Dietary Protein Restriction and Health (LOWPRO)

May 6, 2024 updated by: Bente Kiens, University of Copenhagen

Dietary Protein, FGF21 and Glucose Homeostasis

The incidence of type 2 diabetes worldwide has increased significantly over the past decades, which is associated with changing dietary habits and physical inactivity. According to the diet, so far there has been a great focus on the quality of carbohydrates and fat in relation to metabolic health, while the importance of protein has been neglected. The Danes' average protein intake is 1.5 g/kg/day, which is at the high end of the recommendations (0.8-1.5 g/kg/day) from the Nordic Nutrition Recommendations (NNR 2023). Recent studies in rodents have shown that protein restriction has positive effects on health, including improved glucose and insulin homeostasis and reduced fat mass, while a high intake of protein has a negative effect on insulin sensitivity. Previously the investigators have shown, in healthy young men, that consuming a diet low in protein (0.9 g/kg/day), compared to the participants usual diet (1.5 g/kg/day), over 7 days, resulted in an increased insulin sensitivity as well as a marked increase in the plasma fibroblast growth factor 21 (FGF21) concentration. The increased insulin sensitivity is thought to be mediated by the increase in plasma FGF21 concentration. However, the effect is not yet fully understood. It is also not clear whether the increase in plasma FGF21 concentration, as well as the mentioned metabolic effects on insulin and glucose homeostasis, will take place if the participants are kept weight stable on a eucaloric diet.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

A three-arm protocol was performed. In protocol 1, participants ingested either a low-protein (LP) meal or a higher protein (HP) meal in a randomized order, separated by 72 h, followed by a 5-week low-protein, high-carbohydrate (LPHC) diet. In protocol 2 and 3, participants ingested either a LPHC diet or a low-protein, high-fat (LPHF) diet for 5 weeks followed by a higher protein diet (HPD) for another 5 weeks. All diets were eucaloric. Resting metabolic rate (RMR) was measured pre, during and post the protein-restricted interventions. A hyperinsulimic-euglycemic clamp was performed post the protein-restricted interventions and post the HPD interventions. A basal subcutaneous abdominal fat biopsy was obtained post the protein-restricted interventions and post the HPD interventions. In a run-in period over 14 days, the participant records the daily number of steps and physical activity, in order to determine their habitual activity level. During this period, a 4-day dietary record is performed, where all ingested food was weighed and recorded. During the experimental period the participant followed the supplied diet. All food consumed during the interventions was handed out to the subject at the institute. All food was packaged and weighed to 1 gram of accuracy. During the dietary intervention, a weekly test in the morning was performed, where the resting metabolic rate was measured and blood samples taken from the arm vein. At week 0, 5 and week 10 body composition was measured by dual energy x-ray absorptiometry scanning (DXA), and the fat biopsy was obtained . At all tests participants arrived fasting at the institute at 8:00 a.m. in the morning. The participant arrived by car or public transport.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
23

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • Denmark
      • Copenhagen, Denmark, 2100
        • University of Copenhagen

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • BMI≤25
  • Maximal oxygen uptake ≤42-51 ml/kg/min) • non-smoking

Exclusion Criteria:

  • The use of medicine

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: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Acute meal test
acute intake of a low protein, high carbohydrate diet. No drug intervention
Other: Dietary protein restriction
The consumption of different diets restricted in protein replaced by either carbohydrate or fat and an habitual diet.
Experimental: Chronic low protein, high carbohydrate diet
Low protein, high carbohydrate diet and habitual diet. No drug intervention
Other: Dietary protein restriction
The consumption of different diets restricted in protein replaced by either carbohydrate or fat and an habitual diet.
Experimental: Low protein , high fat diet
Low protein, high fat diet and habitual diet. No drug intervention
Other: Dietary protein restriction
The consumption of different diets restricted in protein replaced by either carbohydrate or fat and an habitual diet.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Energy balance
Time Frame: from week 0 to week 10.

Energy balance was measured in an over-night fasted state via indirect calorimetry expressed in MJ/day

prolonged eucaloric dietary protein restriction compared with a higher habitual protein intake
from week 0 to week 10.
Insulin sensitivity
Time Frame: Measured at week 5 (low protein, high carbohydrate diet) and week 5 on habitual diet and at week 5 (low protein high fat diet) and week 5 on habitual diet
Insulin sensitivity was measured by the hyperinsulinemic, euglycemic clamp procedure
Measured at week 5 (low protein, high carbohydrate diet) and week 5 on habitual diet and at week 5 (low protein high fat diet) and week 5 on habitual diet

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Adipose tissue proteomics
Time Frame: After 5 weeks low protein, high carbohydrate and 5 weeks low protein, high fat. On the tenth week on habitual diet
Mass spectroscopy
After 5 weeks low protein, high carbohydrate and 5 weeks low protein, high fat. On the tenth week on habitual diet
Plasma FGF21
Time Frame: Every week from week 0 to week 10
Measured by Elisa
Every week from week 0 to week 10

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Copenhagen

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Bente Kiens, D.sci, PhD, University of Copenhagen

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 1, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 31, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 31, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 7, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 18, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 20, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 7, 2024

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 6, 2024

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2024

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • lowprotein

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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