Eating sauerkraut, pickles and yoghurt may be the answer for young adults suffering from social anxiety.
Students who ate more fermented food had fewer social anxiety symptoms, say researchers from the University of Maryland and the William and Mary college in Virginia.
"It is likely that the probiotics in the fermented foods are favourably changing the environment in the gut, and changes in the gut in turn influence social anxiety," says Professor Matthew Hilimire.
"I think that it is absolutely fascinating that the micro-organisms in your gut can influence your mind."
About 700 students were asked about fermented foods consumed over the previous 30 days, their exercise and consumption of fruit and vegetables.