The sweet taste of sugar, energy intake and the regulatory process of hunger and satiety.
The sweet taste of sugar is very popular worldwide. In Austria and Germany, the annual intake per person is about 33 and 34 kilograms, respectively. Thus, sugar plays an increasing role in the nutrition and health of the population, especially with regard to body weight. However, little is known about the molecular (taste) mechanisms of sugar that affect dietary intake, regardless of its caloric load.
Taste receptor and saturation regulation
“We have therefore investigated the role of activation of sweet taste receptors in the regulation of satiety,” says Veronika Somoza, Deputy Head of the Department of Physiological Chemistry at the University of Vienna and Director of the Leibniz Institute of Food Systems Biology at the Technical University of Munich .
To this end, the scientists conducted a blinded, cross-intervention study with glucose and sucrose. A total of 27 healthy men, between 18 and 45 years old, received a 10 percent glucose or sucrose solution (weight percent) or one of the sugar solutions supplemented with 60 ppm lactisol. Lactisol is a substance that binds to a subunit of the sweet receptor and reduces the perception of sweet taste. Despite different types of sugar, all solutions with or without lactisol have the same energy content.
Two hours after drinking each of the test solutions, the participants were able to eat as much breakfast as they wanted. Shortly before and during the 120-minute waiting period, the researchers regularly took blood samples and measured their body temperature.
Additional 100 kilocalories on average
After ingesting the sucrose solution containing the lactisol, the subjects had an increased energy intake of about 13 percent, about 100 kilocalories more, from breakfast than after drinking the sucrose solution without lactisol. In addition, the subjects of this group showed lower body temperature and lowered plasma serotonin concentrations. Serotonin is a neurotransmitter and tissue hormone that has, among other things, an appetite suppressant effect. In contrast, the researchers observed no differences after administration of the lactisol-containing glucose solution and the pure glucose solution.
“This result suggests that sucrose, regardless of energy content, modulates the regulation of satiety and energy intake via the sweet taste receptor,” says Barbara Lieder, head of Christian Doppler’s laboratory for taste research and also deputy head of the Department of Physiological Chemistry. from the Faculty of Chemistry at the University of Vienna.
The first study author of the study, Kerstin Schweiger, University of Vienna, adds: “We still do not know why we could not observe the lactisol effect with glucose. However, we suspect that glucose and sucrose activate the sweet receptor in different ways. We also assume that mechanisms play a role independent of the sweet receptor. ‘
“Therefore, much research is still needed to elucidate the complex relationship between sugar consumption, taste receptors and saturation regulation at the molecular level,” says Veronika Somoza. In particular, since sweet receptors also occur in the digestive tract, and little is known about their function there. The first steps were taken nonetheless.
Reference: “Sweet Taste Antagonist Lactisole Administers in combination with sucrose but not glucose, increases energy intake and decreases peripheral serotonin in male subjects” by Kerstin Schweiger, Verena Grüneis, Julia Treml, Claudia Galassi, Corinna M. Karl, Jakob P. Ley, Gerhard E. Krammer, Barbara Lieder and Veronika Somoza, 14 October 2020, Nutrients.
DOI: 10.3390 / nu12103133