[imark3000]

what do you think?
Imad

Do Antioxidants Curb an Exercise Benefit?Study Shows Some Supplements May Affect the Impact of Exercise on Insulin Sensitivity
By Miranda Hitti
WebMD Health NewsReviewed by Elizabeth Klodas, MD, FACC May 11, 2009 -- Taking antioxidant supplements -- specifically, vitamin C and vitamin E pills -- may dull one of the benefits of exercise, new research shows.

The exercise benefit in question is better sensitivity to insulin, a hormone that regulates blood sugar.

The new study shows that when healthy men took vitamin C and vitamin E supplements daily during a month of exercise, their insulin sensitivity didn't improve, though other men following the same exercise plan and taking placebo pills did improve their insulin sensitivity.

The antioxidant supplements shut down the brief, normal spike in oxidation that follows exercise; that temporary bout of oxidation is needed to improve insulin sensitivity, according to the researchers, who included Michael Ristow, MD, chair of the department of human nutrition at Germany's University of Jena.

"The data confirm that exercise exerts positive effects on glucose metabolism, and thus may prevent type 2 diabetes," Ristow tells WebMD via email. He adds that the results also "suggest, for the first time, that these effects are mediated by free radicals or oxidative stress that are caused by exercise, and that antioxidants interfere with this health-promoting effect of exercise."

But Andrew Shao, PhD, vice president for scientific and regulatory affairs at the Council for Responsible Nutrition (a trade group for the supplements industry), says people shouldn't jump to conclusions based on one report.

Supplements and Exercise Study
Ristow's study included 40 healthy men in Germany. When the study started, half of the men were sedentary and half got regular exercise.

The researchers put all of the men on a monthlong exercise plan. For four weeks, the men got 85 minutes of exercise on five consecutive days per week.

During each session, the men wore heart rate monitors while they biked or ran for 20 minutes, did circuit training for 45 minutes, and spent a total of 20 minutes warming up and cooling down.

Throughout the study, half of the men took 500 milligrams of vitamin C twice daily and 400 international units of vitamin E daily. For comparison, the other men took placebo pills.

Lab tests done at the beginning and end of the study show that insulin sensitivity improved for all of the men taking the placebo pills -- but not for any of the men taking the antioxidants.

"Physical activity induced an increase in insulin sensitivity only in the absence of antioxidants," Ristow and colleagues write in the advance online edition of Proceedings of the National Academy of Sciences.

But don’t take this study to mean that if you’re active you should avoid antioxidant-rich fruits and vegetables. Fruits and vegetables are still beneficial because they "contain hundreds of other substances and compounds that are health-promoting," Ristow tells WebMD.

Supplements Industry Responds
Ristow's study was "well designed" and "interesting," says Shao.

But Shao says the study was small and "is really an incomplete picture" of the relationship between antioxidants and exercise.

Shao notes that antioxidants may help mend muscle damage, that not all antioxidants may act like vitamins C and E, and that different doses or the timing of when the doses were taken may matter.

Ristow says it's possible that the timing of when the supplements were taken might matter, "but we have not studied this."

[imark3000]

Moderate exercise is an antioxidant: upregulation of antioxidant genes by training.
Gomez-Cabrera MC, Domenech E, Viña J.

Department of Physiology, Faculty of Medicine, University of Valencia, Blasco Ibañez, 15, 46010 Valencia, Spain.

Abstract
Exercise causes oxidative stress only when exhaustive. Strenuous exercise causes oxidation of glutathione, release of cytosolic enzymes, and other signs of cell damage. However, there is increasing evidence that reactive oxygen species (ROS) not only are toxic but also play an important role in cell signaling and in the regulation of gene expression. Xanthine oxidase is involved in the generation of superoxide associated with exhaustive exercise. Allopurinol (an inhibitor of this enzyme) prevents muscle damage after exhaustive exercise, but also modifies cell signaling pathways associated with both moderate and exhaustive exercise in rats and humans. In gastrocnemius muscle from rats, exercise caused an activation of MAP kinases. This in turn activated the NF-kappaB pathway and consequently the expression of important enzymes associated with defense against ROS (superoxide dismutase) and adaptation to exercise (eNOS and iNOS). All these changes were abolished when ROS production was prevented by allopurinol. Thus ROS act as signals in exercise because decreasing their formation prevents activation of important signaling pathways that cause useful adaptations in cells. Because these signals result in an upregulation of powerful antioxidant enzymes, exercise itself can be considered an antioxidant. We have found that interfering with free radical metabolism with antioxidants may hamper useful adaptations to training.
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This supports the argument against antioxident supplements !!?
Imad

[imark3000]

Antioxidant Function of Vitamin A, C and E-Vitamin
By Robin Kumar Lim
Vitamin C, vitamin E (tocopherols), and some precursors to vitamin A (the carotenoids) exhibit antioxidant activity. Each of these vitamins has independently been shown to alter immunity. The antioxidant function of these vitamins is of interest to some athletes primarily because exercise increases the production of reactive oxygen species (ROS) which have been associated with muscular fatigue and muscular damage. In addition, neutrophils and macro phages produce ROS. The ROS produced by the immune system may have a role in modulating post-exercise muscle damage.

The other reason that vitamins A, C, and E may be of interest to athletes relates to their potential immunostimulatory properties. The antioxidant properties of the vitamins may differ from the immunomodulatory effects.

Reactive oxygen species (ROS) are produced during strenuous exercise, result in oxidative stress, and are associated with a depletion of antioxidants, muscle damage, and fatigue. High concentrations of antioxidants may protect against the damaging effects of ROS. An assumption has been made that a high intake of vitamins A, C, E, or betacarotene may protect against the exercise-induced oxidative stress and several studies have examined this possibility. Vitamin E (alpha-tocopherol) is considered the most important scavenger of ROS at the level of membranes and is probably the most well studied with respect to exercise.

Several studies have established that exercise training is associated with a decrease in the accumulation of the products used to assess oxidative stress or an enhancement of antioxidant enzymes. The findings from some studies suggest that vitamin E supplementation may protect against the oxidative damage induced by exercise. However, the results from both human and animal studies show that vitamin E supplementation does not improve performance and may not attenuate muscular damage following a marathon.

An understanding of interactions between the immune system, ROS production, and muscle damage may provide some insight regarding antioxidants and exercise-induced muscle damage. Although these interactions are not completely understood at this time, it appears that the production of ROS by cells of the immune system may be an important part of the post-exercise muscle repair process. Neutrophils and macrophages appear to infiltrate sites of post-exercise muscle damage and both of these cell types produce ROS. The release of ROS can enhance the release of cytokines and cytokines can induce the production of ROS The release of both cytokines and ROS are important in removing damaged muscle tissue and may assist in the repair process. The findings from a recent study suggest that the generation of ROS post-exercise may be beneficial in the repair process. In this study, normal mice demonstrated greater oxidative stress post-exercise than mice with inhibited neutrophil function; however, 4 days later normal mice showed evidence of less muscle damage Based on this evidence and findings from other studies mentioned previously, it should be noted that the production of free radicals or ROS during exercise may be an important part of the muscle tissue repair process and the consumption of high levels of antioxidants may not necessarily be beneficial
Some researchers have examined life span and whether it can be extended by increased antioxidant intake. The evidence from two recent studies suggests that supplementing diets with high levels of antioxidants does not increase maximum life span and exercised rodents fed a diet containing additional antioxidants did not have a greater life span than exercised rodents on a normal diet. It appears that although exercise may be associated with a greater production of ROS, this does not result in a shortened life span and the consumption of additional antioxidants confers no additional increase in longevity.Taken together, the findings from the studies above suggest that additional antioxidants do not improve performance, do not appear to improve muscle tissue repair post-exercise, and are not beneficial in terms of increasing life span in exercised rodents. Although the interactions between the immune system and ROS produced during exercise need further research, at this time it does not appear that additional antioxidants will enhance immune responses such as post-exercise muscle tissue repair.

Author has an experience of more than 4 years writing about benefits of vitamins. He also holds experience writing about fitness supplements and history of yoga.

Article Source: http://EzineArticles.com/?expert=Robin_Kumar_Lim

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Imad

[Conductor71]

Originally Posted by imark3000

[/B][/COLOR]Taken together, the findings from the studies above suggest that additional antioxidants do not improve performance, do not appear to improve muscle tissue repair post-exercise, and are not beneficial in terms of increasing life span in exercised rodents.

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Imad

Imad,

I can see how this conclusion might look confusing when seen through our eyes or looking at what is hppening in our brains, but I question why a study like this is even necessary. ROS, is in and of itself not a bad thing; it is in fact good for us; it sets the stage for aptoptosis or timed cell death; it rids our system of the very things that would make us sick; it works to clear our system of malformed or damaged cells; the kind that can proliferate into cancers. etc. Note how we have been posting about balance and homeostasis? Well, in healthy individuals, ROS is beneficial because they have a normal supply of a range of enzymes to keep the ROS in check.

In a dis-ease state we lose that balance, somewhere in the enzyme protection area, I think IMHO, or later in process with mitochondrial dysfunction. Problem is in PD this is the key to our problem; research shows that it could be a variety of things at this point that cause PD. PD starts as a normal, healthy immune response to maintain our balance and state of health, somehow (this is what we need to know) our brains do not know how to shut off this process and in the absence of any viral or bacterial invader, our brains end up attacking our normal, healthy dopamine cells.

I think Wikipedia provides the clearest overview of ROS

http://en.wikipedia.org/wiki/Reactive_oxygen_species

Hope this helps answer your question.

Laura

[imark3000]

My problem is that I exercise vigorously daily for one or two hours and I take a load of vitamines and antioxidants. These articles indicate that the antioxidant supplements may negate the benifits of exercise, at least in healthy people.
I enjoy exercise and feel it is doing me good but I don't know if I should continue taking the antioxidants.
I know it is a delicate balance which is lost in disease but who knows what best to do to regain it?
Imad

[paula_w]

Originally Posted by imark3000

My problem is that I exercise vigorously daily for one or two hours and I take a load of vitamines and antioxidants. These articles indicate that the antioxidant supplements may negate the benifits of exercise, at least in healthy people.
I enjoy exercise and feel it is doing me good but I don't know if I should continue taking the antioxidants.
I know it is a delicate balance which is lost in disease but who knows what best to do to regain it?
Imad

hi imad,
The exercise is imperatve. Next doctor's appt.can you have your vitamin levels checked? you don't want to lose the benefits of exercise. it will actually slow the progression of illness, if not pd, other illnesses that strike the aged. eat oranges perhaps? orange juice? You are one of the most disciplined exercisers i know. it is the best thing we can do. i have no back spasms and have gained 12 pounds since i started aquafit classes. Don't want to gain anymore. I wasn't sure I' d ever have that problem again.

you may not need these vitamins and they might be expensive "pee" excuse my language.

[imark3000]

Hoping that the topic interest you ? If so, I am waiting for your science
Imad

[Conductor71]

Originally Posted by imark3000

My problem is that I exercise vigorously daily for one or two hours and I take a load of vitamines and antioxidants. These articles indicate that the antioxidant supplements may negate the benifits of exercise, at least in healthy people.
I enjoy exercise and feel it is doing me good but I don't know if I should continue taking the antioxidants.
I know it is a delicate balance which is lost in disease but who knows what best to do to regain it?
Imad

Apologies, I didn't see that you shared this earlier in the thread so didn't get that you were looking at this as applying to your own routine. From this view point, I can see what you mean, but I agree with Paula that benefit of exercise far outweighs any thing else in their findings.

Oh, by saying that the research seemed unnecessary I didn't mean they are not relevant here or inconsequential in any way; I honestly did not know the author's intent or get the gist of the research itself. Are they saying that many people use supplements to control ROS? I guess if we know it is normally benign I don't see why anyone would choose to do so. In other words, I am even more dazed and confused than usual.

Yes, where exactly are you Rick? Leave behind the aldosterone for awhile and help us out!

Laura