Agarose oligosaccharides (AOS) — marine-derived sugar compounds — extended both mean and maximum lifespan in aging fruit flies while restoring intestinal stem cell homeostasis through a precise microbiome mechanism. The treatment increased Acetobacter persici bacteria populations, which produce acetic acid that modulates JAK/STAT signaling pathways to balance stem cell proliferation and reduce oxidative stress. This represents a significant advance in understanding how specific prebiotic compounds can target the gut-longevity axis through defined bacterial metabolites. The mechanistic clarity — from AOS to specific bacteria to metabolite to cellular pathway — provides a roadmap for microbiome-based longevity interventions that current probiotics lack. While fruit fly studies don't directly translate to humans, the JAK/STAT pathway is evolutionarily conserved, and acetic acid (found in vinegar) is well-tolerated in human diets. The findings suggest marine-derived oligosaccharides could offer more targeted gut health benefits than traditional fiber supplements by selectively promoting beneficial bacteria that produce specific anti-aging metabolites. However, dosing, safety, and efficacy in mammals remain unestablished.