Figure 3.

Thyroid function related to changes in gut microbiota. The figure shows how thyroid diseases influence the gut or vice-versa. Studies in individuals with normal THs levels or in euthyroidism (1), they share a gut microbiota in balance (2), with a normal production of SCFAs being acetate, propionate and butyrate produced in a molar ratio of 60:20:20 respectively (126), and when their microbiota is compared with the microbiota of patients with thyroid disorders (3), these patients shows intestinal dysbiosis with an increase in the abundance of pathogenic bacteria there is an increase in the abundance of pathogenic bacteria with a reduced abundance of commensal bacteria and reduced abundance of commensals that share functions such as SCFAs production, as it has been found in patients with Grave’s disease (127, 128).