Bubbles dupe brain's sweetness perception

Fooling the brain into perceiving artificial sweeteners as sugar is easy: just add carbonation. According to a new article in Gastroenterology, the official journal of the American Gastroenterological Association, carbonation affects the brain’s perception of sweetness, making it harder to determine between sugar and artificial sweeteners.

“This study proves that the right combination of carbonation and artificial sweeteners can leave the sweet taste of diet drinks indistinguishable from normal drinks,” said Rosario Cuomo, Associate Professor of Gastroenterology at the University of Naples Federico II, who authored the study.

While this sounds like good news, unfortunately, there’s a downside. Despite initially believing the drink contains sugar, the brain eventually realises it’s been duped - and sends out signals that encourage increased sugar and food consumption to redress the balance. The researchers say this may explain the prevalence of eating disorders, metabolic diseases and obesity among diet soft drink fanatics.

To conduct the research, scientists used functional magnetic resonance imaging to monitor changes in regional brain activity in response to naturally or artificially sweetened carbonated beverages. The findings were a result of the integration of information on gastric fullness and nutrient depletion conveyed to the brain.

The researchers say further studies into the effect of carbonation on sweetness detection - and the responses elicited by carbonated sweetened beverages in the gastrointestinal cavity - will be required to clarify the puzzling link between diet drinks and obesity and other metabolic diseases.