John Glendinning, the Ann Whitney Olin Professor of Biology, studies feeding and taste focusing on the role of the modern diet and overeating. One of his areas of research is the link between taste buds in the mouth and insulin release in the gut. In a recent paper in the American Journal of Physiology, he revealed the connection between a sweet taste pathway in the mouth and insulin release by the pancreas. The paper was co-authored by Yonina Frim ’17, Ayelet Hochman ’16, and Gabrielle Lubitz ’17. Glendinning explained the significance of this discovery.
How are taste buds linked to insulin release?
When most of us think about taste, we think about conscious sensations—if you put a potato chip in your mouth, for example, you sense a salty taste. Candy elicits a sweet taste. But what we’re talking about in this paper is a novel sweet taste pathway, which elicits a physiological response—insulin release—but no apparent sweet taste sensation. The response helps us process foods.
What is the significance of your findings?
Scientists previously knew there was a sweet taste pathway that could trigger insulin release from the pancreas and help increase glucose tolerance, but our work gained insight into concrete mechanisms for how this pathway works. There are multiple kinds of sugars—sucrose, glucose, fructose, maltose, lactose—and then there are artificial sweeteners, but we discovered that only glucose activates the insulin release in this sweet taste pathway. We also found that artificial sweeteners don’t activate it.
How could this impact people with diabetes?
Given the rapid rise in incidence of type 2 diabetes, it is critical to gain a more complete understanding of the mechanisms that control insulin secretion. People who have diabetes either produce too much insulin or too little, and that impacts their ability to process sugar. The value of this work is that we know this taste-elicited insulin release can dramatically improve the ability of people to regulate their blood sugar. By understanding these mechanisms, we may be able to help people who are producing excessive insulin by limiting its secretion, or people who don't produce enough insulin by enhancing its secretion.
How does this finding suggest potential for drug discovery in the future?
This novel sweet taste pathway may provide a target for manipulating insulin release in diabetic patients. There are a lot of treatments that do work—for example, there are medications that target the beta cells in the pancreas, and there are patients who inject insulin into their body to help regulate blood sugar. But my feeling is that targeting taste cells in the mouth could lead to a more natural method. Our work establishes that the taste system does more than just help us identify and enjoy sugary foods. It also helps the body prepare for the oncoming onslaught of sugar.
Here Prof. Glendinning explains why new foods taste better when you’re on vacation.
Here he discusses new research on the impact of fetal alcohol exposure on taste.
And in this video, he discusses how he became interested in his field of study.