The story about NMN has been reported in another topic, I have blogged about NAD boosting news recently here:
This is what I said about NR
At the same time we have had Study: Popular dietary supplement causes cancer risk, brain metastasis which is based upon A bioluminescent-based probe for in vivo non-invasive monitoring of nicotinamide riboside uptake reveals a link between metastasis and NAD+ metabolism.
The first one was not really something intentional, and may be changed by discussion and/or legal action. It also only has effect in the USA. The second one, however, is more serious and is likely to put the cat amongst the pigeons. In essence what it says is that if you increase NAD+ availability it can increase both the risk of certain cancers and make them more likely to metastise.
I am not entirely suprised by this report. I stopped taking NMN a few weeks ago because I was concerned that increasing the levels of NAD+ could power the dedifferentiation of cells which I am unsurprisingly wishing to avoid. That can also feed into the process of getting cancerous cells. The reason for this is that the Sirtuins remove acetylation from the histone and the level of this activity is NAD+ dependent.