The gut health benefits of sauerkraut

Authors Maria Marco, professor with the Department of Food Science and Technology, and Lei Wei, a postdoctoral researcher in Marco's lab, looked at what happens during fermentation -- specifically, how the metabolites in sauerkraut compared to those in raw cabbage.

Researchers tested whether sauerkraut's nutrients could help protect intestinal cells from inflammation-related damage. The study compared raw cabbage, sauerkraut and the liquid brine left behind from the fermentation process. The sauerkraut samples included both store-bought products and fermented cabbage made in the lab.

They found that sauerkraut helped maintain the integrity of intestinal cells, while raw cabbage and brine did not. Marco said that there was also no noticeable difference between grocery store sauerkraut and the lab-made version.

"Some of the metabolites we find in the sauerkraut are the same kind of metabolites we're finding to be made by the gut microbiome, so that gives us a little more confidence that this connection we found between the metabolites in sauerkraut and good gut health makes sense," Marco said. "It doesn't matter, in a way, if we make sauerkraut at home or we buy it from the store; both kinds of sauerkraut seemed to protect gut function."

Digestive benefits

Chemical analysis shows that fermentation changes cabbage's nutritional profile, increasing beneficial metabolites such as lactic acid, amino acids and plant-based chemicals linked to gut health. These changes may explain why fermented foods are often associated with digestive benefits.

Marco said she and Wei identified hundreds of different metabolites produced during fermentation and are now working to determine which ones play the biggest role in supporting long-term gut health.

"Along with eating more fiber and fresh fruits and vegetables, even if we have just a regular serving of sauerkraut, maybe putting these things more into our diet, we'll find that can help us in the long run against inflammation, for example, and make our digestive tract more resilient when we have a disturbance," Marco said.

Fermented vegetables and foods are already a staple in many diets, but this research suggests they could be more than just a flavorful side dish. Marco said the next step is to conduct human trials to see if the gut-protective metabolites found in sauerkraut can have the same positive effects when included in everyday diets, as was shown in the lab.

"A little bit of sauerkraut could go a long way," she said. "We should be thinking about including these fermented foods in our regular diets and not just as a side on our hot dogs."

This research was funded by a grant from the California Department of Food and Agriculture, as well as a Jastro Shields Graduate Research Award from the UC Davis College of Agricultural and Environmental Sciences.