People have linked the brain to the gut for decades because of the digestive problems that accompany stress, but scientists have increasing evidence that gut health has an impact on the brain, too.

Scientists in Ireland, Canada, Los Angeles and Iowa City are finding connections between the gastrointestinal tract, its trillions of microbes, and brain performance and disease.

The area is “a really hot, emerging area” of research, said Robert Hutkins, a scientist in the University of Nebraska-Lincoln’s Gut Function Initiative, a think tank that studies the gut and its microbes. “It’s not opinion,” he said. “It’s based on an accumulation of data — pretty strong data.”

The ultimate question, though, is the degree to which physicians will eventually be able to manipulate the gut with diet, probiotics and medicine to affect mood, behavior, performance, depression and disease, Hutkins said.

David Fuller's view

We are what we eat and drink, and we ignore this at our peril.