Coeliac disease is an autoimmune disease that causes the body to react abnormally to gluten consumption. Even very minuet amounts can cause a reaction.
Gluten is found predominantly in wheat, rye, triticale, and barely. Although there are small amounts in oats (which is a complicated topic) and ingredients made from the above grains such as malted barley, wheat starch and maltodextrin.
Unlike IBS where foods that cause a reaction can be consumed with no long-term damage occurring. Gluten consumption with coeliac disease does cause damage to the small intestine even when no symptoms are present.
The small intestine is where most nutrients are absorbed when passing through the digestive tract. So significant damage to the small intestine can reduce the absorption of nutrients and result in deficiencies.
The lining of the small intestine is covered with small finger-like projections called villi. These villi are there to increase the total surface area of the small bowel so that as many nutrients can be absorbed as possible.
However, when gluten is consumed, the villi become inflamed and the surface area of the small intestine lining is reduced and thus its effectiveness in absorbing nutrients is also reduced.
What are the symptoms of coeliac disease?
Common symptoms of untreated coeliac disease include:
- Iron deficiency anaemia
- bloating and flatulence
- Issue with stools such as diarrhea and constipation
- Fatigue & lethargy
- nausea and vomiting
- stomach cramps and abdominal pain
- weight loss
Symptoms can range from mild to severe. Some people with coeliac disease, who are eating gluten, can even be asymptomatic and can go undiagnosed for a long time. Typically in these cases, testing for coeliac disease is done after finding abnormalities with iron stores or other nutrient deficiencies.
How is coeliac disease diagnosed?
The first port of call in the diagnosis of coeliac disease is a blood test which is used as an initial screening tool. Coeliac serology measures antibody levels in the blood that will be elevated if someone has coeliac disease and is consuming gluten.
Nonetheless, diagnosis is not made on the basis of the blood test alone. The blood test is just to check if there is reasonable suspicion of coeliac disease to perform a biopsy of the small intestine.
A gastroscopy is performed to take several small biopsies of the small intestine to check for inflammation of the villi.
Because inflammation of the villi is not often visible to the naked eye, the biopsies are examined under a microscope to confirm or deny the diagnosis. This procedure is performed under light anesthetic sedation and takes about 10 minutes
It is important to note that both the screening blood test and biopsy may result in a false negative if you have already taken gluten out of your diet.
It is fairly common for people who suspect they have issues digesting gluten or have coeliac disease, to trial a gluten-free diet.
However, prior to testing for coeliac disease, you must be consuming a normal diet, as the tests rely on markers of inflammation and auto-immune response for diagnosis.
If gluten has been removed from the diet, you will need to resume a regular, gluten containing diet for at least six-weeks prior to testing. For adults, a minimum of four slices of wheat bread or equivalent should be consumed every day during this time.
It is important the gluten challenge is carried out properly to ensure reliable test results.
Other gluten and wheat-related disorders
Gluten really has copped a bad rap over the last decade, being villainized as the culprit for all of our woes. The phrase “I’m intolerant to gluten” is tossed around a lot. But what does that even mean?
Outside of coeliac disease, there are few other reasons why someone may react to gluten containing products.
Wheat allergy is an IgE-mediated response to gliadins in wheat products. The symptoms of wheat allergy are typically noticeable within minutes to hours after ingestion and look like typical allergic reactions. The reaction may present with itching and swelling in the nose and throat, a rash, and/or wheezing. A severe reaction could even result in life-threatening anaphylaxis.
This type of reaction to wheat products is very specific and unlikely to be confused with gluten intolerance or coeliac disease although gastrointestinal symptoms can also be present.
Irritable bowel syndrome
Irritable bowel syndrome or IBS is characterized by gut symptoms that can differ from person to person. There is no unusual pathology associated with IBS.
This is actually what makes diagnosis difficult for clinicians. IBS is diagnosed simply by the elimination of other possible conditions such as testing for coeliac disease and inflammatory bowel disease.
IBS is typically diagnosed and managed with a low fodmap diet. This diet aims to cut out all potential trigger foods and reintroduce them one group at a time to identify individual triggers and thresholds for different people.
One of the fodmap groups is called fructans. Fructans are small chain carbohydrates that are not well absorbed in the body. For some people who are sensitive to fructans this can cause some unpleasant gastrointestinal symptoms such as bloating, gas and issues with stool consistency.
Fructans are most commonly found in wheat products which also happen to be a major source of gluten. It is common for people to refer to a fructan sensitivity as gluten intolerance, however, when it comes to IBS, gluten itself is not the culprit.
Fructans are not only found in wheat, but also rye, barley, chickpeas, bananas, onions, lettuce, garlic, leeks, artichokes, and asparagus. So even once wheat has been eliminated from the diet, people with fructan sensitivity may still get symptoms after consuming these other foods.
Non-coeliac gluten sensitivity
Although non-coeliac gluten sensitivity has been mentioned in scientific literature since 1986, there is still a lot that is not known about the condition.
It typically manifests with both IBS-like gut symptoms as well as non-gut symptoms such as migraines, headaches, fatigue, ‘foggy mind’, heartburn, musculoskeletal pain, itchiness and rashes, dermatitis and forgetfulness.
Whilst fructans can typically be linked to gut symptoms post consumption of wheat products, it remains unclear how and why the non-gut symptoms occur in some patients.
It is not even clear if the other symptoms are related to wheat or gluten consumption at all.
Managing a gluten-free diet
There is no cure for coeliac disease. People with coeliac disease must maintain a strict, gluten-free diet for life.
It is even important to avoid cross-contamination with gluten-containing products. As little as 50mg of gluten (equivalent to 1/100th of a slice of wheat bread) can cause damage and inflammation to the small intestine.
Managing this type of gluten free diet isn’t always easy. It takes a good understanding of gluten containing ingredients, the ability to read labels effectively and manage cross-contamination.
Identifying gluten-free foods
There are four main groups of non-gluten containing foods
Naturally gluten-free foods
This includes a number of food from a variety of food groups and is limited to unprocessed, wholefoods that occur gluten-free naturally such as,
- Fresh fruit and vegetables
- Fresh meats
- Fats and oils
- Naturally gluten free grains such as rice
These foods don’t require you to check the ingredients list or do further investigation. They can be eaten freely.
Products labeled gluten-free
Due to strict labelling laws in Australia, all products labelled gluten free contain no gluten and are not at risk of cross-contamination. You can eat these foods freely.
When these foods are tested, there must be ‘no detectable gluten’. Currently, this test is sensitive to 0.0003 per cent (three parts per million), which is the lowest amount that can be detected.
Foods with the Coeliac Australia endorsement logo
Along with products labelled gluten free, you can be sure that any product with the Coeliac Australia logo is coeliac safe.
Not all gluten free products will have this logo as companies have to pay for certification but it does make it easy to identify gluten-free, coeliac friendly products.
Products that are gluten-free by ingredient
This is where things can get a little more tricky. Processed foods that are not labeled gluten-free and do not have the Coeliac Australia certification need to be checked on a case-by-case basis before consumption.
Label reading is extremely important to maintaining a gluten-free diet.
Luckily in Australia, all products that contain gluten in any form or may be contaminated with gluten require an allergen warning.
If any ingredient in a product is derived from wheat, rye, barley or oats, then this must be declared on the ingredients panel as well as stated in the allergy statement (e.g. Contains gluten).
Cross-contamination can be avoided by identifying statements on food packaging such as ‘may contain gluten’.
Despite companies being required to put allergen notices on all gluten containing or potentially contaminated products, it is always a good idea to have some label reading skills.
When reading ingredients lists look out for all of the definite sources of gluten as well as possible sources of gluten.
Definite sources of gluten
A food must be avoided if any of the following ingredients are listed on the package:
Possible sources of gluten
The following ingredients may contain gluten, depending on the grain that they are made from:
If these ingredients are made from a gluten containing grain, it must be stated on the packages such as ‘modified starch thickener (from wheat)’.
It is also worth noting that not all products made from wheat actually contain gluten. Some foods are so highly processed that they actually become gluten-free. Common examples include glucose, glucose syrup, caramel colour, dextrose and monosodium glutamate which are all derived from wheat but are gluten free and can be included in a gluten free diet.
However, always refer to the allergen statement to be sure a product is gluten-free. If you are not sure if a product is gluten-free, it is best not to consume it.
Managing cross-contamination at home
When someone with coeliac disease is living with others who don’t avoid gluten, measures should be taken to avoid cross contamination.
You should always avoid using the same utensils that have been used to prepare gluten containing products unless you can be totally sure that all residue is cleaned from them
A common utensil that is difficult to clean is a toaster. Having two separate toasters is a good idea to avoid cross contamination. Everyone in the household should be aware of the gluten-free toaster and ensure that no gluten products are cooked in there.
Any spread that you commonly dip your utensils into such as margarine or peanut butter are also common grounds for cross-contamination. The easiest thing to do in this case is for the person with coeliac disease to have their own which is clearly labeled.
You will also need to store gluten free foods in separate containers that are clearly marked.
It is best practice for the household to make easy switches to gluten free products where possible. Common pantry foods with gluten free alternatives that everyone can enjoy include soy sauce and stock powders.
Eating out with coeliac disease
Eating out with coeliac disease can be difficult, particularly in avoiding cross-contamination.
Aim to only eat at places that can guarantee that there is no cross contamination. It is not enough to simply order a gluten free meal.
This can be particularly hard for chain restaurants such as dominos. Smaller establishments will typically have coeliac protocols in place.
When ordering a gluten-free meal, also mention that you are coeliac and require no cross-contamination. With the rise of people choosing to eat gluten-free but do not have coeliac disease, not all gluten-free meals will automatically be coeliac friendly. Always ask.
Also, be aware that many places will use the chip fryer for other products containing gluten such as things that have been crumbed or battered.
Take home points
- Much of the confusion around coeliac disease and other gluten/wheat-related conditions, is in part from a failure to distinguish clearly between the gluten and fructan components of wheat.
- Not every one that reacts poorly to wheat products in coeliac
- Coeliac requires a diagnosis via an initial blood test followed by a biopsy
- It is imperative that one’s diet contains gluten prior to testing for coeliac disease
- People with coeliac disease should avoid both gluten-containing products and foods that are at risk of being cross-contaminated
- Due to strict allergen labelling laws in Australia, it is fairly simple to identify gluten-containing foods even when the gluten-containing ingredient is not an obvious one
- Measures should be taken to avoid cross-contamination in the home as well as when eating out
- How to do the gluten challenge prior to testing
- Australian gluten-free shopping list
- List of gluten-free and gluten-containing foods
- Unsure if you should be eating oats?
- Healthy gluten-free recipes
- More tips on eating out with coeliac disease
Leah is an accredited practising dietitian from Brisbane. She also competes as an under 75kg powerlifter with Valhalla Strength Brisbane. As both an athlete and dietitian, she spends much of her time developing her knowledge and skills around sports nutrition, specifically for strength-based sports. Although, she works with a range of athletes from triathletes to combat sports and powerlifting.
Leah also follows a plant-based diet and her greatest passion is fuelling vegan/vegetarian athletes and proving that plant-based athletes can be just as competitive as their non-vegan counterparts.