Savory snacks are not only a treat for the mouth, but now scientists find the tummy can also say "yummy."
A new study shows that the same sweet-detecting proteins in your tongue also reside in the gut where they can likewise "taste" sugars.
"Cells of the gut taste glucose through the same mechanisms used by taste cells of the tongue," said study author Robert Margolskee, a neuroscientist at Mount Sinai School of Medicine in New York.
While you might not consciously experience the gut tasting as you would when sugars hit the tongue's tasters, Margolskee suspects you would feel some type of sweet sensations.
"Probably in people, it's a sense of satisfaction from some foods," Margolskee told LiveScience. "A very rich sugar- or fat-filled dessert could make you have a sense of well-being and happiness."
The research results, published online in the early edition of the Proceedings of the National Academy of Sciences (PNAS), are based on experiments with mouse and human intestinal tissues as well as other mouse experiments.
Margolskee and his colleagues found gut taste cells analogous to those in the tongue. Past research has shown the taste receptor T1R3 and protein called gut-expressed gustducin play key roles to sweet taste in the tongue.
The scientists suggest the receptors work by triggering hormone release.
Once your mouth has completed its washing-machine-like cycling of a snack, the mushed food slides to the stomach for liquefaction and other processing and then into your small intestine, where it gets further broken down into simpler components such as the simple sugar glucose. The sugar molecules bind to and stimulate the gut's protein receptors (sweet sensors), which then rev up the release of hormones, including an intestinal hormone that helps regulate insulin production and also appetite.
And like the tongue's tasters, the belly could have taste-specific cells. "It's very likely that there are gut cells that respond to sweet compounds, fatty compounds and amino acids, and even bitters," Margolskee said. "So in that regard, there will be similarity to the ability you have in your taste cells in your tongue to respond to all these different types of tasting compounds. You'll have the ability to respond to them in your gut too."
The findings have implications for treatments for obesity and diabetes, the authors say. In a related paper published in the same issue of PNAS, scientists found these gut taste receptors also lead to the production of a chemical that determines how much sugar from snacks gets absorbed by the body. Since sugar-packed foods are sometimes implicated in diabetes and obesity, the link could be one avenue for treatments.
In addition, one hormone controlled by the taste receptors affects appetite and so could be used to decrease appetite.
The study was funded by the Wellcome Trust, University of Liverpool and the National Institutes of Health (NIH).
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