The gut-brain axis is a bidirectional communication system involving the vagus nerve, microbiome, immune responses, and hormones.

The ENS—the ‘second brain’—controls digestion, but it also produces neurotransmitters like serotonin. In fact, 90% of serotonin is made in the gut. This affects mood, cognition, and even memory.

The National Institute of Health’s Human Microbiome Project has established that gut microbes influence signaling pathways between the gut and brain, playing a crucial role in neurodevelopment and neurodegenerative conditions.