The Effects of N-acetylcysteine on Performance and Redox Homeostasis
Condition: Glutathione Metabolism Anemias
Study type: Interventional
Phase: Phase 2

Summary: 
      The main objective of the present study was to investigate whether N-acetylcysteine
      supplementation in individuals with low glutathione levels would confer ergogenic effects by
      replenishing glutathione levels and by reducing oxidative stress. Towards this aim,
      investigators sought to exploit the large inter-individual variability in redox biomarker
      levels. More specifically, investigators screened 100 male participants for glutathione
      baseline levels in blood and formed three stratified groups according to this value (i.e.,
      low, moderate and high; 12 individuals per group). After by-passing the regression to the
      mean artefact by performing a second glutathione measurement in the three aforementioned
      groups, investigators assessed both aerobic and anaerobic physical performance in order to
      acquire a more comprehensive view about the ergogenic effectiveness of the antioxidant
      treatment. This was accomplished by implementing three different whole-body physical
      performance tests (i.e., VO2max test, time trial and Wingate), as opposed to most in vivo
      studies that either applied isolated body-part exercise tests (e.g., by isokinetic
      dynamometry) or performed a single exercise test (e.g., time-to-fatigue test). It was
      hypothesised, that data of the present investigation will bridge the chasm between the
      scientific (i.e., chronic antioxidant supplementation blunts exercise performance and
      adaptations) and the community-based (i.e., free radicals should anyway be counteracted by
      "protective" exogenous antioxidants) truths about the role of antioxidants as ergogenic aids.
      It was also hypothesised that the results will show that low glutathione levels are linked to
      decreased aerobic and anaerobic physical performance accompanied by increased levels of
      oxidative stress and that N-acetylcysteine supplementation will restore both performance and
      redox homeostasis. Based on the findings of the present investigation, the widespread routine
      practice of consuming antioxidants during exercise training could be changed and the
      consumption of antioxidants would be restricted only for those who are deficient in
      glutathione.
    


Intervention name(s): N-acetylcysteine; Lactose
Intervention type(s): Drug; Drug
Intervention description(s): The antioxidant group received orally two N-acetylcysteine tablets (each tablet contained 600 mg of NAC; Lamberts Health Care Ltd, Kent, United Kingdom). The participants were instructed to receive the capsules every twelve hours in order to achieve high concentration of N-acetylcysteine throughout the 24 h. Each individual received the capsules pre-packed in daily doses labeled with the day of consumption. The supplementation period was 30-day for N-acetylcysteine.; The placebo group received orally two lactose tablets per day. The participants were instructed to receive the capsules every twelve hours. Each individual received the capsules pre-packed in daily doses labeled with the day of consumption. The supplementation period was 30-day for placebo.
Intervention MeSH terms: Acetylcysteine; N-monoacetylcystine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Screening