Our tongues are integral to our ability to taste food. It is the tongue that recognizes sweet, sour, salty, savory and bitter tastes. Without the tongue’s ability to sense taste, human livelihood just wouldn’t be the same. But it seems that the human tongue can do more than merely sense taste. It may even sense carbohydrates.
Testing the Tongue Senses
Dr. Nicholas Gant from the Sport and Exercise Science department at the University of Auckland’s Centre for Brain Research conducted a study on the tongue’s detection of carbohydrates and the brain’s response. Gant and his team utilized functional MRIs to observe the effects of three different mouth rinses given to 10 study subjects. The three rinses were composed of one sweet carbohydrate solution, a sweet solution without carbs and a third solution that was neither sweet nor contained carbohydrates.
When subjects swished the sweet carbohydrate solution in their mouths, there was greater activation in brain regions associated with sensation and muscle performance than with either the sweet rinse without carbs or the tasteless solution without carbs. The sweet carbohydrate solution also produced another effect. It led to greater activation in brain regions that control vision and in regions associated with reward.
The tongue’s ability to detect carbohydrates and carbohydrates’ effect on the brain are intriguing in their implications. The fact that the sweet, non-carbohydrate-containing solution didn’t activate brain regions on the scale that the carbohydrate-containing one did could explain why diet foods—made with artificial sweetener—leave us unsatisfied. We might consciously think “hey it’s sweet just like real sugar,” but the tongue knows better. When it doesn’t sense carbohydrates, it basically tells the brain to “stand down.”
The increased activation of regions controlling vision and muscle performance could explain why athletes respond immediately to carbs. Upon drinking carbohydrate laden drink—e.g. Gatorade, Powerade, any sports drink—athletes often liven up, long before the carbohydrates have a chance at being digested and converted into energy. Eating disorders may also be linked to the signaling between the mouth and the brain. A failure in this connection could be the cause of eating disorders as the brain may not activate the feeling of satisfaction. This would lead to unbalanced and unhealthy eating behaviors.
It’s incredible what our body is capable of. Because humans have mastered so many areas of science, we sometimes grow arrogant in our understanding our own biology. We thought artificial sweeteners would be the answer to sugar through deceiving our taste buds. As it turns out, there’s no deceiving the tongue.
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