Gut health researchers have been studying the link between digestion and breath odor for decades. What they've consistently found is this: when the balance of bacteria in your gut is disrupted — by stress, poor diet, antibiotics, or irregular eating — certain bacteria multiply and begin producing gases called volatile sulfur compounds (VSCs).

In a healthy gut, those gases are neutralized before they go anywhere. In an imbalanced gut, they're not. They absorb into the bloodstream, travel to the lungs, and come out with every breath.