I posted months ago about a study showing rats had 35% reduction in exercise performance [...] But some may say that since this reveiw was written one human study has been published, but did they measure exercise performance? Also there were only16 people in that study.
This stuff is far from proven and my own experience with it was that it did curtail my exercise performance.
This study wasn't a mainstream study
I have a sense of what politicians mean when they say that a judicial nominee is "outside of the mainstream," and I know what commentators mean when they say that a scientist's views are "outside of the mainstream." I have no idea at all what it means to say that a "study wasn't a mainstream study." Would you clarify?
and had absolutely no funding.
Of course, one cannot do a study with absolutely no funding. Are you referring to the statement that the authors had "No funding to declare" in the "Declarations" section? This simply means that they weren't' getting funding from an interested party, such as Chromadex, Life Extension, or one of their competitors, and possibly also that they didn't get any dedicated funding for it, but instead took it out of their lab's internal unallocated funding. The former is a good thing, and the latter is certainly not problematic.
Or did you mean something else? And if so, why is the lack of such funding a problem in your view?
It was conducted at the Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Agios Ioannis, Serres, 62110 Greece.
Indeed: a place with actual expertise in exercise physiology. Nice, huh?
Bryan wrote: The materials used were purchased "NAD+ Cell Regenerator™" containing microcrystalline cellulose, vegetable cellulose (capsule), silica, vegetable stearate administered daily for 21 days via gavage at a dose of 300 mg/kg body weight. This was an off the shelf preparation. The rats in the control group received a saline vehicle "only" not containing the excipients (microcrystalline cellulose, vegetable cellulose (capsule), silica, vegetable stearate). So we have an issue with the NR source anyway with multiple ingredients.
Well, we don't have a problem with the NR source — it's all Chromadex, yes? (If it was some manufacturer we knew nothing about, you might worry that they or their suppliers were substituting sawdust or plain NAM — but this is Life Extension, and whatever else you think about them, their quality is unimpeachable). And, obviously, the capsule itself would not be included in the gavage administration: while they don't say so, I think we can safely assume that they emptied the capsule out first.
However, you do have a point about the excipients not being included as part of the control — but not one that I think should concern one overmuch. MCC is quite inert: if they had fed enormous amounts of it with a meal, you might worry that the MCC might have inhibited their appetite by filling them up, thereby reducing their energy intake and lowering performance, but that isn't a realistic concern at the ratios it's present in LEF's capsules (and even less so when it's delivered via gavage rather than as part of the chow). The effect of the vegetal stearate is a more serious question, but the worst this would do would be to reduce the uptake of NR: that wouldn't explain the supplemented group having poorer performance than the controls.
Bryan quoted: "Evidently, these hypotheses are speculative and are currently being investigated in order to reveal the potential metabolic and redox mechanisms involved in our finding. Further studies are warranted to acquire mechanistic insights on the effect of nicotinamide riboside on exercise performance."
I'm not sure why you were quoting this material. Quoted in isolation, a reader (either you, or someone reading your post) might mistakenly think that the authors were suggesting that their findings were somehow speculative and hypothetical, which wouldn't make any sense.
Rather, they are offering up a couple of possible hypotheses to explain their findings, and then correctly noting them to be tentative and calling for research to test them:
Based on the similar effects of nicotinic acid and nicotinamide riboside on NAD+ metabolism, the impairments in exercise performance observed in our study may stem from the same sources as in the studies used nicotinic acid [, namely] ... reduced exercise-induced increases in plasma free fatty acids. Therefore, it is likely that nicotinamide riboside decreased fatty acid oxidation during exercise leading to an earlier fatigue.
In addition, the redox properties of NAD+ and NADP+ could also provide a plausible explanation for the impaired performance observed, namely by disrupting redox homeostasis [10]. In particular, nicotinamide riboside administration may have altered redox homeostasis leading cells to a more reductive (non-optimal) state ... in line with other recent studies stressing the potential detrimental effects of redox-related supplements on exercise capacity [12].
Evidently, these hypotheses are speculative and are currently being investigated in order to reveal the potential metabolic and redox mechanisms involved in our finding.
I will point out again that there is an additional possible explanation, connected with their hypothesis about the redox coupling of NADP(H). (Nearly?) all NR studies reporting positive effects of megadose NR (on exercise performance, muscle stem cell function, diabetic obesity, etc) have used C57Bl/6J mice, which carry the strain's NNT mutation, leading to inadequate reduction of NADP+ in their mitochondria. One possibility is that megadose NR partially offsets this defect by augmenting the cellular level of NAD+, facilitating a more normal level of NADP+ reduction to NADPH. By contrast, in an animal with an intact NNT gene (such as a rat (as in this study), or the C57BL/6JRcc mice used in this study, or the vast majority of humans) — in such an organism, increasing the level of NAD+ via megadose NR might instead disrupt optimal NADP:NADPH redox coupling, leading to functional impairments. (See here, here, and here).
Bryan wrote: All they had to do was ask Chromadex for Nicotinamide Riboside without the excipients and perhaps this would have received some outside review but the experiment was deficient in so many ways. So you are not going to engage anyone on speculation because the authors didn't go deep enough.
You've pointed out one deficiency (the non-administration of the MCC and vegetal cellulose in the control gavage), which I don't find very troubling for reasons given above; in what other ways would you say it is deficient and did not go deep enough?
Bryan wrote: We [Chromadex] do have a full scale human experiment going on at the University of Minnesota. So if you want better data, they are looking at Traumatic Brain Injury with football players but if the subjects suffered an adverse reduction in exercise stamina this should come to light and this is the experiment to watch.
Here are some relevant terms used in the football players experiment. "Brain Concussion, Brain Injuries, Brain Diseases, Central Nervous System Diseases, Nervous System Diseases, Craniocerebral Trauma, Trauma, Nervous System, Head Injuries, Closed, Wounds and Injuries, Wounds, Nonpenetrating"
Er ... first, people are taking NR now on the basis of (other) rodent studies. Second: re-read those relevant terms: none of them is "ergogenic aid." The U of M trial's primary outcome is (indirectly-measured) change in brain NAD+ levels, with "physical assessment" as a secondary outcome: it's not clear to me that "physical assessment" would involve testing exercise performance. And even if it did, it's quite different to show that a person with exercise deficits related to TBI recovers following NR supplementation (supposing they were to find that) than to find that exercise performance was improved in uninjured, otherwise-healthy trained or untrained people. So I'd be surprised if this study were all that informative on the issues raised by this study.
Edited by Michael, 08 May 2017 - 03:43 AM.