The relationship between gut health and the thyroid gland is an area of growing research, and there is evidence to suggest that the two may be interconnected. The gut and thyroid axis refers to the bidirectional communication between the gut microbiota and the thyroid gland. The interactions between the gut microbiota and thyroid function are so intricate it has been termed the gut-thyroid axis [1].

Key Links Between the Gut and the Thyroid Gland

The gut is host to 70% of the immune tissue in the body. This portion of the immune system is collectively referred to as GALT, or gut-associated lymphoid tissue. The GALT is made of many different types of cells including the T & B lymphocytes, that carry out attacks and produce antibodies against antigens, molecules recognized by the immune system as potential threats. Problems occur when the protective functions of the gut are compromised and the thyroid gland can be susceptible when this happens.

  • Microbiome Balance & Inflammation: The gut plays a crucial role in immune function, and imbalances in gut bacteria can lead to inflammation. These imbalances in the gut microbiota are known as dysbiosis and have been associated with various autoimmune diseases. Additionally, dysbiosis can lead to inflammation and chronic inflammation is associated with various health conditions, including autoimmune diseases such as Hashimoto’s thyroiditis and Graves’ disease, which affect the thyroid [1].
  • Nutrient Absorption: Iodine, selenium, zinc, and iron are all needed for proper thyroid health. These nutrients must be assimilated appropriately to be utilized effectively by the thyroid. The gut is responsible for absorbing these nutrients, and any disruptions in gut health may impact their absorption, potentially affecting thyroid function [2,3].
  • Short-Chain Fatty Acids (SCFAs): The gut microbiota produces short-chain fatty acids through the fermentation of dietary fiber. SCFAs have been implicated in modulating the immune system and may influence the development of autoimmune conditions. These SCFAs, especially butyrate, have been found to impact immune regulation and have anti-inflammatory effects. This would aid in preventing autoimmune thyroid disorders and support healthy thyroid output [1].
  • Leaky Gut Syndrome: Increased intestinal permeability, or “leaky gut,” is a condition where the lining of the gut allows larger molecules to pass through, potentially triggering an immune response []. Some studies suggest that leaky gut may be associated with autoimmune thyroid disorders like Hashimoto’s thyroiditis and Grave’s disease [5,6].

Current research has identified specific gut microbiota taxa at the genetic level that are predicted to have a causal relationship with thyroid function, which may serve as useful biomarkers for early disease diagnosis in the future [3]. It’s important to note that while there is evidence suggesting a connection between gut health and thyroid function, more research is needed to fully understand the mechanisms involved and establish clear cause-and-effect relationships. Additionally, individual responses can vary, and factors such as genetics, diet, and lifestyle also play significant roles in thyroid health.

Final Thoughts

Maintaining a balanced and healthy diet, promoting gut microbiota diversity through the consumption of probiotics and prebiotics, and managing stress are generally considered beneficial for overall health, including thyroid function. However, specific recommendations should be discussed with a healthcare professional, especially if you have concerns about thyroid health or existing thyroid conditions.



[1] Knezevic, J., Starchl, C., Tmava Berisha, A., & Amrein, K. (2020). Thyroid-Gut-Axis: How Does the Microbiota Influence Thyroid Function?. Nutrients, 12(6), 1769.

[2] Jiang, W., Lu, G., Gao, D., Lv, Z., & Li, D. (2022). The relationships between the gut microbiota and its metabolites with thyroid diseases. Frontiers in endocrinology, 13, 943408.

[3] Fröhlich, E. and Richard Wahl, R. (2019). Microbiota and Thyroid Interaction in Health and Disease. 30(8),

[4] Xie L, Zhao H and Chen W (2023). Relationship between gut microbiota and thyroid function: a two-sample Mendelian randomization study. Front. Endocrinol. 14:1240752.

[5]  Zheng, D., Liao, H., Chen, S., Liu, X., Mao, C., Zhang, C., Meng, M., Wang, Z., Wang, Y., Jiang, Q., Xue, Y., Zhou, L., & Chen, Y. (2021). Elevated Levels of Circulating Biomarkers Related to Leaky Gut Syndrome and Bacterial Translocation Are Associated With Graves’ Disease. Frontiers in endocrinology, 12, 796212.

[6] Cayres, L. C. F., de Salis, L. V. V., Rodrigues, G. S. P., Lengert, A. V. H., Biondi, A. P. C., Sargentini, L. D. B., Brisotti, J. L., Gomes, E., & de Oliveira, G. L. V. (2021). Detection of Alterations in the Gut Microbiota and Intestinal Permeability in Patients With Hashimoto Thyroiditis. Frontiers in immunology, 12, 579140.