At present, very little information is known about the manner that sweetness perception is contributing to an individual's satiety.
A study conducted by a team of Austrian-German researchers led by chemists Veronika Somoza and Barbara Lieder, and published in the Nutrients journal, provides new perceptions into the link between the sugar's sweet taste, intake of energy "and the regulatory process of hunger and satiety."
The sweet taste of sugar is quite famous all over the world. Specifically, in Austria and Germany, the intake of sugar per person each year adds up to roughly 33 and 34 kilograms, respectively.
Therefore, sugar plays a vital role in the population's nutrition and health, particularly that of body weight. Nevertheless, not much is known about the molecular mechanisms of sugar that impact dietary intake, separately from its caloric load.
Sweet Taste Receptor Examined
According to the Department of Physiological Chemistry at the University of Vienna deputy head, Veronika Somoza, they therefore examined the function of sweet taste receptor stimulation "in the regulation of satiety." Somoza is also the director of Leibniz Institute for Food Systems Biology at the Technical University of Munich
For this purpose, the study investigators conducted a blind, crossover intervention research with glucose and sucrose. To achieve results, they involved a total of 27 healthy male respondents aged 18 to 45 years old.
They were given either 10 percent glucose or sucrose solution or one of the sugar solutions accompanied by 60 ppm lactisole. This substance binds to the sweet receptor's subunit and decreases the sensitivity of sweet taste.
Despite different sugar types, all solutions, with or without lactisole, had similar energy content. After two hours from the consumption of each of the test solutions, the volunteers were allowed to eat as much as much as breakfast they wanted.
Shortly prior to and during the waiting period of 120 minutes, the scientists took blood samples in standard intervals and had the participants' body temperature gauged.
Results After Consumption of Lactisole-Containing Sucrose Solution
After their consumption of the sucrose solution that contained lactisole, the male participants were found to have an increased intake of energy from breakfast of roughly 13 percent, around 100 kilocalories more, compared to after they consumed the sucrose solution without lactisole.
Furthermore, participants from this group presented lower body temperature and reduced concentrations of plasma serotonin, a neurotransmitter and tissue hormone which, the study specified, "has an appetite-controlling effect."
On the contrary, the study investigators saw no differences following the administration of the glucose solution that contained lactisole, as well as the pure glucose solution.
University of Vienna's Kestin Schweiger, the study's first study author, added, "We do not know yet why we could not observe the effect of lactisole with glucose."
Nevertheless, Schweiger also said they suspect it is because the sweet receptor is activated by sucrose and glucose in different ways. The researchers have also assumed that mechanisms reliant on the sweet receptor play a role.
Therefore, explained Somoza, more research is needed to clarify the complex links between sugar consumption, taste receptors, and regulation of satiety "on the molecular level.
Specifically, as sweet receptors are found too, in the digestive tract, and there is not much known about their role there. The initial steps have, however, been taken.
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