How are Insulin and longevity related?

The relationship between insulin and longevity is complex and mediated by the insulin/IGF-1 signaling pathway. In model organisms such as worms, flies, and mice, reduced insulin/IGF-1 signaling extends lifespan, likely via FOXO transcription factors and enhanced stress resistance. In humans, findings are mixed: high insulin sensitivity is associated with metabolic health, but chronically low insulin output (e.g., from caloric restriction) may be protective. Conversely, insulin resistance increases risk for age-related diseases like type 2 diabetes, cardiovascular disease, and cancer. The provided context contains no direct studies on insulin and longevity, so this answer is based on general mechanistic knowledge. Evidence is primarily mechanistic and derived from animal models; human longitudinal data are limited and confounded. Individual genetic counseling on insulin and longevity is not currently evidence-based.