Brain can detect carbohydrate “kick” before stomach: New Zealand study

WELLINGTON, June 4 (PNA/Xinhua) — The human mouth has a “sixth taste sense” that can pick up the presence of carbohydrates and could explain why diet drinks lack the “kick” of their sugar-laden equivalents, New Zealand scientists said Wednesday.

Despite the drinks having identical tastes and smells, the brain could detect more about the make-up of the drinks than the tongue, according to the study by the Centre for Brain Research at the University of Auckland.

“Liquid solutions used in our study were sweetened artificially, but when carbohydrate was present, we saw increased activation in the brain that we don’t see when only sweetness is present,” study leader Dr Nick Grant said in a statement.

“This helps explain the ‘kick’ people complain is absent in diet beverages or products,” he said.

“We may be able to use the experimental platform in this study to help develop functional foods and artificial sweeteners that are as hedonistically rewarding as the real thing.”

The study used a unique brain imaging sequence to test the behavioral and neural response of 10 participants who performed arm exercises while their mouths were rinsed with carbohydrate, artificial sweetener or placebo solution.

The study found a 30-percent increase in task-related brain activity when carbohydrate was present even though the liquid wasn’t swallowed.

“This study provides further evidence of a ‘sixth taste sense’ for carbohydrate by receptors in the human mouth. The mouth signals that energy is on its way, which in turn leads to increased activity in key regions of the brain including those that control movement and vision,” said Grant.

The findings could also explain why the “perk up” response noted in athletes after they had drunk carbohydrate was immediate, even though the body had no time to absorb it and convert it to energy.

“Carbohydrates are extremely powerful oral stimuli that have profound and immediate effects on the brain and the mouth is a more capable sensory organ that we currently appreciate,” Grant said. (PNA/Xinhua)