How can interactions in your gut affect your thyroid and your eyes?

A healthy gut microbiota promotes a good balance between T cells in the gut keeping autoimmunity & inflammation in check.

Studies both in animal models and in humans with inflammatory and autoimmune diseases have identified a role for the gut microbiota in shaping the immune system. At any one time, the gut associated lymphatic tissue (GALT) contains about 50% of the cells of the immune system. The interaction between gut epithelium, antigen presenting cells such as dendritic cells and the ‘healthy’ gut microbiota produces cytokines and other metabolites which preserve the balance between regulatory T cells (Treg) and proinflammatory Th17 and Th1 cells.

In the case of dysbiosis when the microbiota is suboptimal, the cytokines produced favour generation of pro-inflammatory Th17 cells which may lead to loss of tolerance. In an individual with a particular genetic predisposition the result of dysbiosis could be Graves’ disease and in extreme cases, Graves’ orbitopathy.