At first glance, “trusting your gut” may seem intuitive, irrational, or even unscientific. However, science confirms that the digestive system is indeed “sensitive”; it contains its own autonomic network, known as the enteric nervous system, comprising approximately 100 million nerve cells. A study in Nature revealed that the gut’s own enteric nervous system can not only detect nutrients but also distinguish between them, showing that it is far smarter than once believed.
New research led by KU Leuven, Leuven, Belgium, researchers from the Translational Research in GastroIntestinal Disorders team shows that neurons in the intestinal wall respond to specific nutrients in a targeted manner. The study conducted on the intestinal tissue of mice showed that the intestine can differentiate between sugars, proteins, and fats. Each nutrient activates its own neurochemical network through reactions involving specific neurons. Using calcium imaging in the mouse jejunum, researchers found that nutrients activate specific groups of enteric neurons, but not directly.
The epithelium, the surface tissue on the inside of the intestine, plays a key role in the detection of different nutrients. The tissue uses serotonin, a well-known neurotransmitter, to send signals to the nervous system. Signals move from the villus epithelium to the myenteric plexus and then to the submucosal plexus, revealing a clear communication pathway across the intestinal walls.
“What we’re seeing is that the enteric nervous system doesn’t just respond to pressure or stretching. It works in a much more targeted way depending on the specific nutrients in the intestine,” said Candice Fung, postdoctoral researcher and first author of the study. “The precision with which the nervous system can differentiate between sugars, proteins, and fats proves how refined and intelligent this system is.”
The LENS (Laboratory for Enteric Neuroscience) research group, led by Pieter Vanden Berghe, PhD, specialises in light microscopy for imaging live cells and tissues. Scientists use fluorescent markers that make neurons light up when activated. Thus, the processes in the enteric nervous system can be visualised in real time.
“When we talk about a ‘gut feeling,’ we shouldn’t be dismissive when it comes to our digestive system and enteric nervous system. This research demonstrates a certain form of intelligence in the gut. This is why people sometimes refer to it as the ‘second brain’ or ‘little brain.’ But if you ask me, the enteric nervous system is too important and too sophisticated to be considered the ‘little brother,’” said Berghe.
This story was translated and adapted from MediQuality.