The integrity of the intestinal barrier is fundamental for a healthy gut. A healthy intestinal barrier will keep pathogens and harmful microbial products away from your body, while being selectively permeable to microbial signaling molecules and metabolites that contribute to the health of our biological processes.

Dysfunctions in the intestinal barrier alter its permeability and lead to what is commonly known as “leaky gut.” Leaky gut is fundamentally about two things:

  • Larger molecules being allowed to pass through intact cell membranes due to changes in the transport mechanisms
  • Loosening of the tight junctions between epithelial cells. This means that the intestinal barrier becomes permeable to things to things you don’t want to get in.

Changes in the permeability of the intestinal barrier compromise its ability to block the access of undesired materials into your body. This may result in chronic inflammatory reactions and altered immune responses.


An immune system antibody called immunoglobulin A (IgA) plays a big role in producing a healthy gut microbiome.  IgA is a type of antibody produced by plasma cells. IgA can bind and coat specific microbes, microbial components, dietary components, and other antigens in the intestine. This creates an additional physical barrier that prevents potentially harmful interactions with the immune system.

IgA supports the establishment of a balanced gut by regulating its composition, controlling microbial gene expression, increasing microbial diversity, and enhancing mutualism between the gut microbiota and the host. In turn, the microbiome impacts the production of IgA by influencing the accumulation of plasma cells, as well as the diversity and severity of IgA responses. IgA concentration in the gut is constantly adjusted in response to changes in microbiome, with increases in microbial diversity leading to increases in the diversity of the IgA pool.