A new pilot study conducted by the Leibniz Institute for Food Systems Biology at the Technical University of Munich suggests that non-nutritive sweeteners may modulate the copy rate of various genes in white blood cells when consumed in dietary intake levels. Sweeteners such as saccharin, acesulfame-K, and cyclamate are commonly found in diet drinks, as they have a high sweetening power but contribute little or nothing to energy intake. These sweeteners affect not only the taste buds in the mouth but also the human immune system, although the underlying molecular relationships are still poorly understood.
The study involved ten healthy participants who drank a beverage-typical mix of approximately 76 mg saccharin, 228 mg cyclamate, and 53 mg acesulfame-K per liter, which converted to a 70kg person resulted in a drinking volume of approximately 0.75 liters. Subsequent blood analysis revealed that four hours after drinking the test solution, sweetener concentrations in the blood were at their highest. The team then investigated how the maximum concentrations of the respective sweeteners determined act in vitro on white blood cells serving the bacterial defense. They also analyzed ex vivo immune cells taken from the blood of the test subjects before and after the intervention.
Both in vitro and in vivo, sweetener administration increased the copy rate of genes containing the blueprint of taste receptors that commonly respond to sweeteners in the mouth. In addition, sweeteners modulated the copy profile of genes encoding regulatory proteins of the immune system. The modulated transcriptional profile shifts cells into a state that makes at least isolated immune cells more sensitive to a bacterial stimulus in the presence of the three sweeteners, although this does not necessarily lead to altered cell functions. Nonetheless, the results suggest that even an average non-nutritive sweetener intake can affect immune cells in the blood.
Dietmar Krautwurst of the Leibniz Institute for Food Systems Biology explains that their data suggest that this modulation sensitizes immune cells to certain immune stimuli and also suggests that taste receptors may act as sweetener sensors of the cellular immune system. He also explains that researchers cannot say at this stage whether this modulation is good or bad for health. Further research is required on this, but the researchers can deduce from their results the hypothesis that taste receptors serve as sensors for food-related stimuli not only in the mouth but also on immune cells.
The study results suggest that even non-nutritive sweetener intake can have an effect on immune cells in the blood. The underlying molecular mechanisms need further research for a better understanding of the relationship between immune cells and sweeteners. The results could also pave the way for further research on the health effects of sweeteners and their impact on the human immune system. The paper on the study is published in the journal Nutrients.
