Impact of selenium on the intestinal microbiome-eCBome axis in the context of diet-related metabolic health in mice

Given the role of selenium (Se) in chronic low grade inflammation during obesity, and the impact it might have on changes in the composition of the intestinal microbiome and endocannabinoidome, we investigated how dietary variations of Se in combination with high fat high sucrose (HFHS) or low fat low sucrose diets (LFLS) impacted intestinal response in mice. Overall, enhanced Se intake was shown to mitigate the inflammatory effects of HFHS diet on the intestine, both through modulation of cytokine gene expression, concentration of intestinal prostaglandins and endocannabinoid-like mediators associated with inflammation. These results support the hypothesis of a potential anti-inflammatory effect of Se consumption in response to the diet and exerted also through alterations of bioactive lipids. We also showed that the microbiome of the ileum and the caecum responded in Se intake in a diet dependent manner and that although the two intestinal segments shared some microbiota modulations, their microbial ecology was strikingly different. Finally, Se strongly influenced weight gain when combined with LFLS diet, an interaction that could potentially explain disagreements in the literature. Taken together, these results demonstrate that the impact of Se on the microbiome is diet-dependent and associated with the inflammatory state of the caecum.