Dr. Ana Montalvão

Hematologist 

Anaemia and iron deficiency:  The "hidden need"

HPA Magazine 22 // 2024

Iron deficiency, and its main consequence – iron deficiency anaemia – is today one of the most common forms of nutritional deficit. It affects more than 2 billion people – more than a third of the world's population. Having a high prevalence in less developed countries, it is also common in industrialized countries.
Since the signs may be barely noticeable, we call it "a hidden need"; and it is for the same reason that adequate treatment often begins in advanced stages of the disease.

 How important is iron in the body?
Some nutrients are considered essential - meaning the body does not have the ability to produce them. Iron is one of them and must be obtained through the diet.
It is essential for the production of haemoglobin – a red pigment that is part of erythrocytes (red blood cells) and whose function is to capture oxygen in the lungs and transport it to all cells (muscles, organs, etc.), in addition to carrying, on the return, some carbon dioxide so that it can be eliminated through breathing.
When iron reserves are depleted, the production of erythrocytes and haemoglobin is compromised: iron deficiency anaemia sets in.

What are the main causes of iron deficiency?
1. At certain stages of life, iron needs increase: periods of accelerated growth such as adolescence, pregnancy (mainly in successive pregnancies), and breastfeeding (especially prolonged). Therefore, appropriate supplementation must be carried out in these phases.
2. “Radical” diets often lead to iron deficiency, as well as changes in dietary balance (for example, in the elderly who no longer have the autonomy to prepare balanced meals). 
A vegetarian diet does not necessarily lead to a lack of iron, but it is necessary to take the necessary precautions to avoid it.
3. Certain gastric diseases and the rest of the digestive tract affect absorption, particularly of iron. This also includes some infections and parasites.
There may be an apparently adequate intake, but the body cannot use the iron, as it does not pass from the intestinal tract into the blood.
4. Bleeding, whether acute or chronic, necessarily leads to iron deficiency. Examples are exaggerated menstrual losses, peri- and postpartum haemorrhages, gastric ulcers, and intestinal lesions.

What are the signs and symptoms of iron deficiency?
Initially, the manifestations are non-specific, such as fatigue, lack of concentration, tiredness with minor efforts, or susceptibility to infections.
Later on, pallor, fragility of the hair and nails, angular cheilitis (cracks in the corners of the mouth), and other changes in the skin (such as dryness) and mucous membranes (such as in the mouth or throat) occur.
These signs and symptoms can help with the diagnosis, but it is necessary to confirm the existence of iron deficiency anaemia (excluding other causes of anaemia) through specific tests.

How is the diagnosis of iron deficiency confirmed?
The main means of diagnosis is through blood tests, determining the concentration of haemoglobin in it. The value must be between 12 and 14 g/dl in women and between 13 and 15 g/dl in men. Below these limits, the individual is considered to have anaemia.
Another fundamental parameter is ferritin, a protein with the function of storing iron. These reserves are essential for the body to respond quickly and adequately to any increase in iron needs to produce haemoglobin. Reference values for ferritin vary depending on laboratories, but it is generally accepted that they should be between 100 and 300 μg/l. Ferritin can be low even before the haemoglobin value drops, and it is important to correct it in time to avoid the onset of anaemia.
It is also worth highlighting the other parameters of "iron kinetics" namely transferrin, its saturation, serum iron, and total iron-binding capacity, through which the Haematologist can assess the patient's situation with greater precision and choose the best treatment.

How is iron deficiency treated?
Treatment will depend on the severity of the iron deficiency:
A. If it is a mild deficiency, adjusting the diet and supplementing with multivitamins may be sufficient.
B. In moderate to severe deficiencies, oral iron administration is the standard treatment. There are several types of oral formulations:
1. Bivalent salts (ferrous sulphate): effective, but with frequent gastric or intestinal side effects (such as metallic taste), interactions with other medications, and decreased absorption with food.
2. Trivalent iron complexes (iron III-polymaltose complex): with greater gastrointestinal tolerance, they can be administered with food, but still have side effects, such as dark coloration of the stool.
3. Liposomal-Sucrosomal Iron Complexes: With the highest absorption rate among oral formulations, it does not lead to metallic taste or dark stools, but effectiveness may be compromised with certain foods.
C. In situations of severe iron deficiency anaemia, where iron replacement must be done quickly, or in patients with intestinal absorption deficits or those who cannot tolerate oral therapy, intravenous iron administration (ferro sucrose or iron-carboxymaltose) is recommended.

How long can the treatment take?
With oral iron, treatment duration is a minimum of 2-3 months. Symptoms may improve after 2 to 4 weeks, as normalization of haemoglobin values takes this time on average; however, it is essential to continue treatment for approximately 2 more months, because the time needed to replenish iron stores is longer. Premature interruption of treatment can lead to a relapse of anaemia and its symptoms.
For intravenous iron, the doses and number of administrations are calculated by the Haematologist based on haemoglobin and ferritin levels, the patient's weight, height, and physical condition, particularly cardiac. The number of treatments can range from a single administration to six treatments, separated by about a week.
In either case, an assessment of the response to treatment is made, ruling out other unresolved causes of iron deficiency anaemia to avoid relapses.

Is it possible to prevent iron deficiency?
Food is the only source of iron, so a balanced diet is the best way to prevent iron deficiency and consequent iron deficiency anaemia.
Especially in situations where needs are increased, such as pregnancy and growth, ensuring adequate iron intake through iron-rich foods and avoiding foods or medications that compromise its absorption is crucial.
This information does not replace a Hematology Consultation; in this, each patient's particular case is evaluated, appropriate tests are requested, and the available treatment options are discussed and decided together with the patient.
With the diagnostic techniques and treatments available today, iron deficiency can be treated with high levels of efficacy and safety. Regardless of the type of treatment, its success always depends on careful prior assessment and post-treatment monitoring at the appropriate times and through the appropriate means.