A lot, actually! Just recently scientists at the University of California discovered a difference in brain structure between people with irritable bowel syndrome (IBS) and those who showed no IBS symptoms.

What they found was that those with IBS actually had less gray matter in the areas of the brain that controlled things like thinking, reasoning and evaluating. Pretty interesting stuff, I thought, and it just goes to prove that the gut and the brain are more connected than we might think.

Experts call this relationship between our digestive system and the brain our gut-brain connection, and it’s been linked to everything from migraine headaches to autism. It’s not surprising though, when you consider that more than 70 percent of your body’s natural defenses are found in your gut. To put this in perspective, it helps to remember that there are only about 10 trillion cells in your entire body, but roughly 100 trillion bacteria cells in your gut. Talk about running the show!

Results of the UCLA study are also helping scientists to better understand IBS, a debilitating disorder with symptoms that include abdominal pain and cramping, along with severe diarrhea or constipation. At one time doctors thought IBS was a psychological disorder, but thanks to studies like this one they’re starting to change their tune—and it’s about time. I see and talk to people every day with IBS, and let me tell you, it’s real!