Optimal Protein Intake to Maximize Whole-Body Protein Balance in Healthy Adults (PAAKO)

April 21, 2026 updated by: Maastricht University Medical Center
The purpose of this study is to assess the optimal protein intake to maximize whole-body protein net balance in healthy adults. In a randomized, double-blinded, crossover design, 12 young, healthy adult males and females aged 18-35 years, will consume a test diet consisting of free amino acid mixtures based on milk protein that vary in protein content 7 separate acute metabolic trials. The main study endpoint is optimal protein intake based on the lowest protein intake that maximizes whole-body protein net balance.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

12

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Aged between 18-35 years
  • BMI between 18.5-30 kg/m2
  • Healthy, recreationally active (exercise at least once per two weeks and a maximum of four days per week)
  • No physical limitations (i.e., able to perform all activities associated with daily living independently)

Exclusion Criteria:

  • Smoking
  • Diagnosed musculoskeletal disorders
  • Use of any medications known to affect protein metabolism (i.e., corticosteroids, non-steroidal anti-inflammatories, or prescribed acne medications)
  • Chronic use of gastric acid-suppressing medication or anti-coagulants
  • Unstable weight over the last three months
  • Diagnosed GI tract disorders or diseases
  • Blood donation in the past 2 months
  • Females: pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 0.4 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 0.6 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 0.8 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 1.0 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 1.2 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 1.5 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.
Experimental: 1.8 g protein･kg BM-1･d-1
Dietary supplement: Amino Acid
Test diet consisting of free amino acid mixtures based on milk protein.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Optimal protein intake
Time Frame: From enrolment through to study completion, minimum 7 weeks
The optimal protein intake to maximize whole-body protein synthesis rates in healthy, young males and females based on the consumption of milk protein.
From enrolment through to study completion, minimum 7 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Maastricht University Medical Center

Investigators

  • Principal Investigator: Luc JC van Loon, PhD, Maastricht University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

August 1, 2026

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

April 1, 2027

Study Registration Dates

First Submitted

April 14, 2026

First Submitted That Met QC Criteria

April 21, 2026

First Posted (Actual)

April 29, 2026

Study Record Updates

Last Update Posted (Actual)

April 29, 2026

Last Update Submitted That Met QC Criteria

April 21, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • METC 24-031
  • NL87239.068.24 (Other Identifier: CCMO)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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