Magnetic resonance imaging findings indicated that patients with celiac disease may exhibit delayed small bowel motility and significant alterations in gut microbiome composition compared with healthy individuals, according to a recent observational cohort study.

In the study, published in Clinical Gastroenterology and Hepatology, researchers aimed to evaluate the impact of celiac disease (CD) and a 1-year gluten-free diet (GFD) on gut function and microbiome composition. They included 36 patients with newly diagnosed CD and 36 age- and sex-matched healthy volunteers (HV). The participants underwent magnetic resonance imaging (MRI)-based assessments of small bowel water content (SBWC), whole gut transit time (WGTT), and colonic volumes at baseline and after 12 months. Stool samples were analyzed using shotgun metagenomic sequencing to evaluate microbiome composition and gene functions.

At baseline, the patients with CD had significantly higher SBWC (157 ± 15 mL) compared with HVs (100 ± 12 mL) (P = .003), and their WGTT was prolonged (68 ± 8 hours vs 41 ± 5 hours, P = .002). While these values showed a numerical decrease following a GFD, the differences did not reach statistical significance, indicating that the improvements may not be clinically meaningful. Microbial analysis showed that patients with CD had a higher abundance of proteolytic gene functions associated with Escherichia coli, Enterobacter, and Peptostreptococcus. After 12 months on a GFD, the patients demonstrated a reduction in Bifidobacteria, which may reflect changes in dietary fiber intake rather than an inherently pathologic shift, and an increase in Blautia wexlerae. Notably, microbiome composition correlated positively with WGTT and colonic volume but inversely with B wexlerae abundance. Significant alterations were observed in carbohydrate-active enzymes (CAZymes), particularly starch- and arabinoxylan-degrading families.

The patients reported significant improvements in well-being following a GFD, though scores did not fully return to HV levels. Depression and anxiety levels, measured by the Hospital Anxiety and Depression Scale, were elevated at baseline but improved after 12 months. However, 30% of patients with CD continued to experience persistent gastrointestinal symptoms in spite of strict adherence to a GFD. These persistent symptoms were associated with higher SBWC, increased colonic volume, and elevated levels of branched-chain fatty acids.

The researchers concluded that although a GFD ameliorated gut dysfunction and altered microbiota composition, it did not fully normalize gut function in patients with CD. The observed reductions in Bifidobacteria and starch-degrading CAZymes suggested that microbiome disruptions may persist despite dietary interventions, warranting further investigation.

Full disclosures can be found in the published study.