The Effects of N-acetylcysteine on Performance and Redox Homeostasis

NCT03121222 | Completed Phase 2

• 1 other identifier: 83022/2015
• Study Type: interventional
• Target: 36
• Locations: 2 countries
• Sites: 3

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.

Conditions

Glutathione Metabolism Anemias

Outcome Measures

Primary Outcomes (1)

• Measurement of maximal oxygen consumption (ml/kg/min)

  Maximal oxygen consumption was assessed (using incremental cycling test to volitional exhaustion) on cycle ergometers (Monark, Vansbro, Sweden). Briefly, after a 5-min warm-up period at 100W, workload increased by 50W every 2.5 minutes until heart rate reached 160 bpm. Then, workload increased by 25W every 2.5 minutes until exhaustion. Respiratory gas variables were measured using a metabolic cart (Quark b2, Cosmed, Italy), which was calibrated before each test using standard gases of known concentration. Maximal oxygen consumption along with time trial and wingate test were used for assessing both aerobic and anaerobic physical performance in order to acquire a more comprehensive view about the ergogenic effectiveness of the antioxidant treatment.

  64 days

Secondary Outcomes (1)

• Measurement of glutathione levels (μmol/g Hb)

  64 days

Study Arms (2)

Lactose

PLACEBO COMPARATOR

The placebo group received orally two lactose tablets per day for 30 days. Each individual received the capsules pre-packed in daily doses labeled with the day of consumption.

Drug: Lactose

N-acetylcysteine

EXPERIMENTAL

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.

Drug: N-acetylcysteine

Interventions

N-acetylcysteine DRUG

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.

N-acetylcysteine

Lactose DRUG

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.

Lactose

Eligibility Criteria

• Age: 18 Years - 29 Years
• Gender Eligibility Details: Study was limited to males in order to avoid any interference with the hormonal fluctuations during the menstrual cycle.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

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

Sponsors & Collaborators

• Aristotle University Of Thessaloniki: lead
• National and Kapodistrian University of Athens: collaborator
• European University Cyprus: collaborator

Study Sites (3)

European University Cyprus

Nicosia, 1516, Cyprus

Location

National and Kapodistrian University of Athens

Athens, 17237, Greece

Location

Aristotle University of Thessaloniki

Thessaloniki, 54124, Greece

Location

Related Publications (4)

• 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.

  PMID: 27596985 BACKGROUND

• 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.

  PMID: 8775164 BACKGROUND

• 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.

  PMID: 25526969 BACKGROUND

• 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.

  PMID: 23628501 BACKGROUND

MeSH Terms

Interventions

Acetylcysteine; Lactose

Intervention Hierarchy (Ancestors)

Cysteine; Amino Acids, Sulfur; Sulfur Compounds; Organic Chemicals; Amino Acids; Amino Acids, Peptides, and Proteins; Disaccharides; Oligosaccharides; Polysaccharides; Carbohydrates; Sugars

Study Officials

• Michalis Nikolaidis, PhD

  Aristotle University Of Thessaloniki

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Double blind crossover design
• Purpose: SCREENING
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: April 6, 2017
• First Posted: April 20, 2017
• Study Start: November 1, 2015
• Primary Completion: February 15, 2016
• Study Completion: September 12, 2016
• Last Updated: April 21, 2017

Record last verified: 2017-04

Data Sharing

• IPD Sharing: Will not share

Locations

CY (1); GR (2)