Iron is an indispensable element in our body. Its best known function is to bind oxygen within hemoglobin (protein in red blood cells that allows the transport of oxygen to tissues) and myoglobin (protein capable of fixing oxygen in muscles). Not only that, it is essential for the synthesis of collagen, for cellular respiration processes and is a component of cytochromes and numerous enzymes (such as nitrogenases and catalases).
According to the LARN tables, the average daily iron requirement varies according to age and sex: 7 mg for infants, 4-5 mg for children, 7-9 mg for adolescent boys and 7-10 mg for female adolescents, 7 mg for male adults, 10 mg for women, dropping to 6 mg in menopausal age. Particular attention should be paid to the period of pregnancy and lactation, which correspond to an average requirement of 22 mg and 8 mg respectively.
In our body it is possible to distinguish: active iron, associated with hemoglobin (about 65%) and myoglobin (about 10%); transport iron, found in the blood; the reserve iron (about 20%), deposited in the tissues, very important because it is recovered and used by the body for its functions. The human body produces about 4 grams of iron which are found in the liver, spleen, bone marrow and blood.
An adequate diet must be able to compensate for the iron that is excreted from our body through physiological losses (faeces, urine, sweat, bile, desquamation of epithelial cells and, in the case of women, during menstruation). Foods rich in iron are red meat, especially offal (spleen, liver), fish, especially seafood such as clams, oysters and mussels, and eggs. Iron is also contained in a good percentage in legumes (beans, peas, lentils), dried fruit (hazelnuts, pistachios, peanuts) and green leafy vegetables (green radicchio, broccoli and spinach).
When we talk about foods that contain iron, we must take into consideration the different bioavailability, that is the actual absorption. In this sense, iron is divided into heme and non-heme. Heme iron is in the Fe2 + oxidation state (ferrous ion, the form that can reversibly bind oxygen) and is easier to absorb. Meat, for example, contains about 40% of heme iron and is more bioavailable than plant-based foods. The latter contain only non-heme iron, which is in the oxidation state Fe3 + (ferric ion) which is more difficult to absorb. To compensate for the lower bioavailability of foods of plant origin, it is recommended to combine a source of vitamin C such as citrus fruits, kiwis, strawberries, papaya, red and yellow peppers. This increases the absorption of iron, helping to reduce it in the most assimilable form; it is the reason why we often find it present in supplements. Furthermore, vitamin C contributes to the formation of collagen for the normal function of blood vessels.
The foods that compromise and hinder the absorption of iron are tea and coffee (due to the presence of tannins), those that contain oxalic acid (whole grains, spinach, beets), as well as those where there is a strong calcium component. Several drugs significantly lower the gut's ability to absorb iron: antacids, anti-inflammatories, and some antibiotics. Finally, a reduction in gastric secretion also negatively affects iron absorption.
What are the cases in which iron deficiency is highlighted?
- inadequate intake to metabolic needs;
- insufficient absorption;
- greater need;
- increased and protracted elimination, as in case of haemorrhages.
Iron deficiency anemia, iron deficiency, can lead to general fatigue, tiredness, drop in immune defenses, restless legs syndrome, and in adolescents it is associated with decreases in learning and behavioral abnormalities. It is a very dangerous condition during pregnancy, as iron performs multiple functions during this phase, and it is therefore necessary to ensure a greater amount. According to the World Health Organization at least 40% of women become anemic during pregnancy and this insufficiency increases the risk for the newborn: premature or underweight birth, delayed growth and problems with the nervous system. Normally, iron supplements for pregnant women also contain folic acid, a water-soluble vitamin that contributes to the growth of the fetus by helping the formation of hemoglobin, fighting some congenital malformations and promoting the correct development of the nervous system. It is also important for the mother because it helps the assimilation of iron reducing the risk of anemia. Sportspeople (iron is also lost through sweat) and blood donors are also at risk of deficiency, since the blood normally collected amounts to about 500 ml, plus 25 ml for analyzes, and the cumulative effect of blood donations without adequate iron replacement or waiting between donations can lead to fatigue and neuromuscular symptoms.
Oral iron is considered a full-fledged therapy, but should not be taken lightly. Some side effects of intestinal disorders such as nausea, abdominal pain, constipation or diarrhea have been reported. Furthermore, if on the one hand we have seen the negative effects of the shortage of this precious mineral, on the other we must not underestimate a possible excess. In those suffering from certain metabolic-genetic disorders, we speak of siderosis and it is due to the accumulation of iron in the organs. So, first of all you need to focus on nutrition, favoring the combination of foods rich in iron accompanied by foods rich in vitamin C and, in the event of a clear deficiency, you must consult your doctor to integrate conscientiously.
Translated by Arianna Giannino