Both NAD levels and autophagy activity decline with age, and genetically or pharmacologically boosting either promotes lifespan extension and attenuates age-related pathology in laboratory animals...It was recently shown that autophagy deficiency induces fatal depletion of NAD+/NADH, that is rescuable by NAD precursor supplementation, suggesting a role of autophagy in NAD maintenance. Therefore, NAD and autophagy form a bidirectional feedback relationship which may be linked to longevity and age-related disease, and could represent a target for therapeutic intervention.