Carbonation In Drinks Can Trick Your Brain
September 18, 2013

The Brain’s Perception Of Sweetness Altered By Carbonation

[ Watch the Video: What Is That Carbonation Doing To Your Brain? ]

redOrbit Staff & Wire Reports - Your Universe Online

If you’ve ever had difficulty telling the difference between the sugar in regular soft drinks and the artificial sweeteners found in diet sodas, chances are that your brain was fooled by the carbonation found in the popular beverages, according to research appearing in the newest edition of the journal Gastroenterology.

Study author Rosario Cuomo, an associate professor in the department of clinical medicine and surgery at "Federico II" University in Naples, Italy, and colleagues used functional magnetic resonance imaging (fMRI) in order to study the impact of carbon dioxide (CO2) on neural processing of taste – specifically, how carbonation alters the way the brain processes sweet stimuli.

“The presence of carbonation produced an overall decrease in the neural processing of sweetness-related signals, especially from sucrose,” the study authors wrote. “CO2 reduced the neural processing of sucrose more than that of artificial sweeteners. These findings might be relevant to dietary interventions that include noncaloric beverages, whereas the combination of CO2 and sucrose might increase consumption of sucrose.”

“This study proves that the right combination of carbonation and artificial sweeteners can leave the sweet taste of diet drinks indistinguishable from normal drinks,” Cuomo said in a statement. “Tricking the brain about the type of sweet could be advantageous to weight loss – it facilitates the consumption of low-calorie drinks because their taste is perceived as pleasant as the sugary, calorie-laden drink.”

However, the research also discovered that there is a downside to this effect. The scientists found that combining carbonation and sugar could result in an increase in sugar and food consumption, since the brain believes that it is taking in less sugar – resulting in impaired energy balance. Cuomo’s team believes that their findings could help explain the prevalence of eating disorders, metabolic diseases and obesity among diet-soda drinkers.

Any future research that includes an analysis of the effect of carbonation on the taste buds’ ability to detect sweetness, as well as the responses elicited by sweetened carbonated beverages in the gastrointestinal cavity, will be tasked with clarifying the link between the reduced calorie intake resulting from diet drinks and the increased incidence of obesity and metabolic diseases in those who consume them, the researchers explained.

The Cuomo team’s study comes less than a month after researchers at Monell Center in Philadelphia reported that the refreshing bite that people experience when consuming carbonated drinks does not come directly from the carbonation itself, but from a chemical reaction between the CO2 in the beverage and the human tongue.

As part of that research, a sensory biologist from the Monell Center and his colleagues recruited 12 healthy adults, had them sample several different carbonated beverages (each with different levels of carbonation concentration), and then rate each drink by the intensity of its bite. The participants then repeated the experiment in a hyperbaric chamber with the atmospheric pressure set to be the equivalent of 33 feet below sea level.

After tasting the same beverages at different pressure levels, the subjects were unable to detect a difference in bite – despite the fact that bubbles could not form inside of the hyperbaric chamber. That led the investigators to conclude that the carbonation bite was an acidic chemical sensation, not just a purely physical one. The August study was published in the open access journal PLOS ONE.