We’ve heard the old cliché ‘gut feelings’ before, and there’s growing evidence that gut bacteria really might influence our minds.
“I’m always by profession a skeptic,” says Dr. Emeran Mayer, a professor of medicine and psychiatry at the University of California, Los Angeles, in an interview with NPR.
“But I do believe that our gut microbes affect what goes on in our brains. It opens up a completely new way of looking at brain function and health and disease.”
It’s believed the bacteria in our digestive systems helps mold brain structure as we age, as well as affecting our moods, behavior and feelings when we’re adults.
Mayer has been examining thousands of MRI scans of volunteered noggins, and is comparing their brain structure to the types of bacteria in their guts. He’s found some connections between brain regions differed depending on which species of bacteria dominated a person’s gut, strongly supporting his hypothesis. This suggests a specific mix of microbes in the gut will determine the types of brains we have.
Learn about microbes in the short video below:
Other researchers are examining the same phenomena, using mice rather than humans as their test subjects. One experiment involved replacing the gut bacteria of anxious mice with bacteria from fearless mice.
“The mice became less anxious, more gregarious,” said Stephen Collins of McMaster University in Hamilton, Ontario, who led a team that conducted the research.
They tried the reverse, and the outcome was expected: the bold mice became timid when they received gut microbes from the anxious ones.
Scientists have also been working on the most obvious question raised in all this research – how the gut microbes could talk to the brain. They’re not entirely sure, but they suspect the vagus nerve, which runs all the way from the brain to the abdomen, is the key link. In fact, when the vagus nerve was cut in the mice study, they no longer saw the brain respond to changes in the gut.
This research opens the doors wide open for developing drugs that mimic the signals being sent from the gut to the brain, preventing or treating problems involving the brain. Giving people ‘good bacteria’ or probiotics in their guts is already being experimented with.
One of their patients, who asked to remain anonymous, suffers from bipolar disorder and notices the effects of this preliminary study.
“It makes perfect sense to me,” said Leah. “Your brain is just another organ. It’s definitely affected by what goes on in the rest of your body.
“I’m doing really well. I’m about to graduate college, and I’m doing everything right.”
Mayer has also started fiddling with probiotics, in one experiment giving healthy women yogurt containing a probiotic and then scanned their brains, followed by an MRI. He found subtle signs that the brain circuits involved in anxiety were less reactive.
Despite the encouraging results, Mayer warns that there’s a lot more work to be done on probiotic research, and if they really can solve problems in the brain.
“We’re in the really early stages,” he said.