It also found “distinct differences” in the composition of Canterbury children’s gut bacteria and found subtle but consistent changes in specific bacteria in the small intestine and stool samples of people with coeliac disease.
Riddet Institute PhD candidate Peter Prendergast.
Prendergast said the research had revealed a gut microbiome associated with coeliac disease and further identified the differences in intestinal bacteria among healthy people, those at high risk of developing the disease and those with coeliac disease.
Prendergast said, until now, there had been only “fragmented evidence” showing the changes.
“We had some bacteria that we found changed across multiple cohorts that were hypothesised to be most likely involved, and then we had ones that weren’t consistently changed as well,” he said.
“Canterbury children had quite a unique typology to the microbiome,” Prendergast said.
“Identifying the changes we see in the [high-risk] children holds promise that maybe one day we could find a pathway that could stop people developing the disease, or reduce its severity.”
The research found that fibre-loving butyrate-producing bacteria and protective metabolites were more common in healthy people, while potentially problematic bacteria were less common.
One possible reason some people develop coeliac disease while others remain healthy could be linked to how fibre is metabolised in the gut, he said.
“Some people didn’t actually have celiac disease yet,” Prendergast said.
“They might have a relative or something like that, which makes them high risk.
“And then [researchers] follow them, they sample them before they were actually diagnosed, and then they follow them for up to two years or even longer in some of these studies.”
In people with coeliac disease, some potentially pathogenic species of bacteria were increased, while protective species were reduced.
The changes in bacteria were less pronounced in people who later developed coeliac disease symptoms but did not have active disease when they were tested.
“It gives us evidence that changes are happening in the gut before disease is occurring,” Prendergast said.
The changes also persisted in people following a gluten-free diet, which may further reduce beneficial bacteria because of the diet’s lower fibre content.
In Canterbury, more than one in 82 people has coeliac disease.
Prendergast said the large gap between genetic predisposition and the number of people who actually develop coeliac disease suggested environmental and dietary factors could play a role in when the disease develops.
“There is a huge non-genetic element to it, so that’s why we are starting to look at diet,” he said.
Researchers believe a better understanding of the complex ecosystem of the gut could be key to finding ways to prevent or treat the disease.
Future treatments may need to focus on restoring healthy gut bacteria, Prendergast said.
One promising approach could involve reintroducing beneficial bacteria that can help digest gluten in the gut.
Another could be increasing fibre intake before the disease develops, potentially disrupting the pathway that leads to coeliac disease.
“We know from lots of microbiome studies that you can change your microbiome,” Prendergast said.
He said the gut microbiome was sensitive to inflammation, but researchers were still unsure which factors had the greatest influence, including antibiotic medicines, infections, diet or a combination of factors.
“There are a large number of people on a gluten-free diet who are not recovering quickly.”
The next step would be to carry out fibre metabolite research on people with active coeliac disease in Canterbury, where Prendergast is based, to determine whether the changes in the gut lead to disease.
Both studies were funded by the Health Research Council of New Zealand, with the funders having no role in the study design, data collection or analysis.