Changing gut bacteria through diet affects brain function, UCLA study shows
By Rachel Champeau
UCLA researchers now have the first evidence that bacteria ingested in food can affect brain function in humans. In an early proof-of-concept study of healthy women, they found that women who regularly consumed beneficial bacteria known as probiotics through yogurt showed altered brain function, both while in a resting state and in response to an emotion-recognition task.
The study, conducted by scientists with the Gail and Gerald Oppenheimer Family Center for Neurobiology of Stress, part of the UCLA Division of Digestive Diseases, and the Ahmanson–Lovelace Brain Mapping Center at UCLA, appears in the current online edition of the peer-reviewed journal Gastroenterology.
The discovery that changing the bacterial environment, or microbiota, in the gut can affect the brain carries significant implications for future research that could point the way toward dietary or drug interventions to improve brain function, the researchers said.
“Many of us have a container of yogurt in our refrigerator that we may eat for enjoyment, for calcium or because we think it might help our health in other ways,” said Dr. Kirsten Tillisch, an associate professor of medicine in the digestive diseases division at UCLA’s David Geffen School of Medicine and lead author of the study. “Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment. When we consider the implications of this work, the old sayings ‘you are what you eat’ and ‘gut feelings’ take on new meaning.”
Researchers have known that the brain sends signals to the gut, which is why stress and other emotions can contribute to gastrointestinal symptoms. This study shows what has been suspected but until now had been proved only in animal studies: that signals travel the opposite way as well.
“Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut,” Tillisch said. “Our study shows that the gut–brain connection is a two-way street.”