Hi everyone, I’m Dr Nick, your friendly neighbourhood Paediatric Gastroenterologist. Well, I suppose I’m not really in the neighbourhood as I live in Canada, but I’m from the neighbourhood so I think that counts.
Dr Megs and I did a lot of our training together at the Royal Children’s Hospital in Brisbane, so she has asked me to help out and contribute to this amazing resource of kids’ health issues!
I will be popping up from time to time to chat about some common (and sometimes less common and more serious) medical issues that can involve the gastrointestinal tract, liver and pancreas of children. If there are specific topics that you want to hear about, please make sure to suggest them in the comments.
Ok, here we go!
Increasingly it has become clear that what we eat has an enormous impact on our health, not only in regards to improving our overall cardiovascular health but also in establishing and maintaining our intestinal cells and gut microbiome (the balance of our intestinal bugs). Trying to decide on the best diet to maintain our health is challenging, and is especially difficult for parents who are trying to do their best for their children. Never before has it been harder to stand in the grocery store aisle and choose school snacks and lunches!
Specific components in our diet have been implicated as contributing to a number of diseases and states of ill health, with one of the most commonly identified culprits being gluten.
But what IS gluten exactly?
Gluten is a mixture of proteins found in cereal grains (predominantly wheat, barley and rye). In food, gluten gives elasticity to dough, helping it rise, giving shape and a chewy texture. Gluten is a staple part of the modern diet because of its high nutritional value, as well as the fact that bread, pizza and pasta are pretty delicious. Consumption of gluten started between 9000 and 4000 BC, when humans settled into a grain heavy diet following the development of agriculture. Since, evolution in breeding of wheat has led to concern around exposure to these plant proteins leading to gluten-related disorders.
Today we will briefly discuss the two most commonly recognized gluten-related disorders–
- Coeliac disease
- Non-coeliac gluten sensitivity (NCGS)
Wheat allergy is another less common but extremely important wheat/gluten related issue. Food allergy is a huge topic, and warrants one (or 100) posts on its own, so we will tackle it next time (stay tuned!)
The clinical presentation of a patient with coeliac disease has been understood since 1888, but only in the 1950s was it recognized that the cereal grains (wheat, barley and rye) were responsible for the intestinal inflammation that occurs in coeliac disease. Initially it was felt that starch was the causing the problem, but over time it was recognized that it was in fact damage caused by gluten proteins that characterized the disease. At the moment, coeliac disease affects 1-2% of the population of western countries.
In people with coeliac disease, eating gluten makes the immune system produce antibodies and inflammatory proteins that damage the intestine. This causes flattening of the villi (the finger-like projections of the lining of the intestine that help absorb nutrients) and alters how ‘leaky’ the intestinal lining is. Over time this damage (if untreated) can lead to a number of significant health issues, so it is very important to accurately recognize and treat coeliac disease appropriately.
There are certain genes that make coeliac disease more likely in individuals, and there is an increased risk if the person has another immune mediated disease (eg – type 1 diabetes, autoimmune thyroid disease, IgA deficiency, juvenile arthritis), or with some syndromes (Down syndrome, Turner syndrome, Williams syndrome). It also runs in families, where people with a first degree relative (someone in their immediate family) with coeliac disease have a 1 in 10 risk of developing coeliac disease.
Coeliac disease can present in a number of different ways. The ‘traditional’ symptoms reflect malabsorption (eg – diarrhoea, poor growth, iron deficiency anaemia), but certainly we know that symptoms of coeliac disease can be much more subtle and difficult to identify.
I would usually suggest testing for coeliac disease with any of the following –
- persistent, unexplained abdominal or gastrointestinal symptoms
- faltering growth/pubertal delay
- prolonged fatigue
- unexpected weight loss
- severe or persistent mouth ulcers/severe dental enamel defects
- unexplained iron, vitamin B12 or folate deficiency
- unexplained fracture(s)
- arthritis or arthralgias
- irritable bowel syndrome
- abnormal liver function tests
If your child is suffering from any of these it is certainly worth discussing the possibility of testing for coeliac disease with your GP or paediatrician. This list describes many, but not all of the clinical symptoms and signs that could represent coeliac disease. Your doctor may suggest coeliac testing in other circumstances. If your child belongs to one of the groups with an increased risk of coeliac disease but has no symptoms, be sure to discuss the role of screening with your doctor.
How do you test for coeliac disease?
Testing initially involves a blood test measuring one or more antibodies, representing immune cell activation. If these tests are positive, your child should be referred to a paediatric gastroenterologist (like me) to discuss the next steps, which in the majority of cases requires an endoscopy (camera through the mouth into the intestine) and biopsies (taking a little sample of tissue) to confirm the diagnosis, and demonstrate the intestinal damage under the microscope. This is the cornerstone of coeliac disease, that it is in fact the immune system responding to the gluten proteins and causing damage.
There are very specific circumstances where a diagnosis of coeliac disease can be made without an endoscopy, but this should always be discussed with your paediatric gastroenterologist. This is important for a number of reasons, as untreated coeliac disease can lead to serious long term health consequences. Unfortunately, if your child is already on a gluten free diet prior to blood testing it makes results difficult to interpret, so be sure to discuss the options in this setting with your doctor.
The National Institute of Health (NIH) in the US has developed an acronym detailing the six key elements to managing kids with coeliac disease:
Consultation with a skilled, registered dietitian (THE MOST IMPORTANT!!)
Education about the disease
Lifelong adherence to a gluten-free diet
Identification and treatment of nutritional deficiencies
Access to an advocacy group
Continuous long-term follow-up by a multidisciplinary team
At the moment, lifelong gluten-free diet (GFD) remains the only therapy for coeliac disease, which in the majority of patients leads to healing of the intestine, long term good health, and a completely normal life. Research is ongoing to try and identify other potential therapies to make managing this condition easier on kids and families.
Non-coeliac gluten sensitivity (NCGS)
Recently there has been a dramatic shift in the availability and consumption of gluten free products in the absence of coeliac disease or wheat allergy, with a recent Australian study of more than 1000 people demonstrating that 10% avoided gluten based products despite only 1% of the group having coeliac disease. One in five of these avoided gluten for healthy lifestyle beliefs, with the rest stating that gluten based products triggered symptoms, including intestinal and extra-intestinal symptoms (eg – fatigue, headache, depression).
In 1978, the term non-coeliac gluten sensitivity (NCGS) was described in a case report where a patient had resolution of persistent gut symptoms with the adoption of a gluten free diet without having coeliac disease. Currently, NCGS has been defined as a condition caused by the ingestion of gluten leading to intestinal and/or extra-intestinal symptoms that resolve once the gluten containing foodstuff is eliminated from the diet – but only when coeliac disease and wheat allergy have been ruled out. Pretty specific. But also… not.
It is an uncertain diagnosis, as it remains highly controversial whether the symptoms of NCGS are in fact due to gluten, or rather one or more of the other complex nutrients present in wheat. Recent data suggests that the fructans (see below for what these are) present in wheat are commonly responsible for symptoms, with only 5-14% of people with NCGS demonstrating symptoms when challenged with gluten.
Fructans are non-digestible and fermentable carbohydrates, made primarily of fructose (the kind of sugar commonly found in fruit and honey). Concentration is highest in rye (3.6%-6.6%), wheat (0.7-2.9%) and least in barley where there are only trace amounts. They are also found in many other common staple foods including onion, garlic and artichokes.
Fructans and other fermentable carbohydrates (fermentable oligo, di, mono-saccharides and polyols – FODMAPS) can trigger symptoms in people who are sensitive to distention of the gut as they attract water into the bowel, and through bacterial fermentation (a process of chemical breakdown of the simple/complex sugar by bacteria that causes gas – kind of like the process of producing beer or wine), resulting in excessive gas production. As such, the immune system is not involved in the development of symptoms. Other non-gluten proteins have also been shown to play a role, especially the natural proteins that protect the plants from pests and parasites (shown in experimental studies to promote inflammation), making it even more difficult to tease out exactly what the issue is.
At the moment there is no good ‘test’ to establish a diagnosis of NCGS, with blood or stool testing being extremely unreliable, and endoscopy and colonoscopy (camera up the bottom into the colon) usually demonstrating normal intestinal lining. This is frustrating for patients and families, and for physicians! To improve the management of patients with NCGS, we need to identify the elements of wheat that are in fact causing symptoms, which will hopefully stimulate the food industry to develop adapted foods, potentially eliminating the need to be always be gluten free in NCGS. Importantly, for people with NCGS the adoption of a gluten free diet can be helpful in improving sometimes debilitating symptoms, but it is not a requirement to maintain intestinal health. Some people with NCGS can tolerate occasional or small amounts of gluten.
This is different to coeliac disease, where it is important to maintain a completely gluten free diet to ensure good long term health and avoid potentially serious consequences.
While choosing to undertake a gluten free diet as a lifestyle choice is a personal decision, it is important to remember that many people who are gluten free ALSO have a reduction in beneficial fibres and whole grains. This has been shown to affect cardiovascular risk, so if you and your child are considering a gluten free diet in the absence of coeliac disease or wheat allergy, be sure to discuss it with your registered dietitian and doctor.
Ok that’s it! This has been a very brief overview of these two conditions, and there is lots more to talk about, but hopefully it’s been a good insight into the differences between coeliac disease and NCGS. Next time we will look at the even murkier world of food allergy… until then!