People who switched in a new study to a diet rich in fermented foods like kimchi or yogurt had more diverse gut microbiome than people who began eating more fiber, the New York Times reports. It adds that a diet with high levels of fermented food was also associated with reduced inflammatory markers.
Researchers from Stanford University followed three dozen people who were randomly assigned to one of the two dietary interventions and underwent omics and immune-related analyses. As they recently reported in the journal Cell, the researchers found a high-fiber diet led to increased microbiome function but also to high levels of carbohydrates in the stool, suggesting that participants' gut microbes were unable to fully break down the high-fiber foods. Meanwhile, a high-fermented food diet led to increased microbiome diversity and decreased inflammatory signals. A diverse microbiome has been linked, the Times notes, to lower levels of type 2 diabetes, metabolic disease, and other conditions.
Stanford's Justin Sonnenburg tells the Times that where some of the new microbes came from is unclear as only a portion came from the fermented foods themselves. "I think there were either low level microbes below the level of detection that bloomed, or the fermented foods did something that allowed for the rapid recruitment of other microbes into the gut environment," he adds.