Clinical trial NCT03121222: The Effects of N-acetylcysteine on Performance and Redox Homeostasis
Official title: N-acetylcysteine Supplementation in Individuals With Low Glutathione Levels: the Effects on Physical Performance and Redox Homeostasis
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Glutathione Metabolism Anemias
Lead sponsor: Aristotle University Of Thessaloniki
Sponsor class: OTHER
Collaborators: name: National and Kapodistrian University of Athens
name: European University Cyprus
First posted: 2017-04-20
Enrollment: 36
Sex: MALE
Minimum age (years): 18
Maximum age (years): 29
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: SCREENING

Brief 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.


Eligibility criteria: Inclusion Criteria:

* Healthy male subjects who participated recreationally in physical activities less than 3 times per week.

Exclusion Criteria:

* Subjects were excluded from the study, if they reported any musculoskeletal injury that would limit their ability to perform the exercise sessions. Participants were asked to recall whether they had participated in regular resistance or aerobic training or in unaccustomed exercise during the period before the study entry. Individuals who reported such activities were precluded from the study. Smoking and consumption of antioxidant supplements the days prior to the study were additional exclusion criteria.

Primary outcomes:
measure: Measurement of maximal oxygen consumption (ml/kg/min)
timeFrame: 64 days
Secondary outcomes:
measure: Measurement of glutathione levels (μmol/g Hb)
timeFrame: 64 days
Other outcomes:
Locations:
city: Nicosia
country: Cyprus
facility: European University Cyprus
city: Athens
country: Greece
facility: National and Kapodistrian University of Athens
city: Thessaloniki
country: Greece
facility: Aristotle University of Thessaloniki
Study officials:
affiliation: Aristotle University Of Thessaloniki
name: Michalis Nikolaidis, PhD
role: STUDY_DIRECTOR
References:
citation: Margaritelis NV, Theodorou AA, Paschalis V, Veskoukis AS, Dipla K, Zafeiridis A, Panayiotou G, Vrabas IS, Kyparos A, Nikolaidis MG. Experimental verification of regression to the mean in redox biology: differential responses to exercise. Free Radic Res. 2016;50(11):1237-1244. doi: 10.1080/10715762.2016.1233330. Epub 2016 Oct 25.
citation: Jeukendrup A, Saris WH, Brouns F, Kester AD. A new validated endurance performance test. Med Sci Sports Exerc. 1996 Feb;28(2):266-70. doi: 10.1097/00005768-199602000-00017.
citation: Paschalis V, Theodorou AA, Kyparos A, Dipla K, Zafeiridis A, Panayiotou G, Vrabas IS, Nikolaidis MG. Low vitamin C values are linked with decreased physical performance and increased oxidative stress: reversal by vitamin C supplementation. Eur J Nutr. 2016 Feb;55(1):45-53. doi: 10.1007/s00394-014-0821-x. Epub 2014 Dec 20.
citation: Nikolaidis MG, Kyparos A, Spanou C, Paschalis V, Theodorou AA, Panayiotou G, Grivas GV, Zafeiridis A, Dipla K, Vrabas IS. Aging is not a barrier to muscle and redox adaptations: applying the repeated eccentric exercise model. Exp Gerontol. 2013 Aug;48(8):734-43. doi: 10.1016/j.exger.2013.04.009. Epub 2013 Apr 28.