Very interesting study

[BBB]

Antioxidants prevent health-promoting effects of physical exercise in humans
Michael Ristowa,b,1,2, Kim Zarsea,2, Andreas Oberbachc,2, Nora Klötingc, Marc Birringera, Michael Kiehntopfd, Michael Stumvollc, C. Ronald Kahne and Matthias Blüherc,2
+ Author Affiliations

aDepartment of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany;
bGerman Institute of Human Nutrition, Potsdam-Rehbrücke D-14558, Germany;
cDepartment of Medicine, University of Leipzig, Leipzig D-04103, Germany;
dInstitute of Clinical Chemistry and Laboratory Medicine, University of Jena, Jena D-07743, Germany; and
eResearch Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215
Contributed by C. Ronald Kahn, March 31, 2009

↵2M.R., K.Z., A.O., and M. Blüher contributed equally to this work. (received for review March 14, 2009)

Next SectionAbstract
Exercise promotes longevity and ameliorates type 2 diabetes mellitus and insulin resistance. However, exercise also increases mitochondrial formation of presumably harmful reactive oxygen species (ROS). Antioxidants are widely used as supplements but whether they affect the health-promoting effects of exercise is unknown. We evaluated the effects of a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) on insulin sensitivity as measured by glucose infusion rates (GIR) during a hyperinsulinemic, euglycemic clamp in previously untrained (n = 19) and pretrained (n = 20) healthy young men. Before and after a 4 week intervention of physical exercise, GIR was determined, and muscle biopsies for gene expression analyses as well as plasma samples were obtained to compare changes over baseline and potential influences of vitamins on exercise effects. Exercise increased parameters of insulin sensitivity (GIR and plasma adiponectin) only in the absence of antioxidants in both previously untrained (P < 0.001) and pretrained (P < 0.001) individuals. This was paralleled by increased expression of ROS-sensitive transcriptional regulators of insulin sensitivity and ROS defense capacity, peroxisome-proliferator-activated receptor gamma (PPARγ), and PPARγ coactivators PGC1α and PGC1β only in the absence of antioxidants (P < 0.001 for all). Molecular mediators of endogenous ROS defense (superoxide dismutases 1 and 2; glutathione peroxidase) were also induced by exercise, and this effect too was blocked by antioxidant supplementation. Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.

 

[nattydisaster]

Antioxidants prevent health-promoting effects of physical exercise in humans
Michael Ristowa,b,1,2, Kim Zarsea,2, Andreas Oberbachc,2, Nora Klötingc, Marc Birringera, Michael Kiehntopfd, Michael Stumvollc, C. Ronald Kahne and Matthias Blüherc,2
+ Author Affiliations

aDepartment of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany;
bGerman Institute of Human Nutrition, Potsdam-Rehbrücke D-14558, Germany;
cDepartment of Medicine, University of Leipzig, Leipzig D-04103, Germany;
dInstitute of Clinical Chemistry and Laboratory Medicine, University of Jena, Jena D-07743, Germany; and
eResearch Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215
Contributed by C. Ronald Kahn, March 31, 2009

↵2M.R., K.Z., A.O., and M. Blüher contributed equally to this work. (received for review March 14, 2009)

Next SectionAbstract
Exercise promotes longevity and ameliorates type 2 diabetes mellitus and insulin resistance. However, exercise also increases mitochondrial formation of presumably harmful reactive oxygen species (ROS). Antioxidants are widely used as supplements but whether they affect the health-promoting effects of exercise is unknown. We evaluated the effects of a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) on insulin sensitivity as measured by glucose infusion rates (GIR) during a hyperinsulinemic, euglycemic clamp in previously untrained (n = 19) and pretrained (n = 20) healthy young men. Before and after a 4 week intervention of physical exercise, GIR was determined, and muscle biopsies for gene expression analyses as well as plasma samples were obtained to compare changes over baseline and potential influences of vitamins on exercise effects. Exercise increased parameters of insulin sensitivity (GIR and plasma adiponectin) only in the absence of antioxidants in both previously untrained (P < 0.001) and pretrained (P < 0.001) individuals. This was paralleled by increased expression of ROS-sensitive transcriptional regulators of insulin sensitivity and ROS defense capacity, peroxisome-proliferator-activated receptor gamma (PPARγ), and PPARγ coactivators PGC1α and PGC1β only in the absence of antioxidants (P < 0.001 for all). Molecular mediators of endogenous ROS defense (superoxide dismutases 1 and 2; glutathione peroxidase) were also induced by exercise, and this effect too was blocked by antioxidant supplementation. Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.

That study is true. There's a whole section on it in a graduate biochemistry book I just got.

That's supplements for you though, you take them for one benefit, but never think to consider all the other mechanisms and roles they play in the body.

 

[nattydisaster]

There's the negatives of antiox's on physical performance.

Now here's some positives:

GRAPE EXTRACT IMPROVES ANTIOXIDANT STATUS AND PHYSICAL PERFORMANCE IN ELITE MALE ATHLETES

Sophie Lafay1, Caroline Jan1, Karine Nardon1, Benoit Lemaire1, Alvin Ibarra2, Marc Roller1, Marc Houvenaeghel3, Christine Juhel4 and Louis Cara4

1Naturex SA, Site d'Agroparc, Avignon Cedex 9, France, 2NAT'Life division, Naturex Inc, South Hackensack, NJ, USA, 3Salvator Hospital, Centre Régional de Médecine du Sport, Marseille Cedex 9, France, 4Avantage Nutrition, Luminy Entreprises, Grand Luminy, Marseille, France .

Received 17 December 2008
Accepted 17 July 2009
Published 01 September 2009

Excessive physical exercise overproduces reactive oxygen species. Even if elite sportsmen increase their antioxidant status by regular physical training, during the competition period, this improvement is not sufficient to limit free radical production which could be detrimental to the body. The aim of this randomized, double-blind, placebo controlled, and crossover study on 20 elite sportsmen (handball = 10, basketball = 5, sprint = 4, and volleyball = 1) during the competition period was to determine if the consumption of a grape extract (GE; Vitis vinifera L.) was able to improve the parameters related to (i) anti-oxidative status and oxidative stress and (ii) physical performance. Specific biomarkers of antioxidant capacity, oxidative stress, skeletal cell muscle damage, and other general biomarkers were determined in plasma and urine before (D0) and after one month (D30) of placebo or GE supplementation (400mg·d-1). Effort tests were conducted using the Optojump® system, which allows determining the total physical performance (EnRJ45), explosive power (RJ110), and fatigue (RJL5). The plasma ORAC value was not modified in the placebo group; however, GE increased the ORAC value compared to the placebo at D30 (14 966+/-335 vs 14 242+/-339 µmol Teq·L-1; p < 0.05). The plasma FRAP value was significantly reduced in the placebo group, but not in the GE group. Therefore, GE limited the reduction of FRAP compared to the placebo at D30 (1 053.7+/-31.5 vs 993.7+/-26.7 µmol Teq·L-1; p < 0.05). Urinary isoprostane values were increased in the placebo group, but were not modified in the GE group. Consequently, GE limited the production of isoprostanes compared to the placebo at D30 (1.24+/-0.12 vs 1.26+/-0.13 ng·mg-1 creatinine; p < 0.05). GE administration, compared to the placebo at D30, reduced the plasmatic creatine phosphokinase concentration (CPK, 695.7+/-177.0 vs 480.0+/-81.1 IU·L-1, p = 0.1) and increased hemoglobin levels (Hb, 14.5+/-0.2 vs 14.8+/-0.2 vs g·dL-1, p < 0.05), suggesting that GE administration might protect cell damage during exercise. The high variability between sport disciplines did not permit to observe the differences in the effort test. Analyzing each individual group, handball players increased their physical performance by 24% (p < 0.05) and explosive power by 6.4% (p = 0.1) after GE supplementation compared to the placebo. Further analyses showed that CPK and Hb were the only biomarkers correlated with the increase in performance. In conclusion, GE ameliorates the oxidative stress/antioxidant status balance in elite athletes in the competition period, and enhances performance in one category of sportsmen (handball). Our results suggest that the enhancement in performance might be caused by the protective action of GE during physical exercise. These findings encourage conducting further studies to confirm the efficacy and mechanisms of action of GE on elite and occasional athletes.

 

[nattydisaster]

I take grape seed extract, but i do not take vitamin C or especially vitamin E. I would never recommend taking vitamin E

 

[tnubs]

why not vitamin e?

vitamin c is supported my many lifters pre/post workout to help with soreness and stuff. myself, i take 1g every morning with my vit-d.

 

[bound]

I think it may actually depend on what type of vitamin E. If I remember correctly, the type commonly found in multi's is essentially useless.