If asked to list problems that bad gut bacteria can cause, most would likely name digestive issues: constipation, excessive gas, or diarrhea.

Researchers are now saying bad gut bacteria -- or an insufficient amount of good bacteria -- may have a direct link to multiple sclerosis as well.

"Every human carries trillions of bacteria in their gut (gut microbiome) and recent advances in research indicate that these tiny passengers play an important role in our overall health maintenance," says Ashutosh Mangalam, PhD, assistant professor of pathology at the University of Iowa Carver College of Medicine.

Since the bacteria are associated with contributing to good health, Mangalam and his colleagues wondered whether those with a chronic autoimmune disorder, such as multiple sclerosis, would then have a gut microbiome that is different than the microbiome found in healthy individuals.

In a study published online in the journal Scientific Reports, Mangalam and his team say that MS patients do, in fact, have a distinct microbiome from their healthy peers.

"Although preliminary, our data suggest that patients with MS have reduced levels of good bacteria responsible for overall benefits obtained from consuming healthy foods, such as soybean and flaxseeds," says Mangalam, who is senior author on the study.

Mangalam and his team from Mayo Clinic -- where all of the work was completed before Mangalam joined the UI in 2015 -- conducted microbiome analysis on fecal samples collected from MS patients as well as healthy control subjects.

"We identified certain bacteria which are increased or decreased in the gut of patients with MS compared to healthy controls," he says.

Mangalam says further research is needed to confirm the team's findings in a larger patient population.