IBS and Gluten: What’s the Link?

If you’re struggling with IBS, you know how debilitating the symptoms can be. There can be a lot of crossover with celiac disease and non-celiac gluten sensitivity, which can both have similar symptoms to IBS. This can make it super hard to know which condition you’re dealing with and whether going gluten free could make a difference to your situation. IBS is more of a symptom of other underlying issues than it is a condition of its own, and avoiding gluten can be a real game-changer.

What happens with IBS?

When food passes through your large intestine, it encourages an “irritable” response and triggers the familiar symptoms associated with IBS - namely constipation, diarrhea or a mixture of both. It’s hugely unpleasant but there is some good news. Whereas some digestive conditions can damage the intestines, this doesn’t happen with IBS. 

Can diet help IBS symptoms?

Diet plays a crucial role in both encouraging IBS symptoms and relieving them, and certain foods are more common triggers than others. Gluten is a big one but other culprits can include beans, legumes, grains, processed foods and dairy. You may notice that your IBS symptoms flare up after eating certain foods, but sometimes it can be unclear as to what’s causing problems for you. 

Food triggers are one of the big reasons why many people with IBS choose to try out a gluten free diet to see if it helps to reduce symptoms. Following a gluten free diet can be hugely successful for some people and there is evidence that many people with IBS can’t tolerate gluten. Eating gluten can also cause intestinal permeability or leaky gut (1) which increases overall inflammation and reactivity to other foods, so it’s one of the first things I recommend my clients eliminate if they are struggling with inflammation and/or gut health.

IBS and celiac disease

With celiac disease, consuming even trace amounts of gluten causes damage to the small intestine. This can affect the absorption of nutrients and have a far wider impact on health and wellbeing. 

Celiac disease can also present with IBS type symptoms (especially along the lines of diarrhea-predominant IBS). It is possible to have both IBS and celiac disease at the same time so for some this can mean that symptoms continue even if gluten is excluded from your diet. 

Testing is the best way to know whether you have IBS or celiac disease but you need to be eating gluten every day to get an accurate result. Going gluten free in the run up to being tested can mean that you test negative, even if you actually have celiac disease. It’s super common for celiac disease to be misdiagnosed as IBS, especially if you’re avoiding gluten to get relief from symptoms. 

IBS and gluten sensitivity

Even if you’re not celiac, gluten can still be problematic. Some people have a sensitivity to gluten, even though they test negatively for celiac disease. This means that eating gluten doesn’t damage the small intestine but it may produce some degree of immune reaction to foods that contain gluten. Every time you eat gluten, you can get symptoms similar to IBS but the problem is actually your body reacting to gluten. 

Some symptoms that appear to be IBS related can sometimes be linked to gluten sensitivity. 

There’s another theory too. Wheat also contains a type of carbohydrate called fructan (a fructose polymer), which is also a FODMAP and can be a trigger for digestive problems. Some people with IBS who are reactive to gluten may be having a reaction to fructans, rather than gluten and may benefit from further GI testing and possibly a low-FODMAP diet temporarily. Foods contain FODMAPs are also prebiotics which feed beneficial bacteria, so this diet should not be followed long-term. Discuss this with your doctor before continuing for more than a week or two on a low FODMAP protocol.

Is it worth avoiding gluten if you have IBS?

Avoiding gluten doesn’t always help IBS symptoms but it can be a game changer for some people.

Diarrhea predominant IBS (IBS-D) can improve if gluten is avoided, even if you don’t have celiac disease. A study published in the Gastroenterology journal found that a gluten free diet reduced diarrhea symptoms in IBS symptoms. 

This is because gluten can be a common culprit for aggravating the gut barrier and digestive health can benefit if this doesn’t happen. If you’re an IBS patient with non-celiac gluten sensitivity, there’s a good chance that things will get better on a gluten free diet. 

One study involved 34 IBS patients whose symptoms were being managed on a gluten free diet. They were split into two groups, with one group asked to eat gluten on a daily basis for 6 weeks. One week later, the gluten group experienced a greater amount of constipation, diarrhea, bloating, discomfort and fatigue compared to the non-gluten group. This led researchers to decide that gluten is at least partly to blame for IBS symptoms. 

If you’ve found grains in general to be problematic, it’s likely due to the insoluble fiber in whole grains which can trigger IBS symptoms, so it’s worth experimenting with a no-low grain diet if going gluten-free hasn’t made a big difference for you. That said, the question to ask is why can’t you tolerate insoluble fiber? This is when it’s a good idea to see a Functional Medicine, Naturopathic, or Integrative Medicine Doctor who can do GI testing to assess the health of your microbiome and treat the root causes versus just treating the symptoms.

Stay tuned for my next installment on how gluten can affect your weight.

Have you seen improvement in your symptoms after going gluten-free? I’d love to hear more so please share in the comments.