Le rôle du fer dans l'organisme : bienfaits, besoins, carences

The role of iron in the body: benefits, needs, deficiencies

Iron is a mineral essential for the proper functioning of the body although present in very small quantities. But what is its role and what are the needs?
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Updated: 09/09/21

Iron is a mineral essential for good oxygenation of the body. Without it, the transport of oxygen to the cells is impossible!
Not synthesized by the body, it is the champion of the circular economy and recycling. In fact, 95% of the iron present in our body is reused.
However, iron deficiency is one of the most prevalent in France, particularly among women and growing children.

To understand everything about this mineral, we will come back to the role of iron in the body, its benefits and needs, as well as the solutions to fight against deficiencies.

The benefits of iron in the body

The main role of iron is to transport oxygen in the blood and allow proper oxygenation of the organs.

More specifically, iron is a constituent of hemoglobin which is a protein present in red blood cells.

It is this protein that will allow red blood cells to transport oxygen from the lungs to all other organs.
Approximately 70% of total iron is contained in hemoglobin.
Iron is also found in myoglobin, which is a muscle cell whose function is to store and transfer oxygen essential to the functioning of tissues and muscles.

In the absence of iron, the body can no longer form hemoglobin and is therefore no longer able to transport oxygen. This induces under-oxygenation of the body which results in the following symptoms: paleness, fatigue, headaches, etc.

Iron also plays a lesser role in the proper functioning of the nervous system and immune system as well as in cellular energy production mechanisms.
Iron is a more than essential trace element : essential.

The different forms of iron

We distinguish between heme iron and non-heme iron.

  • Heme iron is incorporated into the heme structure of hemoglobin (the pigment that gives blood its color) and comes from foods of animal origin (meat, fish). We also speak of Ferrous Iron (chemically Fe2+).
  • Non-heme iron is also called “ plant iron ” or Ferric Iron (Fe3+). It is found in plants (oilseeds, cereals, fruits, vegetables) but also eggs and dairy products.

Heme iron is better assimilated by the body than non-heme iron: 20 to 25% for the first, 2 to 10% for the other.
In reality, iron absorption depends on other nutrients present at the same time, in the stomach and the upper part of the intestine. We will then distinguish the nutrients which boost absorption from those which reduce it.

  • Boost them: Vitamin C* and group B vitamins help improve absorption. Dietary fiber also seems to play a positive role on assimilation by regulating intestinal transit .
  • Those that reduce absorption: Certain nutrients such as chocolate or tannins in coffee and tea will reduce it.

*with a moderate dosage to avoid other less desirable effects: the Fenton reaction.

Iron requirements in adults

Since iron is not synthesized by the body, it must be supplied daily through food. However, the needs are very different between categories of people (adult men/women and growing young people).

The daily requirements for iron absorbed by the body are:

  • approximately 1 mg in adult humans
  • approximately 2 mg in women between puberty and menopause, due to menstruation

The body contains approximately 3.5 to 4 grams of iron in men and 2.5 to 3 grams in women.

Most of the iron present in our body is constantly recycled. This is why the need for external supplies is relatively low except in the event of blood loss (including menstruation) and during growth because the volume of blood increases. It is also estimated that 25% of young people are iron deficient (= asymptomatic deficiency).

Taking into account the very low absorption of iron*, the recommendations for daily intake* are:

  • Adults and adolescents: 9 to 10 mg/day
  • Regular women: 14 to 16 mg/day

Please note: the amount ingested corresponds to the quantity swallowed and should not be confused with the quantity absorbed (= which remains in the body)

* absorption (relative to what is ingested) is around 20% for heme iron (iron contained in animal products), and around 3 to 10% for iron contained in plants : hence the interest in combining absorption boosters.

Two other important points:

  • The optimal dosage of iron in the blood is particularly important: an excess of iron is as harmful as a deficiency . Therefore, taking an iron food supplement for more than 60 days in a row must be accompanied by a blood test.
  • Due to its molecular structure, iron interacts with other minerals and vitamins . It is therefore preferable to space out the intake of your supplement or another supplement.

Iron deficiency: the symptoms

Iron deficiency is considered the most important nutritional deficiency in France.

Anemia, or hemoglobin deficiency, is characterized by a decrease in the number of red blood cells in the blood or their hemoglobin content.
As a result, tissues and organs no longer receive a sufficient amount of oxygen.

Iron deficiency is assessed by blood tests which will determine the hemoglobin level.

But several symptoms can alert you. The most significant are:

  • Cognitive disorders (delayed growth, development, poor concentration abilities which can lead to poor learning abilities)
  • Body weaknesses
  • Pallor
  • Dizziness
  • Decreased physical strength
  • Early shortness of breath during physical exertion
  • Sensitivity to cold
  • Heart problems
  • Tachycardia or palpitations

The causes of iron deficiency or lack of iron

There are many causes of iron deficiency , but the main ones are:

  • Insufficient iron intake in the body:
    Malnutrition or poor diet are obvious factors, but we must also take into account the poor assimilation of plant iron which leads to unpleasant surprises. This is a particularly common situation among mature women who consume little red meat. Vegans aren't the only ones affected!
  • Acute or chronic blood loss : Menstruation is the leading cause of deficiency in women.
  • Pregnancy: the development of the fetus and the increase in blood volume lead to higher iron requirements. An old report from the WHO (world health organization), dating from 2011, estimated that 30% of women of childbearing age or pregnant women had an iron deficiency.
  • The growth period: During growth, blood volume gradually increases.

In all cases, iron deficiency must be noted and diagnosed by a doctor who can recommend or not take an iron food supplement.

Without being deficient, Athletes, particularly those doing long aerobic efforts, have every interest in having a high blood iron level in order to optimize the transport of oxygen to the muscles. Again, a blood test is the best method before deciding on supplementation.

To find out more about the different types of IRON for good supplementation: consult the article: to help you choose your iron supplement .

Our Iron Bisglycinate supplement with absorption boosters (acerola, carrot) and vitamin B9 , in gastro-protective capsule for the greatest comfort of intake, certified vegan:

iron image Blog

Iron + Vitamin C, B9 and Carrot
€18.50 for 2 months of treatment!

The Argalys team.