Gluten vs Wheat Intolerance – What is the Difference?

Having trouble eating gluten? Or is it wheat that you’re avoiding? Are they the same?

Introduction

Gluten-free diets are on the rise. And looks like they’ll be here to stay! There seems to be a growing number of people who are struggling to digest gluten and/or wheat – not including those who are diagnosed with Celiac Disease (CD for short) or Wheat Allergy (WA). For these people who don’t fully fit into the CD or WA category, but can suffer from many of the same symptoms, it can be hard to know exactly what the culprit is. Is gluten to blame, or wheat? 

To put it bluntly, the internet is full of websites containing a lot of incorrect information on the subject. They mean well – they just haven’t properly done their research.

Unfortunately as a result, many people aren’t really sure whether they have a gluten or wheat intolerance, and they also aren’t sure what foods they should be eating or avoiding.

It doesn’t help that this area hasn’t yet had much scientific study either, so we don’t yet have reliable medical tests/diagnoses to help us identify what’s going on.

So as a non-science major (I studied history instead… and languages…), I’ve attempted to comb through the world of scientific journals on food science to understand the details of gluten and wheat intolerance and to translate that into layman’s terms for you. And for me. After all, I’m one of those same people who has been asking for years “Am I gluten intolerant? Or wheat intolerant?” and “What can I eat?!”

Gluten: What exactly IS gluten?

Well! You would think this should be straight forward to answer by now! But alas, it’s not… 

It seems some people have got themselves really confused and it has led to a huge spread of misinformation on the subject.

Gluten, quite literally, refers to gliadin and glutenin, two types of protein which are found in the grain of wheat, and close relatives spelt and kamut. These are not found in any other grain (with the exception of triticale, which is a wheat/rye hybrid).

Aside from these three, neither gliadin nor glutenin are contained in any other grain. However, gliadin belongs to the prolamin protein family. Prolamins are a defined group of proteins found only in cereal grains. The prolamins in each cereal type have a different name: gliadin in wheat, kamut and spelt; hordein in barley; secalin in rye; avenin in oats; and zein in maize.^[1] Although these prolamins are all different, they can have some similar properties and consequently, in some people, can cause a similar pathophysiological reaction to gliadin.^[2] This is why, for those diagnosed with CD, it is recommended to avoid all prolamins to avoid potential health risks.^[3]

Technically however, these other prolamins are NOT gluten. Although some people choose to lump all these prolamins together under the gluten name, remember that they are different. 

Yes, they can have some similar properties to gluten, but they are not actually gluten.

Can I eat Oats?

Additionally, as you now know, oats contain a protein called avenin. As a fellow prolamin, avenin has some similar properties to gliadin.

Consequently, some people (but not all!) diagnosed with CD have found that they also struggle to digest this protein as well. That is why you will see the Celiac Disease Foundation generally advising anyone diagnosed with CD to avoid all prolamins (contained in wheat, kamut, spelt, rye, barley, triticale and oats), just to be on the safe side.

A word about Wheat

Before we can contemplate whether we might have a wheat sensitivity, rather than gluten intolerance, it’s worth understanding exactly what wheat is and how it relates to other grains.

Wheat is a cereal grass which produces edible grains, belonging to the Triticum genus or group. Other grains belonging to this group are kamut and spelt, so consequently they share many of the same characteristics as wheat. As a result, some people choose to class kamut and spelt as a species of wheat. The Triticum genus is part of the Triticacaea tribe, which is part of the Pooideae subfamily, which is part of the Poacea family.^[4]

Figure 1 below shows how each group sits within the other.

The more groups that a grain shares with wheat, the closer they will be in nature and the more characteristics they will share.

For example, oats are part of the Pooideae subfamily (along with barley, rye, kamut, spelt and wheat), but are not part of the Triticacaea tribe (barley, rye, kamut, spelt and wheat), or the Triticum genus (kamut, spelt and wheat). So, while oats will share some characteristics of wheat, barley and rye will share more. And kamut and spelt will share even more!

Species and common forms of wheat include (but are not limited to):^[5]

• Common Wheat
• Durum Wheat (includes Bulghur Wheat)
• Club Wheat
• Emmer Wheat
• Semolina
• Einkorn Wheat
• Couscous
• Farina
• Bran
• Sprouted Wheat
• Wheat Berries

As mentioned above, kamut and spelt are very closely related to wheat (come from the same group Triticum) and consequently share many of the same properties – including gliadin and glutenin proteins (though in different amounts).

That’s why for those people diagnosed with Celiac Disease or wheat allergy, it is highly recommended to avoid kamut and spelt also!

What does a Wheat Allergy look like?

These days Wheat Allergy (WA) is easily recognized by the medical profession, as there has been ample research and testing done in this area. As a result, if you think that you may have a Wheat Allergy then you can easily get this tested and confirmed by your doctor.

People with a confirmed WA suffer a quick, adverse reaction shortly after consuming wheat. Symptoms can be gastrointestinal, respiratory, include skin reactions, and in rare cases anaphylaxis or angioedema.^[6]

Common symptoms include:^[7]

• Swelling, itching or irritation of mouth or throat
• Itching, hives or rash on the skin
• Congested nose
• Headache
• Breathing problems
• Cramps, nausea, vomiting
• Diarrhea

WA is considered to be an IgE mediated allergy. When the body’s immunoglobulin E (IgE) antibodies detect the wheat protein they react abnormally and quickly, producing a range of physical responses.^[8] In other words, when the body detects wheat protein in the system, it generates a whole immune-system response to combat it – producing a wonderful array of physical reactions (my attempt at sarcasm…).

Because the reaction is quick and obvious, it can be more straightforward to recognize if you have a full-blown WA. 

What does a reaction to Gluten look like?

To understand what severe gluten intolerance looks like, let’s turn to Celiac Disease (or CD for short).

Like WA, CD is well known and has been well studied, and consequently there are now reliable tests which can detect whether you have this condition.

CD is classed as a type of autoimmune disease, which occurs in genetically susceptible individuals with HLA-DQ2 and/or HLA-DQ8 genotypes.^[9] It is characterized by an inability to properly digest and break down gluten proteins, in addition to producing an autoimmune response where the body attacks the small intestine and creates damage.

The symptoms of CD are many and varied and include a mixture of gastrointestinal as well as extra-intestinal symptoms (meaning non-stomach related symptoms).

They commonly include: bloating, abdominal discomfort and pain, diarrhea and flatulence, iron deficiency and weight loss. Additional extra-intestinal symptoms are: fatigue, headache or migraines, depression and anxiety.^[10]

Although there is some overlap, the signs of severe gluten intolerance (CD) and WA are a bit different;

• Allergic reactions to wheat are often immediate and physiological.
• Severe gluten intolerance or Celiac Disease symptoms start to appear once gluten enters the intestinal tract, but can often take longer to manifest. Also, CD symptoms can commonly include depression, anxiety and fatigue – issues not normally found with a wheat allergy.

Other issues with Wheat

Unfortunately, there may be other components of wheat that could be causing people health issues, which scientists are only recently beginning to look into.

One article examining Non-Celiac Gluten Sensitivity found that another part of the wheat grain (agglutinin carbohydrate binding protein) along with exorphins have been shown to affect the immune system and can create intestinal damage, once digested.

Additionally, wheat contains some albumin proteins (called ATI’s) which are resistant to being broken down by the gut and can create an immune response and intestinal inflammation in some people.^[11]

These are only initial findings and a lot more research needs to be done in this area. But there are strong signs to suggest that an intolerance to wheat may not simply be about gluten. There are other components of wheat which may be responsible for causing a reaction.

As if it wasn’t confusing enough already!

So which is it: Gluten or Wheat Intolerance?

By this point you must be yearning for some clarity. Some definites would be nice – this or that, yes or no answers, right?

I’m sorry to say, if you are struggling with a mild (i.e., not chronic) intolerance to either gluten or wheat then there are still a lot of grey areas.

However, it should be easier by now to understand and rule out the extremes. CD and WA are much easier to tell apart, as there are clear differences in the rate of onset symptoms and the nature of the symptoms. Plus, both of these conditions have been well researched and are well understood by the medical community, and consequently can be clearly tested for.

If you haven’t tested positive for CD or WA, then like me you likely fall into the Non-Celiac Gluten or Wheat Sensitivity (also referred to as NCGS or NCWS) category. 

Scientists are split over which term should be used. Some argue that for those who test negative for CD, but experience some of the same intestinal and extra-intestinal symptoms, then the term NCGS should be used as it likely to be gluten that is the culprit.^[12]

However, a few others suggest that NCWS is more likely. Wheat not only contains gluten, but also contains other proteins and components which can cause intestinal and extra-intestinal symptoms.^[13] What they all agree on though, is that a lot more research needs to be done in this area to understand why so many of us are experiencing stomach issues, and tiredness, headache and ‘foggy mind’ etc when eating wheat and occasionally other particular grains.

In my experience, trial and error is likely the best way to understand whether it’s gluten (specifically gliadin and glutenin proteins) or wheat which is causing the concern.

For example, over the years I have noticed that I can no longer eat wheat or spelt without feeling ill. However, barley, rye and oats seem to be fine for me. Neither of these cereals contain gluten or wheat, however, barley and rye have prolamins which are very similar to gluten and yet I seem to digest these fine. And oats have even less in common with wheat (remember the diagram above), so definitely no issues there! So perhaps the wheat grain itself is the culprit for me?

Some questions that may help with your own search:

• Can you digest foods well that don’t contain gliadin or glutenin?
• What type of symptoms are you experiencing?
• How are you with digesting barley and rye?

At the end of the day, if we’re defining wheat as the Triticum group (wheat, kamut and spelt), then gluten and wheat intolerance aren’t too dissimilar. All of these species of wheat contain gliadin and glutenin proteins. So, if you’re intolerant to gluten OR wheat, then either way you will need to avoid these three grains.

If you’re very sensitive to prolamin proteins, they you may also have trouble with barley and rye too. Although they don’t contain gluten proteins, remember that they are wheat’s very close cousin!

Conclusion

There’s a plethora of information out there on gluten and wheat intolerances, but many of the most common websites have misinterpreted the facts either by accident, or for their own convenience. 

I’m not aiming to give you a diagnosis here (if only I could… wouldn’t that be helpful!). But I CAN give you the truth. Scientific facts, even.

If you have Celiac Disease or wheat allergy, then by now you should hopefully have a clearer understanding of the different grains and how they relate to wheat. It should also be helpful to know once and for all what grains actually contain gluten (gliadin and glutenin), and what grains do not – and to understand why some foods are incorrectly lumped under the gluten umbrella (e.g., oats).

For those of you, like me, who have Non-Celiac Wheat/Gluten Sensitivity, then this should have provided you with some scientific information (for a change!) and some clarity too. Although the NCWS world is still vague and trickier to navigate, at least now you have some facts and accurate information to make empowered choices about foods that might and might not work for you.

Now go forth and discuss gluten proteins in confidence! 😉

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^[1] ‘What is Gluten – Why Is It Special?’: https://www.frontiersin.org/articles/10.3389/fnut.2019.00101/full

^[2] ‘Characterization and Relative Quantitation of Wheat, Rye, and Barley Gluten Protein Types by Liquid Chromatography–Tandem Mass Spectrometry’: https://www.frontiersin.org/articles/10.3389/fpls.2019.01530/full

^[3] ‘What is Gluten?’: https://celiac.org/gluten-free-living/what-is-gluten/

^[4]  ‘How Is Wheat Related to Other Grains?’: http://www.whfoods.com/genpage.php?tname=george&dbid=382

^[5]http://www.whfoods.com/genpage.php?tname=george&dbid=382; ‘Wheat Allergy’: https://www.webmd.com/allergies/wheat-allergy

^[6]  ‘The Overlapping Area of Non-Celiac Gluten Sensitivity (NCGS) and Wheat-Sensitive Irritable Bowel Syndrome (IBS): An Update’: https://www.mdpi.com/2072-6643/9/11/1268/htm

^[7] https://www.webmd.com/allergies/wheat-allergy

^[8] ‘IgE Mediated Food Allergies’: https://www.chop.edu/conditions-diseases/ige-mediated-food-allergies

^[9] ‘Non-Celiac Gluten Sensitivity: A Review’: https://www.mdpi.com/1010-660X/55/6/222/htm

^[10] ‘Symptoms of Celiac Disease’: https://celiac.org/about-celiac-disease/symptoms-of-celiac-disease/

^[11] https://www.mdpi.com/1010-660X/55/6/222/htm

^[12] https://www.mdpi.com/2072-6643/11/10/2325/htm

^[13] https://www.mdpi.com/1010-660X/55/6/222/htm; ‘Non-Celiac Gluten/Wheat Sensitivity’: https://celiac.org/about-celiac-disease/related-conditions/non-celiac-wheat-gluten-sensitivity/