Coeliac Disease, Non-Coeliac Gluten/Wheat Sensitivity, Irritable Bowel Syndrome What is it all about?
Marianne Williams, Specialist Gastroenterology Community Dietitian
As a Specialist Gastroenterology Community Dietitian who regularly sees patients in clinic with irritable bowel syndrome (IBS), I predominantly use the Low FODMAP Diet which improves symptoms in many patients. However, I am increasingly seeing a number of patients with what appears to be 'non-coeliac gluten sensitivity'. Hence, I was particularly interested in this webinar, hosted by the Dr Schär institute, in which Professor David Sanders, a leading researcher in the gluten-related disorders field, discussed the latest research findings in this clinical area. The following article is a summary of the points from his fascinating presentation.
Globally, gluten-free diets are on the increase, but why? Over the last 10 years they have been rising in popularity with many companies providing gluten-free products and improving patient choice. But is this health or hype? There is potential overlap between these clinical conditions as all three can have almost identical gastrointestinal symptoms. However, with coeliac disease we have the opportunity to obtain a cast iron diagnosis through blood tests and duodenal biopsy and it is vital to rule this out before moving on to suspect either IBS or non coeliac gluten/wheat sensitivity (NCGS).
However, in coeliac disease there are many ‘grey cases’ where a diagnosis may be unclear – see Figure 1. At what point is it not coeliac disease? In patients with the potential to develop coeliac disease the intraepithelial lymphocyte (IEL) is the initial ‘attack cell’. In those with positive HLA DQ genetic typing and a possible positive EMA blood result, the IELs enter the small bowel and initiate the inflammatory response. Dr Mike Marsh, who established the March criteria, noted that IELs could be raised in the bowel of relatives of coeliac patients and he referred to this cohort as ‘Potential Coeliac Patients’. Could this be modern day ‘gluten sensitivity’?
Coeliac disease
Figure 1: The Reality of the Coeliac Iceberg 2015
Introduction
It affects 1% of the population and, historically, it was seen in children with classic malabsorption symptoms, but now there are far more adult cases than paediatric cases and we are still only recognising about 20% of cases in the UK. They could have a normal BMI, or even be overweight, and it is important that we change the way we look at coeliac disease. The prevalence of coeliac disease appears to be changing with a Finnish study showing a population increase of 1% to 2% over the last 20 years. Their data also showed that Type 1 diabetes was following a similar trajectory.1 Are all autoimmune diseases on the increase? Is it a sign of a bored Western World immune system? At the same time, in developing countries that are adopting western-style diets, coeliac disease is also rising – e.g. China.2
HLA status DQ2: DQ8 (>95% coeliac disease; 25% general population)
In a Finnish study looking at patients with mild enteropathy, i.e. Marsh 1, with positive EMA and no villous atrophy, it showed that those who continued to eat a gluten containing diet exhibited a deteriorating histology, while those who used a gluten-free diet showed an improved histology similar to clinically diagnosed coeliac patients. Those eating the gluten containing diet then swapped on to a gluten-free diet and their histology also improved.3 The important message from this study is that those who have a positive EMA, normal biopsy with low marsh level are in the ‘waiting room’ for coeliac disease. In Professor David Sanders clinical experience they will re-present if they decide not to follow the gluten-free diet.
Diagnosed
Classical coeliac disease (0.2%) Villous Atrophy Sub-Clinical coeliac disease (0.8%)
Potential coeliac disease
Healthy individuals
Equivocal
Normal Mucosa
CN Vol.16 No.1 Feb/Mar 2016 | 25