Research out today finds that a substantial portion of people have a sensitivity to gluten or wheat but don’t have celiac disease.

Scientists in the UK and elsewhere reviewed dozens of studies conducted across the globe. They estimate that about one in every ten people worldwide report having a condition called non-celiac gluten/wheat sensitivity, or NCGWS. They also found that people with NCGWS are more likely to have other health issues, including anxiety and irritable bowel syndrome.

The findings highlight that “NCGWS is both common and linked to a significant emotional and psychological burden,” lead author Mohamed Shiha, a gastroenterologist at the University Hospitals of Leicester NHS Trust, told Gizmodo.

A systematic look

Various studies in recent years have tried to assess the toll of NCGWS. But according to Shiha, theirs is the first to systematically pool together and evaluate this data to provide reliable figures on the worldwide prevalence of the condition.

They ultimately analyzed 25 studies conducted between 2014 and 2024 across 16 countries, collectively involving nearly 50,000 adults. Overall, they found that the global rate of self-reported NCGWS was 10.3%, though this could vary widely between countries. In the UK, for instance, the rate was 23%, while in Chile, it was 0.3%. About 5% of Americans reported having NCGWS, though this estimate is based on a single study.

The most common symptoms associated with NCGWS were gastrointestinal and included bloating, abdominal pain, and diarrhea. But some people also reported symptoms like fatigue, joint pains, and headaches. Women were more likely to report having NCGWS, and NCGWS was more common in people with depression, anxiety, and IBS. Less than half of people with the condition (40%) reported sticking to a gluten-free diet as a result.

The team’s findings were published Tuesday in the journal Gut.

A broad umbrella

While celiac disease can be screened for with a simple blood test, there is no standard criteria or reliable markers for diagnosing NCGWS. And it seems to be a complex condition with no single, unifying cause, the authors say.

“Our findings suggest that NCGWS is an umbrella term that describes a broad group of individuals with wheat or gluten-related symptoms that often stem from different underlying mechanisms, ranging from gut–brain interaction disorders like IBS to psychological and social factors, rather than a single, uniform biological condition,” Shiha said.

In some cases, it could be akin to a social contagion. Rising public awareness and media attention might influence how “people interpret their symptoms,” he explained. In other cases, NCGWS could be getting mixed up with other conditions.

“Most cases may not be directly related to gluten or wheat themselves but rather overlap with irritable bowel syndrome and other gut–brain interaction disorders such as functional dyspepsia,” Shiha said. “The significant association we found with IBS, anxiety, and depression supports this hypothesis.”

Just last week, a review in the Lancet presented evidence that most people with a professed gluten sensitivity are actually more likely to be sensitive to fermentable carbohydrates (FODMAPs) or to other wheat ingredients. This review also argued some cases could be caused by a nocebo effect, or the mere expectation that eating gluten will cause harm—a finding echoed by a small clinical trial published earlier this July.

Whatever the causes, more should be done to properly diagnose and treat these cases, the authors say. To that end, the team is working on creating clearer, symptom-based criteria for identifying NCGWS. “We also want to explore how to best manage these symptoms without resorting to unnecessary restrictive diets, which can affect quality of life and nutrition,” Shiha said.