The Psycho-Neuro-Endocrine-Immune (PNEI) Axis: Unravelling the Intricate Link Between Mind, Motor Neurons, Master Immune-Endocrines, Motility, Microbiome and Metabolic Chaos

Abstract The global obesity epidemic, coupled with the alarming rise of insulin resistance and metabolic syndrome, poses a formidable challenge to public health. Interaction between the gut and the brain is essential for energy homeostasis. In obesity, this homeostasis is disrupt. While traditional views have focused on diet and exercise, a more nuanced understanding is emerging—one that connects our mental state, nervous system, hormonal balance, and immune function to the all-rounder par excellence gut secreto-motility aspects affecting trillions of microorganisms in our gut. This intricate communication network is known as the psycho-neuro-endocrine-immune (PNEI) axis, and its disruption may be a key driver of the obesity crisis. The crucial role of the gut microbiota in the Gut–Brain Axis in obesity cannot be underestimated. For too long, the mind and body have been treated as separate entities, a philosophical and medical duality that has hindered our understanding of complex illnesses. The PNEI framework shatters this outdated concept, providing a cohesive model that shows how psychological stress can initiate a cascade of biological changes that disrupt gut health and metabolism.