Vitamin C supplementation (VC) (either 500 or 1000 mg/d for 2 wk) was compared to a placebo treatment (P) to ascertain if VC could influence oxidative stress. Twelve healthy males (25 ± 1.4 y) were randomly assigned in a counter-balanced design with a 2-wk period between treatments. Data were analyzed using repeated measures ANOVA. Exercise intensity measures (VO2, RER, RPE, HR, lactate) were similar across treatments. Resting blood oxidative-stress markers were unaffected by treatment. Exercise decreased total blood glutathione (TGSH) and reduced glutathione (GSH) and increased oxidized glutathione (GSSG) (P < 0.01) independent of treatment. Protein carbonyls (PC) increased 3.8 fold in the P (P < 0.01). VC attenuated the PC exercise response in a dose-dependent manner (P < 0.01). Thiobarbituric acid reactive substances (TBARS) was not influenced by exercise (P = 0.68) or VC. These data suggest that VC supplementation can attenuate exercise-induced protein oxidation in a dose-dependent manner with no effect on lipid peroxidation and glutathione status.
Allan H. Goldfarb, Stephen W. Patrick, Scott Bryer and Tongjian You
Allan H. Goldfarb, Richard J. Bloomer and Michael J. McKenzie
To examine the effects of an antioxidant treatment on blood lactate, protein carbonyls (PC), and glutathione status, 42 male rats were assigned to either a control treatment (water, C) or one of two Microhydrin® treatments (added to water, MH I or MH II). Rats from each treatment were assigned to either exercise (60 min of running) or rest. A treatment-by-time interaction was noted for blood lactate, with elevations only in the C and MH I treatments post-exercise (~ 2.54 and 2.5 mM, respectively). Both treatment and time main effects were noted for PC. Exercise resulted in an increase in PC for both Microhydrin treatments with significantly greater PC compared to C. Total blood glutathione was unaffected by treatment or exercise. Exercise increased the ratio of oxidized to total glutathione and the MH II treatment resulted in a greater ratio compared to the other treatments. In conclusion, MH II results in lower blood lactate, while resulting in an increase in the concentration of oxidized protein and glutathione, suggesting heightened oxidative stress.
Helaine M. Alessio, Allan H. Goldfarb and Guohua Cao
Vitamin C (ascorbic acid) was supplemented (1 g/day) for 1 day and 2 weeks in the same subjects. Plasma thiobarbituric acid reacting substances (TB ARS) and oxygen radical absorbance capacity (ORAC) before and after 30 min submaximal exercise were measured. Different vitamin C supplementations did not affect resting TB ARS or ORAC. Following 30 min exercise, values for TBARS were 12.6 and 33% above rest with 1 day and 2 weeks of vitamin C supplementation, respectively, compared to 46% higher with placebo. ORAC did not significantly change (11%) after exercise with a placebo, nor when subjects were given vitamin C supplements for 1 day or 2 weeks (4.9% and 5.73%, respectively). TBARS:ORAC, a ratio representing oxidative stress, increased 32% (p < .05) with placebo compared to 5.8 and 25.8% with vitamin C supplements for 1 day and 2 weeks, respectively. It was concluded that exercise-induced oxidative stress was highest when subjects did not supplement with vitamin C compared to either 1 day or 2 weeks of vitamin C supplementation.
Allan H. Goldfarb, Changmo Cho, Hojune Cho, Brett Romano-Ely and M. Kent Todd
The purpose of this study was to determine whether an isocaloric beverage with added protein and vitamins (CHOPA) would influence oxidative stress and inflammation after cycling to exhaustion as indicated by plasma protein carbonyls (PC), lipid hydroperoxides (LOOH), and interleukin-6 (IL-6). Twelve trained men (18–33 yr) volunteered and performed this randomized crossover study. Participants cycled at 70% VO2peak until fatigue and at 80% VO2peak 22–24 hr later to fatigue with either carbohydrate or CHOPA. Blood collected before the cycling at rest and 24, 48, and 72 hr after the exercise was analyzed for PC and LOOH spectrophotometrically and for IL-6 via an enzyme-linked immunosorbent assay. The data were analyzed with SPSS using repeated-measures ANOVA. PC demonstrated significant treatment (p = .037) and time (p = .004) effects with no Treatment × Time interaction. PC was higher in the CHOPA treatment than with CHO independent of time and increased at 24 (48%), 48 (59%), and 72 (67%) hr after exercise compared with preexercise values. Resting LOOH and IL-6 did not have any significant changes with time or treatment. These data indicate that an isocaloric CHOPA drink after 2 cycling bouts to exhaustion will exacerbate the resting PC level compared with an isocaloric drink, with no influence on plasma LOOH or IL-6. In addition, a modest significant increase in PC over time independent of treatment occurred, which suggests a mild oxidative stress in the days after exhaustive exercise.
Scott D. Murdoch, Terry L. Bazzarre, Ian P. Snider and Allan H. Goldfarb
This investigation examined the metabolic and performance effects of ingesting solid compared to slurried carbohydrate food (bananas) between two prolonged exhaustive exercise bouts. Eight highly trained bale triathletes performed four exhaustive endurance tests (ET), each separated by at least 2 weeks. Each ET consisted of a 90-min run followed by 90 min of cycling, both at 70%