Certain foods are known as "heating" foods in Chinese medicine. Over-consumption of these foods can lead to symptoms known as "heating up". These symptoms have been shown to be symptoms of systemic low-grade
inflammation. However, the mechanism by which these foods cause
inflammation is not clear. In this preliminary study, we investigated
dysbacteriosis of the gut microbiota as a possible cause of
inflammation by litchi, a typical "heating" food. A human flora-associated (HFA) mouse model (donor: n = 1) was constructed. After gavaging the mice with litchi extract
suspension at low, medium and high doses (400, 800, 1600 mg/kg·d-1, respectively) (n = 3) for 7 days, the serum levels of inflammatory
cytokines, gut microbiota, the concentration of SCFAs and the integrity of the intestinal mucosal barrier were measured. The results revealed significant increases in the abundance of Prevotella and Bacteroides. A significant increase in the abundance of Bilophila and a decrease in Megasomonas was observed in the high-dose group. High-dose litchi intervention led to a decrease of most SCFA levels in the intestine. It also caused a more than two-fold increase in the serum TNF-α level and LPS level but a decrease in the IL-1β and
IL-6 levels. Medium- and high-dose litchi intervention caused widening of the intestinal epithelial cell junction complex and general weakening of the intestinal mucosal barrier as well as reduced energy conversion efficiency of the gut microbiota. These data suggest that litchi, when consumed excessively, can lead to a low degree of systematic
inflammation and this is linked to its ability to cause
dysbacteriosis of the gut microbiota, decrease SCFAs and weaken the intestinal mucosal tissues.