How Your Thyroid Impacts Your Gut
Did you know that your thyroid can have an impact on your gut? And vice versa?
If you’re struggling with chronic gut issues, including IBS, and/or thyroid dysfunction… that connection you thought was there but nobody seemed to address yet… is real!
This blog will break down how the most common forms of thyroid dysfunction, hypo- and hyperthyroidism, impact digestion and the theories of how the thyroid and gut are connected.
What is the thyroid?
This is a butterfly shaped gland in your neck that is responsible for producing thyroid hormone, which then impacts metabolism, tissue function throughout the body, and more!
How this process works: your brain releases thyroid stimulating hormone (TSH) that tells the thyroid gland to produce inactive thyroid hormone (T4), which is sent out to tissues in the body and is converted to active thyroid hormone (T3). This is used inside the cells of tissue to produce ATP (aka energy for that cell to use for metabolism and functions it is responsible for).
Because of how cells use thyroid hormone, this process directly impacts basal metabolic rate, oxygenation, respiratory rate, cardiac output, and heart rate.
Hypothyroidism is an endocrine disorder where there is an underproduction of thyroid thyroid. This means the brain is producing a large amount of TSH, but the thyroid gland isn’t producing T4, or the tissues in the body aren’t converting T4 to T3 properly to be used.
Hypothyroidism can lead to decreased metabolic rate, cardiac output, heart rate, and respiratory rate. Due to this impact on metabolic rate, which can also impact the nervous system, hypothyroidism can lead to constipation and slowed gut motility.
The same is true for Hashimoto’s thyroiditis which is an autoimmune condition that is the top cause of hypothyroidism. Another common cause of hypothyroidism is iodine deficiency as iodine is necessary for thyroid hormone production.
On the opposite end of the spectrum, hyperthyroidism is an endocrine disorder that causes an overproduction of thyroid hormone. This leads to an increased metabolic rate, heart rate, respiratory rate, and so on. Because this puts the body in a heightened state, this can lead to diarrhea and fast motility. For some, this will also lead to an increase in nausea and vomiting.
The same is true for Grave’s Disease, which is an autoimmune condition that causes hyperthyroidism.
What’s your poop personality? Find out here!
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What about the reverse relationship?
The more we learn about the gut, especially gut microbes, the more connected the gut seems to be to the rest of the body. This is especially true of the endocrine (aka hormone) system.
The gut-thyroid axis is a proposed connection between thyroid function and the impact of thyroid hormone with gut function and gut microbes.
The gut environment includes the makeup of gut microbes, the byproducts of fermentation by gut microbes, and the strength of the intestinal wall.
When it comes to gut microbes, their fermentation byproducts seem to be connected to thyroid function. Short chain fatty acids (SCFA), in particular, seem to have the greatest impact. SCFAs are byproducts of fiber fermentation by benefiical microbes in the gut. These can impact many systems in the body, and have been positively correlated with thyroid function - both in the production of and use of thyroid hormone in the body.
This means that having beneficial microbes present and feeding those microbes to increase SCFAs may be key to preventing thyroid dysfunction.
Going back to the autoimmune conditions earlier than directly impact thyroid function… increased intestinal permeability, which refers to a weakened intestinal wall can alter immune function and may play a role in the development of autoimmune disease - including that of Hashimoto’s thyroiditis and Grave’s disease.
While we may not have clear mechanisms of action of how the gut impacts the thyroid, we see these correlations enough to know there is a connection. This means that supporting the gut may help improve thyroid function… and maybe this is a missing piece for those with thyroid dysfunction that aren’t responding to current treatments.
We cover what to do for both the gut and the thyroid in the MASTER Method Membership - so if you’re feeling suck and looking for resources, the membership may be a great fit for you!
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