Study: Vitamins 'undo exercise efforts'

[askthetrainer]

Here's a link to the original BBC article:

http://news.bbc.co.uk/2/hi/health/8043456.stm

Does anyone have any experience and/or strong opinions about the science behind antioxidant supplements and exercise?

[ozcoltsfan]

Would be interesting to know if they used real Vit C and E or the synthetic versions.

[askthetrainer]

I wondered the same thing. I looked on PubMed for the abstract for the study and couldn't find it. The Dr. who did the study seems pretty respectable... maybe I'll email her for more details?

http://www.sportex.bham.ac.uk/about/...ahaldred.shtml

I'm very curious because I have been religious about taking antioxidants before and after my workouts along with my carbrotein beverages...

[ozcoltsfan]

I wondered the same thing. I looked on PubMed for the abstract for the study and couldn't find it. The Dr. who did the study seems pretty respectable... maybe I'll email her for more details?

http://www.sportex.bham.ac.uk/about/...ahaldred.shtml

I'm very curious because I have been religious about taking antioxidants before and after my workouts along with my carbrotein beverages...

I always try to take those sort of supps with food, try to trick the body in to thinking its real food. Don't know if theres anything to back it up however.

[dirkwright]

The New York Times reported on the study also.

So they are basically saying that taking vitamins C and E increases insulin resistance in men who exercise? I'd like to know if there were any positive effects from taking the vitamins. I'm guessing that insulin resistance is only a small piece of the bigger picture of what these vitamins do for us, but I could be wrong.

[SheWulf]

Interesting... I had always heard something about Vitamin C having a negative effect on endurance...

[partsRheavy]

Odd.

Would it have something to do with inflammation? I believe that the anti-oxidant vitamins decrease inflammation in the body. This is normally good for health, when inflammation is due to low-grade infection or whatever.

However, inflammation of muscle tissue from exercise promotes hypertrophy, which is the logic behind supp's that contain arachidonic acid.

I know this is bro-science, but I'm wondering if it's connected.

By the way, since I'm over 40, I stay away from arachidonic acid...

[GeneGnomeX]

It is not new news that antioxidants prevent some of exercise's benefits.

ROS/RNS mediate many adaptations to (endurance) exercise and blocking them with common antioxidants reduces those adaptations, most importantly mitochondrial biogenesis/VO2max, endogenous antioxidant enzymes, glucose disposal.

I feel strongly that large dosing of antioxidants with the exception of a few will reduce lifespan. The body responds favorably to stress by adapting and increasing stress resistance and some research supports that antioxidants block this resistance.

It is supported by research on endurance exercise, caloric restriction, resveratrol, other "antioxidants" induce mild stress responses, moderate alcohol consumption, irradiation, cell membrane composition (ie more PUFA= more oxidative stress but better health outcome), many anti-ageing drugs etc.

Out with the old antioxidant dogma.

It should be noted that weight lifting doesn't really induce mitogenesis though anyway.

[Heracles25]

It is not new news that antioxidants prevent some of exercise's benefits.

ROS/RNS mediate many adaptations to (endurance) exercise and blocking them with common antioxidants reduces those adaptations, most importantly mitochondrial biogenesis/VO2max, endogenous antioxidant enzymes, glucose disposal.

I feel strongly that large dosing of antioxidants with the exception of a few will reduce lifespan. The body responds favorably to stress by adapting and increasing stress resistance and some research supports that antioxidants block this resistance.

It is supported by research on endurance exercise, caloric restriction, resveratrol, other "antioxidants" induce mild stress responses, moderate alcohol consumption, irradiation, cell membrane composition (ie more PUFA= more oxidative stress but better health outcome), many anti-ageing drugs etc.

Out with the old antioxidant dogma.

It should be noted that weight lifting doesn't really induce mitogenesis though anyway.

Is this meant for Pre/Post workout or just in general with antioxidants? I remember seeing some of Dinoiii's posts related to antioxidants and that they can be detrimental post workout.

Could you elaborate on beneficial antioxidants, dosing and timing?

[Peter LeDrew]

Would be interesting to know if they used real Vit C and E or the synthetic versions.

x2
You really have to dig deeper into these studies. I would guess they used one form of Vit.E alpha-tocopherol and it'd be nice to know the doses as well.

Also classifying all antioxidants or vitamins as one group, by stating 'Vitamins' undo some of the beneficial effects of the workout, is not accurate. It was only two vitamins used and likely one form of Vit.E, which is not a good idea anyways.

[OrangeBowTie]

Full Article:http://www.pnas.org/content/early/20....full.pdf+html

I think I may switch to just eating lots of fruits and vegetables instead of supplemental vitamins.

Interesting question to ponder...

[dirkwright]

Vitamin C and E Supplementation Effects in Professional Soccer Players Under Regular Training

Exercise training is known to induce an increase in free radical production potentially leading to enhanced muscle injury. Vitamins C and E are well known antioxidants that may prevent muscle cell damage. The purpose of this study was to determine the effects of these supplemental antioxidant vitamins on markers of oxidative stress, muscle damage and performance of elite soccer players. Ten male young soccer players were divided into two groups. Supplementation group (n = 5) received vitamins C and E supplementation daily during the pre-competitive season (S group), while the placebo group (PL group, n = 5) received a pill containing maltodextrin. Both groups performed the same training load during the three-month pre-season training period. Erythrocyte antioxidant enzymes glutathione reductase, catalase and plasma carbonyl derivatives did not show any significant variation among the experimental groups. Similarly, fitness level markers did not differ among the experimental groups. However, S group demonstrated lower lipid peroxidation and muscle damage levels (p < 0.05) compared to PL group at the final phase of pre-competitive season. In conclusion, our data demonstrated that vitamin C and E supplementation in soccer players may reduce lipid peroxidation and muscle damage during high intensity efforts, but did not enhance performance.

http://www.pubmedcentral.nih.gov/art...?artid=2129167

[dirkwright]

Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance

Background: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation.

Objective: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans.

Design: The human study was double-blind and randomized. Fourteen men (27?36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area).

Results: The administration of vitamin C significantly (P = 0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator?activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase.

Conclusion: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.

http://www.ajcn.org/cgi/content/abstract/87/1/142

[dirkwright]

I think I'll give up vitamin C and see if that helps me gain endurance faster.

[weightroomguy]

Study has to be taken with a grain of salt, while it might be a bad idea to use Vitamins C and E pre workout, they are nothing but useful in recovery post workout. I blogged about my take on this here: http://weightroomtalk.blogspot.com/2...-exercise.html

[dirkwright]

Study has to be taken with a grain of salt, while it might be a bad idea to use Vitamins C and E pre workout, they are nothing but useful in recovery post workout. I blogged about my take on this here: http://weightroomtalk.blogspot.com/2...-exercise.html

Well, since Vitamin C is a water soluable chemical, it washes out of the body pretty fast, so timing would be important in taking it. However, Vitamin E is oil soluable, I think so anyway, so wouldn't it persist much longer in the body? The studies don't mention when they gave the vitamins to the participants.

Also, there are chemicals like NAC that directly stimulate the release of glutathione. I wonder what effect that has on exercise?

[dirkwright]

Does glutathione enhance exercise performance? A case study

Endogenous glutathione, a tripeptide often referred to as "Reduced Glutathione," is composed of three amino acids: L-Cysteine, Glycine, and L-Glutamic Acid. Smaller peptides of 2 or 3 amino acids are absorbed without further reduction or delay, but there is some debate as to the effectiveness of taking peptides as opposed to free amino acids for enhancing endogenous glutathione stores. Most glutathione is found in the liver where it detoxifies harmful compounds later excreted in bile. Some glutathione is found in the red and white blood cells, lungs, and intestinal tract. The primary biological function of glutathione is to act as a non-enzymatic reducing agent to assist in cysteine thiol side chains in a reduced state on the surface of proteins. Reduced glutathione is involved in the synthesis and repair of DNA, assists the recycling of vitamins C and E, blocks free radical damage, enhances the antioxidant activity of vitamin C, facilitates the transport of amino acids, and plays a critical role in detoxific ation. It is the base material for several other key antioxidant enzyme systems: glutathione-peroxidase, glutatbione-reductase, and glutathione-transferase. Decline in glutathione concentrations in intracellular fluids correlate directly with indicators of longevity. Decline in endurance performance may parallel decline in glutathione concentrations imposed by the aging process.

Extreme Endurance Training Accelerates glutathione Loss

Researchers assessed the antioxidant status and markers of oxidative damage in the members of the US Men's Alpine Ski Team during 10 days of intense training. Seven measures of antioxidant status were determined using Trolox-equivalent antioxidant capacity, uric oxidase, alpha-tocopherol, total glutathione, cytosolic glutathione peroxidase, and superoxide dismutase. The results suggested that antioxidant status of elite alpine skiers declined during training. (1)

Further studies of blood values determined the importance of glutathione (GSH) on potentiating maximal oxygen-carrying capacity. Higher glutathione levels influence red blood cell count, hematocrit, and hemoglobin. Conversely, when red blood cells, hematocrit, and hemoglobin are reduced during anemia, low glutathione is implicated; the addition of GSH has been shown to resolve the aforementioned low blood markers. Whether antioxidant supplementation will enhance performance remains controversial. Exercise-induced changes in antioxidant scavengers and associated enzymes (e.g., glutathione, tocopherol, and glutathione peroxidase) provide clues about demand imposed on the defense system. Exercise training is observed to result in an augmented antioxidant system and a reduction in lipid peroxidation. Supplementation with antioxidants appears to reduce lipid peroxidation but has not been shown to enhance exercise performance. (2)

.... there is more here:
http://findarticles.com/p/articles/m.../ai_104259139/


Since glutathione decreases after exercise, it makes sense to take NAC or some other chemical that stimulates the release of it. This article also showed that at least in one person, administration of glutathione before exercise increased his performance.

[nastyimpulse89]

so when should i take my vitamins

[Peter LeDrew]

Does glutathione enhance exercise performance? A case study

Endogenous glutathione, a tripeptide often referred to as "Reduced Glutathione," is composed of three amino acids: L-Cysteine, Glycine, and L-Glutamic Acid. Smaller peptides of 2 or 3 amino acids are absorbed without further reduction or delay, but there is some debate as to the effectiveness of taking peptides as opposed to free amino acids for enhancing endogenous glutathione stores. Most glutathione is found in the liver where it detoxifies harmful compounds later excreted in bile. Some glutathione is found in the red and white blood cells, lungs, and intestinal tract. The primary biological function of glutathione is to act as a non-enzymatic reducing agent to assist in cysteine thiol side chains in a reduced state on the surface of proteins. Reduced glutathione is involved in the synthesis and repair of DNA, assists the recycling of vitamins C and E, blocks free radical damage, enhances the antioxidant activity of vitamin C, facilitates the transport of amino acids, and plays a critical role in detoxific ation. It is the base material for several other key antioxidant enzyme systems: glutathione-peroxidase, glutatbione-reductase, and glutathione-transferase. Decline in glutathione concentrations in intracellular fluids correlate directly with indicators of longevity. Decline in endurance performance may parallel decline in glutathione concentrations imposed by the aging process.

Extreme Endurance Training Accelerates glutathione Loss

Researchers assessed the antioxidant status and markers of oxidative damage in the members of the US Men's Alpine Ski Team during 10 days of intense training. Seven measures of antioxidant status were determined using Trolox-equivalent antioxidant capacity, uric oxidase, alpha-tocopherol, total glutathione, cytosolic glutathione peroxidase, and superoxide dismutase. The results suggested that antioxidant status of elite alpine skiers declined during training. (1)

Further studies of blood values determined the importance of glutathione (GSH) on potentiating maximal oxygen-carrying capacity. Higher glutathione levels influence red blood cell count, hematocrit, and hemoglobin. Conversely, when red blood cells, hematocrit, and hemoglobin are reduced during anemia, low glutathione is implicated; the addition of GSH has been shown to resolve the aforementioned low blood markers. Whether antioxidant supplementation will enhance performance remains controversial. Exercise-induced changes in antioxidant scavengers and associated enzymes (e.g., glutathione, tocopherol, and glutathione peroxidase) provide clues about demand imposed on the defense system. Exercise training is observed to result in an augmented antioxidant system and a reduction in lipid peroxidation. Supplementation with antioxidants appears to reduce lipid peroxidation but has not been shown to enhance exercise performance. (2)

.... there is more here:
http://findarticles.com/p/articles/m.../ai_104259139/


Since glutathione decreases after exercise, it makes sense to take NAC or some other chemical that stimulates the release of it. This article also showed that at least in one person, administration of glutathione before exercise increased his performance.

Exactly. I have read a thousand similar studies showing benefits to athletes from nutritional supplements. Think about this for a second. Creatine is an antioxidant. Hundreds of compounds can act as antioxidants. Not all antioxidants are the same and they should not all be classified as one, which studies seem to continue to do. Why do they keep using the wrong forms of nutrients and only one of two at a time? Am I that much more informed than educated scientists doing these studies? Seriously, what's going on here.


Direct Antioxidant Properties of Creatine


John M. Lawler1, William S. Barnes, Gaoyao Wu, Wook Song and Scott Demaree

Redox Biology and Cell Signaling Laboratory, Department of Health and Kinesiology, Department of Nutrition, Texas A&M University, College Station, Texas, 77843-4243


Abstract
Creatine is the most popular supplement proposed to be an ergogenic aid. There is some evidence in the literature that creatine supplementation increases lean body mass, muscular strength, and sprint power. However, the efficacy of creatine has not been consistent, and the potential mechanisms are unresolved. While limited evidence that suggests that creatine could possess an antioxidant effect this has not been tested directly. Because oxidants such as free radicals can affect muscle fatigue and protein turnover, it is important to know whether creatine can neutralize free radicals and other reactive oxygen species. We tested the hypothesis that creatine would remove superoxide anions (O?−2), peroxynitrite (OONO−), hydrogen peroxide, and lipid peroxides (t-butyl hydroperoxide). We also determined whether creatine displayed a significant antioxidant scavenging capacity (ASC) using 2,2′-azino-bis(3-ethylbenzothiazolamine-6-sulfonic acid) (ABTS+) quenching as a marker. Creatine did not significantly reduce levels of hydrogen peroxide or lipid peroxidation. In contrast, creatine displayed a significant ability to remove ABTS+, O?−2, and OONO− when compared with controls. Creatine quenching of ABTS+ was less than physiological levels of reduced glutathione (0.375 mM). To our knowledge, this is the first evidence that creatine has the potential to act as a direct antioxidant against aqueous radical and reactive species ions.




They used 1000mg Vit. C and 400iu of Vit.E from what I guess would be alpha-tocopherol and perhaps even a synthetic form? Anyone know this for sure?

Your body needs more than just two antioxidants to supplement and 8 forms of Vit.E with Tocotrienols playing a crucial function. 400iu of one form would be too much anyways... I am not a fan of high dosing most nutrients except in certain conditions.

It's just one study and doesn't seem to be a great one to me... Maybe it has some uses, but I believe proper supplementation can be a great thing.


They tested two 'vitamins' and likely one which is simply only one form of the nutrient (Vit.E) when there are 8 isomers of Vit.E that need to be supplemented in the ideal ratios, with gamma higher than alpha and with both tocopherol and tocotrienol nutrients available.


Simply using alpha tocopherol at a fairly high dose combined with Vit.C and then using the title, "Antioxidants prevent health-promoting effects of physical exercise in humans", seems rather misleading to me... well there are more than two antioxidants, many more... thousands more, so this is a very misleading title.

Now we have people thinking that all antioxidants and all vitamins may reduce exercise effects and be unhealthy. I don't believe this at all and think there are many reasons to use the right supplements at the right doses and forms. If we could post the thousands of positive studies on such nutrients on health, we would spend a week trying to read through the full thread.

[GeneGnomeX]

Exactly. I have read a thousand similar studies showing benefits to athletes from nutritional supplements.

?

Think about this for a second. Creatine is an antioxidant. Hundreds of compounds can act as antioxidants.

Lots of "antioxidants" that have potent reducing potential in vitro do not in vivo or even quite the opposite. I am far from expert but I do not believe you can strongly state that creatine in an biological context would do the same. Or, maybe it interrupts/prevents oxidation after signaling has taken place, or other reasons perhaps.

Not all antioxidants are the same and they should not all be classified as one, which studies seem to continue to do. Why do they keep using the wrong forms of nutrients and only one of two at a time? Am I that much more informed than educated scientists doing these studies? Seriously, what's going on here.

The point was to use a well established compound that has reducing potential which alpha tocopherol does. Most people who supplement with vitamin E take alpha tocopherol, I know you know this. Using all forms of E would not likely change these results, because there is existing research on the critical importance of ROS signaling mechanisms so they used something common and made it relevant.

Some authors go as far as suggesting that the negative results form the large meta analyses on "antioxidants" such as alpha tocopherol are because they attenuate the body's stress responses to environmental stressors. It is certainly a reasonable alternative to thinking it is only because of specific forms being used, as hormesis theory also has a lot of backing to it.

Your body needs more than just two antioxidants to supplement and 8 forms of Vit.E with Tocotrienols playing a crucial function. 400iu of one form would be too much anyways... I am not a fan of high dosing most nutrients except in certain conditions.

I know you are criticizing the title but that is the media interpretation, not the authors' conclusion.

And you must consider exercise intensity and duration- they may be warranted in extra intense exercise to mitigate overstressing but in the average weight trainer no way.

[GeneGnomeX]

Is this meant for Pre/Post workout or just in general with antioxidants? I remember seeing some of Dinoiii's posts related to antioxidants and that they can be detrimental post workout.

Could you elaborate on beneficial antioxidants, dosing and timing?

I would not take any in supplemental form around endurance exercise. Last I checked we don't know much about the role of ROS/RNS in adaptive response to resistance training, because signaling responses are completely different.

There are some that have "bigger" roles than their direct reducing potential, e.g. resveratrol, possibly quercetin, curcumin, etc. but these again may have both antioxidant and prooxidant effects in different biological contexts. I don't feel comfortable telling anyone to take any of them in supplemental form yet though.

And, many of the "antioxidants" from fruits/veg likely have subtoxic prooxidant effects which is why they are good for us- they initiate cellular stress protection mechanisms to better resist stressors (just like endurance exercise).

[factotum]

I would not take any in supplemental form around endurance exercise. Last I checked we don't know much about the role of ROS/RNS in adaptive response to resistance training, because signaling responses are completely different.

There are some that have "bigger" roles than their direct reducing potential, e.g. resveratrol, possibly quercetin, curcumin, etc. but these again may have both antioxidant and prooxidant effects in different biological contexts. I don't feel comfortable telling anyone to take any of them in supplemental form yet though.

And, many of the "antioxidants" from fruits/veg likely have subtoxic prooxidant effects which is why they are good for us- they initiate cellular stress protection mechanisms to better resist stressors (just like endurance exercise).

I'm thoroughly confused now. I was under the perception (perhaps now misconcpetion?) that ROS like H2O2 reduces the activity of kinases/PTPs in the insulin signaling cascade eventually leading to temporary cellular insulin resistance. This is a feeback loop system that ensures cells don't continue to absorb glucose until they explode like a Monty Python skit and ensures other cells have a chance to absorb glucose. Could it be that these aoxs are actually acting as pro-oxidants further driving H2O2 production and thus inducing insulin resistance? This would support the notion that aoxs are actually acting as pro-oxidants and causing minute damage that causes an upregulation in ROS defense mechanisms like SOD or in repair mechanisms. And also why large dosages should be avoided as you create too much damage.

But would taking something like r-ala which converts to dihydrolipoate which can buffer H2O2 be of benefit as it should reduce insulin resistance to some degree?

[Heracles25]

I would not take any in supplemental form around endurance exercise. Last I checked we don't know much about the role of ROS/RNS in adaptive response to resistance training, because signaling responses are completely different.

There are some that have "bigger" roles than their direct reducing potential, e.g. resveratrol, possibly quercetin, curcumin, etc. but these again may have both antioxidant and prooxidant effects in different biological contexts. I don't feel comfortable telling anyone to take any of them in supplemental form yet though.

And, many of the "antioxidants" from fruits/veg likely have subtoxic prooxidant effects which is why they are good for us- they initiate cellular stress protection mechanisms to better resist stressors (just like endurance exercise).

Thank you for the informative reply Gene!

[Peter LeDrew]

?

I know you are criticizing the title but that is the media interpretation, not the authors' conclusion.

The authors' title I have is: Antioxidants prevent health-promoting effects of physical exercise in humans. That was what I was referring to.

You make some excellent points and maybe there is more to this... but I really think the study designs need much improvement before jumping to conclusions.


I am not certain the results would be the same using a full spectrum of Vit.E and I don't think you could draw such a conclusion when only 400iu of Alpha was used. Adding in other important network antioxidants (CoQ10, the other 7 E isomers, selenium, NAC, R-lipoic acid) and antioxidant network boosters from fruit/herb extracts (Grape seed, Green tea, curcumin, cocoa, pine bark, etc.) would also be useful in such an experiment when drawing conclusions to a study titled: 'Antioxidants' prevent health-promoting effects of physical exercise in humans.

Actually looking at the research on many of these compounds I listed above, they have quite a few solid studies showing benefits against insulin resistance, syndrome X, obesity and reducing the risk of type 2 Diabetes. Exactly the opposite results of this study, which unfortunately only used 1000mg vit.C and 400iu of alpha-tocopherol as their 'Antioxidants' of choice.


I remain inclined to believe that a smart moderate regimen of the compounds I listed above, alongside an ideal diet, will actually INCREASE the health-promoting effects of exercise. We still have no proof either way and this study does little to change that imo.

[dirkwright]

What I don't understand is that if glutathione decreases after exercise, as shown by the article I posted, how can anyone say that the body responds to oxidative stress by increasing the production of free radical scavenging molecules like glutathione? Here's an older article about this:

Exhaustive physical exercise causes oxidation of glutathione status in blood: prevention by antioxidant administration

J. Sastre, M. Asensi, E. Gasco, F. V. Pallardo, J. A. Ferrero, T. Furukawa and J. Vina
Departamento de Fisiologia, Universidad de Valencia, Spain.

We have studied the effect of exhaustive concentric physical exercise on glutathione redox status and the possible relationship between blood glutathione oxidation and blood lactate and pyruvate levels. Levels of oxidized glutathione (GSSG) in blood increase after exhaustive concentric physical exercise in trained humans. GSSG levels were 72% higher immediately after exercise than at rest. They returned to normal values 1 h after exercise. Blood reduced glutathione (GSH) levels did not change significantly after the exercise. We have found a linear relationship between GSSG-to-GSH and lactate-to-pyruvate ratios in human blood before, during, and after exhaustive exercise. In rats, physical exercise also caused an increase in blood GSSG levels that were 200% higher after physical exercise than at rest. GSH levels did not change significantly. Thus, both in rats and humans, exhaustive physical exercise causes a change in glutathione redox status in blood. We have also found that antioxidant administration, i.e., oral vitamin C, N-acetyl-L-cysteine, or glutathione, is effective in preventing oxidation of the blood glutathione pool after physical exercise in rats.

http://ajpregu.physiology.org/cgi/co...act/263/5/R992


I think that's pretty clear at least as regards what happens to our glutathione levels after exercising.

[dirkwright]

N-acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals

I. Medved,1 M. J. Brown,2 A. R. Bjorksten,3 K. T. Murphy,1 A. C. Petersen,1 S. Sostaric,1 X. Gong,1 and M. J. McKenna1
1Muscle, Ions and Exercise Group, School of Human Movement, Recreation and Performance; Centre for Aging, Rehabilitation, Exercise and Sport Science, Victoria University of Technology, Melbourne 8001; 2Department of Anaesthesia, Austin and Repatriation Medical Centre, Melbourne 3084; and 3Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne, Victoria 3052, Australia

Submitted 6 April 2004 ; accepted in final form 7 June 2004

The production of reactive oxygen species in skeletal muscle is linked with muscle fatigue. This study investigated the effects of the antioxidant compound N-acetylcysteine (NAC) on muscle cysteine, cystine, and glutathione and on time to fatigue during prolonged, submaximal exercise in endurance athletes. Eight men completed a double-blind, crossover study, receiving NAC or placebo before and during cycling for 45 min at 71% peak oxygen consumption (O2 peak) and then to fatigue at 92% O2 peak. NAC was intravenously infused at 125 mg?kg?1?h?1 for 15 min and then at 25 mg?kg?1?h?1 for 20 min before and throughout exercise. Arterialized venous blood was analyzed for NAC, glutathione status, and cysteine concentration. A vastus lateralis biopsy was taken preinfusion, at 45 min of exercise, and at fatigue and was analyzed for NAC, total glutathione (TGSH), reduced glutathione (GSH), cysteine, and cystine. Time to fatigue at 92% O2 peak was reproducible in preliminary trials (coefficient of variation 5.6 ? 0.6%) and with NAC was enhanced by 26.3 ? 9.1% (NAC 6.4 ? 0.6 min vs. Con 5.3 ? 0.7 min; P < 0.05). NAC increased muscle total and reduced NAC at both 45 min and fatigue (P < 0.005). Muscle cysteine and cystine were unchanged during Con, but were elevated above preinfusion levels with NAC (P < 0.001). Muscle TGSH (P < 0.05) declined and muscle GSH tended to decline (P = 0.06) during exercise. Both were greater with NAC (P < 0.05). Neither exercise nor NAC affected whole blood TGSH. Whereas blood GSH was decreased and calculated oxidized glutathione increased with exercise (P < 0.05), both were unaffected by NAC. In conclusion, NAC improved performance in well-trained individuals, with enhanced muscle cysteine and GSH availability a likely mechanism.

http://jap.physiology.org/cgi/conten...ract/97/4/1477


So NAC is good then? Having higher glutathione levels is good too?

I know NAC is not vitamin C or E, but I thought this is a related topic anyway.

[Peter LeDrew]

N-acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals

I. Medved,1 M. J. Brown,2 A. R. Bjorksten,3 K. T. Murphy,1 A. C. Petersen,1 S. Sostaric,1 X. Gong,1 and M. J. McKenna1
1Muscle, Ions and Exercise Group, School of Human Movement, Recreation and Performance; Centre for Aging, Rehabilitation, Exercise and Sport Science, Victoria University of Technology, Melbourne 8001; 2Department of Anaesthesia, Austin and Repatriation Medical Centre, Melbourne 3084; and 3Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne, Victoria 3052, Australia

Submitted 6 April 2004 ; accepted in final form 7 June 2004

The production of reactive oxygen species in skeletal muscle is linked with muscle fatigue. This study investigated the effects of the antioxidant compound N-acetylcysteine (NAC) on muscle cysteine, cystine, and glutathione and on time to fatigue during prolonged, submaximal exercise in endurance athletes. Eight men completed a double-blind, crossover study, receiving NAC or placebo before and during cycling for 45 min at 71% peak oxygen consumption (O2 peak) and then to fatigue at 92% O2 peak. NAC was intravenously infused at 125 mg?kg?1?h?1 for 15 min and then at 25 mg?kg?1?h?1 for 20 min before and throughout exercise. Arterialized venous blood was analyzed for NAC, glutathione status, and cysteine concentration. A vastus lateralis biopsy was taken preinfusion, at 45 min of exercise, and at fatigue and was analyzed for NAC, total glutathione (TGSH), reduced glutathione (GSH), cysteine, and cystine. Time to fatigue at 92% O2 peak was reproducible in preliminary trials (coefficient of variation 5.6 ? 0.6%) and with NAC was enhanced by 26.3 ? 9.1% (NAC 6.4 ? 0.6 min vs. Con 5.3 ? 0.7 min; P < 0.05). NAC increased muscle total and reduced NAC at both 45 min and fatigue (P < 0.005). Muscle cysteine and cystine were unchanged during Con, but were elevated above preinfusion levels with NAC (P < 0.001). Muscle TGSH (P < 0.05) declined and muscle GSH tended to decline (P = 0.06) during exercise. Both were greater with NAC (P < 0.05). Neither exercise nor NAC affected whole blood TGSH. Whereas blood GSH was decreased and calculated oxidized glutathione increased with exercise (P < 0.05), both were unaffected by NAC. In conclusion, NAC improved performance in well-trained individuals, with enhanced muscle cysteine and GSH availability a likely mechanism.

http://jap.physiology.org/cgi/conten...ract/97/4/1477


So NAC is good then? Having higher glutathione levels is good too?

I know NAC is not vitamin C or E, but I thought this is a related topic anyway.

I think NAC is a great supplement esp. combined with various other synergistic nutrients and antioxidants. I wouldn't go too high dosing wise though.

[michael3435]

I feel strongly that large dosing of antioxidants with the exception of a few will reduce lifespan.

like which few? very interested in this topic.

[Autobody]

Fish oil kills anabolism :O

[JacktheHero]

Now we have people thinking that all antioxidants and all vitamins may reduce exercise effects and be unhealthy.

I really hope so. It is easier to screw up your metabolism than it is to improve it. If there's no positive data (that you know of) you should always assume those substances to be dangerous.

...there are many reasons to use the right supplements at the right doses and forms.

Probably, yes. The only issue is that we don't know what the right supplements and right doses are in most cases....