Iron is a trace element essential for life, even though it is present in only small quantities in the body. In its natural state, it is a metal found in various minerals, such as haematite or magnetite. In the environment and within the body, it circulates in the form of ferrous (Fe²⁺) or ferric (Fe³⁺) ions, which are soluble in water.
These ionised forms are involved in many vital biological processes and natural cycles, including oxygen transport, energy production and DNA synthesis. As the body cannot produce or store it for long periods, a regular intake through diet or via supplements, where necessary, is essential to prevent iron deficiency.
Which foods contain iron?
Iron is found in many foods of both animal and plant origin. Among the foods richest in iron are:
Liver, red meat, offal
Fish and seafood
Pulses (lentils, chickpeas, red beans)
Green vegetables (spinach, parsley, Swiss chard)
Seeds (sesame, pumpkin) and certain oilseeds
Seaweed such as spirulina
However, the form in which iron is present in these foods affects its bioavailability.
Haem iron and non-haem iron: what is the difference?
There are two types of iron in the diet:
Haem iron: bound to haemoglobin (in red blood cells) and myoglobin (in muscles), it is essential for the transport and storage of oxygen. Of animal origin, it is found in meat and fish and is best absorbed by the body (around 25 per cent).
Non-haem iron: of plant origin, found in cereals, vegetables and plant-based dietary supplements. Its absorption rate is lower than that of haem iron (often less than 17 per cent) and it is more susceptible to interactions with other nutrients.
How can iron absorption be improved?
Iron absorption, particularly that of non-haem iron (from plants), can be optimised through certain dietary choices. Vitamin C is an essential cofactor: it makes iron more soluble and neutralises inhibitors such as phytates (pulses, whole grains), polyphenols (tea, coffee, red wine) or calcium found in dairy products.
Furthermore, consuming haem iron (meat, fish) alongside plant-based iron also improves its absorption. Conversely, it is best to avoid drinking tannin-rich beverages (tea, coffee) at the same time as meals containing iron to minimise their impact.
In summary: combining iron with vitamin C, varying your sources and spacing out the intake of inhibitors helps to maximise its absorption.








