Hypothyroidism (Underactive Thyroid) and IBS

doctor examining thyroid patient
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Although there is no direct causal relationship between hypothyroidism, commonly known as underactive thyroid, and irritable bowel syndrome (IBS), some people find themselves having to deal with both problems simultaneously. If you are one of those people, this article will help you to understand the digestive ramifications of hypothryroidism and offer you some self-care tips for managing both conditions.

What Is Hypothyroidism?

Hypothyroidism is a condition in which the thyroid does not produce a sufficient amount of hormones necessary for the cells throughout the body to work properly. This deficiency can result in a slowing of many bodily processes and manifests itself through a wide variety of symptoms. Although there are many causes of hypothyroidism, the most common ones are Hashimoto’s disease, (an autoimmune condition), and hypothyroidism resulting from damage to the thyroid by treatment for hyperthyroidism.

Effect of Hypothyroidism on Digestion

Hypothyroidism affects systems throughout the body, but for the purposes of its relationship to IBS, this discussion is limited to its effects on the digestive system.

In severe cases, hypothyroidism can slow down the movement of the esophagus, which could result in dysphagia, dyspepsia, and/or gastroparesis.

More pertinent to IBS, hypothyroidism can result in constipation and bloating.

Diarrhea is not unheard of with hypothyroidism and is thought to be a result of small intestine bacteria overgrowth (SIBO). People who have Hashimoto’s disease are at increased risk for celiac disease, something that should be ruled out for all IBS patients.

What to Do If You Have IBS and Hypothyroidism

The most important thing to do is to stay on top of your thyroid disease by attending your doctor appointments, having your thyroid levels monitored, and taking your medication as prescribed.

This will help to ensure that thyroid problems are not making your IBS worse. Here are some other things to keep in mind, depending on your predominant bowel habit.

Constipation-predominant IBS (IBS-C) : One of the main recommendations for managing the symptoms of IBS-C is to increase your intake of dietary fiber. As a high fiber meal may interfere with the way that your body absorbs your medication, be sure to take your medication on an empty stomach. It is also important to know that some high fiber vegetables contain goitrogens, which are substances that can negatively impact the thyroid. Mary Shomon, About.com Guide to Thyroid Disease offers a more comprehensive discussion on the subject:

Diarrhea-predominant IBS (IBS-D) : Diarrhea is a less frequent symptom with hypothyroidism and as discussed above, may be related to the development of SIBO secondary to the slowed motility resulting from the thyroid dysfunction. If your IBS-D symptoms include gas and bloating, you may want to discuss with your doctor the possibility of being tested for the presence of SIBO. The disorder is diagnosed through the use of a hydrogen breath test and is treated with specific antibiotics.

For more information, see:

Essential Reading from Dr. Bolen, Your IBS Guide


Daher, R., et.al. "Consequences of dysthyroidism on the digestive tract and viscera" World Journal of Gastroenterology 2009 15:2834-2838.

Ebert, E. "The Thyroid and the Gut" Journal of Clinical Gastroenterology 2010 44:6 402-406.

"Hypothyroidism" National Endocrine and Metabolic Diseases Information Service website Accessed October 17, 2012.

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