About this trial
Soccer players display elevated inflammatory and oxidative stress markers combined with reduced soccer specific performance over a 72-hour period. However, in modern soccer, players participate very often in 2 or 3 matches within a week, with a recovery period of 72 hours between successive matches, that is insufficient to restore skeletal muscle homeostasis and performance. Of note, reduced glutathione (GSH) levels, a tripeptide consisting of the amino acids cysteine, glycine and glutamic acid, are substantially reduced during the 72-hour recovery period after a match because of the trauma-related acute inflammatory and oxidative stress response. GSH availability is a crucial regulator of cellular redox status, affecting numerous intracellular and physiological processes such as redox signalling, immunoregulation and muscle metabolism. Indeed, enhanced GSH availability following muscle damaging exercise has been shown to be beneficial for skeletal muscle and performance recovery by mitigating the inflammatory and oxidative stress response. Thus, the enhancement of GSH availability through dietary interventions would be a promising strategy to accelerate skeletal muscle and performance recovery following a soccer game. S-Acetyl Glutathione (SAG) is a glutathione precursor with enhanced absorption kinetics due to chemical S-acetylation of the thiol group on the cysteinyl amino acid of GSH and oral administration of SAG has been shown to be more effective in restoring intracellular glutathione levels compared to oral glutathione. The aim of this study is to (i) perform a pharmacokinetic assessment of 200 mg/day vs 500 mg/day of SAG during a 7-day supplementation period (pre-loading) and (ii) to establish the pharmacodynamic effect of the two dosages at 24, 48 and 72h following a 90-minute official soccer match.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
participation at elite (top three division leagues) for ≥ 4 years
no recent history of febrile illness, musculoskeletal problems and metabolic diseases
no consumption of medications and performance-enhancing supplements (including anti-inflammatory, antioxidants, vitamins and multivitamin supplements) for at least 6 months prior to the study
participation in at least 5 training sessions and 1 match per week
Disqualifiers
musculoskeletal injury
consumption of medication and performance-enhancing supplements
illness during the course of the study
loss of follow-up measurements
Trial design
Crossover
Treatments tested in this trial
200 mg S-Acetyl Glutathione
Dietary supplementParticipants will be supplemented daily with 200 mg of S-acetyl glutathione, orally, over the 11-day experimental period.
500 mg S-Acetyl Glutathione
Dietary supplementParticipants will be supplemented daily with 500 mg of S-acetyl glutathione, orally, over the 11-day experimental period.
Placebo Supplementation
Dietary supplementParticipants will be supplemented daily with placebo, orally, over the 11-day experimental period.
Treatment groups
Trial outcomes
Primary outcomes
Change in creatine kinase levels
Creatine kinase concentration will be measured in serum using a Clinical Chemistry Analyzer
Change in myoglobin levels
Myoglobin concentration will be measured in serum using a Clinical Chemistry Analyzer
Change in reduced glutathione
Reduced glutathione will be photometrically determined in red blood cell lysates using a spectrophotometer
Change in oxidized glutathione
Oxidized glutathione will be photometrically determined in red blood cell lysates using a spectrophotometer
Secondary outcomes
Change in total distance covered
Total distance (km) covered during training and match play will be monitored using Global Positioning System (GPS)
Change in internal load
Heart rate during training sessions and the match will be monitored using heart rate monitors
Change in dietary intake
Dietary intake will be assessed using diet recalls
Change in time spent in moderate-to-vigorous physical activity
The time (minutes) spent in moderate-to-vigorous physical activity on a daily basis will be monitored using accelerometers
Sponsors and contacts
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University of Thessaly
Lead sponsor
Lesaffre International
Collaborator
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