What is iron?
Two forms of iron are found in food: haem iron and non-haem iron:
- Haem iron is found exclusively in foods of animal origin, because it is derived from proteins such as haemoglobin.
- Non-haem iron is found in most foods, regardless of whether they are of animal or plant origin.
The absorption rate of haem iron is higher than that of non-haem iron. Our ability to absorb dietary iron depends on the body's reserves, the proportion of haem iron in our diet and the presence of compounds that increase absorption, such as vitamin C, or decrease it, such as tannins in tea.
What are the main dietary sources of iron?
Iron requirements can be met by eating liver, meat, fish and seafood, pulses, nuts, cereals, egg yolk and green leafy vegetables.
The list of foods with a high iron content can be found in the Ciqual table of nutritional composition of foods.
Why is iron important to health?
Iron is necessary for oxygen transport and use by red blood cells, and also for the functioning of certain enzymes.
The balance between iron intake and loss is generally well regulated in healthy people, since there is efficient recycling of iron from red blood cells. Regular iron intake also helps maintain a balanced iron status.
There are also a few reserves in the liver, spleen and bone marrow, which can be mobilised by the body to meet increased needs in certain physiological situations such as pregnancy or growth.
What are the health risks in the event of a deficiency?
A lack of iron can lead to "iron-deficiency anaemia". The body becomes less able to transport oxygen to the cells. This can cause fatigue, headaches, dizziness and shortness of breath, among other things.
What are the health risks in the event of excessive intake?
The risk of excess iron is negligible in people with normal intestinal function.
However, chronic iron overload can occur in individuals with haemochromatosis, a genetic disease characterised by excessive intestinal iron absorption, leading to iron deposits in all tissues and causing joint, liver and heart problems.
Are some population groups more susceptible to iron deficiency than others?
The population groups most at risk are those with high iron requirements due to:
- growth, such as infants, children and pregnant women,
- heavy menstrual bleeding in some women,
- health conditions associated with bleeding such as haemophilia,
- poor absorption of iron by the body, for example due to inflammation or infection.