From Sweeteners to Sleeplessness: The Hidden Effects of Sucralose and Saccharin on the Gut–Brain Axis

Sweetener consumption has increased considerably in recent decades, driven by the growing demand from consumers of low-calorie products for weight control and, especially, from diabetic patients who require safe sweetener alternatives without affecting their glucose levels. However, the latest scientific evidence seems to indicate that the continued consumption of various sweeteners could significantly alter the gut microbiota, triggering consequences that go beyond metabolic health and could affect sleep quality. Among the most used non-caloric sweeteners in the food industry are sucralose and saccharin. Several studies have shown that prolonged consumption of these sweeteners can significantly alter the composition of the gut microbiota. In particular, its consumption might lead to a decrease in beneficial bacteria such as <i>Lactobacillus</i> and <i>Bifidobacterium</i>, along with an increase in potentially pathogenic microorganisms such as <i>Clostridium difficile</i> and <i>Escherichia coli</i>. This dysbiosis creates a chronic low-grade inflammatory environment and contributes to the deterioration of glucose metabolism, factors that negatively impact the regulation of the gut–brain axis. Consequently, these alterations could interfere with the neuroendocrine mechanisms involved in sleep, promoting the development of disorders such as insomnia, sleep fragmentation, and decreased subjective sleep quality. The aim of this narrative review is to synthesize the current scientific evidence on the impact of artificial sweeteners on the gut microbiota and their potential involvement in sleep disorders. The underlying biological mechanisms will be analyzed and the clinical relevance of these interactions discussed, laying the groundwork for future research that will contribute to the development of dietary recommendations and therapeutic strategies aimed at modulating the microbiota to improve sleep health.