The digestive system of our body is already activated before we take the first bite. Scientists from the Max Planck Institute for Metabolism Research in Cologne show how sensing food activates neurons in the brain which prime the liver for digestion.

In order to process ingested food efficiently, the body begins digestion as soon as it perceives the food. In the so-called cephalic phase, the production of gastric acid is stimulated in order to digest incoming food directly. However, not only the gastrointestinal tract is important for digestion and the absorption of nutrients.

Claus Brandt and his colleagues from the research group of Max Planck director Jens Brüning, have now been able to show that during this cephalic phase, the liver is also prepared.  A group of neurons, called POMC neurons in the hypothalamic region of the brain are activated solely by smelling and seeing the food. These neurons in turn signal to the liver to start to prepare for the incoming nutrients. 

 “The body does not only react to the food which is absorbed but already to the sensory signals communicating that it will soon be metabolized in the organism. Thus, it can minimize disturbance in whole body homeostasis” summarizes Brandt.

Original publication:
Claus Brandt, Hendrik Nolte, Sinika Henschke, Linda Engström Ruud, Motoharu Awazawa, Donald A. Morgan, Paula Gabel, Hans-Georg Sprenger, Martin E. Hess, Stefan Günther, Thomas Langer, Kamal Rahmouni, Henning Fenselau, Marcus Krüger, and Jens C. Brüning: Food Perception primes hepatic ER-homeostasis via Melanocortin-dependent control of mTOR-activation. Cell, 2018.

Source: Max-Planck-Institute for Metabolism Research. Good preparation is half the digestion