Do the bacteria in our intestine influence the metabolism of iron, an essential component for a healthy body? For the first time, teams from Inra and Inserm, in collaboration with the CNRS (French National Centre for Scientific Research), have demonstrated how bacteria can alter the distribution and storage capabilities of iron in the intestinal cells. Microbiota may be considered a new pathophysiological regulator in intestinal iron absorption. This research is published online in The Faseb Journal on 15 September 2015.
Escherichia Coli, enterobacteria, normal host in the digestive tract. ©Inserm
Iron is a vital element that the body cannot do without. The regulation and control of iron in the body are essential to good health. An iron deficiency can have a negative impact, while an iron overload can also be a health risk. Many societal issues are currently being raised, particularly the effectiveness and the need for people to supplement their diets with iron.
The bacteria that make up the microbiota in the intestine and the intestinal cells live in symbiosis and each require iron to survive. Dietary iron’s only gateway to the body is through the intestine. When the body requires iron, its absorption is promoted by the intestinal cells. The cells also reduce absorption capacity when iron intake needs to be decreased. These defined regulatory mechanisms also respond to the hormone hepcidin, which was discovered several years ago by an Inserm research team.
Researchers at Inra and Inserm, in collaboration with the CNRS, are interested in the effect that the microbiota has on the intestinal absorption of iron, regardless of hormonal effects. To do this, they compared animals (rodents) deprived of intestinal microbiota (“axenic” animals) with animals whose microbiota is controlled. Without the microbiota, intestinal cells have very low iron stores and the transport systems to the body are quite scarce. However, as soon as the microbiota are present in the intestine, the intestinal cells acquire a high iron storage capacity (in the form of ferritin) and promote its transport to the body (increased ferroportin).
Thus, the intestinal cells adapt their ability to store and distribute iron when microbiota bacteria are present.
The identification of this new pathway for iron metabolism control will lead to better control of iron intake and should help better understand iron anomalies in diseases involving microbiota imbalances called “dysbiosis”.