NAD^(+) and its possible role in gut microbiota:Insights on the mechanisms by which gut microbes influence host metabolism

Nicotinamide adenine dinucleotide(NAD^(+))is an enzyme cofactor,co-substrate,and redox factor in all living cells and is necessary for maintaining cell metabolism.It has been shown that appropriate supplementation of NAD^(+)precursors or inhibition of NAD^(+)-depleting enzymes can promote mitochondrial oxidative phosphorylation and improve host energy utilization efficiency.In addition,increasing evidence indicates that the gut microbiota plays a pivotal role in host metabolism.Theoretically,there should be a close correlation among NAD^(+),gut microbiota,and host metabolism;however,the information is limited.In this review,we summarize the metabolic process of NAD^(+)and its impact on host metabolism,the link between gut microbiota and host metabolism,as well as the potential effects of NAD^(+)on microbial metabolism,providing a new perspective on the interaction between gut microbiota and host metabolism.