All this study confirm that all precursor looks bad way to increase NAD+ since you will expose yourself then to homocysteine etc. And curently there is no data performed on the safety profile of NR, especially looking at the its methylation mechanism. Thats really bad especially when all studies show the need to use large dose for both NA and NR.
Safety assessment of nicotinamide riboside, a form of vitamin B3 There is a safety profile don't suggest there isn't.
There have been no studies associating higher homocysteine levels to Nicotinamide Riboside. This is absurd, you provide no evidence of this at all. Niacin on the other hand does show evidence of increasing homocysteine levels.
Is this now become a witch hunt were if we throw enough unsubstantiated doubt at Nicotinamide Riboside something will stick. Gentlemen I don't have enough hours in a day to run down all of your "opinions." If you make a statement like "All this study confirm that all precursor looks bad way to increase NAD+ since you will expose yourself then to homocysteine etc" then link and point to the exact study findings your citing.
Tom you want so bad for all the precursors to be the same to make your point that this is not the way to go. If you think NAD Repletion/NAD boosting through Nicotinamide Riboside increases the risk of Cardiovascular disease, present your data. You want to be the scientist but linking unrelated studies to (NR) wont get you there and does this thread a disservice.
What you have done is say Niacin has this problem and it can be corrected by taking other supplements like "B6, B9 or B12 given alone or in combination and should be used for preventing cardiovascular events" No association to Nicotinamide Riboside has been demonstrated.
Bryan sorry but I do not make any personal attack. And so far you always said to not have any financial interest into niagen isnt ?
What I see is the opposite, while you advice people to take large and frequent dose of niagen (the first few pages of this thread), you should rely on data that show there is no effect on the methyl process (very unlikely) unlike niacinamide. You propose this safety paper. Great. However very short period and no homocysteine monitored. This study monitored on a short period if whever or NR was mutagenic using different dosage versus control and niacinamide group.
More than that: your paper authors state the following:
each group was gavaged daily with either vehicle (water), 300, 1000, 3000 mg/kg of Niagen or 1260 mg/kg/day of nicotinamide, which is equivalent to 3000 mg/kg/day of Niagen on a molar basis.
And indeed niagen is half nicotinamide (niacinamide) and half ribose. So thats was my speculation but will come back to that point just after
Its important to note that all their biomarker showed that Niagen showed exact same result as niacinamide then as you can all in this study, for instance in the conclusion they give me a good point:
In addition, NR is thought to exhibit the same toxicity profile as nicotinamide, because evidence from a single dose pharmacokinetic study in humans suggests that it is metabolized in a manner similar to nicotinamide (unpublished results). Because there are no publicly available 90-day studies on either nicotinamide or NR, a toxicology study was completed where 300, 1000, or 3000 mg/kg body weight/day of NR, or 1260 mg/kg body weight/day of nicotinamide, which is equivalent to 3000 mg/kg/ day dose of NR on a molar basis, was administered to rats over the course of 90 days. Adverse effects at 3000 mg/kg body weight/day of NR included treatment-related adverse effects in liver, kidneys, testes, epididymides and ovaries. These effects included increases in clinical chemistry parameters related to hepatocyte damage (ALT, ALP, and GGT) and a corresponding increase in liver weight, centrilobular hepatocellular hypertrophy, and single cell necrosis. In addition, thyroid follicular cell hypertrophy and increased kidney weight with exacerbation of chronic progressive nephropathy were observed.
That being said, since nicotinamide is much more old studied molecule, we have that :
http://www.ncbi.nlm....pubmed/23768418
Nicotinamide had gene-specific effects on the methylation of CpG sites within the promoters and the expression of hepatic genes tested that are responsible for methyl transfer reactions (nicotinamide N-methyltransferase and DNA methyltransferase 1), for homocysteine metabolism (betaine-homocysteine S-methyltransferase, methionine synthase and cystathionine β-synthase) and for oxidative defence (catalase and tumour protein p53). It is concluded that nicotinamide-induced oxidative tissue injury, insulin resistance and disturbed methyl metabolism can lead to epigenetic changes. The present study suggests that long-term high nicotinamide intake may be a risk factor for methylation- and insulin resistance-related metabolic abnormalities.
http://www.ncbi.nlm....pubmed/18996527
In tissue culture nicotinamide treatment led to an increase in adipose tissue homocysteine secretion.
http://www.ncbi.nlm....pubmed/21918528
It also revealed that hypertensives had an abnormal methylation pattern, characterized by elevated fasting plasma levels of unmethylated substrates, nicotinamide, Hcy and norepinephrine. Therefore, it seems likely that high nicotinamide intake may be involved in the pathogenesis of Hcy-related cardiovascular disease.
etc...
Finally it seems more than likely that we should rely on current data that suggest half NR weight should be considered as nicotinamide isnt ? so when one point high dosage for NAD+ boosting, they have to also take these facts above into account.
Especially since nicotinamide is released already from NAD+ ase enzyme and since this vitamin form is already present in average foods.
Some persons here experienced bad sides from B3s so cautious even with NR.
EDIT: Bryan you said consume 1g of niagen per day, so means you get around 500mg nicotinamide + the ones from your NAD+ release + the ones from your normal food intake. If you think its safe then its fine. But is such amount high enough to really get significant boost over NAD+ ? its also the second concern closely linked to the first
Edited by Tom Andre F. (ex shinobi), 11 July 2016 - 08:03 PM.