Science Round-Up Seconds: NAC Reduces Inflammation, Muscle Injury & Cytokine Expression, but Impairs Anabolic Signaling, Satellite Cell Activity and Recovery
|Inflammatory cytokines won't build muscle, but without them your body won't notice that it's time to adapt.|
In this context, the feared "inflammatory" markers, IL-6 (interleukin 6) and TNF-alpha (tumor necrosis factor alpha) are of paramount importance as they are part of the singaling cascade that will have our bodies' own defenses target and cull the said degenerate cells before they become "immortal" cancer cells.
Inflammation and the adaptive response to exercise - the hormesis hypothesis
|Figure 1: Health and longevity as a function of mitochondrial reactive oxygen species (ROS) formation (learn more)|
Yet, while there are studies that would confirm this notion, the available data is by no means conclusive and a recent close review of the literature reveals that the consumption of "passive" anti-oxidants (e.g. vitamin C, vitamin E & co, i.e. molecules that simply eradicate reactive oxygen species and will thus blunt not regulate the cytokine response) appears to have either no, or detrimental effects in younger, relatively healthy individuals, the majority of the currently available data in older and sick individuals points to benefits of modest anti-oxidant supplementation.
We know that we know too little...
In short, we are still in the limbo as far as the "to use or not to use antioxidant supplements" question is concerned. Against that background I am grateful for every study that may help us solve this "mystery" and further our understanding of when a perfectly healthy and normal physiological response becomes pathologic and whether, when and for whom the use of specific anti-oxidants may be beneficial.
If you want to hear and learn more about the study at hand, the effects of other anti-oxidants and NSAIDs, and have not had the chance to listen live to yesterday's installment of the Science Round-Up on the Super Human Radio Network I suggest you download the show before you go on reading (click here to download).Now without taking away too much in advance the latest of theses studies, I can already tell you that the actual outcomes of the latest study from the Democritus University of Thrace in Komotini and a couple of other European institutes, could confirm the scientists' hypotheses that the use of NAC [N-acetyl-cysteine; one of the most potent anti-oxidant supplements] during an 8-day eccentric and thus particularly "muscle damaging" exercise intervention would lead to an increase in GSH availability that would [...]
- ameliorate skeletal muscle performance by reducing inflammatory processes and exercise-induced muscle injury
- attenuate intracellular redox dependent signaling pathways
- an attenuation of the exercise induced elevation of inflammatory markers of muscle damage (creatine kinase activity, C-reactive protein, proinflammatory cytokines), nuclear factorkB phosphorylation, and
- an amelioration of the damage-induced strength decrease during the first 2 d of recovery,
Now, you could well argue that this is simply a result of less damage, right?
|Was it mitohormesis that helped Walter Breuning live to the biblical age of 114 (learn more)?|
(Unfortunately?) this is nothing but a neat hypothesis - one that is not supported by the results of the study at hand, in which the scientists also observed
- a blunted increase in myogenic (=satellite cell replenishing / recruiting and muscle repairing and building) factors and
- the failure to fully recover from eccentric exercise
|It's only logical that you wouldn't want to suppress the reactive oxygen species (green-yellow) too much, as their presence in the vicinity of muscle cells (blue) is not just a "stressor", but also important signal that will trigger and regulate the adaptive response to exercise (learn more)|
For other individuals which have to re-establish a healthy baseline level of glutathione and cut back on non-exercise induced oxidative damage (elderly, obese, diabetics, etc.), it may yet well be the other way around. These people may only be able to benefit from the exercise-induced cytokine response, if it is not drowned by an over-abundant amount of "pro-inflammatory" cytokines from other stressors.
- Michailidis Y, Karagounis LG, Terzis G, Jamurtas AZ, Spengos K, Tsoukas D, Chatzinikolaou A, Mandalidis D, Stefanetti RJ, Papassotiriou I, Athanasopoulos S, Hawley JA, Russell AP, Fatouros IG. Thiol-based antioxidant supplementation alters human skeletal muscle signaling and attenuates its inflammatory response and recovery after intense eccentric exercise. Am J Clin Nutr. 2013 May 29.