antiossidanti e pesi

[Dott.FreeRadical]

1) Abbiate pazienza.. se vi allenate usate l'ossigeno, e più ossigeno usate maggiore è l'ossidazione, a meno che non siete marziani ed usate l'azoto per respirare.
2) chi si allena ha un livello di stress ossidativo più basso di chi non si allena ma lo ha! lo studio postato dice se la valutazione è stata fatta dopo 30 min, 1 ora, 2 ore ,3 ore dopo l'allenamento???
3) provate su di voi, fatevi una valutazione prima dell'allenamento e 30 min dopo ..a quel punto postate i risultati.

Eagle mi sembra in gamba ed anche ricercatore, mi fido di lui. (se fosse stato più vicino glielo avrei fatto io in 5 min davanti a lui).

4) non abusate MAI di antiossidanti cmq, perchè i radicali liberi servono.

[Dott.FreeRadical]

inoltre...

l'organismo prevede l'esistenza di radicali liberi tant'è che ha sviluppato 3 enzimi antiossidanti (che abbiamo tutti) per eliminare i radicali liberi dell'osigeno. I tre enzimi antiossidanti sono la Superossido dismutasi, Il Glutatione perossidasi e la Catalasi. Secondo voi la natura li ha creati inutilmente?

[master wallace]

Tutte le attivita' che aumentano il consumo di ossigeno, aumentano di pari passo l'ossidazione, se non altro perche' i mitocondri lavorano di piu'.
E i recuperi nel BB, specie fra le serie, aumentano il consumo d'ossigeno.Se poi ci aggiungiamo anche un po' d'aerobica, una dieta ricca di proteine,e altri fattori, e' evidente che l'ossidazione globale aumenta con conseguente maggiore produzione di radicali liberi.
E' pero' vero che gli atleti allenati hanno un sistema antiossidante endogeno piu' forte e l'ossidazione e ' minore.Ma nulla toglie alla grande utlita' degli antiossidanti, sia ai fini del recupero che ai fini della salute.
Ormai il ruolo dei radicali liberi nella eziologia di numerose patologie e' acclarata, e rinunciare alla difesa dell'organismo, non assumendo dosi adeguate di antiossidanti naturali e sintentici e' autolesionismo puro.

[Socio]

comunque gli sprint non erano eccentrici

[master wallace]

l'organismo prevede l'esistenza di radicali liberi tant'è che ha sviluppato 3 enzimi antiossidanti (che abbiamo tutti) per eliminare i radicali liberi dell'osigeno. I tre enzimi antiossidanti sono la Superossido dismutasi, Il Glutatione perossidasi e la Catalasi. Secondo voi la natura li ha creati inutilmente?

Certo che li ha creati, e i radicali liberi hanno una funzione utile sull'organismo, ma solo entro certi limiti.Quando sono eccessivi arrivano i danni, inoltre con l'eta' il sistema lavora sempre meno bene.Da qui l'utilita' d'integrare sia con antiossidanti esogeni, sia con sostanze che potenziano quelli endogeni tipo la glutamina, l'acetilcisteina e altri.
Forse pochi sanno che gli steroidi aumentano di paercchio la produzione del coenzima q-10, e da questo fatto alcuni ricercatori hanno ipotizzato che nonostante questi farmaci possono danneggiare il cuore attraverso meccanismi diretti(ipertrofia cardiaca) o indiretti( pressione ateriosa piu' alta, dislipidemie. .) in realta' in danni sono minori del previsto proprio in relazione all'aumento del q-10 che come e' noto protegge il cuore e ne migliora la funzione.
Bisogna poi citare il ruolo cruciale dei radicali liberi nel danno ossidativo a carico delle arterie, che secondo molti ricercatori e' la vera causa della arteriosclerosi e aterosclerosi, indipendentemente dai livelli di colesterolo.

[bloodz]

1) Abbiate pazienza.. se vi allenate usate l'ossigeno, e più ossigeno usate maggiore è l'ossidazione, a meno che non siete marziani ed usate l'azoto per respirare.
2) chi si allena ha un livello di stress ossidativo più basso di chi non si allena ma lo ha! lo studio postato dice se la valutazione è stata fatta dopo 30 min, 1 ora, 2 ore ,3 ore dopo l'allenamento???
3) provate su di voi, fatevi una valutazione prima dell'allenamento e 30 min dopo ..a quel punto postate i risultati.

Eagle mi sembra in gamba ed anche ricercatore, mi fido di lui. (se fosse stato più vicino glielo avrei fatto io in 5 min davanti a lui).

4) non abusate MAI di antiossidanti cmq, perchè i radicali liberi servono.

quoto in tutto e chiedo: come possiamo valutarlo da noi?

[bloodz]

Ormai il ruolo dei radicali liberi nella eziologia di numerose patologie e' acclarata, e rinunciare alla difesa dell'organismo, non assumendo dosi adeguate di antiossidanti naturali e sintentici e' autolesionismo puro.

[corlis1]

Tutte le attivita' che aumentano il consumo di ossigeno, aumentano di pari passo l'ossidazione, se non altro perche' i mitocondri lavorano di piu'.
E i recuperi nel BB, specie fra le serie, aumentano il consumo d'ossigeno.Se poi ci aggiungiamo anche un po' d'aerobica, una dieta ricca di proteine,e altri fattori, e' evidente che l'ossidazione globale aumenta con conseguente maggiore produzione di radicali liberi.
E' pero' vero che gli atleti allenati hanno un sistema antiossidante endogeno piu' forte e l'ossidazione e ' minore.Ma nulla toglie alla grande utlita' degli antiossidanti, sia ai fini del recupero che ai fini della salute.
Ormai il ruolo dei radicali liberi nella eziologia di numerose patologie e' acclarata, e rinunciare alla difesa dell'organismo, non assumendo dosi adeguate di antiossidanti naturali e sintentici e' autolesionismo puro.

ahime' sono daccordo

[Eagle]

1) Abbiate pazienza.. se vi allenate usate l'ossigeno, e più ossigeno usate maggiore è l'ossidazione, a meno che non siete marziani ed usate l'azoto per respirare.
2) chi si allena ha un livello di stress ossidativo più basso di chi non si allena ma lo ha! lo studio postato dice se la valutazione è stata fatta dopo 30 min, 1 ora, 2 ore ,3 ore dopo l'allenamento???
3) provate su di voi, fatevi una valutazione prima dell'allenamento e 30 min dopo ..a quel punto postate i risultati.

Eagle mi sembra in gamba ed anche ricercatore, mi fido di lui. (se fosse stato più vicino glielo avrei fatto io in 5 min davanti a lui).

4) non abusate MAI di antiossidanti cmq, perchè i radicali liberi servono.

non ho capito la frase in rosso e come facciamo a fare una valutazione da soli ... prego chiarire

Ribadisco che non sono assolutamente un esperto in radicali liberi e altre diavolerie di questo tipo.

Ho solo fatto qualche ricerchina in rete, letto e ragionato.
Mi sembra di capire che gli antiossidanti ci vogliono, e ci sono già, li fabbrica l'organismo, e una eventuale integrazione NON necessaria possa portare anche a danni.

Solo questo.

Poi che in alcune patologie sia accertato il ruolo dei radicali liberi, così come il fatto che ogni attività, di qualsiasi tipo o quasi, produca radicali liberi, sono considerazioni che lasciano il tempo che trovano, secondo me.

Il punto è capire se fare i pesi e seguire il famoso stile di vita del bb, conduca ad una situazione in cui fa bene assumere dosi extra di antiossidanti, e QUALI dosi (basse, alte, a cicli, pre e post wo, boh?) oppure sia superfluo, oppure addirittura potenzialmente dannoso.

Devo dire che quanto letto, e riportato negli studi, non è particolarmente a favore di una integrazione, di certo non di una integrazione a dosaggi elevati.

Se qualcuno ha qualche cosa da aggiungere sarebbe molto bello ed utile che la corredasse di evidenze REALI. Le opinioni le abbiamo tutti e sono molto interessanti, ma, dati alla mano, spesso cambiano di anno in anno, e, quindi, contano molto poco (sempre secondo me).

Eagle

[Eagle]

Altre "chicche" da leggere ...

neurotossicità da eccesso di vitamina B6, negli uomini ... i topini che integrano con la vit C crepano prima ... etc etc

http://www.medrounds.org/encyclopedia-of-aging/2005/12/antioxidants.html

antioxidants


antioxidants
With normal metabolism, free radicals (a free radical is a small molecule with an impaired electron) are a normal byproduct. Antioxidants prevent or neutralize free radicals.
Antioxidants are a diverse group of chemicals that include vitamins A and C, selenium, cysteine, and the food preservative BHT. The Life Extension Foundation in Florida advocates high doses of antioxidants as one of the regimens for prolonging life. However, detractors, including the House Select Committee on Aging, believe such views are false and misleading with no evidence to support retarding, much less reversing, the aging process. Many of the food-related ingredient antioxidants are dangerous in very large quantities, although they are quite safe in the much smaller amounts found in a normal diet. The known risks of the antioxidants include headaches, intestinal disorders, and kidney damage.

Megadoses of vitamin C actually shortened the lives of guinea pigs in laboratory experiments.

Long-term consumption of two grams a day of vitamin B6 has been shown to produce disabling sensory neuropathy in humans. Selenium is an essential nutrient and may play an antioxidant role in the body, but in excessive amounts is toxic.
There may be additional risks that have not yet been identified.

[Eagle]

E ancora ...


Are Antioxidants Bad for the Heart?

From Richard N. Fogoros, M.D.,
Your Guide to Heart Disease.
FREE Newsletter. Sign Up Now!
About.com Health's Disease and Condition content is reviewed by our Medical Review Board
A new study suggests this might be so

Dateline: August 20, 2001
Researchers from the University of Washington have reported that patients taking antioxidant vitamins in addition to statin and niacin therapy failed to increase their HDL cholesterol (the "good" cholesterol) as much as patients not taking antioxidants. These results, reported in the August 9, 2001 issue of Arteriosclerosis, Thorombosis, and Vascular Biology, are but the latest in a series of disappointing results in trials examining the ability of antioxidants to prevent heart disease.
It has long been believed that antioxidant supplements like vitamins E and C might help slow or even prevent the formation of plaques within coronary arteries. Indeed, several epidemiological studies seem to confirm that antioxidant vitamins can improve outcomes. As a result, millions of individuals (including many doctors) now routinely take vitamin E and C supplements. Randomized trials have not been kind to antioxidants

During the last two years, a number of randomized trials using antioxidant vitamin supplements have finally been reported, and the results have generally been disappointing. Because of the failure of randomized trials to demonstrate a benefit from taking antioxidants, both the American Heart Association and the Institute of Medicine have released recent statements saying that, while a diet rich in antioxidant vitamins seems prudent, there is insufficient evidence to recommend using supplements of of vitamin C, vitamin E, beta-carotine, selenium, or other antioxidants to prevent heart disease. The latest study suggests the possibility of harm

The study from the University of Washington, reported last week, brings up the possibility that antioxidant therapy may do more than merely fail to halt the progression of coronary artery disease. This new study suggests the possibility of harm.
In this trial, patients with coronary artery disease who also had low levels of HDL cholesterol were randomly assigned to one of 4 groups: 1) low-dose statin and niacin therapy; 2) low-dose statin and niacin therapy plus a cocktail of antioxidants; 3) a cocktail of antioxidants without statin and niacin, and 4) placebo. The cocktail of antioxidants consisted of vitamin E, vitamin C, beta-carotene, and selenium. The study results showed that the increase in HDL levels seen in patients receiving statin-niacin therapy was eliminated when they also received the antioxidants. That is, in these patients the antioxidants were potentially harmful.
As it turns out, this "negative" finding is less than statistically perfect. (The finding that antioxidants would reduce HDL levels was not postulated ahead of time by the investigators, but instead was discovered in a routine review of their data, bringing up the possibility that the reported finding was a random data error instead of an actual physiologic phenomenon.) But the primary endpoints of the study also suggest that antioxidants blunt the benefits seen with statin-niacin therapy. (While patients receiving statin-niacin had a 4% reduction in coronary artery blockage, those who received antioxidants in addition to statin-niacin had a 7% increase in blockage. In contrast, those receiving antioxidants alone had a 15% increase in blockage, and those receiving placebo had a 34% increase in blockage.)
The bottom line: this new study seems to validate the unpopular stance on antioxidant supplements taken by both the American Heart Association and the Institute of Medicine. What to do about antioxidants

DrRich is sorry to say that he must agree with the policy statements of the AHA and the IOM. So far, there is insufficient data from well-designed randomized trials to issue a general recommendation for people to take supplements of the antioxidant vitamins in order to prevent heart disease. Eating lots of fruits and vegetables - in other words, a good diet - seems the most prudent course at the moment. But are antioxidants actively harmful? Based on data from randomized trials completed to date, it is likely that they are usually not harmful. But it does seem prudent to recommend that - especially if statins and niacin are being used in the attempt to increase HDL levels - either antioxidant supplements should be avoided, or at the very least, HDL levels should be remeasured both with and without antioxidant supplementation, in order to document whether those supplements are blunting the benefits of statin-niacin therapy.

[Eagle]

...



4 May 2004
Antioxidants May Increase "Bad" Cholesterol
The idea that antioxidant vitamins provide a safe, convenient way to protect the heart from disease appears to have hit a snag. Instead of protecting the heart, a new study suggests that the vitamins, such as E, C, and beta carotene, could raise the liver's production of the so-called bad form of cholesterol, which transports cholesterol into artery walls.
The study, led by New York University School of Medicine researcher Edward A. Fisher, is published in the Journal of Clinical Investigation.
"It does appear that antioxidant vitamins may be potentially harmful for the heart based on their ability to increase the secretion of VLDL (very low density lipoprotein) in the liver cells and in the mice that we studied," says Dr. Fisher.
After its secretion from the liver, VLDL is converted in the bloodstream to low-density lipoprotein (LDL), the so-called bad form of cholesterol. The liver is the major source of atherosclerosis-causing lipoproteins. "However, our study is the first to document this association between antioxidant vitamins and VLDL cholesterol, and more studies are needed to back up our findings," says Dr. Fisher. "Until more data becomes available, we can't make any recommendations about whether people should not use these vitamins."
Antioxidants usually have been considered healthful. The vitamins scavenge "free radicals", which are highly reactive and damaging forms of oxygen produced by natural metabolic processes in the body and by external sources like the sun's UV rays, ozone, and toxins in pesticides. In the early 1990s, laboratory studies suggested that antioxidant vitamins prevented biochemical changes that made cholesterol form plaques that can block blood flow through the arteries. Although some subsequent clinical studies seemed to back up these findings, others did not.
The new study by Dr. Fisher and his colleagues provides a different perspective on antioxidants. Surprisingly, his group found that antioxidants hampered a process in the liver that prevents the production of harmful lipoproteins.
In further experiments, vitamin E, a well-known antioxidant, prevented the activation of the lipoprotein-breakdown pathway in rat and mouse liver cells. Thus, the liver destroyed fewer of the bad lipoproteins.
The study also explains why polyunsaturated fatty acids, the good fatty acids found in cold water fish, are healthy for the heart. In another series of experiments, the scientists show that omega-3 and omega-6 fatty acids activated the pathway in the liver that breaks down the bad lipoproteins. Dr. Fisher's group recently described this pathway, which they dubbed PERPP for post-ER presecretory proteolysis.
The scientists also found that the polyunsaturated fatty acids increased the generation of lipid peroxidation products (these compounds produce the nasty smell of rancid fish) and stimulated the PERPP pathway. In addition to the studies with liver cells in laboratory dishes, they also demonstrated the relationship between lipid peroxidation and reduced production of bad lipoproteins in living mice.
Dr. Fisher plans to conduct further experiments in mice to confirm these findings. Direct experimentation in people to explore the inner workings of the liver is difficult, says Dr. Fisher, "but there are already observational studies in normal people showing that a diet enriched in polyunsaturated fats increases blood levels of lipid peroxides and decreases levels of VLDL and LDL." Antioxidants may still have beneficial affects on other parts of the body, says Dr. Fisher. The molecules, for example, have been shown in some animal studies to protect the arteries from atherosclerosis and the pancreas and other organs from damage caused by diabetes. "In other words, oxidant stress is damaging in some contexts, but probably beneficial in others," he says. "In terms of the risk of cardiovascular disease," he adds, "the previous view that all oxidant stress is bad is probably an oversimplification."

[Eagle]

... possono accelerare la comparsa del diabete ...

When Good Antioxidants Are Bad

Selenium-Based Protein Linked to Type 2 Diabetes By Daniel DeNoon
WebMD Medical News Reviewed By Brunilda Nazario, MD
on Monday, June 14, 2004

June 14, 2004 -- Antioxidants have a dark side. The toxin-clearing nutrients may set the stage for diabetes, new studies suggest.
The most provocative of these studies links selenium -- an essential mineral and potent antioxidant -- to insulin-resistant and type 2 diabetes. Cornell University researcher Xin Gen Lei, PhD, and colleagues created a mutant strain of mice that overproduces a selenium-based protein called GPx.

The mice got fat. They also got high blood-sugar levels despite high insulin levels. That's a condition known as insulin resistance. In humans, insulin resistance is the entrance ramp to the type 2 diabetes highway.

What happened? Lei notes that antioxidants remove dangerous compounds called free radicals -- highly reactive oxygen molecules -- from the body. But the body needs some of these free radicals to grease the wheels of the systems that regulate how it burns off and stores energy.

"Antioxidants aren't bad. But too much is not always good," Lei tells WebMD. "What we are trying to say is that we don't completely understand the function of antioxidants in nutrition and health. Most people focus only on the benefits rather than the possible negative effects."

Natural Antioxidants Raise Insulin Resistance in Pregnancy

The Lei team's report appears in the June 15 issue of the Proceedings of the National Academy of Sciences. It's focused on mice. But the findings help explain a previous report from a study on pregnant women.

In that study, Theresa O. Scholl, MD, and colleagues at the University of Medicine and Dentistry of New Jersey, looked at 408 normal pregnant women.

They measured levels of the same selenium-based protein -- GPx -- overproduced by Lei's mutant mice. As normal pregnancy progresses insulin resistance occurs. Their study showed that pregnant women made increasing amounts of the protein. Women with fatty diets made a lot of it. And the more GPx they made, the higher their insulin resistance.

"Dietary fat is related to GPx," Scholl tells WebMD. "And GPx is related to insulin resistance. So yes, diet and antioxidant supplements have an effect on insulin resistance."

Lei notes that this makes his mouse findings strikingly relevant to humans.

"What he is saying is that if you have too much of an antioxidant, it can interfere in the body's signaling system," Scholl explains. "When you have a lot of antioxidants in the body, it quenches the free radicals needed to send signals from cell to cell."

The studies do not show that selenium supplements are necessarily bad for you. But GPx is where about 60% of the body's selenium goes.

"Before people blindly supplement their diets with antioxidants, such as selenium and vitamins E and C, more research is needed," Lei says, in a news release

[Eagle]

...

Antioxidant vitamins are bad for your health

By Jonathan M. Gitlin | Published: February 27, 2007 - 04:15PM CT
Yesterday, I wrote about research that debunked the notion that garlic supplements could lower LDL cholesterol. Today it's more bad news for the supplement industry with a report of a meta-analysis study that examines the effects of antioxidants on mortality.
A range of different vitamins and minerals have been identified as having antioxidant properties, including vitamins A and C, beta carotene and selenium. Although a well-balanced diet with plenty of fresh fruit and vegetables contains ample amounts of these antioxidants, an army of talking heads and 'experts' make their living by promoting the use of supplementary antioxidants at ever-increasing doses as cure-alls against cancer, aging, and any number of other ailments. Even Linus Pauling, noted Nobel Laureate, spent the latter years of his career claiming that vitamin C was a panacea for just about every complaint he could think of.
However, a new meta-analysis of existing studies published in JAMA regarding the use of antioxidant supplements shows that far from prolonging longevity, beta carotene, vitamin A, and vitamin E usage were associated with increased mortality. Dr Bjelakovic and his team at Copenhagen University Hospital identified 68 different trials, encompassing 232,606 patients in total. These were sorted into high-bias risk and low-bias risk, based on the quality of the methods employed.
When all of these trials were pooled there was no significant finding, but when the 47 low-bias trials were examined, there was a five percent increased risk of mortality. Individually, beta carotene increased risk of mortality by seven percent, vitamin A increased risk of mortality by 16 percent, and vitamin E increased risk of mortality by four percent.
Although this is contrary to common sense, the authors suggest a reason for this finding. Although antioxidant production is associated with a number of diseases, many physiologic processes also involve free radical generation. They propose that "eliminating free radicals from our organism, we interfere with some essential defensive mechanisms like apoptosis, phagocytosis, and detoxification." As ever, the best advice would seem to be to make sure you get those five portions of fresh fruit and vegetables a day, and lay off the pills.

[corlis1]

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