Sodium benzoate may reduce appetite in Drosophila melanogaster through serotonin upregulation

Abstract

Sodium benzoate is a common artificial preservative in processed food, yet little is known about its long-term health effects. Since sodium benzoate could upregulate serotonin, we hypothesized that it may induce satiety and activate processes underlying caloric restriction that can lead to lifespan extension. In this study, the effects of sodium benzoate on tryptophan metabolism and its potential association with lifespan and stress tolerance in Drosophila melanogaster were investigated. We administered varying doses of sodium benzoate to male and female flies, monitoring their daily food consumption, serotonin levels, kynurenine/tryptophan (kyn/trp) ratio, Sirt1 levels, and survival under normal conditions. Additionally, separate groups of flies were exposed to stressors such as heat, ultraviolet A (UVA) radiation, and energy deprivation to assess the compound’s effects on lifespan under diverse stress conditions. Our results demonstrated that fruit flies fed sodium benzoate exhibited reduced food consumption, decreased kyn/trp ratio, and increased serotonin. The expression of Sirt1, an indicator of the effect of caloric restriction, increased. Their lifespan was prolonged under normal and energy-deprived conditions but was unaffected under heat and UVA stress. Overall, our findings are consistent with our hypothesis that the upregulation of Sirt1 through sodium benzoate supplementation is associated with increased serotonin levels, which may explain delayed senescence and resilience under energy-deprived conditions.

Keywords

• sodium benzoate
• longevity
• caloric restriction
• serotonin
• sirt1
• energy deprivation