The effects of a high-sucrose diet on the survival of Drosophila melanogaster from a bacterial infection

Excess sucrose intake has been linked to a variety of health conditions. Sucrose and other dietary sugars have inflammatory effects that can negatively impact immune health. However, sucrose’s influence on immune function is not fully understood, and its effects during bacterial infection may vary depending on factors such as infection method. Previous studies have used the model organism Drosophila melanogaster to study the effects of sucrose during bacterial infection because this species is genetically similar to humans and has a similar innate immune response. Additionally, this species is relatively simple and easy to manipulate. This study investigated the influence of sucrose on the survival of D. melanogaster after an oral bacterial infection with the pathogen Serratia marcescens. We hypothesized that a diet composed of 20% added sucrose would decrease the survival of D. melanogaster after S. marcescens infection compared to a 0% added sucrose control diet. To test this hypothesis, we orally inoculated two groups of flies with S. marcescens and fed each group diets with different sucrose concentrations. Contrary to our expectations, flies given the 20% added sucrose diet had significantly longer survival times than those given the 0% added sucrose diet. It is possible that high sucrose intake negatively impacts immunity, but our results suggest that sucrose can positively impact immunity under certain conditions. More research is needed to fully elucidate which contexts make excess sucrose harmful.