Non-Coeliac Gluten Sensitivity

non-coeliac gluten sensitivity

Differences between coeliac disease, non coeliac gluten sensitivity and IBS.

Gluten is a much-debated scientific topic that causes confusion in the health and wellness sectors and is the subject of misleading information in the food industry. We now know that there is a spectrum of responses to gluten beyond coeliac disease. But it is challenging for those who gets symptoms after eating wheat but don’t have coeliac disease to get an accurate diagnosis.


Researchers have started investigating how different compounds in wheat might cause symptoms such as lethargy, ‘brain fog’, bloating, wind and abdominal pain. The logical question for a person who knows they feel better when they don’t eat bread would be “which part of wheat am I sensitive to”?


To help you answer this question, let’s start by asking you a few questions – which of these sounds most like you?


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Suspected coeliac disease, coeliac risk or undiagnosed coeliac disease profile

  • Have been tested for coeliac disease (negative)
  • May have been on gluten free diet when biopsy conducted
  • Positive coeliac gene and blood test
  • Family member has coeliac disease
  • Feel better on gluten free diet
  • No noticeable problems eating onions, garlic or legumes
  • Symptoms mainly gut-related.


Non coeliac gluten sensitivity profile

  • Negative coeliac gene and/or blood tests
  • Feel better on a gluten free diet
  • No noticeable problems eating onions, garlic or legumes
  • Symptoms could include ‘brain fog’ extreme fatigue, chronic neurological type pain.


IBS-type profile

  • Symptoms start a few hours after eating wheat, and are worse with more wheat
  • Symptoms mainly pain, wind, bloating, constipation in the lower gut (IBS)
  • OR symptoms mainly pain and bloating in mid to upper gut (functional dyspepsia)
  • Symptoms resolve in a few days if no wheat eaten
  • Also react to onions, garlic, legumes
  • Symptoms may be worse when stressed or anxious
  • Symptoms can occur sooner (within an hour) if anxious about eating



Coeliac risk or coeliac ‘lite’ or undiagnosed coeliac disease

Gluten sensitivity is defined as self-reported gluten intolerance, with negative coeliac biopsy results and no allergic response to other wheat proteins. A higher proportion of people with gluten sensitivity have the genetic marker and a positive coeliac blood test result.


They often report having a first degree relative with coeliac disease and follow a gluten-free diet. If this sounds like you, ensure that you have had all the necessary tests and followed testing procedures.


For example, if you are on a gluten free diet when you have a coeliac blood test or biopsy, the results may be negative because the immune response and gut damage are only triggered by eating gluten.


Non coeliac gluten sensitivity

If coeliac disease and wheat allergy are ruled out, then we have to work out whether individuals are sensitive to gluten via another mechanism. Or whether it’s not the gluten in wheat at all, but something else causing symptoms.


Most of the research into wheat sensitivity uses wheat rather than pure gluten in test foods, and participants have not been ‘blinded’ to what they are being tested for, which compromises the study findings.


New research is needed to determine if wheat related symptoms, particularly neurological ones like ‘brain fog’ and extreme fatigue are related to gluten, or not. People who suffer more symptoms that relate to an inflammatory or nervous system response than from gut symptoms are likely to have heard of ‘leaky gut’ and probably tried or considered some type of dietary approach or supplement promoted as healing a leaky gut.


In the absence of a specific blood or other diagnostic test for gluten sensitivity and with so much pseudoscience about this topic, it is nearly impossible, even for scientists, to work out whether proteins from gluten cause increased intestinal permeability.


If this was the case, then the immune and nervous systems would be less well protected, which in theory could explain symptoms like ‘brain fog’, fatigue and (non-gut) chronic pain. However, most of the research on this topic has been done in labs, in animals or in coeliac disease, so has little relevance to most people who report symptoms after eating wheat.


IBS and FD

To complicate the picture even more, people who feel better on a gluten-free diet could be feeling better NOT because they have reduced their intake of gluten but because they have reduced their FODMAP intake.


If you consistently experience lower gut pain or bloating a few hours after eating bread, pasta or other wheat foods, even if they are plain (without topping or sauces) and if you also notice symptoms after eating onions, garlic or legumes. The symptoms are most likely related to the fermentable carbohydrates in wheat, mainly fructans (chains of fructose) and more likely to be IBS-related.


If your symptoms occur within an hour or so after eating wheat or are in the upper to mid gut region then they are less likely to be bowel related, because it takes at least a few hours for food to get to the bowel!


Upper gut pain is more likely to be related to functional dyspepsia, another functional gut disorder that wheat is implicated in. While there is no simple blood test for gluten sensitivity, an experienced gut dietitian can work with you to determine which of the above is most likely for you.


This would involve stepping through some dietary challenges and then formulating a personalised eating plan that considers your results and food preferences. When we come up with a simple test to distinguish non coeliac gluten sensitivity from other gut conditions, we will be sure to let you know!


Make a booking for a video consultation with one of our gut health dietitians.