The NAD+ turnover rate in mouse small intestine is approximately 40 times higher than in muscle.

“when you have the skin having a very I need to constantly repair itself and then you take away its ability to do that then suddenly you see this manifestation in the skin in the gut what's happening is I think part of it is that it's so energy intensive to maintain the cell turnover in the ground but it's also the case that just like the skin the gut is exposed to so many insults of just total lack of quality control over the things that come inside it”