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Habitual Protein Intake and Muscle Protein Synthesis (Pro-Hab)

This study has been completed.
Information provided by (Responsible Party):
Maastricht University Medical Center Identifier:
First received: November 12, 2013
Last updated: November 27, 2014
Last verified: November 2014

Protein intake stimulates muscle protein synthesis. From the standpoint of maintaining skeletal muscle mass with aging, it is important to optimize the adaptive response to food intake. However, a paucity of information is available describing the effects of habitual dietary protein intake (i.e. either high or low amounts of dietary protein consumed on a regular basis), on the subsequent meal-induced stimulation of muscle protein synthesis. An adaptation to a diet of several days or weeks may involve splanchnic and/or skeletal muscle adaptations that may further enhance, or decrease, the amino acid sensitivity of muscle protein synthesis after protein ingestion.

The aim of this study is to investigate the effect of a habitual (14 days) high protein diet when compared with low protein diet on digestion and absorption kinetics and the subsequent muscle protein synthetic response to dietary protein ingestion.

Condition Intervention
Dietary Supplement: Protein diet

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Prevention
Official Title: The Impact of Habitual Dietary Protein Intake on the Anabolic Response in Elderly Men

Resource links provided by NLM:

Further study details as provided by Maastricht University Medical Center:

Primary Outcome Measures:
  • Muscle protein synthesis rates [ Time Frame: 0-5 h postprandial period ]
    Change in MPS rates during the postprandial phase when compared with the basal phase

Secondary Outcome Measures:
  • Digestion/Absorption kinetics [ Time Frame: 0-5 h postprandial period ]
    Difference in digestion of the intrinsically labeled protein after a 14-day period of high vs. low protein diet

Other Outcome Measures:
  • Plasma insulin [ Time Frame: 0-5 h postprandial period ]
  • Plasma amino acid concentrations [ Time Frame: 0-5 h postprandial period ]
  • Whole-body protein metabolism [ Time Frame: 0-5 h postprandial period ]
    Protein metabolism (breakdown, synthesis, oxidation, net balance)

Enrollment: 24
Study Start Date: January 2014
Study Completion Date: July 2014
Primary Completion Date: July 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Low protein
Subject will receive a low protein diet (0.7 g/kg BW/day) for 14 days prior to the experimental trial
Dietary Supplement: Protein diet
Subjects will receive either a low protein or a high protein diet for 14 days. High protein will be realized with protein supplements.
Experimental: High protein
Subjects will receive a high protein diet (1.5 g/kg BW/day) for 14 days prior to the experimental trial
Dietary Supplement: Protein diet
Subjects will receive either a low protein or a high protein diet for 14 days. High protein will be realized with protein supplements.

Detailed Description:

During the adult life skeletal muscle mass remains fairly constant until the fourth or fifth decade. Then, the slow process of sarcopenia (the age-related loss of muscle mass) is believed to begin. The maintenance of skeletal muscle mass is regulated by a balance between the opposing processes of muscle protein synthesis and muscle protein breakdown. Food intake, dietary protein in particular, stimulates muscle protein synthesis and allows net muscle protein accretion throughout the day, which allows the normal maintenance of muscle mass in healthy individuals. Many studies have described the postprandial muscle protein synthetic response to protein intake and/or physical activity, and these acute findings have led to recommendations for protein intake for both athletes wishing to gain muscle mass as well as patients and elderly individuals to help them maintaining muscle mass. However, translating the acute findings from a single meal to long-term recommendations is perhaps premature, since scientists know very little with regard to how previous consumed meals affect the anabolic responsiveness to subsequent food intake. A characteristic of the adaptation to habitual high or low protein intake is thought to be associated with a change in the amplitude of diurnal cycle of whole body proteins. If this speculation is accurate, it implies that the muscle protein synthetic responses to feeding (differences between fasting and feeding muscle protein synthesis rates) are adapting to differing habitual protein intake, which may reduce (or enhance) the anabolic responsiveness to protein intake.

To gain a more complete scientific understanding, it is necessary to examine whether an adaptation does in fact occur after habitual high or low amounts of protein intake with regard to the anabolic response to subsequent protein intake. In the present investigation, we wish to investigate the impact of the habitual consumption of either high or low protein diets for 14 days on the anabolic responsiveness to a protein meal in healthy elderly. Previous work has determined that whole body adaptations to protein intake occur after >10 days. Collectively, our findings will be valuable to maximize the skeletal muscle adaptive response to food intake and, ultimately, to develop nutritional strategies for maintenance or enhancement of skeletal muscle mass in elderly men.


Ages Eligible for Study:   55 Years to 75 Years   (Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy males
  • Age between 55 and 75 y
  • BMI between 18.5 and 30 kg/m2

Exclusion Criteria:

  • Lactose intolerance
  • Smoking and alcohol abuse
  • Diabetes
  • Diagnosed GI tract diseases
  • Arthritic conditions
  • A history of neuromuscular problems
  • Any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
  • Use of anticoagulants
  • Participation in exercise program
  • Hypertension, high blood pressure that is above 140/90 mmHg.
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Please refer to this study by its identifier: NCT01986842

Maastricht University
Maastricht, Limburg, Netherlands, 6200 MD
Sponsors and Collaborators
Maastricht University Medical Center
Principal Investigator: Luc JC van Loon, PhD Maastricht University Medical Center
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Maastricht University Medical Center Identifier: NCT01986842     History of Changes
Other Study ID Numbers: METC 13-3-050
Study First Received: November 12, 2013
Last Updated: November 27, 2014

Keywords provided by Maastricht University Medical Center:
Muscle protein synthesis
Digestion and absorption kinetics
Whey protein

Additional relevant MeSH terms:
Muscular Atrophy
Neuromuscular Manifestations
Neurologic Manifestations
Nervous System Diseases
Pathological Conditions, Anatomical
Signs and Symptoms processed this record on March 28, 2017