PHILADELPHIA – Almost everyone understands that a major role of our sense of taste is to inform us of the presence of sugar in foods and drinks by arousing the sweetness on our tongues. A study by the Monell Chemical Senses Center, published this month in PLOS ONE, identifies a new human sensory ability to detect sugars in the mouth with a molecular calorie detector, of sorts.
“Our mouths can identify when a sweetener has the potential to provide calories versus a non-caloric sweetener, which cannot,” said first author Paul Breslin, PhD, Monell researcher and professor of nutritional science at the ‘Rutgers University.
The article describes the first demonstration in humans of a pathway that uses glucose sugar, a component of table sugar and high fructose corn syrup, to signal the presence of calories, in addition to the receptor. sweet taste well studied in taste. buds.
Glucose comprises about half of the commercial sweeteners in use today. Over the millennia, humans have derived glucose in their diets from foods high in sugar such as fruits and honey, and today from added sugars, such as sucrose (table sugar) from sugar beets or sugar cane and high fructose corn syrup.
“Humans love fruit and sugar, like many other monkeys, which get most of their calories from sugar,” Breslin said.
Spurred on by recent data from Monell which showed that taste bud cells in mice could identify when a sweetener has calories to burn for energy, the current team investigated whether the ability to sense glucose in the mouth human may also involve this additional pathway. The team asked if this calorie detector works and, perhaps most importantly, affects our responses to sugar in our diet.
“Now that we know that this calorie-sensing taste system works in humans, it could help explain the overall preference for sugary drinks over non-caloric sweetening drinks,” Breslin explains.
In a series of three elegant experiments on human taste, the team compared sensitivity to oral glucose with the ability to detect the artificial sweetener sucralose and a special form of glucose that cannot be metabolized. “Overall, there are two pathways for detecting sweetness in the mouth: one for sweetness and another for detecting potentially energy-consuming sugars,” said co-author Linda J. Flammer, PhD, associate at main research at Monell.
Breslin, an experimental psychologist interested in human oral perception and its genetic basis, has long been puzzled by diet sodas that had never captured a significant share of the beverage market. He now has the beginnings of an answer: “Diet drinks are not as satisfying as sugary drinks. As a public health initiative, could we get more rewarding low-sugar foods and drinks? Now that we know there is this second system for sensing glucose in the mouth, maybe we can tap into it to create healthier drinks that people love to drink.
After swallowing, the calories in sugars are detected in the gut and blood, but this study establishes that humans can also register sugars as different from non-caloric sweeteners in the mouth. “It is remarkable that we have developed a mechanism not only to taste oral sugars as sweet, but also to feel that they have a metabolic or caloric signal,” said Breslin. “This means the mouth is a lot smarter than we thought and it will be hard to fool it by simply providing non-caloric sweeteners.”
The co-authors are Anilet Tharp, Nancy E. Rawson and Robert F. Margolskee of Monell, and Akiko Izumi, Tadahiro Ohkuri and Yoshiaki Yokoo of Suntory.
This research was funded in part by a grant from Suntory Global Innovation Center Limited. The funder consulted on the general design of the study and provided support in the form of salaries to some authors and a scientist from Suntory helped collect data under the supervision of the Monell Center. The funder played no role in the specific study design, data analyzes, decision to publish, or preparation of the manuscript.
The authors do not declare any competing interest in the work. The participation of Suntory Global Innovation Center Limited does not alter the authors’ adherence to PLOS ONE’s policies on data and document sharing.