The World Of Gluten
What is gluten?
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. 2So what’s with all the gluten avoidance?
Enter non celiac gluten sensitivity (NCGS).
Gluten-related sensitivity - non-celiac gluten sensitivity
This is something 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.
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 the gluten in wheat.
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, it 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 5Isolating 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. 6That good ol’ brain-gut connection thing is at it again.
Does A Gluten Free Diet Help IBS?
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?
- 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.
Gluten free diets without FODMAPs don't help nearly as much
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 to insignificant levels in some studies where researchers have controlled FODMAPs in participant diets.121314
The takeaway from these studies
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.
- 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.
- 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.
- 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
- 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
- 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
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.