When most of us think about intelligence, the brain naturally takes the spotlight. Yet tucked away in your digestive system is another network that scientists often call the “second brain.” This system not only helps with digestion but also plays an important role in emotional regulation, immune function, and overall health.
Lining the walls of the gut is the enteric nervous system, containing around 500 million neurons, more than the spinal cord. Remarkably, this system can function independently, which helps explain why digestive activity persists even when cognitive attention is directed elsewhere.
Communication between the gut and brain occurs primarily via the vagus nerve, a key component of the parasympathetic nervous system. This bidirectional communication is evident in our day-to-day experiences: anxiety prior to significant events often leads to gastrointestinal discomfort, while chronic stress is known to impair digestive efficiency.
Beyond these psychosomatic interactions, the gut also plays a critical biochemical role. Approximately 90% of the body’s serotonin, a neurotransmitter closely linked to emotion is produced in the gastrointestinal tract. Moreover, the gut microbiota, consisting of trillions of microorganisms collectively known as the microbiome, significantly influences metabolism, immune response, and mental health through the production of neuroactive compounds.
Current research suggests that disruptions in the gut microbiome may be associated with anxiety, depression, obesity, and chronic inflammatory diseases. These findings underscore the importance of maintaining digestive health as a foundational component of overall well-being.
Recommendations for promoting gut health include:
- Consuming a diet rich in dietary fiber, including fruits, vegetables, and whole grains.
- Minimising intake of processed foods, which may negatively impact microbial balance.
- Ensuring adequate hydration to support optimal digestive function.
- Managing psychological stress, given the strong connection between emotional states and gastrointestinal health.
In conclusion, the gastrointestinal system serves functions that extend far beyond nutrient absorption. Its intricate neural and microbial networks engage in continuous dialogue with the brain, influencing mood, cognition, and systemic health. As such, prioritising gut health is not only beneficial for digestion but also for long-term physical and mental well-being.
About the Author:
ASSOC. PROF. DR. SARAVANAKUMAR (SK)
Associate Professor of Anatomy, Faculty of Medicine, SEGi University.
Assoc. Prof. Dr. Saravanakumar is a highly accomplished dental surgeon with a double Master’s degree in Medical Anatomy and Psychology, and a PhD in Medical Anatomy focusing on stem cell regeneration. A member of the Royal College of Surgeons (UK) and the British Association of Clinical Anatomists (UK), as well as a registered clinical practitioner with the Dental Council, he has over 15 years of experience teaching anatomy to medical and dental students. His expertise spans gross anatomy, histology, embryology, neuroanatomy, and osteology, complemented by an impressive portfolio of more than 50 published research articles, a patent, and a government-funded research grant on mesenchymal stem cells. Recognised with multiple awards for research, teaching, and professional excellence, he has served as an examiner at various academic levels and as a keynote speaker and chairperson at national and international conferences, including the Malaysian Surgical Society.