In yeast, a substance called nicotinamide riboside can be used to make an important molecule called NAD+, and it does so through a different route than the one scientists used to think was the only way.

What we've found so far is that nicotinamide riboside may provide an alternative pathway for NAD+ production in yeast. The evidence we've reviewed leans toward this idea, based on the data currently available. Our analysis of the research shows that in yeast, nicotinamide riboside can be used to produce NAD+, a molecule important for cellular function [1]. This process appears to happen through a route different from the one previously thought to be the primary method [1]. What this means is that yeast cells might have more than one way to build NAD+, and nicotinamide riboside could play a role in one of these backup pathways [1]. The evidence we’ve examined comes from one key assertion, which is supported by three study references, and no studies in our current review contradict this finding [1]. Still, we are working with a limited number of sources. At this point, we can’t say how significant this alternative pathway is compared to others, or how it functions under different conditions. Our current analysis does not allow us to draw firm conclusions about the broader implications, as we only have evidence specific to yeast and only one assertion to base our summary on. We also cannot assume this applies to humans or other organisms without further data. Practical takeaway: In yeast, nicotinamide riboside might help make NAD+ in a way that’s different from the usual method, but we need more evidence to understand how this works and how important it really is.