Irritable Bowel Syndrome (IBS) is a widespread digestive condition that affects the gastrointestinal tract. It occurs more frequently in women and commonly causes symptoms such as abdominal pain, constipation, or diarrhea. The exact cause of IBS remains uncertain. However, scientists believe that conditions inside the intestine, including the gut microbiota and the chemical messenger serotonin, play an important role.

Serotonin is widely recognized as a neurotransmitter in the brain that influences mood. Yet more than 90 percent of the body's serotonin is actually produced in the gut. There it regulates bowel activity through the enteric nervous system, often referred to as the "gut-brain."

Earlier studies have shown that bacteria living in the gut, known collectively as the gut microbiota, can influence how much serotonin the body produces.…