A report on the “Effect of Carbonation on Brain Processing of Sweet Stimuli in Humans” (Gastroenterology 2013; 145: 537-39) highlights how the addition of carbonation could lead to increased consumption of sugar products.  The authors examined neural activity in response to carbonated beverage consumption with the aid of functional MRI.  An easy-to-read analysis of this study can be found at this link:  Carbonation affects brain processing of sweet stimuli : Family …

An excerpt:

Carbonation produces a decrease in the neural processing of sweetness-related signals, particularly those from sucrose, a small functional neuroimaging study shows.

The findings, which suggest that the combination of CO₂ and sucrose might increase consumption of sucrose, could have implications for dietary interventions designed to regulate caloric intake, according to Dr. Francesco Di Salle of Salerno (Italy) University and his colleagues.

To assess the interference between CO₂ and perception of sweetness, as well as the differential effects of CO₂ on sucrose and aspartame-acesulfame, (As-Ac, an artificial sweetener combination commonly used in diet beverages), the investigators performed two functional magnetic resonance imaging (fMRI) experiments to evaluate changes in regional brain activity…

The first experiment, performed in nine volunteers, analyzed the effect of carbonation in four sweet Sprite-based solutions, including one carbonated and sweetened with sucrose, one noncarbonated and sweetened with sucrose, one carbonated and sweetened with As-Ac, and one noncarbonated and sweetened with As-Ac. The second experiment evaluated the spatial location of the strongest neural effects of sour taste and CO₂ within the insular cortex of eight subjects.

On fMRI, the presence of carbonation in sweet solutions “independently of the sweetening agent, reduced neural activity in the anterior insula (AI), orbitofrontal cortex (OFC), and posterior pons … the effect of carbonation on sucrose was much higher than on perception of As-Ac,” they noted, explaining that “at the perceptual level … carbonation reduced the perception of sweetness and the differences between the sensory profiles of sucrose and As-Ac.”

This effect may increase sucrose intake, but is also favorable to diet beverage formulations being perceived as similar to regular beverage formulations, the investigators reported…

It may be that taste and CO₂-related information influence food choices and intake through integration in the tractus solitarius with input from the gastrointestinal tract, they suggested, explaining that “the reduced discrimination between sucrose and As-Ac induced by CO₂ would promote the consumptions of low-calorie beverages and would converge with CO₂-induced gastric distention in limiting caloric intake.”

This study was supported in part by the Coca-Cola Company. One author, Dr. Rosario Cuomo, was sponsored by the Coca-Cola Company. The remaining authors reported having no disclosures.

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