Recent research shows that low levels of gut bacterial diversity are linked to a surprising range of health problems, including rheumatoid arthritis.

The bacteria in your gut do more than break down your food. They also can predict susceptibility to rheumatoid arthritis, suggests Veena Taneja, PhD, an immunologist at the Mayo Clinic. Taneja recently published two studies - one in Genome Medicine and one in Arthritis and Rheumatology - connecting the dots between gut microbiota and rheumatoid arthritis.

Scientists have a limited understanding of the processes that trigger rheumatoid arthritis. Taneja and her team identified intestinal bacteria as a possible cause; their studies indicate that testing for specific microbiota in the gut can help predict and prevent the onset of rheumatoid arthritis. “These are exciting discoveries that we may be able to use to personalise treatment for patients,” Taneja says.

Based on mouse studies, researchers found an association between the gut microbe Collinsella and the arthritis phenotype. The presence of these bacteria may lead to new ways to diagnose patients and to reduce the imbalance that causes rheumatoid arthritis before or in its early stages. The second paper explored another facet of gut bacteria. Taneja treated one group of arthritis-susceptible mice with a bacterium, Prevotella histicola, and compared that to a group that had no treatment. This study found that mice treated with the bacterium had decreased symptom frequency and severity, and fewer inflammatory conditions associated with rheumatoid arthritis. The treatment also produced fewer side effects, such as weight gain and villous atrophy - a condition that prevents the gut from absorbing nutrients - that may be linked with other, more traditional treatments.