Hypo-Poo: Hypothyroidism and the SIBO Relationship


Ah, crap. It’s happening again. The dreadful run to the bathroom murmuring ‘oh no’ the whole way. You slam the door behind you and know that it may be hours before you come out again. And you forgot to grab a book.

This is what I like to call hypo-poo. Gastrointestinal issues such as chronic constipation or diarrhea, bloating, and gas are common among patients living with hypothyroidism. Not to mention the incredible fatigue that follows after emptying your body of everything you have. Honestly, this is one of my least favorite aspects of living with this condition because it can ruin a whole day of plans. Hypothyroidism can cause disruption in other body systems too. As a congenital hypothyroid patient, digestive issues have been a battle most of my life and have motivated me to make better life habits for myself including diet and vitamin intake. But to do this – I needed to do more research.
Hypothyroidism and SIBO (Small Intestinal Bacterial Overgrowth) are two separate health conditions that share a surprising link. Recent research has shown that there is a strong correlation between the two and that those with hypothyroidism are more likely to develop SIBO.

In this article, we will explore what these conditions are, how they are linked, and what you can do to manage them.

What is Hypothyroidism?

First, let’s review. What is hypothyroidism?

Hypothyroidism is an autoimmune condition where the thyroid gland does not produce enough thyroxine, the thyroid hormone. Thyroxine is responsible for energy regulation and the basic motor function of vital organs. A lack of this hormone can be problematic and can lead to a variety of symptoms, including fatigue, weight gain, depression, and constipation. Hypothyroidism is typically treated with medication to replace the missing thyroid hormone, generally known as Synthroid or Levothyroxine. These are the most popular thyroid hormone replacement, however, there are other options.

Read more about Hypothyroidism here.

What is SIBO?

SIBO is a condition where there is an overgrowth of bacteria in the small intestine. This can lead to symptoms such as bloating, gas, diarrhea, and abdominal pain. SIBO is typically treated with antibiotics and dietary changes. These symptoms tend to overlap with the gastrointestinal symptoms of hypothyroidism.

The Link Between Hypothyroidism and SIBO

Research has shown that there is a strong correlation between hypothyroidism and SIBO. This is because thyroid hormone plays an important role in regulating the movement of food through the digestive system.

“SIBO is associated with the increase in level of microorganisms above 106 colony-forming units/ml in intestinal aspirate. This may be associated with colonic-type of bacteria in the small intestine. SIBO occurs when mechanisms controlling enteric bacterial growth are disturbed. One of the most common mechanisms is the small intestinal dysmotility. Thus small intestinal dysmotility constitutes one of the risk factor for development of SIBO.”

Anant D. Patil

Essentially, this means that since the digestive tract is lacking the proper mobility to break down foods with high bacteria content this can cause issues for smooth, um, well you know.

When there is not enough thyroid hormone, this can lead to a slowing down of the digestive system, which can create an environment where bacteria can overgrow in the small intestine.

Managing Hypothyroidism and SIBO

If you have hypothyroidism and are experiencing symptoms of SIBO, it is important to work with your healthcare provider to manage both conditions. Treatment for SIBO may involve antibiotics and dietary changes, while treatment for hypothyroidism may involve medication to replace the missing thyroid hormone. In some cases, treating one condition may help improve the symptoms of the other.
In addition to medical treatment, there are also lifestyle changes that can help manage both hypothyroidism and SIBO. These include eating a healthy diet that is low in sugar and processed foods, getting regular exercise, and managing stress.

Since I have sensitive intestines, I tend to stick to foods that reduce bloating, gas, and diarrhea. That is known as the SIBO Diet! While SIBO is typically treated with probiotics, eating foods that reduce bacteria growth will help with ‘oh no’ incidents. Plus it may even boost your energy if suffering from chronic and extreme fatigue, symptoms of hypothyroidism.

Before discovering the SIBO diet, many of the sources I found on a hypothyroidism diet mentioned cruciferous vegetables. There was always a debate as to whether or not they should be avoided. I can definitely say that I felt a lot better when I started cooking for myself and ate out less. Whilst in college I stuck to a strict diet of chicken and spinach in some variety. It was easy on the wallet as

Check out the related sources below!


Hypothyroidism and SIBO are two separate health conditions that are linked by the role that the thyroid hormone plays in regulating the digestive system. If you are experiencing symptoms of either condition, it is important to work with your healthcare provider to manage both conditions and make lifestyle changes that can help improve your overall health.

Cited Sources

Patil AD. Link between hypothyroidism and small intestinal bacterial overgrowth. Indian J Endocrinol Metab. 2014 May;18(3):307-9. doi: 10.4103/2230-8210.131155. PMID: 24944923; PMCID: PMC4056127.

Related Sources


The SIBO Diet Plan: Four Weeks to Relieve Symptoms and Manage SIBO by Kristy Regan, Allison Siebecker ND, MSOM, LAc (Foreword by)

This book has helped me understand more about my condition than any doctor has ever told me. If you’re looking for answers, Mary J. Shomon has got them!

Get your copy here!

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