The Importance of Non-essential Amino Acids for Maintaining Skeletal Muscle Protein Synthesis Rates in Healthy Young Men (NEAA)

Background: Protein intake is important for maintaining skeletal muscle mass. These proteins consist of a collection of small building blocks which are called amino acids. There are two types of amino acids that are needed to build muscle: essential amino acids (EAA) and non-essential amino acids (NEAA). EAAs cannot be made in the body and must be consumed through foods, while NEAAs can be made within the body. However, if NEAA are not consumed through foods, the process of making NEAA in the body costs the body energy. It is still unknown what the impact of a diet containing too few non-essential amino acids is for muscle building and the body's energy metabolism.

Objective: To determine if a diet lacking NEAA, with or without being replaced by additional EAA, influences muscle protein building and whole-body metabolism.

Study design: Randomized, parallel design, double-blind, 10-day dietary intervention study.

Study population: 45 healthy (BMI 22-30 kg/m2) young males (age: 18-35 y inclusive).

Hypothesis: It is hypothesized that a diet lacking NEAA, with or without being replaced by additional EAA, decreases muscle protein building in humans.

Study Overview

• Status: Recruiting
• Conditions: Healthy Males
• Intervention / Treatment: Dietary supplement: EAA Supplement; Dietary supplement: NEAA Supplement; Dietary supplement: Maltodextrin Supplement

• Study Type: Interventional
• Enrollment (Estimated): 64
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Heather Petrick, MSc; Phone Number: 0031883887244; Email: h.petrick@maastrichtuniversity.nl
• Study Contact Backup: Name: Luc van Loon, Prof, Dr.; Phone Number: 0031433881397; Email: l.vanloon@maastrichtuniversity.nl

Study Locations

• Netherlands
  • Maastricht, Netherlands
    • Recruiting
    • Maastricht University Medical Center
    • Contact: Heather Petrick, MSc; Phone Number: 0031883887244; Email: h.petrick@maastrichtuniversity.nl
    • Contact: Luc van Loon, Prof, Dr.
    • Contact: Heather Petrick, MSc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male
• Age between 18 and 35 y inclusive
• BMI between 22 and 30 kg/m2
• Non-smoker
• Having given informed consent

Exclusion Criteria:

• Participating in a structured (progressive) exercise program
• Smoker
• Diagnosed GI tract disorders or diseases
• Diagnosed musculoskeletal disorders
• Diagnosed metabolic disorders (e.g. diabetes)
• Cardiovascular disease
• Hypertension (blood pressure above 140/90 mmHg)
• Donated blood 3 months prior to test day
• Use of any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories).
• Chronic use of gastric acid suppressing medication
• Chronic use of anti-coagulants
• Any intolerance to foods included in the standardized diet intervention
• Any implants that would be a contra-indication for performing an MRI scan

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: EAA + NEAA; Dietary intake of both EAA and NEAA, representing a normal diet	Dietary supplement: EAA Supplement; Dissolved in water and ingested 4 times a day; Dietary supplement: NEAA Supplement; Dissolved in water and ingested 4 times a day
Experimental: EAA + maltodextrin; Dietary intake of EAA, with NEAA replaced by maltodextrin	Dietary supplement: EAA Supplement; Dissolved in water and ingested 4 times a day; Dietary supplement: Maltodextrin Supplement; Dissolved in water and ingested 4 times a day
Experimental: EAA; Dietary intake of EAA, with NEAA replaced by additional EAA	Dietary supplement: EAA Supplement; Dissolved in water and ingested 4 times a day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Integrated skeletal muscle protein fractional synthesis rates	Calculated by the change in deuterium labelled alanine in skeletal muscle protein	10 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dietary protein intake	Assessed by calculating the actual intakes from the provided diet	10 days
Dietary fat intake	Assessed by calculating the actual intakes from the provided diet	10 days
Dietary carbohydrate intake	Assessed by calculating the actual intakes from the provided diet	10 days
Integrated skin protein fractional synthesis rates	Calculated by the change in deuterium labelled alanine in skin protein	10 days
Muscle mass	Measured using Magnetic resonance imaging (MRI)	Baseline, 10 days
Body fat composition	Measured using MRI	Baseline, 10 days
Resting energy expenditure	Measured using indirect calorimetry	Baseline, 10 days
Systolic and diastolic blood pressure	Measured using automated device	Baseline, 5 days, 10 days
Resting heart rate	Measured using automated device	Baseline, 5 days, 10 days
Plasma amino acids	Measured in plasma samples	Baseline, 5 days, 10 days
Blood metabolites	Assessed in plasma and serum samples	Baseline, 5 days, 10 days
Urine metabolites	Measured in fasted urine samples	Baseline, 5 days, 10 days
Skeletal muscle mitochondrial respiration	Measured in skeletal muscle tissue collected from muscle biopsy	Baseline, 10 days
Skeletal muscle signalling pathways	Measured in skeletal muscle tissue from muscle biopsy	Baseline, 10 days
Body mass	Assessed using scale	Baseline, 5 days, 10 days
Liver fat	Measured using MRI	Baseline, 10 days
Body lean mass composition	Measured using MRI	Baseline, 10 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Age	At baseline, assessed using questionnaire	Baseline
Height	Assessed using stadiometer	Baseline

Collaborators and Investigators

• Sponsor: Maastricht University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): November 14, 2024
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: November 7, 2024
• First Submitted That Met QC Criteria: November 12, 2024
• First Posted (Actual): November 13, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 19, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: muscle protein synthesis; amino acids
• Other Study ID Numbers: NL83031.068.22 / METC22-074

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No