Irritable bowel syndrome (IBS) and celiac disease are conditions that can cause similar symptoms, but the causes of those symptoms are very different. The similarities between the two conditions can make them difficult to tell apart. In fact, studies have reported that somewhere between 5% and 15% of people with celiac disease were initially diagnosed incorrectly with IBS.
What is celiac disease?1,2
Celiac disease is an autoimmune disorder that causes damage to a person’s small intestine and prevents the person’s body from absorbing enough nutrients from digested food. People with celiac disease are unable to process proteins called gluten, which are found in foods containing wheat, rye, and barley, for example.
When people with celiac disease eat gluten, their immune systems react by damaging the inner lining of the small intestine. This damage makes it difficult for their bodies to absorb the nutrients from any foods that they eat, which can lead to malnourishment regardless of how much food is being consumed.
What are the symptoms of celiac disease versus IBS?1
Celiac disease and IBS can cause a similar set of symptoms. These include:
However, an important difference between the two conditions is that celiac disease does not always cause a person to experience symptoms related to the digestive system, like those listed above. On the other hand, everyone who has IBS has at least one or more of those symptoms. IBS is a syndrome, not a disease. This means that IBS is diagnosed on the basis of the symptoms that a person is experiencing, whereas a person with celiac disease may not have any symptoms despite the ongoing damage to the small intestine.
People with celiac disease may also have symptoms that are not related to the digestive system, while IBS does not cause those types of symptoms. For example, celiac disease can cause symptoms such as joint pain, weakened bones (osteoporosis), or dental problems.
What are some other differences between IBS and celiac disease?2,3
IBS is a condition that mainly affects the large intestine (colon), while celiac disease mainly affects the small intestine. IBS is a “functional” disorder, which means that the digestive system is not working like it should, but not due to damage. In contrast, celiac disease has symptoms that are caused by damage to the small intestine. In people with IBS, symptoms are thought to be caused by changes in the patterns of movement inside the intestine as digested food moves through the digestive tract. People with celiac disease have symptoms that are caused by damage in the intestines due to their immune system’s response to gluten, not to changes in the way the intestines move.
Celiac disease not the only condition that can make person unable to digest gluten well–it may be caused by a gluten sensitivity or a gluten allergy. This can make figuring out the cause of symptoms more difficult, because some people with IBS have gluten sensitivity that causes IBS symptoms. These symptoms sometimes improve when they cut gluten out of their diet, making it harder to tell if the problem stems from gluten sensitivity, IBS, or both.
Currently there is no specific test that can be used to make a definite diagnosis of IBS, but there are tests that can be used to diagnose celiac disease. Healthcare providers can use these tests to help make a diagnosis if it is unclear what the cause of a person’s symptoms are.
Brichford C. Celiac disease and IBS: differences and similarities. Available at http://www.everydayhealth.com/celiac-disease/celiac-disease-and-ibs-differences-and-similarities.aspx
PubMed Health. Celiac disease (gluten intolerance). Available at http://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024528/
Anderson J. Gluten vs irritable bowel syndrome: which is it? Available at https://www.verywell.com/gluten-vs-irritable-bowel-syndrome-562696