Thyroid Irritable Bowel Syndrome

Inside: The Connection between thyroid and stomach problems, mainly IBS, and how hypothyroidism can lead to stomach bloating, gas, constipation and water retention.

If you’ve been diagnosed with a malfunctioning thyroid, hypo- or hyperactive, it’s likely that there are other symptoms you are struggling with.

Malfunctioning thyroid manifests itself by its effects on other organs and systems in the body. The thyroid dysfunction stomach symptoms include –constipation, diarrhoea, fatigue, weight gain, skin problems etc.

In fact, these symptoms generally become a cause of concern which leads people to get them checked.

The digestive system is frequently involved in thyroid disorders and the majority of the people will have some form of symptoms related to their digestion.

And because of so frequent involvement of the digestive tract, the concern arises about the connection between thyroid disorder and IBS.

IBS is defined as functional digestive disorder and IBS symptoms are :

  • Diarrhoea
  • Constipation
  • Alternating Constipation and Diarrhea
  • Gas and Bloating
  • Fatigue
  • Abdominal pain

The symptoms of IBS and digestive symptoms arising from thyroid dysfunction are almost similar. And thus the name Thyroid Irritable Bowel Syndrome.  

Importance of Thyroid Gland

The Thyroid Gland, although small in size has a magnanimous impact on our bodies. It is the gland which is responsible to produce hormones (T3 and T4), and both these hormones do quite a lot of work in our bodies.

Brain signals the production of T4 by releasing Thyroid Stimulating Hormone (TSH) in the blood and both T3 and T4 are produced from Iodine.

These thyroid hormones are needed by each and every cell in your body to carry out their metabolic activities appropriately. If there is insufficient iodine in the body, these hormones cannot be produced.

Also, when the thyroid gland is not functioning properly, there aren’t enough of those hormones available for the proper functioning of the cells.

Disturbed metabolism means disturbed chemical reactions in different parts of the body leading to the malfunction of the organs and the whole systems.

Cells receive messages for the required increased or decreased activity in the body. These messages are transmitted through thyroid hormones.

Disturbance in their levels means problems in the metabolic reactions inside the cells, e.g. disturbance in protein synthesis due to hypothyroidism would cause hair loss.

Correlation Between Thyroid Dysfunction and IBS

Following are thyroid dysfunction stomach symptoms associated with Hypothyroidism —

  • Constipation
  • Abdominal discomfort and bloating
  • Stomach ache
  • Water retention
  • Increased bacterial growth causing diarrhea or constipation
  • Reduced appetite but weight gain
  • Reduced bile flow to the gut
  • Fatigue
  • Reduced motility of esophagus and intestine

There have been quite a lot of studies which show that malfunctioning thyroid has a direct impact on your gut.

One such study shows that there are various gastrointestinal symptoms of a dysfunctioning thyroid which involve all parts of the GI tract [1]. 

These symptoms are discussed in detail below.

Constipation, Reduced appetite due to impaired Gastrointestinal motility

Studies have shown that there is a reduction in esophageal and gastric motility in hypothyroidism [2, 3].

This leads to reduced appetite and constipation. Reduced motility also causes increased bacterial growth in the small intestine; a condition known as Small Intestinal Bacterial Overgrowth (SIBO). 

Normally, the large intestine is the home of bacteria but due to bacteria now being the highly accumulated residents of small intestine patients suffer from diarrhea and thus, continues the cycle of bowel disturbance.

Bacterial overgrowth also causes abdominal discomfort, bloating and flatulence.

Hashimoto’s disease the most common form of hypothyroidism is associated with reduced esophageal motility which presents as nausea, vomiting, bloating, dysphagia (difficulty swallowing), heartburn etc. [4].

Related Read: SIBO as the cause of IBS.

Thyroid and Stomach Bloating

Research shows that abdominal discomfort and bloating in hypothyroidism is so severe that it mimics functional bowel disease [5].

People having hypothyroidism, besides being mostly tired and cold all the time, struggle with severe bloating. 

Generally, patients complain of a feeling of fullness and food hanging in their chest.

Despite giving up sodas and beverages like tea and coffee, as well as following a careful diet plan, their bloating persists and never seems to go away and that’s where malfunctioning thyroid might be contributing to this abdominal pain.

Majority of the patients with IBS have abdominal pain and bloating as their major symptom, so it makes sense to check the thyroid as the potential cause of this abdominal discomfort. 

Now the treatment of hypothyroidism is levothyroxine but the medicine can itself cause bloating and discomfort.

One of the inactive ingredients of levothyroxine is lactose. People who are intolerant to lactose are unable to digest it properly and suffer from symptoms of abdominal discomfort, nausea, vomiting, bowel disturbances and hypothyroidism gas

These symptoms are similar to irritable bowel syndrome and celiac disease that are hard to diagnose if dysfunctional thyroid is not already established.

Regular intake of levothyroxine can also have a cumulative effect and even a small amount can cause severe discomfort.

Dysthyroid Bloating and Water Retention

If you have hypothyroidism, one of the major symptoms you’d be suffering from is — cold.

Low metabolic rates cause reduced activity of the cells throughout the body leading to low body temperature. This, in turn, causes water retention in the body which is the underlying cause of bloating, swollen ankles, puffy face and eyes.

Having said so, people presenting with complaints of depression, fatigue, weight gain and swelling elicit doctors to suspect a hypoactive thyroid who then recommend blood screening for TSH, T3 and T4.

However, treatment of hypothyroid normalizes the body temperature and symptoms of water retention then fade away completely.

Reduced Bile Flow

Bile flow to the intestine is reduced in hypothyroidism and increased in hyperthyroidism [6] which has a direct impact on fat metabolism.

This is one of the reasons why hypothyroidism and hyperthyroidism cause weight gain and loss respectively, as it affects the digestion of fat.

In addition, according to research, there is an increased risk of development of pathologies in the gastrointestinal system in patients having thyroid dysfunction. It is either due to disturbances in thyroid hormone levels or related particularly to a thyroid disease [1].

After exploring the various research and studies associated with the thyroid and its impact on the gut, the symptoms are very similar to IBS.

The IBS symptoms of bloating, constipation, diarrhea, fatigue and abdominal pain are very similar to those present in thyroid disorders also.

People with IBS symptoms should also be evaluated for thyroid dysfunction. As the cluster of symptoms of thyroid dysfunction and IBS overlap and thyroid can be the underlying cause of IBS. I call this Thyroid Irritable bowel Syndrome

Related Reading

Association between Gluten and the development of Hashimoto’s Disease.

6 Benefits of Garlic for your Thyroid Disease.

Research-Based Hashimoto’s Diet.

Why Epstein-Barr Virus Evaluation Should Be Part Of Your Graves And Hashimoto’s Treatment Plan.

The connection between Thyroid and stomach problems mainly IBS. How hypothyroidism can lead to stomach bloating, gas, constipation and water retention.


1. Consequences of dysthyroidism on the digestive tract and viscera Ronald Daher, Thierry Yazbeck, Joe Bou Jaoude, and Bassam Abboud. World J Gastroenterol. 2009 Jun 21; 15(23): 2834–2838. Published online 2009 Jun 21. doi: 10.3748/wjg.15.2834

2. Wright RA, Penner DB. Myxedema and upper esophageal dysmotility. Dig Dis Sci. 1981;26:376–377.[PubMed]

3. Greenspan FS, Rapaport B. Thyroid gland. In: FS Greenspan, JD Baxter, et al., editors. Basic and Clinical Endocrinology. New York: Saunders; 1992. pp. 188–246. [Google Scholar]

4. J Clin Gastroenterol. 2010 Jul;44(6):402-6. doi: 10.1097/MCG.0b013e3181d6bc3e.The thyroid and the gut. Ebert EC1.

5. Maser C, Toset A, Roman S. Gastrointestinal manifestations of endocrine disease. World J Gastroenterol. 2006;12:3174–3179. [PubMed]

6. Bile flow to the duodenum is reduced in hypothyreosis and enhanced in hyperthyreosis.

Laukkarinen J, Koobi P, Kalliovalkama J, Sand J, Mattila J, Turjanmaa V, Porsti I, Nordback I.

Neurogastroenterol Motil. 2002 Apr;14(2):183-8.

Thyroid Irritable Bowel Syndrome

About The Author

Dr. Anshul Gupta, MD

I am Dr.Gupta, a Functional Medicine and Integrative Medicine physician. I like to write about Functional medicine approach to managing different diseases and want to empower people to reclaim their health through this modern approach. Come join me on this healing journey.

Thyroid Irritable Bowel Syndrome