Endurance athletes generally have a greater need for iron compared to people who do little or no sport. To improve athletes on their endurance performance, iron supplementation is sometimes recommended or prescribed. The importance of anemic iron deficiency is not discussed here, but it is useful for athletes with an iron deficiency, but without anemia. Before you consider supplementation, please read this blog.
Iron and our genes
The need for iron in food is strongly influenced by the presence of certain genetic variations. For example, a genetic variant in the TMPRSS6 gene, which has about 25% of the Western population, can disrupt the uptake of iron in the intestines. An increased need for iron in food will then be indicated.
In the other direction, two other genetic variants in the HFE gene can also influence iron uptake. Here they disrupt the feedback mechanism that reduces iron uptake if the iron status in the body is sufficiently high. The body then continues to absorb iron while this is not necessary. This leads to excessive iron concentrations or iron accumulation and can lead to organ damage or worse. Iron supplementation without prior blood control of the iron status is not recommended, knowing that this genetic variant occurs regularly and that there are health risks associated with excessively high iron levels.
In addition to the two described genetic variants that can disrupt iron uptake in both directions, there is also a known genetic variant that influences the transport of iron in our bodies. This variant is in the TF or transferrin gene and reduces the binding capacity of transferrin to iron. Transferrin is one of the most important transport proteins of iron. A reduced binding capacity of transferrin to iron could result in more free (i.e. unbound) iron. Unbound iron is quite aggressive for our body and can therefore be avoided as much as possible. Iron supplementation for persons with this genetic variant, in the case of anaemia, must therefore be done with some vigilance and with great care.
What to remember
Iron supplementation is therefore not without risk, but in certain cases it is advisable. In order to determine whether an iron supplement is desirable, a DNA analysis together with a blood test for iron status is an important starting point. DNA analysis is the only way to find out which genetic variants are present, explain different iron values and underpin a suitable nutritional strategy.