Does the intestinal microbiota hold clues about celiac disease?

Although much has been learned about celiac disease, questions still remain. One top question is whether alterations in the intestinal microbiota of a child with celiac disease are the cause of the disease or if it’s the result of the disease as well as treating the disease with a gluten-free diet. A report in Gastroenterology examines the issue.¹

The researchers collected 167 fecal samples from 141 children in Glasgow, Scotland. Among the 141 children, 20 had new-onset celiac disease; 45 had been treated with a gluten-free diet; 57 healthy children; and 19 unaffected siblings of children who had celiac disease. Each sample was analyzed with 16S ribosomal RNA sequencing and the diet metabolites were measured with gas chromatography. Additionally, researchers got fecal samples from 13 children with new-onset celiac disease after 6 and 12 months of following a gluten-free diet.

They found that no difference in microbiota α diversity among the studied groups. No microbial dysbiosis was found in the children who had new-onset celiac disease. However, 2.8% (Bray-Curtis dissimilarity index, P = .025) and 2.5% (UniFrac distances, P = .027) of the microbiota composition variation could be explained by following a gluten-free diet. Additionally, between 3% and 5% of all taxa in the microbiota was found to differ in the group comparisons. There were 11 distinctive taxonomic units that made a microbe signature specific to celiac disease. A high number of the operational taxonomic units that were different between patients on a gluten-free diet with new-onset celiac disease versus healthy children were linked to nutrient and food group intake (from 75% to 94%) as well as with the biomarkers of gluten ingestion. The researchers also found that the fecal levels of ammonia and butyrate went down during a gluten-free diet.

The investigators concluded that many alterations in the intestinal microbiota seem to occur because of a child following a gluten-free diet, but there were specific bacteria that seem to be distinct biomarkers for celiac disease. They said further study would be needed to find out whether those specific bacteria are involved in the pathogenesis of celiac disease.

Reference

1. Zafeiropoulou K, Nichols B, Mackinder M. Alterations in Intestinal Microbiota of Children With Celiac Disease at the Time of Diagnosis and on a Gluten-free Diet. Gastroenterology. November 11, 2020. Epub ahead of print. doi:10.1053/j.gastro.2020.08.007