Last Updated: 27 March 2023

Gluten Free Diet For IBS – Does It Help?

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Although previously unheard of, thanks to mass media, gluten free diets (GFD) have become all the rage in our diet-crazed culture. So unless you have been living under a rock for the last decade, chances are you’ve heard of the GFD and seen the rapidly growing number of gluten free products in grocery stores. But does it actually help with IBS symptom relief? Well, that's exactly what we'll look at in this guide to gluten and IBS.
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Table of Contents

The World Of Gluten

What is gluten?

So what is gluten? In short, gluten refers to a family of proteins found in several types of grains, such as wheat, rye, and barley.1

Gluten-related conditions - celiac disease & wheat allergy

Although a number of wheat and gluten-related conditions exist, the primary ones you are probably familiar with are celiac disease (CD) and wheat allergy (WA).

Both of these are distinct conditions that have relatively straightforward diagnostic criteria, thanks to specific biomarkers and tests doctors can order to identify them. If you have either CD or WA, it’s extremely important to avoid wheat and/or gluten.

However, both CD and WA are pretty rare, with a reported prevalence of 1% or less each. So what’s with all the gluten avoidance?

Enter non celiac gluten sensitivity (NCGS).

Gluten-related sensitivity - non-celiac gluten sensitivity (NCGS)

NCGS is also known as non-celiac wheat sensitivity (NCWS). Or non celiac wheat protein sensitivity (NCWPS). Or just wheat sensitivity (WS). Long story short, a condition so contentious they can’t even agree upon a name. Although maybe not completely accurate to the condition, let’s just stick with NCGS, since that’s the name that is still used most often.

There’s a lot to discuss here, so we’ll dedicate the entire next section to it.

Gluten and IBS
Gluten refers to a family of proteins found in several types of grains, such as wheat, rye, and barley, and is an issue for CD and WA, and possibly people with NCGS

Non-Celiac Gluten Sensitivity

What is NCGS?

Well, as you may be able to guess from the name, it’s thought to be a disorder characterized by sensitivity to gluten.

Symptoms may vary from person to person, but the most common ones include abdominal pain, eczema and/or rash, headache, ‘foggy mind, fatigue, and diarrhea.2

How do you diagnose it?

Like IBS, NCGS is a symptoms-based diagnosis, as there are not yet any NCGS-specific tests you can run that are specific and sensitive enough to identify it.

More specifically, a diagnosis is ideally made by monitoring symptoms while doing a double blind placebo controlled (DBPC) gluten challenge, where someone is first put on a GFD, then challenged with a gluten-containing product and a placebo.3

Theoretically simple, but in practice? Not so much.

Why it's hard to diagnose, especially in people with IBS

First off, we don’t even really know if it is the gluten in wheat that triggers symptoms. Turns out there are other types of proteins in wheat that may actually be to blame, such as amylase-trypsin inhibitors (ATIs) or wheat germ agglutinin4. So that’s fun.

Second, when you add IBS into the picture, of course things get even messier. In addition to the proteins, gluten-containing grains like wheat also contain fructans, a type of short-chain carbohydrate that falls within the group of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (aka FODMAPs). FODMAPs, such as fructans, have been shown to worsen symptoms for some people with IBS Isolating the wheat protein vs fructan effect is tough, and only a few studies have attempted it.

Lastly, it just so happens that our crazy powerful brains are capable of inducing symptoms if we believe gluten might be bad for us, regardless of whether or not it’s actually true. This phenomenon caused by negative expectations is referred to as a “nocebo” effect, the opposite of the placebo effect. A review of NCGS DBPC challenges found that up to 40% of study participants with suspected NCGS had a nocebo response, reporting increased symptoms while receiving a placebo. That good ol’ brain-gut connection thing is at it again.

Okay so now that we’ve talked a bit about background issues around NCGS (or whatever term floats your boat), let’s get into the research.

Does A Gluten Free Diet Help IBS?

Gluten free diets reduce IBS symptoms
Up to 70-80% of IBS patients show significant symptom improvement when placed on a strict GFD

Gluten free diets often reduce IBS symptoms

Here’s what we can say: a large portion of IBS patients show significant symptom improvement when placed on a strict GFD in the first step of DBPC trials. We are talking response numbers of 70-80% or more in some studies.789

Pretty impressive, right? Sure.

But don’t forget all those NCGS issues we talked about earlier.

What is really causing the improvement?

  • Gluten?
  • Fructans?
  • Any of those other wheat proteins?
  • Nocebo/placebo effect?

To answer this, the next phase in these studies is to do the DBPC gluten challenge, where both the researchers and participants are unaware of when the participant is getting a placebo, and when they are getting the actual challenge product, such as gluten.

The true culprit is likely the FODMAP content, not gluten

So what do these time intensive, expensive, but highly controlled gluten challenge studies show? Drum roll please…the answer is…it’s complicated!

You thought you were going to get a straightforward answer? Nice try.

A good number of studies show that a statistically significant number of people on a GFD do react to gluten or gluten containing products compared to the placebo.710119

However, the proportion of true gluten sensitive participants seems to dwindle significantly in some studies where researchers have controlled FODMAPs in participant diets.121314

The takeaway from these studies

Based on the current research, there does seem to be a small number of people with IBS and true NCGS, however those with IBS reporting some sort of wheat/gluten intolerance are more likely to be reacting to the FODMAPs in wheat, not the gluten itself.

The Problems With A Gluten Free Diet

5 key problems

The GFD isn’t without its problems and we’ll run through the main ones now.

  1. Nutrient deficiencies can be a concern for those following a strict GFD. 15While it’s possible to eat an adequately balanced GFD, it may take some intentional effort and extra planning.
  2. Unnecessarily following a restrictive diet can impact quality of life, 16in part by limiting your food options and potentially increasing your grocery bill. Nobody needs that, especially if your quality of life has already taken a major hit from IBS.
  3. We don’t fully understand the long term impacts of a GFD on the microbiome. At least in the short term, some research has shown decreased counts of beneficial gut microbial genera  such as Bifidobacterium and Lactobacillus, and increased numbers of potentially harmful microbial species and families such as  E. coli and Enterobacteriaceae.17
  4. There’s a concern for increased arsenic intake when switching to a GFD, as rice and rice-based foods are frequently substituted for wheat-based foods.15
  5. Some gluten free foods may contain more FODMAPs than the regular wheat version, potentially worsening symptoms unless gluten really is what is causing symptoms.18
Problems with gluten free diets
For many IBS sufferers keeping gluten and opting for a low FODMAP diet may be more beneficial

The takeaway after considering the problems

Because of the reasons listed above, as well as insufficient evidence showing that most people with IBS have a true gluten sensitivity, those looking for symptom relief are likely better off trying the low FODMAP diet.

However, a gluten-free diet may be beneficial if NCGS has been diagnosed after completion of a blinded placebo controlled gluten challenge or otherwise prescribed by a doctor.

Summary & Verdict

IBS ebook

Which Foods Really Trigger Your IBS?

Discover exactly which foods you should and shouldn’t eat using our IBS Food Journal.

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