Proteins are indispensable nutrients that contain Essential Amino Acids, which animals cannot synthesize on their own. Hence, when body lacks proteins, it must seek Essential Amino acids through food sources.
When there is protein deficiency in the body, gut responds to it through 2 co-ordinated pathways
- A fast neural circuit rapidly informs the brain that essential amino acids are lacking,
- A slower hormonal signal sustains protein-seeking behaviour over time.
When the body is deprived of dietary protein, specialized intestinal cells in the gut produces a peptide hormone called CNMa. This signal first activates gut-associated enteric Neurons, which rapidly relay information about amino acid deficiency to the brain through a direct gut-brain neural circuit.
At the same time, CNMa enters circulation as a hormone and reaches the brain more slowly, reinforcing and sustaining the appetite for essential amino acids over time.
Our gut is not just only a digestive organ, but an active sensory system that continuously monitors nutritional state and directly guides behavioural decisions.
MBH/DB