Oral 'Breath Test' to Measure Anabolic Sensitivity to a Protein Meal Across the Age and Physical Activity Spectrum

Not yet recruiting

• Conditions: Inactivity, Physical; Aging; Healthy Aging; Growth & Development; Sex Differences; Anabolic Sensitivity; Protein Metabolism; Physical Activity

• Registration Number: NCT06744491
• Lead Sponsor: University of Toronto

Brief Summary

The purpose of this study is to determine how anabolic sensitivity, in response to the ingestion of a liquid protein meal, differs across the lifespan, between biological sexes, and with varying physical activity levels.

Detailed Description

Skeletal muscle is a dynamic tissue that responds to anabolic (i.e., growth) stimuli such as protein ingestion and exercise. Differences in age and physical activity levels will influence an individual's ability to respond to these anabolic stimuli; this concept is known as anabolic sensitivity. For instance, older and less physically active individuals will display lower anabolic sensitivity (i.e., anabolic resistance) to a bout of exercise or the consumption of protein in comparison to younger, more physically active individuals. Seeing that individuals with anabolic resistance are at a greater risk for losing muscle mass over time, it is important to understand the anabolic sensitivity/resistance of an individual to assess for the efficiency of growth across the health and lifespan, in addition to a potential screen for metabolic alterations that could manifest into changes in lean body and muscle mass.

Traditional methods to assess for skeletal muscle anabolism and protein metabolism requires in-person and invasive research methods (i.e., stable isotope infusions and muscle biopsies) in controlled laboratory or clinical settings. However, there are many risks associated with these invasive procedures and they are not always feasible in all populations (e.g., children, clinical populations, etc..). Our lab has recently developed a non-invasive 13C breath test which employs an oral stable isotope tracer. Our breath test allows us to assess for anabolic sensitivity in response to protein ingestion, by determining how much of the ingested protein was used to build (synthesize) new proteins in our body (i.e., anabolism) or used as a source of energy (through a process called oxidation). As such, the purpose of the present study is to determine how anabolic sensitivity, in response to the ingestion of a liquid protein meal, differs across the lifespan and with varying physical activity levels.

Study Timeline

• Status Verified: 2024-11
• Study First Submitted: 2024-12-16
• Study First Submitted QC: 2024-12-16
• Last Update Submitted: 2024-12-16
• Study Start: 2024-12-20
• Study First Posted: 2024-12-20
• Last Update Posted: 2024-12-20
• Primary Completion: 2025-05-30
• Study Completion: 2025-08-31

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 80

Inclusion Criteria

• Healthy will be defined as screened by the PAR-Q+ (The Physical Activity Readiness Questionnaire for everyone)
• Chronological age for Healthy Young (age: 18-35 years) or Older (age: 60-80 years) adults
• Chronological age between 8 to 16 years, with maturity offset < -1 year from age of Peak Height Velocity (aPHV) for children and between -0.5 to +1.5 years from aPHV in adolescent participants
• BMI between normal to overweight (18.5 - 29.9 kg/m2)

Exclusion Criteria

• Regular use of nonsteroidal anti-inflammatory dugs (with the exception of daily low-dose aspirin)
• use of anticoagulants
• use of a walker, cane, or assistive walking device
• infectious or gastrointestinal disease
• inability to comply with study protocol (e.g., unable to track diet)
• regular tobacco use
• self-reported illicit drug use (e.g., growth hormone, testosterone, etc.)
• diagnosed chronic illness (e.g., type 2 diabetes, heart disease, thyroid disease)
• pregnant
• hormonal replacement therapy

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Amino acid oxidation and net protein balance	6 Hours	Amino acid oxidation and net protein balance assessed by oral 1-13C Leucine tracer. Net protein balance is derived from the difference between amino acid intake (known) and total amino acid oxidation over the 6h post-prandial measurement period.

Trial Locations

Locations (1)

Goldring Center for High Performance Sport; 🇨🇦 Toronto, Ontario, Canada