A new study in mice challenges assumptions of how the body metabolizes this type of sugar
When it comes to processing fructose, the liver is a pinch hitter for the small intestine.
To use fructose for energy, the body needs to convert it into another type of simple sugar called glucose or into other smaller molecules. Scientists knew fructose could be metabolized in both the liver and the small intestine, but believed the liver was mainly responsible for the process. A new study in mice suggests otherwise, showing that moderate doses of fructose — a sugar found in honey and fruit as well as such corn syrup‒sweetened products as soda — are transformed in the small intestine. The liver steps in only when the small intestine gets inundated, researchers report February 6 in Cell Metabolism.
In that way, the small intestine shields the liver from dangerously high doses of fructose, says Joshua Rabinowitz, a metabolism researcher at Princeton University. In humans,