Effects of Protein and NAC Co-ingestion on Skeletal Muscle Recovery

NCT ID: NCT06367413

Last Updated: 2025-06-04

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-04-08
• Study Completion Date: 2025-07-30

Brief Summary

Previous evidence suggests that though N-acetylcysteine (NAC) supplementation following eccentric exercise-induced muscle damage disrupts the skeletal muscle's repair and remodelling process at 8 days of recovery, it attenuates substantially the decline of skeletal muscle performance during the first 48 hours of recovery. The enhanced performance capacity during the first phase of recovery in response to NAC supplementation might be attributed to the altered redox status in skeletal muscle as a consequence of the NAC-mediated elevation of reduced glutathione (GSH) levels. The rise in GSH results in a redox-dependent attenuation of immune cell mobilisation and reduction of oxidative stress response, leading to a blunted rise of muscle damage and inflammatory markers during the first 2-3 days of recovery. However, following exercise-induced muscle damage, protein synthesis increases in skeletal muscle over the next 24-48 hours to support its repair process, and thus protein supplementation might accelerate the recovery process by enhancing the protein synthetic response. Therefore, the present study aims at investigating for first time the combined effect of NAC and whey protein supplementation on the short-term (during the first 72 hours) recovery process of skeletal muscle following damaging exercise (eccentric exercise) and compared it with the well-documented efficacy of NAC supplementation. The results of this study might be particularly useful for athletes, such as those in soccer and basketball, that participate in 3 games or intense training sessions during the same macrocycle with only 48-72 hours of recovery in-between.

Detailed Description

Participants will initially undergo baseline testing including assessment of their (i) anthropometrics, (ii) body composition via DXA, (iii) habitual physical activity level via accelerometry, (iv) resting metabolic rate via indirect calorimetry, (v) daily dietary intake via 7-day dietary recalls and (vi) cardiorespiratory fitness using a treadmill ramp test. After baseline testing, participants will be assigned to (a) a Placebo, (b) a N-acetylcysteine (NAC) or (c) a N-acetylcysteine + Whey protein (PRoNAC) group, in a randomized, double-blind, placebo-controlled, parallel group, repeated measures design. In all groups, participants will execute an eccentric exercise protocol on an isokinetic dynamometer consisted of 150 eccentric muscle contractions. Before exercise as well as at 1-, 2-, 3-, 24-, 48- and 72-hours post-exercise they will undergo assessment of their maximal voluntary isometric peal torque, maximal countermovement jump height and muscle soreness level. In addition, blood sample will be drawn before exercise and at 24-, 48- and 72-hours post-exercise for the determination of myoglobin concentration, reduced (GSH) and oxidized (GSSG) glutathione content, protein carbonyl formation and catalase activity.

Throughout the 4-day experimental period (Day 1: exercise day, Days 2, 3 and 4: 24-, 48- and 72-hours post-exercise, respectively) participants will receive daily, 3 doses from the respective supplement as follows: the 1st dose at mid-morning (between breakfast and lunch), the 2nd dose at mid-afternoon (post-exercise on day 1 and between lunch and dinner on days 2-4) and the 3rd dose before sleep. In Placebo group, participants will be supplemented with 0.31 gr of maltodextrin per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of maltodextrin per kg of body weight in the pre-sleep serving (1.1 gr maltodextrin/kg BW/day). In NAC group, participants will be supplemented with 13.33 mg of N-acetylcysteine per kg of body weight per serving (40 mg NAC/kg BW/day). In PRoNAC group participants will be supplemented with 0.31 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the pre-sleep serving (1.1 gr Whey protein + 40 mg NAC /kg BW/day).

Conditions

Aseptic Muscle Injury

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Placebo

Participants in this arm will execute 150 eccentric muscle contractions an receive a placebo supplement consisted of carbohydrate (maltodextrin).

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DIETARY_SUPPLEMENT

Participants will receive three servings of carbohydrate per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of maltodextrin per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of maltodextrin per kg of body weight in the pre-sleep serving (1.1 gr maltodextrin/kg BW/day).

NAC

Participants in this arm will execute 150 eccentric muscle contractions an receive a N-acetylcysteine supplement.

Group Type: EXPERIMENTAL

NAC

Intervention Type: DIETARY_SUPPLEMENT

Participants will receive three servings of N-acetylcysteine per day during the 4-day experimental period. In specific, they will be supplemented with 13.33 mg of N-acetylcysteine per kg of body weight per serving (40 mg NAC/kg BW/day).

PRoNAC

Participants in this arm will execute 150 eccentric muscle contractions an receive a supplement consisted of N-acetylcysteine and whey protein.

Group Type: EXPERIMENTAL

NAC + Whey Protein

Intervention Type: DIETARY_SUPPLEMENT

Participants will receive three servings of N-acetylcysteine + whey protein per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the pre-sleep serving (1.1 gr Whey protein + 40 mg NAC /kg BW/day).

Interventions

Placebo

Participants will receive three servings of carbohydrate per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of maltodextrin per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of maltodextrin per kg of body weight in the pre-sleep serving (1.1 gr maltodextrin/kg BW/day).

Intervention Type: DIETARY_SUPPLEMENT

NAC

Participants will receive three servings of N-acetylcysteine per day during the 4-day experimental period. In specific, they will be supplemented with 13.33 mg of N-acetylcysteine per kg of body weight per serving (40 mg NAC/kg BW/day).

Intervention Type: DIETARY_SUPPLEMENT

NAC + Whey Protein

Participants will receive three servings of N-acetylcysteine + whey protein per day during the 4-day experimental period. In specific, they will be supplemented with 0.31 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the first two servings (at mid-morning and mid-afternoon supplements) and with 0.49 gr of whey protein and 13.33 mg of N-acetylcysteine per kg of body weight in the pre-sleep serving (1.1 gr Whey protein + 40 mg NAC /kg BW/day).

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

• Free of asthma, kidney disease, bleeding disorders, peptic ulcers.
• Free of musculoskeletal injuries and limitations.
• Abstain from dietary energy restriction.
• Do not use medication such as anti-inflammatory drugs, antibiotics, antihypertensive drugs or anticoagulants.
• Do not use dietary supplements such as protein, carbohydrate, antioxidants, vitamins etc.
• Free of N-acetylcysteine intolerance.
• Non-smokers.
• Abstain from alcohol throughout the study.

Exclusion Criteria

• Presence of asthma, kidney disease, bleeding disorders, peptic ulcers.
• Musculoskeletal injuries and limitations.
• Dietary energy restriction.
• Use of anti-inflammatory drugs, antibiotics, antihypertensive drugs or anticoagulants.
• Use of dietary supplements such as protein, carbohydrate, antioxidants, vitamins etc.
• N-acetylcysteine intolerance.
• Smoking.
• Alcohol consumption during the study.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 27 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of Thessaly

OTHER

Sponsor Role: lead

Responsible Party

Dimitrios Draganidis

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Dimitrios Draganidis, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Thessaly, Department of Physical Education and Sport Science

Locations

Department of Physical Education and Sport Science, University of Thessaly

Trikala, Karies, Greece

Site Status: RECRUITING

Countries

Greece

Central Contacts

Dimitrios Draganidis, PhD

Role: CONTACT

ddraganidis@uth.gr

+30 2431047078

Ioannis G Fatouros, PhD

Role: CONTACT

ifatouros@uth.gr

+302431047047

Facility Contacts

Dimitrios Draganidis, PhD

Role: primary

ddraganidis@uth.gr

+30 2431047078

Ioannis G Fatouros, PhD

Role: backup

ifatouros@uth.gr

+302431047047

Other Identifiers

UTH-PRoNAC Study

Identifier Type: -

Identifier Source: org_study_id