Clinical trial NCT01986842: Habitual Protein Intake and Muscle Protein Synthesis
Official title: The Impact of Habitual Dietary Protein Intake on the Anabolic Response in Elderly Men
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Sarcopenia
Keywords: Muscle protein synthesis
Digestion and absorption kinetics
Leucine
Whey protein
Lead sponsor: Maastricht University Medical Center
Sponsor class: OTHER
First posted: 2013-11-19
Enrollment: 24
Sex: MALE
Minimum age (years): 55
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: 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.

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Muscle protein synthesis rates
timeFrame: 0-5 h postprandial period
Secondary outcomes:
measure: Digestion/Absorption kinetics
timeFrame: 0-5 h postprandial period
Other outcomes:
measure: Plasma insulin
timeFrame: 0-5 h postprandial period
measure: Plasma amino acid concentrations
timeFrame: 0-5 h postprandial period
measure: Whole-body protein metabolism
timeFrame: 0-5 h postprandial period
Locations:
city: Maastricht
country: Netherlands
facility: Maastricht University
state: Limburg
Study officials:
affiliation: Maastricht University Medical Center
name: Luc JC van Loon, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Gorissen SHM, Trommelen J, Kouw IWK, Holwerda AM, Pennings B, Groen BBL, Wall BT, Churchward-Venne TA, Horstman AMH, Koopman R, Burd NA, Fuchs CJ, Dirks ML, Res PT, Senden JMG, Steijns JMJM, de Groot LCPGM, Verdijk LB, van Loon LJC. Protein Type, Protein Dose, and Age Modulate Dietary Protein Digestion and Phenylalanine Absorption Kinetics and Plasma Phenylalanine Availability in Humans. J Nutr. 2020 Aug 1;150(8):2041-2050. doi: 10.1093/jn/nxaa024.
citation: Gorissen SH, Horstman AM, Franssen R, Kouw IW, Wall BT, Burd NA, de Groot LC, van Loon LJ. Habituation to low or high protein intake does not modulate basal or postprandial muscle protein synthesis rates: a randomized trial. Am J Clin Nutr. 2017 Feb;105(2):332-342. doi: 10.3945/ajcn.115.129924. Epub 2016 Nov 30.