Interestingly, there are actually specific types of gut bacteria that correlate with the development of rheumatoid arthritis. According to the National Institutes of Health (NIH),8 a gut bacterium called Prevotella copri appears to play a role in the disease. Besides outcompeting several microbes known for their beneficial health effects, DNA sequencing of Prevotella has revealed that it contains genes that specifically correlate with RA.
After analyzing DNA in stool samples from both healthy people and rheumatoid sufferers, researchers discovered the bacterium was present in the intestinal microbiome of 75 percent of those with new-onset, untreated rheumatoid arthritis, compared to only 21 percent of healthy controls. This isn't the first time a microorganism has been linked to the development of RA though.