Where does chronic inflammation start?
The gut represents the largest surface area for contact and exchange in the human body. It allows nutrients to pass through it, but also stops unwanted substances, from food, bacteria, viruses, or other foreign bodies (medicines, pesticides, additives, etc.), via various defence mechanisms (physical barrier, gut microbiota and intestinal immune system).
However, the gut can be adversely affected by a number of factors, including chronic stress or repeated infections, causing loosening of its tight junctions. The gut’s permeability is then increased, allowing it to let unwanted substances through into the blood circulation
This phenomenon is known as leaky gut syndrome. A chronic inflammatory reaction then develops.
The cytokine balance is a very good marker of inflammatory status. Cytokines (interleukins, TNF-alpha, etc.) are proteins synthetised in small amounts by the immune cells in response to a stimulus.
Pro- or anti-inflammatory, they play a role in all phases of inflammation.
It is the balance between these pro- and anti-inflammatory cytokines that will locally control the intensity and duration of the inflammatory reaction.
What is the leaky gut syndrome ?
How can inflammation be limited by probiotics?
By restoring the balance of the gut microbiota (which used to be known as the gut flora), probiotics reinforce the barrier effect of the gut lining (gastrointestinal mucosa) by keeping it intact. They help protect the body against inflammation:
by limiting the spread of harmful agents either via competition for nutrients, thereby reducing the growth of pathogens ;
by competition for the binding site on the gut wall ;
or by synthesis of metabolites toxic to these pathogens.
Probiotics can change the cytokine balance because they have anti-inflammatory properties. In fact, they are capable of regulating the profile of the mediators involved in inflammation:
they stimulate the secretion of anti-inflammatory cytokines ;
and/or they reduce the secretion of pro-inflammatory cytokines.