Impact of Fermented Food and Fiber Diets on Microbiome

A recent study by researchers from the Stanford School of Medicine showed that a diet high in fermented foods increased the diversity of gut microbes and decreased the signs of inflammation, while a diet high in plant-based fiber increased microbiome function but did not change microbiome diversity.

Diet modulates the microbiome, which in turn impacts the immune system and overall health. Low diversity of the microbiome has been associated with obesity and diabetes. This study compared the effects of two different diets over a 10-week period on the microbiome and the immune system. One group implemented a diet rich in fermented foods such as yogurt, kefir, kimchi and other fermented vegetables, and kombucha tea. The other group was placed on a diet rich in vegetable fiber found in legumes, seeds, whole grains, nuts, vegetables, and fruits.

Researchers found that the fermented-food diet increased the diversity of the microbiome and decreased inflammatory markers. Fermented foods can help with weight control and reduce the risk of diabetes, cancer, and heart disease.

The study showed that while the high-fiber diet neither changed the diversity of the microbiome nor decreased inflammatory markers, it did indicate an increase in microbiome function. The high-fiber participants had more carbohydrates in their stool samples, supporting other research that indicates there may be a decrease of fiber-degrading microbes in the gut of people living in the industrialized world. Nevertheless, high-fiber diets continue to be associated with lower rates of mortality.