Study highlights high prevalence of non-coeliac gluten sensitivity lacking clear markers

Around one in ten people worldwide report gastrointestinal and other symptoms such as fatigue and headache after eating foods containing gluten or wheat despite not having a diagnosis of either coeliac disease or wheat allergy, finds a large systematic review and meta-analysis published online in Gut.

These people have a condition known as non-coeliac gluten/wheat sensitivity (NCGWS), which appears to be more common in women and associated with irritable bowel syndrome, anxiety and depression. 

Symptoms of NCGWS tend to improve when gluten or wheat is avoided and recur when foods containing them are returned to the diet. However, in contrast to coeliac disease and wheat allergy, the disease process underpinning NCGWS is unclear and it has no specific associated blood markers, making diagnosis challenging.

Currently NCGWS is diagnosed by excluding coeliac disease and wheat allergy in individuals who report adverse symptoms after eating gluten or wheat, and little is known about the prevalence and presenting clinical features.

To address this, the authors identified all studies published between 2014 and 2024 evaluating the prevalence of self-reported NCGWS in the general population. Twenty five studies including 49,476 participants from 16 countries met the inclusion criteria and these data were extracted for use in their pooled analysis.

The results of this analysis showed the overall prevalence of self-reported NCGWS was 10.3% but that distinct differences in prevalence were evident between individual countries. Prevalence varied from 0.7% in Chile to 23% in the UK and 36% in Saudi Arabia.

The data also revealed that four in ten people reporting NCGWS followed a gluten-free diet to avoid gastrointestinal and other troublesome symptoms, often doing so in the absence of formal medical advice or a diagnosis.

The most common symptoms reported by participants were bloating (71%), abdominal discomfort (46%), abdominal pain (36%) and fatigue (32%). Other symptoms reported included diarrhoea, constipation, headache and joint pain.

In addition, self-reported NCGWS was significantly more common in women and significantly more likely to occur in people reporting anxiety, depression and irritable bowel syndrome.

The authors acknowledge the study had several limitations including its reliance on self-reporting of NCGWS by participants, that some of the authors had contributed to a subset of studies included in the meta-analysis, and that substantial differences in prevalence between the studies included could not be fully explained by regression analyses. They suggest these differences in prevalence could reflect variability in diagnostic criteria and confounding factors or be true differences in prevalence across populations and countries.

Nevertheless, the authors conclude, "Self-reported non-coeliac gluten/wheat sensitivity affects approximately one in ten people worldwide, with a considerable geographical variation and strong association with female sex, psychological distress and irritable bowel syndrome."

They add that non-coeliac gluten/wheat sensitivity needs to be recognized within the disorders of the gut-brain interaction framework – a neurogastroenterology concept that emphasizes the bidirectional communication between the gut and the brain – and symptom-based diagnostic criteria developed "to guide a more tailored management approach focusing on individual symptom patterns and dietary triggers beyond gluten and to reduce unnecessary dietary restriction in this common condition".