How Do You Know if You Have a Wheat Allergy, a Gluten Sensitivity or Celiac Disease?

What’s the deal with wheat? 

It seems to be a potential issue for many of my clients and it’s not always clear why.  Especially because the symptoms of wheat allergy, wheat intolerance, non-Celiac gluten sensitivity (NCGS) and Celiac disease are very similar.  

So how do we know what’s really going on? 

What exactly is Gluten?

Gluten are types of proteins found in certain grains including wheat, barley, and rye. It helps wheat-based foods hold their shape.

Why do some people react to wheat/gluten?

  • They could have a wheat allergy
  • They could have Celiac disease, which is an autoimmune condition where your body attacks the small intestine in the presence of gluten  
  • They could have an intolerance to a carbohydrate found in wheat called a fructan, which is a type of FODMAP restricted on a low-FODMAP diet
  • They could have non-Celiac gluten sensitivity

What are the Symptoms of Wheat/Gluten Reactions?

  • Bloating, gas, abdominal Discomfort
  • Diarrhea and/or constipation
  • Hyperactivity
  • Food Cravings
  • ADHD
  • Joint Pain/Muscle Weakness
  • Headaches/Migraines
  • Fatigue/Lethargy/Sluggishness
  • Brain Fog/Difficulty Focusing
  • Mood Swings
  • Rash or hives

How is a Wheat Allergy Diagnosed?

  • A wheat allergy can be diagnosed by visiting an allergist to get an IgE blood test
  • This can be done at any time and you don’t need to be eating wheat for accurate test results

How is Celiac Disease Diagnosed?

Celiac disease is difficult to diagnose and you must be eating wheat for 6 – 8 weeks in order to have an accurate diagnosis.

  • The first step is to take a blood test that looks for the Celiac genes HLA-DQ2 & HLA-DQ8 genes.  97% of those with Celiac disease have these genes. 
  • If it’s negative, then it’s highly unlikely you have Celiac disease. 
  • If it’s positive, then there is a chance you have Celiac disease and you should pursue further testing.  It doesn’t mean you have it.
  • Take the Celiac panel blood test that looks for Celiac antibodies (you can even take both the genetic test and the Celiac panel at the same time)
  • Celiac disease is also confirmed with an endoscopy and biopsy of tissue in the small intestine

How is Wheat Intolerance or Gluten-Sensitivity Diagnosed?

This is where the waters gets muddy, my friends!

It can be tricky to diagnose NCGS or wheat intolerance as there aren’t any definitive diagnostic tests.

Elimination diets are considered to be the gold standard in determining NCGS or an intolerance to wheat.   We eliminate certain foods for a period of time and then reintroduce them to assess how the body reacts when eating them.

But you must first rule out Celiac disease!  Why?

  • You must be eating wheat for 6 – 8 weeks.  If we remove gluten, and you feel amazing are you really going to want to go back to eating gluten again in order to get an accurate test? 
  • Those with Celiac disease may have delayed reactions to the gluten reintroduction, whereas most of those with wheat intolerance or NCGS may react within a day of reintroducing wheat/gluten (more on that below)
  • If you don’t have an immediate reaction to the gluten reintroduction, you may have Celiac disease and we won’t know  

How Common is Non-Celiac Gluten Sensitivity?

It’s hard to know exactly how many people have NCGS, but a large study looked at over 12,000 people and only 486 were suspected to have NCGS – that’s 4%. Out of those 486 people…

  • 47% of them have IBS
  • 35% have food intolerance
  • 22% have IgE mediated food allergy
  • 14% have an autoimmune condition such as Hashimoto’s Thyroiditis, Graves Disease, and psoriasis

Of those in the study who have NCGS, 90% of them had their symptoms appear within a few hours to one day after ingesting gluten. In comparison, those with Celiac disease may have delayed symptoms ranging from weeks to years. Therefore, it’s important to rule out Celiac disease before undergoing any gluten-free elimination diet.

What Causes Non-Celiac Gluten Sensitivity?

Why would someone without Celiac disease be sensitive to gluten?

This is a complex answer involving the small intestine. The lining of the small intestine is supposed to be permeable enough to allow the passage of nutrients into the blood stream. The intestinal lining is a barrier that separates digested food, bacteria, and other molecules from entering the blood stream. Gluten causes increased intestinal permeability (aka “leaky gut”) in everyone who consumes gluten.

This isn’t necessarily a bad thing for those without Celiac or NCGS. There are plenty of people who can eat gluten without an issue. However, for those with Celiac disease or NCGS, gluten creates even greater intestinal permeability, which allows large gluten molecules to escape into the blood stream causing an inflammatory response that could manifest as a variety of symptoms across the whole body.

Essentially, the body is reacting to gluten in the very same way it does with Celiac disease but with NCGS, it doesn’t cause the same damage to the cells of the small intestine.

What Causes Wheat Intolerance?

As we have seen in the study above, in those with NCGS, 47% of them have IBS.  But are their symptoms caused by gluten or by the carbohydrate in wheat?  I told you the waters are getting muddy!

  • Those with IBS may have an intolerance to wheat, which is high in a certain carbohydrate known as a fructan, a type of FODMAP.  A low-FODMAP diet restricts most foods containing wheat but not all.  
  • Interestingly, a recent study demonstrated that 60% of those with IBS had allergic-type reactions to wheat even though they did not test positive for an IgE allergy to wheat.

So as you can see, wheat can be problematic for many people for a variety of reasons.  So before you embark on a gluten-free elimination diet, it’s very important to rule out Celiac disease (yes, I have said this 3 times now).  And of course, I recommend working with a skilled nutrition practitioner to help suss out whether your symptoms are related to a NCGS or a wheat intolerance or something else all together. 

Ready to figure out if wheat is playing a role in your digestive issues?


Fritscher-Ravens, A., et al. (2019). Many patients with Irritable Bowel Syndrome have atypical food allergies not associated with Immunoglobulin E. Gastroenterology, 157(1), 109-118.e5.

Hollon, J., Leonard Puppa, E., Greenwald, B., Goldberg, E., Guerrerio, A., & Fasano, A. (2015). Effect of gliadin on permeability of intestinal biopsy explants from celiac disease patients and patients wit non-celiac gluten sensitivity. Nutrients, 7(3), 1565–1576.

Volta, U., Bardella, M. T., Calabrò, A., Troncone, R., & Corazza, G. R. (2014). An Italian prospective multicenter survey on patients suspected of having non-celiac gluten sensitivity. BMC Medicine, 12, 85.

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