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Gluten Allergies and Intolerances: What’s the Difference?

Gluten is a thick protein produced in the grain of wheat, barley or rye as a storage medium for their seeds. Humans have been enamoured of these three cereals for thousands for years. The first high gluten food was, of course, bread: around 85% of all the vegetable protein in bread is provided by gluten. 

Eventually, however, people realised that grain was a very versatile substance that could be made into other foods. If you grind grain into flour and pour in water, you end up with dough, from which you can make all sorts of other temptingly chewy delicacies like pasta, pies and cakes. Meanwhile, others figured out how to brew beer from wheat and barley.

As we arrived at the 20th century came the invention of processed foods. Manufacturers of these supermarket staples realised that the addition of gluten flour could add thickness, texture and elasticity to all sorts of foods. Nowadays you will find gluten in:

  • Salad dressing
  • Mayonnaise
  • Some beers and ales
  • Sauces and gravy
  • Breakfast cereals
  • Sweets
  • Sausages and hot dogs
  • Vegetarian meats
  • Crackers
  • Crisps
  • Ice cream and flavoured yoghurt
  • Canned fruits
  • Canned soups

…and that’s only a selection.

What is gluten intolerance?

‘So what?’ you may be thinking. The problem with gluten is that some people struggle to digest it.

Gluten intolerance is surprisingly common. More than 12% of the population will experience this at some point in their lives. For a variety of reasons, the bodies of people who develop this condition do not break down gluten well and this can trigger some unpleasant symptoms.

Although fundamentally a digestive disorder, gluten intolerance can involve the immune system. If the person continues to consume gluten in spite of experiencing uncomfortable reactions (see below for more on those), junctions within their stomach and intestines may be loosened, allowing molecules of food to escape the gut and attract the attention of a type of antibody called immunoglobulin G4, or IgG4. This condition is known as ‘intestinal permeability’ or ‘leaky gut syndrome’. It may sound alarming but this is a completely reversible condition.

The terms ‘gluten sensitivity’ and ‘gluten intolerance’ are sometimes used interchangeably. More typically however, ‘gluten sensitivity’ is reserved for the milder kind – often referred to as ‘non-coelic gluten sensitivity’ – while ‘gluten intolerance’ usually refers to the more severe variety in which IgG4 antibodies intervene.

What are gluten allergies?

Although the terms are often used interchangeably, allergies are in fact a quite different form of reaction to intolerance. Allergies involve the immune system. If this becomes wrongly sensitised to harmless substances, it will respond to these as though they were germs or harmful microscopic organisms.

There is no true allergic reaction to gluten specifically, but wheat allergies are relatively common. 

Coeliac disease has some similarities, but is in fact not a true allergy: instead it is an autoimmune disorder, in which the body attacks its own intestines. The condition is triggered by gluten, however: if people with coeliac disease eat food containing the problematic protein, they may experience such symptoms as chronic diarrhea and bloating. Long term, coeliac disease causes inflammation and damages the intestines, sometimes irreversibly. Although rare, coeliac disease is a serious medical condition that requires management with medication and management via a strict diet.


As we saw above, gluten intolerance and wheat allergies are quite distinct. Nevertheless, there is some overlap. Let’s take a look at some of the symptoms they share, along with typical differences.


Gluten intolerance and wheat allergy sufferers can both experience:

  • Bloating and indigestion
  • Diarrhea
  • Stomach cramps and pain
  • Physical aches and pains


The following symptoms are more common in gluten intolerance sufferers:

  • Constipation
  • Disproportionate tiredness
  • Feelings of anxiety
  • Low moods, depression
  • Difficulty concentrating, ‘brain fog’
  • Headaches

Meanwhile, people with a wheat allergy could experience these more physical reactions:

  • Skin rashes – hives, eczema
  • Feelings of nausea, vomiting
  • A runny nose, nasal congestion

Although not a common occurrence, wheat allergies, like others, can trigger severe and even life-threatening reactions. This extreme form of allergy, called anaphylaxis, requires rapid medical treatment to avoid the risk of respiratory or heart failure. People prone to anaphylactic shock are usually given ‘epi-pens’ to carry with them: these easily portable devices allow them to rapidly self-administer an injection of adrenaline.

Gluten intolerance and allergy FAQ

How do you avoid gluten?

Become a self-taught expert in which foods may contain gluten, and make closely reading food labels a habit. Cut down on processed foods altogether: not only is this better for your overall health, but fresh foods will not contain any hidden gluten.

Although it’s still a widely used ingredient in processed food, life is easier these days for people with gluten intolerance and allergies. There is more awareness and a much wider range of appetising gluten-free food is available on supermarket shelves and in health food stores.

Should I see a doctor about my symptoms?

This depends on how unwell you feel on average. If your symptoms are a passing inconvenience, a doctor’s appointment is probably unnecessary, but if you regularly experience genuinely uncomfortable or painful reactions then dial that number today and suggest a gluten allergy test.

Order a gluten intolerance test

Alternatively, why not order a food allergy test you can take at home? Send back a small blood sample in the included vial and in just a few days you will receive a full report, setting out the food groups, if any, the antibodies in your blood sample responded to. This test incorporates no less than 38 different food types, including allergy testing for wheat, barley and rye.

Health Hub also offers a full spectrum food intolerance test, focused on detectable IgG4 antibody levels. Do note that there is no test currently available for non-coeliac gluten sensitivity.

As we saw above, high levels can indicate the development of a food intolerance. So if you struggle with gluten, a gluten test could be a very sensible investment.