IBS vs. Celiac Disease vs. Gluten Sensitivity: How Do I Know Which One I Have?

Overlapping symptoms mean one can be mistaken for the other

Symptoms of irritable bowel syndrome (IBS) often overlap with symptoms of celiac disease and non-celiac gluten sensitivity. This can make it hard to know which condition you might have. There are some important differences, however.

When you have irritable bowel syndrome (IBS), your symptoms can run the gamut from diarrhea to constipation. You will probably also have bloating, gas, and abdominal pain. The symptoms of celiac disease and gluten sensitivity can be similar, but may also include non-digestive symptoms like fatigue, brain fog, and joint pain.

This article will help you tell the difference between IBS, non-celiac gluten sensitivity, and celiac disease.

A loaf of gluten free bread
Volodymyr Rozumii / Getty Images

IBS vs. Celiac and Non-Celiac Gluten Sensitivity

IBS is thought to affect around 11% of the population. Multiple studies, however, have shown that many diagnosed cases of IBS are actually celiac disease in disguise. Sometimes, people who have been told they have IBS find relief when they eliminate gluten grains from their diets, even though they've tested negative for celiac disease.

IBS and celiac affect different parts of the digestive system, which can cause vastly different symptoms. IBS mainly involves your large intestine, also known as your colon. The function of the colon is to reabsorb fluids and process waste products from the body so they can be eliminated. With IBS, your colon becomes "irritable" (hence the condition's name) and acts up as waste passes through.

Celiac disease, by contrast, involves the small intestine. The small intestine is where 90% of the digestion and absorption of nutrients and minerals from food occurs. With celiac, symptoms occur when damage to the small intestine interferes with the absorption of nutrients.

Non-celiac gluten sensitivity is less well understood. Some researchers believe it is caused not by gluten but by other components found in wheat and related grains. These nutrients may ferment in the gut, causing gastrointestinal symptoms like bloating and pain.

IBS is distinguished by the fact that it affects the colon (also known as the large intestine). By contrast, celiac disease and non-celiac gluten sensitivity involve the small intestine.

Although it can cause unpleasant symptoms, IBS doesn't cause any damage to your intestinal tract. It's known as a "functional disorder." This means your digestive system functions poorly but isn't actually damaged.

Celiac, however, is an autoimmune disorder. When people with celiac disease eat gluten (a protein found in grains like wheat, rye, and barley), their immune system reacts by attacking cells in the small intestine. Over time, this can cause damage to the intestinal tract. 

Symptoms

People with IBS may have urgent diarrhea, constipation, or a combination of both. They may also have other gastrointestinal symptoms, such as gas and bloating.

People with celiac disease and non-celiac gluten sensitivity may experience similar symptoms. Because celiac is a whole-body disease, however, people with celiac may also experience other symptoms that don't appear related to their gastrointestinal symptoms. These may include:

  • Fatigue
  • Anemia
  • Joint pain
  • Headaches
  • Vertigo
  • Delayed or missed periods
  • Miscarriage
  • Infertility
  • Depression or anxiety
  • Peripheral neuropathy
  • Seizures

IBS, celiac disease, and non-celiac gluten sensitivity share many of the same symptoms. Celiac disease, however, is associated with ulcers, bleeding, or significant weight loss, while IBS and gluten sensitivity are not. In addition, celiac disease is inflammatory, and IBS is not.

Diagnostic Challenges

IBS is diagnosed by exclusion. This means your healthcare provider may diagnose you with IBS after first excluding other conditions that might be causing your symptoms. Only then can they decide if your symptoms meet the criteria for IBS.

Incorrect diagnoses may happen when healthcare providers aren't aware of the latest research and exclude celiac based on outdated information. If this happens, you may be incorrectly diagnosed with IBS.

This is a very common problem. Research has found that around 5% of IBS patients actually have celiac disease. This means a gluten-free diet should help to improve or eliminate their symptoms.

Similarly, non-celiac gluten sensitivity is diagnosed after excluding celiac disease and wheat allergy. Healthcare providers typically look to see if symptoms improve when you stop eating gluten and increase when you start again.

People are often misdiagnosed with celiac before completing the entire diagnostic process. Some of those misdiagnosed with celiac have IBS. In one study, of 107 participants with a previous celiac diagnosis, only 64 had their diagnosis confirmed through a full diagnostic re-evaluation.

Celiac disease, gluten sensitivity, and IBS are diagnosed in different ways. Celiac disease can be diagnosed with tests, but there are no tests that can confirm IBS or gluten sensitivity.

IBS and the Gluten-Free Diet

It's also possible that some IBS patients who are negative for celiac disease may still benefit from a gluten-free diet. Studies have found that a subset of people who have IBS but not celiac disease also have non-celiac gluten sensitivity. These people may see their IBS symptoms improve or disappear when they eat gluten-free.

A 2011 study involved 34 IBS patients whose IBS symptoms were controlled on a gluten-free diet. Researchers assigned 19 of them to eat gluten-containing bread and muffins every day for six weeks. The other 15 ate non-gluten-containing bread and muffins.

After one week, those who ate the gluten-containing foods reported significantly more pain, bloating, tiredness, constipation, and diarrhea than the control group. This suggests that their symptoms were triggered at least in part by gluten.

Another study conducted celiac disease genetic tests and a particular celiac blood test on people with IBS whose primary symptom was diarrhea. Researchers then placed their subjects on a gluten-free diet for six weeks.

A total of 71% of those who were positive for a celiac disease gene found that their IBS symptoms improved on the gluten-free diet. Many continued to follow a gluten-free diet for 18 months and experienced ongoing relief from their IBS symptoms.

Since there are no tests for IBS and non-celiac gluten sensitivity, it is possible they can co-exist with celiac disease. They may occur either as separate entities or as extensions of celiac disease with similar triggers and causes.

Role of FODMAPS

Research shows that around three-quarters of people diagnosed with IBS get some relief on what's called the low-FODMAP diet.

The low-FODMAP diet focuses on eliminating foods with certain complex carbohydrates. These foods ferment in the large intestine, which may cause bloating, pain, and other IBS-type symptoms.

Gluten contains a type of FODMAP called fructan. Wheat is usually banned on the low-FODMAP diet. Some experts, however, say it can be eaten in small quantities.

A 2013 study concluded that some people who believe they are gluten-sensitive actually are reacting to FODMAPs. Other studies, however, have indicated that some people who believe they are gluten-sensitive do indeed react to pure gluten. There's also speculation that other components of wheat and other gluten grains could play a role in both celiac disease and gluten sensitivity.

Summary

IBS and celiac disease can have very similar symptoms. Both cause symptoms like gastrointestinal upset, bloating, and gas. Because celiac disease is an autoimmune condition, however, people with celiac may also have whole-body symptoms like fatigue, joint pain, and anemia. 

Healthcare providers sometimes misdiagnose celiac disease as IBS. Because there are no tests for IBS, it can be hard to tell the difference. People with celiac disease and non-celiac gluten sensitivity improve when gluten is eliminated from the diet. Sometimes, however, people with IBS can also see improvement when they stop eating gluten.

A Word From Verywell

If you've been diagnosed with irritable bowel syndrome but haven't been tested for celiac disease, ask your healthcare provider about ordering celiac disease blood tests.

If you tested negative for celiac, you might still want to consider trying a gluten-free diet. Currently, there are no accepted medical tests to diagnose gluten sensitivity. This means the only way to determine if you have it is to remove gluten from your diet and see if your symptoms clear up.

You also can try a low-FODMAP diet to see if that helps your symptoms. Many low-FODMAP recipes also are gluten-free, so it's easy to follow both diets at the same time.

Frequently Asked Questions

  • Can you suddenly become celiac?

    You can develop celiac at any age. Researchers believe people who develop it later in life may be reacting to overexposure of gluten, either by eating grains with more gluten or eating more grains overall. Your gut bacteria may also play a role.

  • What are the early warning signs of celiac disease?

    The most common sign of celiac is chronic diarrhea. However, you may also have constipation, or alternate between diarrhea and constipation. In addition, other digestive issues like gas, bloating, and abdominal pain are typical.

  • How do you test to see if you have IBS?

    There is not a test that can definitively diagnose IBS. However, you may need blood tests, fecal testing, and food allergy testing to rule out other conditions.

  • Does gluten worsen IBS?

    It can. Many people with IBS notice an increase in symptoms when they eat gluten. It’s unclear whether gluten itself causes this or if it occurs due to sensitivity to other nutrients. It's also possible that someone with celiac disease may be misdiagnosed with IBS.

  • How long does it take for gluten symptoms to go away?

    It depends. Bloating in people without celiac disease may take a few days to a week to subside. Those with celiac may experience symptoms for up to six months after stopping gluten.

  • What do celiac bowel movements look like?

    Celiac bowel movements tend to be pale, greasy, and have a bad odor. In addition, you may experience both diarrhea and constipation.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Canavan C, West J, Card T. The epidemiology of irritable bowel syndromeClin Epidemiol. 2014;6:71–80. doi:10.2147/CLEP.S40245

  2. Card TR, Siffledeen J, West J, Fleming KM. An excess of prior irritable bowel syndrome diagnoses or treatments in celiac disease: evidence of diagnostic delay. Scand J Gastroenterol. 2013;48(7):801-7. doi:10.3109/00365521.2013.786130

  3. Fritscher-Ravens A, Schuppan D, Ellrichmann M, et al. Confocal endomicroscopy shows food-associated changes in the intestinal mucosa of patients with irritable bowel syndrome. Gastroenterology. 2014;147(5):1012-20. doi:10.1053/j.gastro.2014.07.046

  4. Caio G, Riegler G, Patturelli M, Facchiano A, Sapone A. Pathophysiology of non-celiac gluten sensitivity: where are we now? Minerva Dietol Gastroenterol. 2016;63(1):16-21. doi:10.23736/S1121-421X.16.02346-1

  5. Chey WD, Kurlander J, Eswaran S. Irritable bowel syndrome: a clinical review. JAMA. 2015;313(9):949-58. doi:10.1001/jama.2015.0954

  6. Sanchez‐Vargas LA, Thomas‐Dupont P, Torres‐Aguilera M, et al. Prevalence of celiac disease and related antibodies in patients diagnosed with irritable bowel syndrome according to the Rome III criteria. A case–control study. Neurogastroenterol Motil. 2016;28(7):994-1000. doi:10.1111/nmo.12799

  7. Ianiro G, Bibbò S, Bruno G, et al. Prior misdiagnosis of celiac disease is common among patients referred to a tertiary care center: a prospective cohort studyClin Transl Gastroenterol. 2016;7(1):e139. doi:10.1038/ctg.2015.48

  8. Biesiekierski J. et al. Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trialAm J Gastroenterol. 2011;106(3):508-14. doi:10.1038/ajg.2010.487

  9. Aziz I, Trott N, Briggs R, North JR, Hadjivassiliou M, Sanders DS. Efficacy of a gluten-free diet in subjects with irritable bowel syndrome-diarrhea unaware of their HLA-DQ2/8 genotype. Clin Gastroenterol Hepatol. 2016;14(5):696-703.e1. doi:10.1016/j.cgh.2015.12.031

  10. Marsh A, Eslick EM, Eslick GD. Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis. Eur J Nutr. 2016;55(3):897-906. doi:10.1007/s00394-015-0922-1

  11. Biesiekierski JR, Peters SL, Newnham ED, Rosella O, Muir JG, Gibson PR. No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates. Gastroenterology. 2013;145(2):320-8.e1-3. doi:10.1053/j.gastro.2013.04.051

  12. Elli L, Tomba C, Branchi F, et al. Evidence for the presence of non-celiac gluten sensitivity in patients with functional gastrointestinal symptoms: results from a multicenter randomized double-blind placebo-controlled gluten challenge. Nutrients. 2016;8(2):84. doi:10.3390/nu8020084

By Jane Anderson
Jane Anderson is a medical journalist and an expert in celiac disease, gluten sensitivity, and the gluten-free diet.