Looking after my gut health has been a really important part of my thyroid health approach for many years now. I always enjoy learning more about the gut-thyroid and gut-brain connection and learnt quite a bit from this conversation with Dr Kozlowski.

Dr Kozlowski is a medical doctor who trained in Functional Medicine. Functional medicine is about getting to the underlying causes of disease so you know WHY you are sick and treat those things.

The Thyroid as a Sponge

Dr Koz explains that the thyroid is like a sponge for things (esp toxins) floating around in the body. How do those things get there? Often through the gut! The gut is the gateway into the body and so the role of the gut as a barrier is really important as it separates the outside world (food) from the inside of your body. Hence why having a LEAKY GUT is so unhelpful. Leaky gut contributes to inflammation in the blood.

Another key gut-thyroid connection is that the thyroid needs nutrients to function, so if you’re not digesting your food properly (even if the food you’re eating is nutritious), the thyroid won’t get the nutrients it needs.

Low Stomach Acid

We talk about some common gut problems that Dr Koz sees in thyroid patients:, the most common being low stomach acid. Some of the signs you might have low stomach acid are feeling bloated, feeling full after a normal (not big) meal, low iron and low Vitamin B12.

Dr Koz talks through an at-home test you can do with basking soda to see if you have low stomahc acid (and goes through it in much more detail in his book Unfunc Your Gut.

Vagus Nerve

You’ve probably heard about the gut-brain connection. It’s the vagus nerve that connects the brain to the gut (and heart/lungs). The gut is surrounded by the enteric nervous system which has more neurons than the brain!

The vagus nerve is part of the autonomic nervous system which has the sympathetic nervous system (fight/fright) and the parasympathetic nervous system (rest & digest). When we experience stress or trauma, the brain tells the gut not to work – the gut has food in it, but it’s getting confused as the brain is saying now is not the time to digest. This is in basic terms how stress/trauma create a barrier to gut healing. 

Support the vagus nerve to help the gut heal. 

The vagus nerve could be the key to unfunc-ing the gut. 

Dr Koz shared that Heart Rate Variability is the best tool to help the vagus nerve (eg Hearth Math).

Gut Imbalances

Whilst dealing with stress and trauma is critical, the physical part of gut healing is dealing with gut imbalances. There are 5 areas to look at:

  1. Food – start with food sensitivities. Remove gluten. In his book Dr Koz goes through a very practical approach to discovering your food sensitivities.
  2. Digestion/Microbiome. Get a stool test to see what’s really going on. You will need to remove the bad bacteria and feed the good. You will need to check for SIBO first
  3. Hormones
  4. Toxins
  5. Mental/emotional/spiritual aspects.

The gut is totally healable – that’s great news!

SIBO = Small Intestinal Bacterial Overgrowth

This is when the microbiome that is meant to live in the large intestine has moved into the small intestine. It is tested via a breath test (you’ll need to go to your doctor).

You MUST deal with SIBO FIRST if you have it – you’ll need to starve the microbiome not feed it. Follow a low FODMAP diet as a short term solution.

Be aware that SIBO can recur and Dr Koz says the most common reason why, in his opinion is  unresolved mental/emotional/spiritual issues.

Unfunc Your Gut

For a deeper dive into understand gut health and the gut-brain connection, get a copy of Dr Kozlowski’s book, Unfunc your Gut.

related podcast episodes

If you enjoyed this episode and are looking for similar discussions, check out these episodes:

#29. How to calm your nervous system.

#7. An interview with Dr Elen Apthomas

#12 Sharon Wilford – A naturopath’s perspective.

#34 Stress, trauma & thyroid.

Meet Doc Koz

As a Functional Medicine M.D., Dr. Peter Kozlowski uses a broad array of tools to find the source of the body’s dysfunction: he takes the time to listen to his patients and plots their history on a timeline, considering what makes them unique and co-creating with them a truly individualized care plan. Currently he works with patients online and in person via his Chicago, Illinois and Bozeman, Montana based offices. Dr. Kozlowski did his residency in Family Practice, but started training in Functional Medicine as an intern. He trained in the clinics with leaders in his field including Dr. Mark Hyman, Dr. Deepak Chopra, and Dr. Susan Blum.

Connect with Dr Kozlowski:



If you’re feeling overwhelmed and not too sure where to start/what to do next, why not book in for a strategy session with me?
I’d love to help you.

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Suspect you have a thyroid issue? PLEASE trust your instincts and get it thoroughly checked out with your health practitioner. This thyroid basics page has an overview of what tests to ask for and an affiliate link to use a private lab if your doctor won't order them.

Disclaimer: This information is not intended to diagnose, treat, cure, or prevent any disease.




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