Maybe it isn’t Gluten’s Fault

While there is no doubt that gluten is to blame for the debilitating symptoms of celiac disease, we might have been too quick to assume that this protein, found in wheat and some other grains, is also responsible for the symptoms associated with non-celiac gluten sensitivity (NCGS), often colloquially called gluten intolerance.

Celiac disease affects just 1% of the population, and an estimated further 6% could have NCGS, yet as we mentioned in the Inside Tract®, issue 189, as many as 22% of Canadians are trying to cut gluten out of their diets. While many individuals believe that gluten is responsible for a vast array of symptoms and ailments, the chance of gluten being the cause is quite low. In addition, our understanding of how NCGS works is still in its infancy. There is much controversy surrounding this disorder, since there are no known physical markers, and studies conducted on the subject continue to show mixed results. Some new research shows that it is even possible that NCGS isn’t really a sensitivity to gluten, but may be to another component of the plant.

So what’s the real story behind wheat, gluten, and non-celiac gluten sensitivity?

How do we know that gluten, and not another wheat compound, affects those with celiac disease?

Physicians observed that some children experienced severe diarrhea, and that when those children eliminated wheat from their diets they no longer experienced this symptom. Through a process of elimination, researchers tested different aspects of wheat to see which specific part caused celiac disease. By removing wheat from celiac disease patients’ diets and then reintroducing different parts of the plant, researchers discovered that gluten caused symptoms to return, but other parts, such as starch, didn’t cause any symptoms.


Non-Celiac Wheat Sensitivity

Some individuals diagnosed with NCGS might actually be sensitive to one of the many other components of wheat, possibly a different protein, or a carbohydrate. Because we already know that gluten causes problems in those who have celiac disease, the common assumption when someone claims to feel better after eliminating wheat is that the symptoms had been a reaction to its gluten. However, wheat is a complex structure with an estimated 95,000 genes, which is several times more than the amount that scientists estimate are contained within the human genome. Wheat’s genes could contain many varied compounds, any one of which, other than gluten, could be causing symptoms. While avoiding gluten makes these individuals feel better, it could be because they are also avoiding all the other compounds in wheat, including whichever one is the true source of their symptoms.

It can be particularly difficult to establish whether symptoms are from gluten or another wheat molecule when diagnosing NCGS. Unlike celiac disease, there are no physical markers for NCGS, so most studies and diagnoses use wheat elimination diets to test for or confirm non-celiac gluten disorders. Using a wheat elimination diet makes it difficult to be certain which aspect of wheat is causing symptoms.

However, it is important to know the difference, since individuals who have difficulty with other substances in wheat could still safely consume gluten. This means that gluten from a non-wheat source, and many common foods with gluten, such as sauces, seasonings, deli meats, salad dressing, oats, and more, could still be safe for some individuals who have various kinds of wheat sensitivity. In addition, if the substance that causes problems for the individual is in other grain products that are gluten-free, that person could continue to experience symptoms even after eliminating gluten. The problem with this is that there is no easy way to find out which part of wheat is causing your symptoms; at this point in time, you can’t just walk into the doctor’s office and ask for a blood test. Perhaps the future will bring more research on these other potential culprits.


One such component of wheat that can cause digestive symptoms is part of a family of fermentable carbohydrates that researchers consider a possible trigger of irritable bowel syndrome (IBS). Collectively referred to as FODMAPs, these include fermentable oligo-saccharides, di-saccharides, mono-saccharides, and polyols. See the Inside Tract®, issue 184, or for more details on FODMAPs. In certain individuals, these compounds cause gastrointestinal symptoms such as bloating and diarrhea. A major source of oligo-saccharides is wheat, but onions and garlic also contain this type of carbohydrate.

Current research is shedding light on the potential connections between these carbohydrates and symptoms in irritable bowel syndrome (IBS). IBS affects 13-20% of Canadians and causes abdominal pain, bloating, and constipation and/or diarrhea. It is possible that confusion could exist between diagnoses of NCGS and IBS with sensitivity to FODMAPs.1 One study found that individuals with IBS and self-reported NCGS actually responded better to a low FODMAP diet than to a gluten-free diet.2

Being unable to tolerate FODMAPs can be much more complicated to manage, as these carbohydrates are in a wide variety of healthy foods, such as many types of fruits and vegetables. Most can tolerate them just fine, but for some individuals they cause gastrointestinal distress. If you think FODMAPs are the source of your symptoms, then you should consult a registered dietitian to ensure that you can eat a well balanced diet while avoiding the foods that trigger your gastrointestinal symptoms.

Too Much Gluten?

The wheat we eat today has undergone some major changes over the last few millennia. While humans have likely been consuming grains for at least 30,000 years, it was roughly 10,000 years ago when we began cultivating wheat in the Fertile Crescent (an area in the Middle East).3 Since then, we have been breeding it to our liking and, since gluten gives wheat products enjoyable textures, we started creating wheat strains with soaring levels of gluten before we even knew what gluten was. Over the past few hundred years, this effect has become even stronger. Our increased scientific understanding of agriculture has led to wheat products with much more gluten than those humans historically consumed.4

Unlike those who have celiac disease, many individuals with NCGS can actually tolerate small amounts of gluten. It’s possible that it is a quantity issue. For example, we all need to eat fibre to keep our guts healthy, but consuming too much at once can cause bloating, constipation, and diarrhea. Similarly, some researchers believe that since the modern cultivation of wheat has created plants that contain much higher quantities of gluten than the wheat of the past, these new strains of wheat are just too full of gluten for certain gluten-sensitive individuals to tolerate.4 If this is the case, many individuals who are going gluten-free could benefit from replacing standard wheat products with ancient grains such as spelt, kamut, red fife, or triticale, so that they can still enjoy the benefits of wheat grains without the intestinal distress.

Wheat isn’t the only plant that has undergone major changes through agriculture. Many of the foods we eat today didn’t exist a few thousand years ago. For example, broccoli, cauliflower, cabbage, kale, and Brussels sprouts all come from specific breeding of the same ancient plant. All of the apple types we enjoy today come from the bitter and unpalatable crabapple. Carrots were originally very bitter and mostly purple before we began breeding them for better flavour and a variety of colours (you can still find carrots like this, called heirloom carrots), and eventually settled on the large orange carrots, which have only been cultivated for approximately 400 years. Seedless varieties of fruits such as bananas, melons, oranges, and grapes are other examples of foods that have changed through human intervention.

Something Else Entirely

In some cases, it really isn’t the wheat or the gluten that causes symptoms. Typically, avoiding gluten means avoiding common, often unhealthy, heavily processed foods. Those who avoid gluten often end up cooking at home more often than going out to eat. If you cut out junk and eat more whole foods (like when you cook at home), then you end up with a diet that is more nutritious, leading you to feel much better than you did while eating gluten-containing convenience foods. In other individuals, the perceived reduction in symptoms could simply be a placebo effect that occurs when taking on new habits that you anticipate will work. For a while, it may seem like going gluten-free is helping, but this effect typically wears off eventually. It’s also possible that these symptoms are actually the result of another ailment. If you are having unexplained gastrointestinal or other types of symptoms, visit your general practitioner before chalking them up to gluten or wheat. It could be something easily treatable, or something more serious that would just get worse as you work on removing gluten from your diet. If you do have problems with gluten, wheat, or FODMAPs, make an appointment with a registered dietitian to make sure you can safely maintain a balanced diet that also treats your symptoms.

First published in the Inside Tract® newsletter issue 191 – 2014
1. Nijeboer P et al. Non-celiac Gluten Sensitivity. Is it in the Gluten or the Grain? Journal of Gastrointestinal and Liver Diseases. 2013;22(4):435-40.
2. Biesiekierski JR et al. 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;145:320-8.
3. Wikipedia. History of Bread. Available at: Accessed: 2014-10-23.
4. De Lorgeril M, Salen P. Gluten and wheat intolerance today: are modern wheat strains involved? International Journal of Food Sciences and Nutrition. 2014;65(5):577-81.
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