed with bovine milk. Milk iron, already scarce, is poorly absorbed; at between 6 months and 2 years of age anemia is almost universal. Maternal breastfeeding, with a highly superior iron absorption, prevents anemia.

In pregnant women of low socioeconomic status: the passage of iron through the placenta, for fetal needs, causes a negative iron balance; if no supplementation is provided, anemia will occur.

In the unassisted elderly: lack of resources, denture in bad state, and inappetence lead to the prevalence of a diet comprised of coffee and milk, bread, soups, virtually without assimilable iron.

In strict vegetarians: cases are rare.

How does iron deficiency anemia develop?

Apart from the cases above, iron deficiency anemia, as a rule, doesn’t depend on the diet; it results from chronic blood loss. In rural and coastal areas without sanitation, privation by verminous diseases, especially in childhood, is a common cause.

In women at fertile age, unnoticed or neglected menstrual excess (hypermenorrhea) is the cause of 95% of iron deficiency anemia cases and the reason why the prevalence thereof is 20 times as high in women as in men. Female patients (at times doctors as well), however, find it hard to believe that this is the cause for anemia; used to hypermenorrhea, they consider it “normal, because that’s the way it’s always been”, and persist on seeking other causes in the diet, in the “increased iron binding capacity”, in detriment of the obvious cause. Human body’s iron has no excretion mechanism and certainly doesn’t evaporate: it’s lost out with blood loss.

In men and a minority of women, iron deficiency anemia results from chronic blood loss in the digestive tract for gastritis, ulcer, tumors and chronic intestinal inflammations. The lost blood exits amid the fecal mass; when the volume exceeds 50 grams, feces become dark and glossy with foul odor (melena). People, in general, don’t pay attention to their own feces: blood loss is almost never noticed.


The diagnosis for iron deficiency anemia is usually easy: the hemogram shows an anemia characterized by the presence of red blood cells whose size is smaller than normal (microcytosis) as they lack hemoglobin content. The serum ferritin level, a chemical form of iron storage in the organism, indicates this as being quite low or absent.


Iron deficiency anemia is cured in two to three months with oral administration of iron sulfate. Other iron compounds, more expensive and marketed under the claim they’re better tolerated by the digestive tract, present an unsatisfactory absorption. To attempt to treat iron deficiency anemia with iron-rich foods (patients usually mention liver, spinach, black beans, beet-this one for its color) has no basis: dietary iron is always insufficient for this purpose. If the cause of iron deficiency anemia persists, as, for instance, in untreatable hypermenorrhea cases, anemia will recur in some months or years after the cure with the treatment. A periodic hemogram control is suggested, with repeat treatment when necessary.