Gut-thyroid axis and emerging role of probiotics in thyroid disorders

ABSTRACT A preliminary knowledge of the gut-thyroid axis based on the studies in the last few years suggests that the intestinal microbiota and its metabolites may affect the thyroid either directly or indirectly by affecting the conversion and storage of iodothyronine, the absorption of thyroid-related micronutrients and playing a crucial role in the onset and progression of thyroid organ-specific autoimmunity. These findings may offer new insights into the pathogenesis of thyroid disorders and their clinical management. The research on thyroid and gut microbiota has however, just touched the surface. Here, in the present review, we have summarized the current scientific evidence related to the gut microbiota and thyroid disorders as well as the studies of probiotic supplementation in thyroid disorders and pave the way for future research on the gut-thyroid axis.