New science proves that saying you’ve got a “gut feeling” is actually pretty accurate—especially if you’re a man.

A new study from the University College Cork found that levels of the mood-regulating hormone serotonin in the adult brain are determined early in life by special microbes in the gut. 

Using mice, researchers proved the connection between the bacteria and brain function, building on earlier work that draws a distinct connection between microbial in the gut and brain function that controls behavior.

Males exhibit more marked effects, but the scientists found that the absence of a certain gut flora permanently changes the brain functions via the neurochemical, which effects emotions. Scientists are hopeful that they can now target the stomach bacteria while designing new mental health drugs.

Evidence that our mental well-being depends on the stasis of our stomach—did we need a study for that? Haven’t these researchers ever eaten a hamburger?

Video by Krishnan Vasuvedan.