For years we were told the brain is in charge of everything. It makes the decisions, controls the body, and sets our mood. But new research shows there’s another powerful player running the show — your gut.
Scientists now call it the “second brain” because it has its own network of more than 100 million nerve cells woven through your digestive system. This network communicates with your brain in a constant two-way conversation, influencing how you feel, how you think, and even the choices you make.
The Gut and Brain Connection
Your gut and brain are linked by something called the gut–brain axis. This is a complex communication system made up of nerves, hormones, and chemical messengers. The most important is the vagus nerve, a superhighway of information between your belly and your brain.
Gut bacteria — the trillions of microorganisms living in your intestines — play a major role here. They produce neurotransmitters like serotonin and dopamine, which are often called “feel-good chemicals.” In fact, about 90% of serotonin is made in the gut, not the brain.
When your gut bacteria are balanced and healthy, they send positive signals to the brain that can improve mood, boost focus, and reduce stress. When they are out of balance, those signals can become distorted, contributing to anxiety, brain fog, and low energy.