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. Sugar thus plays an increasingly important role in the diet and health of the population, especially with regard to body weight. However, little is known about the molecular (taste) mechanisms of sugar that influence dietary intake, independent of caloric load.
Taste receptor and satiety regulation "We therefore investigated the role of sweet taste receptor activation in the regulation of satiety," said 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. the Technical University of Munich.
For this purpose, the scientists conducted a blinded, crossover intervention study with glucose and sucrose. A total of 27 healthy male subjects between the ages of 18 and 45 were given a 10 percent (weight percent) glucose or sucrose solution 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 sugars, all solutions with or without lactisol had the same energy content. Two hours after drinking each of the test solutions, the participants were allowed 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.
An average of 100 extra kilocalories
After consuming the lactisol-containing sucrose solution, the subjects had an increased energy intake from breakfast of about 13 percent, about 100 kilocalories more, than after drinking the sucrose solution without lactisol. In addition, the subjects of this group showed a lower body temperature and decreased plasma concentrations of serotonin. Serotonin is a neurotransmitter and tissue hormone that, among other things, has an appetite suppressant effect. In contrast, the researchers did not see any differences after administration of the lactisol-containing glucose solution and the pure glucose solution.
“This result suggests that sucrose, regardless of its energy content, modulates the regulation of satiety and energy intake through the sweet taste receptor,” said Barbara Lieder of the University of Vienna.
The study's first study author, Kerstin Schweiger, University of Vienna adds:“We don't yet know why we couldn't observe the lactisol effect with glucose. However, we suspect that this is because glucose and sucrose activate the sweet receptor in different ways. We also assume that mechanisms independent of the sweet receptor are involved.”
“So much research is still needed to elucidate the complex relationships between sugar consumption, taste receptors and satiety regulation at the molecular level,” says Veronika Somoza. Especially since sweet receptors are also found in the digestive tract and little is known about their function there. Nevertheless, the first steps have been taken.
