Over 2,000 years ago an ancient Greek doctor named Hippocrates once said,”All disease starts in the gut”. However, it’s only now that health experts have fully understood what Hippocrates said so long ago. Many studies have been done which further show the link between a person’s thyroid gland and gut health. The “gut” refers to the hollow tube that moves from somebody’s mouth to the anus. This way, anything that’s being ingested in the mouth that can’t be digested will be excreted through the opposite end of the gut.

Important Function

This is a most basic yet most important function of the intestine – to prevent any foreign objects or substances from penetrating in someone’s body. Another vital role is to sponsor 70% of the immune system within the body. This is the portion of the immune system that’s jointly called GALT (Gut-Associated Lymphoid Tissue). The GALT is comprised of different kinds of lymphoid cells that are capable of keeping immune cells like the B & T lymphocytes.

These are the sorts of lymphocytes that defend the body by producing antibodies that fight against antigens that are identified by the immune system as disease-causing.

Protection Function

A problem occurs when these protective functions of someone’s gut has been compromised. For instance, when someone suffers from leaky gut syndrome whereby the intestinal obstruction becomes permeable, then in addition, it becomes much easier for large protein molecules to enter into the bloodstream. Unfortunately, these large protein molecules shouldn’t be out of the gut and if they are, the individual’s immune system will instantly tag it for destruction.

These attacks created by the immune system, in a bid to defend the body against diseases-causing germs, can also cause the development of autoimmune diseases and one of them is Hashimoto’s Disease. The tight junctions within your gut and your intestines are also being strongly influenced by your thyroid hormones. The thyroid hormones T3 and T4 play an essential role in protecting the mucosal lining of the gut from stress induced ulcer formation. Studies show that people with gastric ulcers were found to have reduced levels of T3 and T4 hormones while their reverse T3 hormones were also in abnormal amounts.


The gut bacteria are also very valuable in the process of converting inactive T4 hormones into an active form called T3 thyroid hormones. About 20 percent of our T4 has been converted to an active form T3 within the gastrointestinal tract with the support of an enzyme called intestinal sulfatase. This intestinal sulfatase is created from healthy gut bacteria. If there is an imbalance between the amount of beneficial bacteria in the gut and the number of pathogens, which is a condition known as intestinal dysbiosis, the correct conversion of thyroid hormones are also reduced. Because of this, many people who have bad bowel health also suffer with the symptoms of thyroid issues.