How Your Gut Tastes What You EatWednesday, June 3, 2015
It turns out that we have a rather sophisticated sensing mechanism in our gut that senses the composition of our diet and interacts with the brain to regulate our appetite and food intake.
Just how exactly this gut “nutrient-sensing” system works, is reviewed by Sophie Hamr and colleagues from the University of Toronto in a paper published in Current Diabetes Reports.
As the authors point out,
“…the gastrointestinal (GI) tract is anatomically positioned to provide initial feedback following a meal via detection of incoming nutrients and relaying signals to the brain and peripheral tissues to prevent excess energy intake and circulating nutrients…..This, coupled with the vast neural and humoral connectivity of the gut to other important sites of energy regulation, such as the brain, allows the gut to effectively relay information to the rest of the body about the size and composition of an incoming meal.”
Each nutrient (fats, carbohydrates, protein) interacts with specific sensory and signal transduction mechanisms in the gut.
Animal studies show that exposing the gut to certain nutrients (for e.g. by tube feeding) can stimulate or suppress feeding behaviour making animals chose or avoid certain foods. Often these effects can persist for days or even weeks, well beyond the time course of a single meal.
Furthermore, these effects appear to be largely dependent on the presence of specific nutrients rather than on the actual nutritional or energy state of the animal.
“…these evidences lend notion for the intestine to sense specific nutrients (i.e., lipid and carbohydrate) at specific concentrations, rather than calories, in an effort to drive further food consumption.”
The authors point out that changes in how the gut senses nutrients may well explain how bariatric surgery works to reduce appetite and change food preferences.
No doubt, a better understanding these mechanisms and the molecular mechanisms involved could lead to novel dietary or pharmacological interventions to prevent or treat obesity.