This 2007 commentary highlights the discovery of nicotinamide riboside (NR) as a novel NAD+ precursor that enhances Sir2 deacetylase activity and extends lifespan in yeast. NR operates through the Nrk and Urh1/Pnp1/Meu1 pathways, offering an alternative to the classical Preiss-Handler and salvage pathways for NAD+ synthesis. The findings suggest that
