Gut Microbiome and Multiple Sclerosis: What a New 2026 Study Found
A new study has found distinct differences in the gut microbiome of people newly diagnosed with multiple sclerosis (MS) compared with healthy individuals.
MS is an inflammatory, neurodegenerative autoimmune disease affecting the central nervous system. The immune cells mistakenly attack the myelin sheath surrounding nerve fibres, damaging nerves and disrupting nerve signaling.
About the study
Italian researchers used shotgun metagenomic sequencing to analyse stool samples from 53 adults with MS, recruited across four centres between 2017 and 2023, and 55 healthy controls. Patients were newly diagnosed, had not yet started disease-modifying therapies, and anyone who had used antibiotics in the previous three months was excluded. Almost half had received a short course of steroids at diagnosis, which the researchers accounted for in their analysis.
Which gut bacteria were linked to MS?
The gut microbiome differed significantly between people with MS and healthy controls:
- Barnesiella sp. An22 and Romboutsia ilealis were more abundant in MS and associated with a higher lesion burden.
- Clostridium innocuum and Ruminococcus sp. JL13D9 were more abundant in MS and associated with spinal cord lesions.
- Bacteroides species (B. ovatus, B. cellulosilyticus) were depleted, which may reflect reduced anti-inflammatory capacity. The MS microbiome also showed a reduced capacity to produce butyrate, an anti-inflammatory short-chain fatty acid.
Could microbiome testing help predict MS progression?
The researchers suggest that gut microbiome profiling at diagnosis may help identify patients at higher risk of faster disease progression and could offer new targets for microbiome-based interventions, though larger studies are needed to confirm this. They concluded that “incorporating microbiome analysis into clinical practice could contribute to more personalised management of MS.”
What this means for autoimmune gut health
In clinic, we often see that targeted microbiome modulation can help shift the gut ecosystem towards a more anti-inflammatory profile.
If you live with an autoimmune condition and want to understand how microbiome testing could inform your overall treatment, book a consultation with me in my Melbourne clinic or online.
References:
Maglione A, et al. (2026) Gut microbiome profiling at multiple sclerosis onset as a potential early prognostic marker of disease course: evidence from an observational cohort study, eBioMedicine,132:106470. doi.org/10.1016/j.ebiom.2026.106470
