Ingen effekt av antioxidantsupplementering på prestationsförmåga vid hård träning

[King Grub]

BACKGROUND:: There is a considerable commercial market, especially within the sports community, claiming the need for antioxidant supplementation. One argument for antioxidant supplementation in sports is that physical exercise is associated with increased reactive oxygen and nitrogen species (RONS) production, which may cause cell damage. However, RONS production may also activate redox sensitive signaling pathways and transcription factors, which subsequently may promote training adaptation.

PURPOSE:: Our aim was to investigate the effects of combined vitamin C and E supplementation to healthy individuals on different measures of exercise performance after endurance training.

METHODS:: Using a double-blinded placebo-controlled design, moderately trained young men received either oral supplementation with vitamins C and E (n=11) or placebo (n=10) before and during 12 weeks of supervised, strenuous bicycle exercise training of a frequency of 5 days/week. Muscle biopsies were obtained before and after training.

RESULTS:: After the training period, maximal oxygen consumption, maximal power output, and workload at lactate threshold all increased markedly (P < .01) in both groups. Also, glycogen concentration, citrate synthase (CS), and beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity in muscle were significantly higher in response to training (P < .01) in both groups. However, there were no differences between the two groups with regard to any of the physiological and metabolic variables measured.

CONCLUSION:: Our results suggest that administration of vitamins C and E to individuals with no prior vitamin deficiencies has no effect on physical adaptations to strenuous endurance training.

Med Sci Sports Exerc. 2009 Dec 14. Antioxidant Supplementation Does Not Alter Endurance Training Adaptation.

[Eddie Vedder]

CONCLUSION:: Our results suggest that administration of vitamins C and E to individuals with no prior vitamin deficiencies has no effect on physical adaptations to strenuous endurance training.

Och angående den här utvalda och fetciterade delen kan jag ju tillägga att det INTE är så att man plötsligt får brister av viteminer och mineraler så fort man lyfter en skivstång.

Finns ju annars en ganska utbredd tro att träning utan att vara elitnivå direkt gör att kroppen ställs inför så ohemula krav att man plötsligt behöver megadoser av allt för att inte dö pladask.;)

[Zorgus]

Andra studier har ju rent av föreslagit att höga doser av C-vitamin kan ge sämre träningseffekt, tex den här:

Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance (http://www.ajcn.org/cgi/content/abstract/87/1/142)

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.

[malfunction]

Och angående den här utvalda och fetciterade delen kan jag ju tillägga att det INTE är så att man plötsligt får brister av viteminer och mineraler så fort man lyfter en skivstång.

Hur är det med kettlebells?

Fanns det inte någon studie från i år som t.o.m. visade på sämre återhämtning vid vitamin C och E tillskott?

[malfunction]

Svaret fick jag tydligen i inlägget ovan.

[Sniggel]

Som idrottande tillverkar man nog tillräckligt med kroppsegna antioxidanter för att inte ha något behov av extra supplementering utöver den mängd som bör finnas i ens kost, tror jag.