What is the difference between GLUTEN INTOLERANCE and COELIAC DISEASE?

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Gluten Intolerance versus Coeliac Disease

For the growing population of people who suffer after eating wheat products, it is important to understand the difference between coeliac disease, gluten intolerance (also known as gluten sensitivity or non- coeliac gluten intolerance) and an actual wheat allergy.

1 in every 100 people suffers with coeliac disease and even then it is thought to be an under-diagnosed condition. Strictly speaking, coeliac disease is not an allergy, it is an autoimmune disorder whereby the body cannot tolerate gluten: the protein found in wheat, barley, rye, and sometimes oats. Symptoms include bloating, diarrhoea, nausea, constipation, tiredness, headaches, hair loss, anaemia and sometimes sudden weight loss. Diagnosis of coeliac disease is via a blood test from your GP followed up with a gut biopsy for confirmation.1

Gluten intolerance is no less uncomfortable for the patient than coeliac disease but the diagnosis is more difficult as patients do not have physically identifiable markers (so they test negative to the coeliac blood test and gut biopsy). Symptoms are wide-ranging and are typically delayed reactions which are dose dependent. Physical symptoms can be very similar to those experienced by patients with coeliac disease in terms of gastrointestinal complaints, ‘foggy head’, migraines, joint pain and more.  The main difference between those with coeliac disease and those with gluten intolerance is that coeliac patients cannot tolerate even a crumb of gluten whereas those with gluten intolerance have reactions which are dose dependent.  Some gluten intolerant patients can reintroduce gluten into their diet after a period of abstinence with no ill-effects; others can only ever have small amounts.2 One of the frustrations for those with gluten intolerance versus coeliac disease is that patients are sometimes told by GPs that they don’t have a problem with gluten if their coeliac test comes back negative.

Patients with a wheat allergy present with an IgE mediated reaction to wheat alone but not to barley, rye or oats. IgE mediated reactions are often what people perceive as a ‘true’ allergy. Symptoms are immediate and can affect the skin (causing swelling and rashes), the cardiovascular system (leading to increased heart rate), the gastrointestinal system (causing nausea, vomiting and diarrhoea), the respiratory system (causing problems breathing) and the central nervous system (including confusion, headache and even loss of consciousness).3 Wheat allergy is less common than coeliac disease or gluten intolerance.


coeliac disease, gluten intolerance, gluten sensitivity

Diagnosis of Gluten Sensitivities

Your first point of call if you suspect your medical symptoms may be diet related is always your GP. They will be able to test you for coeliac disease.

Testing for coeliac disease

This is a simple blood test for particular antibodies (called EMA and tTGA) and positive results are quite conclusive. There are cases of false negative results6 so blood testing is often followed up by a gut biopsy. In addition, a negative coeliac test does not mean that you aren’t still intolerant to gluten; this is often where patients become unstuck when they suspect food intolerances but the doctor says they mustn’t have a problem because they aren’t coeliac.

Testing for gluten intolerance

Diagnosis of gluten intolerance as opposed to coeliac disease can be challenging. Currently, the only medically accepted way to diagnose food intolerance is an elimination diet, which involves following a limited diet for a number of weeks to allow the gut to heal, followed by reintroducing new foods one at a time and monitoring the patient’s reaction to the introduction of individual foods.4 Details of what foods are eaten and symptoms experienced are kept in a food diary which is then analysed by a healthcare professional to spot patterns in symptoms and foods eaten.  Intolerances can be dose dependent and after a period of abstinence from the offending food, the patient may find they can tolerate it again (although whether tolerance develops and what quantity is tolerated varies from patient to patient).5 Understandably, elimination diets are a difficult and time consuming process and patients often therefore look for a definitive test that will point them in the right direction.  It is also very difficult to get a dietician’s appointment for elimination diet testing, and for this reason a number of patients turn to alternative medicines to help them.

Naturopathic practitioners have alternate ways of diagnosing food intolerances, however some of these tests are more reliable than others and none have been scientifically proven to be effective.

  1. IgG testing – this is the only testing method for intolerances which has shown a small amount of promise and is endorsed by some high profile people such as Dr Hilary Jones and Patrick Holford. It involves a blood test for Immunoglobulin G, which is thought to be involved in sensitivity reactions to food. (In other words, IgE is known to be involved in allergies and IgG is thought to be involved with intolerances). There was a high profile study done in 2006 on more than 5,000 patients, of whom 76% reported a marked improvement in their symptoms having eliminated the foodstuffs recommended by IgG testing.7 Sceptics argued that it wasn’t so much that the test was accurate, but that around 50% of those tested had cut wheat from their diets which is the main culprit in food sensitivity, and that explained why they had an improvement in symptoms.
  2. ALCAT testing – this is an Antigen Leukocyte Cellular Antibody Test. This is another blood test which examines the reactions of white blood cells to foodstuffs, and is said to diagnose food intolerances which are not mediated by antibodies (such as IgG). This test has not been clinically proven.8
  3. Vega testing – this test measures an electric current applied to acupressure meridians in the body and tests the ‘resistance’ of your body to different food groups. This type of test is sometimes offered in naturopathic clinics, but scientific evidence to prove its efficacy is not forthcoming.9

Other methods which are generally discredited by both traditional and naturopathic doctors include eye, hair and fingernail analysis, kinesiology, and dowsing (using the movement of a pendulum to ‘test’ foodstuffs). Please don’t waste your money on these!

Of course, as debilitating as food intolerances can be for the patient, the danger of cutting out foods without proper medical supervision is twofold:

1) You may have an underlying condition that hasn’t been picked up and the quest to cut out different food groups leads to a missed diagnosis elsewhere

2) You may suffer from malnutrition if you try to cut out too many food groups and don’t replace them with proper substitutes

Treatment of Gluten Sensitivities

Your first port of call should always be your GP for a coeliac test- you need to have eaten gluten for a period of at least 6 weeks before the test for it to work properly.  A diagnosis of coeliac disease means that you must avoid ANY gluten for life.

In order to diagnose a gluten intolerance, simply try cutting gluten out of your diet for 4 weeks and see if your symptoms improve.  Keep a symptom diary during this time and you can use the results to take to your GP. Anecdotal evidence is that many people find the intolerance tests described above helpful in terms of diagnosing multiple food intolerances, however they are not scientifically proven and although it is possible to be intolerant of any food, two of the most common food groups which cause problems for people are gluten and dairy. Some people find it easier to try cutting these two groups first in an elimination diet and then trying to add other groups back in.  Gluten intolerance is dose dependent so some patients find that after cutting gluten out of the diet for a period of time (4-6 weeks) they can then add gluten back into their diets.  This varies from patient to patient; some patients find they can not tolerate any gluten and others find they can have it again in moderate amounts.

Also remember that your symptoms may not be food related at all – you may have other medical issues which need addressing so please always make sure you consult a healthcare professional.

For further information and easy to make gluten-free recipes, please download my book:


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  1. ‘About Coeliac Disease.’ Coeliac UK. https://www.coeliac.org.uk/coeliac-disease/about-coeliac-disease-and-dermatitis-herpetiformis/
  2. ‘Wheat and Gluten Intolerance.’ Allergy UK. http://www.allergyuk.org/downloads/factsheets/intolerances-and-sentivities/wheat-and-gluten-intolerance.pdf
  3. ‘Anaphylaxis.’ The Free Dictionary. http://medical-dictionary.thefreedictionary.com/Anaphylaxis
  4. ‘Identifying your food intolerances.’ Allergy UK. http://www.allergyuk.org/food-intolerance/identifying-your-food-intolerances
  5. ‘Identifying your food intolerances.’ Allergy UK. http://www.allergyuk.org/food-intolerance/identifying-your-food-intolerances
  6. ‘About Coeliac Disease.’ Coeliac UK. https://www.coeliac.org.uk/coeliac-disease/getting-diagnosed/
  7. Gazzola, Alex, Living with food intolerance and living with food allergy. (Great Britain, Sheldon Press, 2005) http://www.ion.ac.uk/information/onarchives/diagnosingallergy
  8. Gazzola, Alex, Living with food intolerance and living with food allergy. (Great Britain, Sheldon Press, 2005) http://www.ion.ac.uk/information/onarchives/diagnosingallergy
  9. Gazzola, Alex, Living with food intolerance and living with food allergy. (Great Britain, Sheldon Press, 2005) http://www.ion.ac.uk/information/onarchives/diagnosingallergy

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