What does the gut have to do with thyroid function? We see many patients with low thyroid function and autoimmune thyroid conditions. As a gut-health specialist clinic we will of course ask about your gut – but particularly so when we hear anything related to the thyroid or thyroid-associated symptoms. Why?
The gut and the thyroid are intimately linked and influence each other in many ways. Essentially – poor gut health suppresses thyroid function and low thyroid function causes inflammation and may contribute to leaky gut.
There is a myriad of contributing factors to gut-thyroid imbalances, such as stress and cortisol release which increase intestinal inflammation and permeability; and sluggish digestion and constipation, gallbladder issues and low stomach acid which can be caused by low thyroid function. However today I will go into a bit of detail about the two important mechanisms that link the thyroid and the gut: GALT and the MICROBIOME.
*Note: the subject is huge one and this blog is by no means an exhaustive explanation of all links.
Ever hear the statistic that 70-80% of the immune system, or rather immune tissue lies in the gut?1 It’s true. I’ll explain…
Apart from digestion – the most important function of the gut is to protect us from the unwanted microorganisms that we ingest when we eat, drink and breathe. The digestive tract runs from mouth to anus and if you think about it, this tract is essentially a hollow tube that is open to the outside world. This means we need a strong barrier and good soldiers to protect our bodies from the barrage of potential invaders every time we eat, drink, breath, kiss – you get the picture.
The body has an ingenious method of protection- its all about the GALT…GALT stands for Gut Associated Lymphoid Tissue2. The digestive tract is lined with vast amounts of this GALT – immune tissue and is comprised of immune cells such as B and T lymphocytes – the soldiers of the immune system. Due to the large amounts of GALT in the gut – any issues in the gut will have a profound effect on the body’s immune system as a whole.
Problems in the immune system occur when this barrier containing immune cells becomes damaged due to various causes such as stress, environmental toxins, low thyroid function and diet – this is called Leaky Gut or Intestinal Permeability.
When the gut lining is damaged it becomes inflamed and as a result larger particles from our food are able to pass through the inflamed gut tissue into our blood stream. This is not normal and the soldiers in our immune system get confused and mount an attack/response in order to protect us. A case of mistaken identity. This causes a massive amount of systemic inflammation and tissue destruction. This ‘hyped up’ immune system plays a key role in the development of autoimmune disorders such as Hashimoto’s - see more info about how to treat leaky gut HERE.
A little known fact is that good bacteria in your gut help to convert inactive thyroid hormone (T4) to the active from (T3) – by producing the enzyme intestinal sulfatase. This enzyme is necessary for this conversion to take place. Some studies suggest about 20% of thyroid hormone is converted in the digestive tract this way. That’s huge!
This illustrates how important it is to have healthy populations of good gut flora in order to support your thyroid, and is commonly why people with compromised gut function also have thyroid symptoms. Additionally diverse populations of gut flora are essential for good gut-barrier function and healthy GALT tissue, and protect against leaky gut and pathogenic microorganisms.
Naturopathically, we say that everything in the body is linked and we like to look at the whole picture. When treating conditions such as Hashimotos we will always look at diet, environment, emotions, stress, sleep and any other factors that may be compromising your thyroid health – and of course address any underlying gut issues.