An observational study published in Nature Microbiology found that people with high levels of the beneficial Faecalibacterium bacteria were more likely to also have low levels of potentially fatal bacteria, such as E.coli. The researchers analyzed gut microbiome samples from more than 12,000 people in 45 countries.

The samples with high levels of Faecalibacterium also had high levels of beneficial short-chain fatty acids, a byproduct from the breakdown of fiber. These findings suggest that eating high-fiber foods such as vegetables, beans and grains might help protect against harmful bacteria. Additional research is needed to test whether fiber prevents the incidence of infections over a longer time span.