Microbe-made molecule tells brain to boost insulin, hunger hormone
Gut microbes cause obesity by sending messages via the vagus nerve to pack on pounds, new research in rodents suggests.
Bacteria in the intestines produce a molecule called acetate, which works through the brain and nervous system to make rats and mice fat, researchers report in the June 9 Nature.
If the results hold up in humans, scientists would understand one mechanism by which gut microbes induce obesity: First, the microbes convert fats in food to a short-chain fatty acid called acetate. Acetate in the blood somehow makes its way to the brain. The brain sends a signal through the vagus nerve to the pancreas to increase insulin production. Insulin tells fat cells to store more energy. Fat builds up, leading to obesity.
Acetate also increases levels of a hunger hormone called ghrelin, which could lead animals and people to eat even more, says Yale University endocrinologist Gerald