A 'Non-Invasive' Breath Test to Determine Anabolic Sensitivity in Females

NCT ID: NCT05422300

Last Updated: 2023-07-13

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-06-20
• Study Completion Date: 2023-12-31

Brief Summary

The maintenance of lean body mass, especially skeletal muscle, is vital for optimal health and performance across the lifespan. The protein component of lean body mass is in a constant state of turnover, involving the simultaneous breakdown of old and/or damaged proteins and the synthesis of new proteins. These processes collectively determine if someone gains or loses lean body mass. Eating a protein-rich meal or performing resistance exercise can stimulate protein synthesis to gain lean body mass. Stable isotope "tracers" are amino acid building blocks that are slightly heavier than those naturally found in the body. In research, these are often used to assess changes in protein turnover in response to feeding and/or exercise. However, traditional stable isotope tracer methods involve the intravenous delivery of a tracer with blood sampling and muscle biopsies, which may be cumbersome or unfeasible for some for participants.

The investigators have recently developed and validated a non-invasive 'breath test' in males that measures the efficiency of the body for using amino acids in food to build new body proteins. The principle of this method is that leucine, an essential amino acid that the body must acquire from normal diet, can be used to build new body proteins or as a source of energy (i.e., oxidized). Since leucine is preferentially used in skeletal muscle, skeletal muscle protein metabolism can be non-invasively inferred . Any leucine "tracer" that is oxidized can be detected and measured in the carbon dioxide exhaled. It has been observed that less dietary leucine is oxidized when active males perform a bout of resistance exercise, meaning more was used to build muscle proteins. When performed habitually, resistance exercise can help skeletal muscles grow, compared to a rested-state, resulting in greater leucine retention in the body to build new proteins. Therefore, the purpose of this study is to validate this non-invasive breath test in females to increase the validity of the method in a wider range of populations. Ultimately, the results will further validate this non-invasive tool that can potentially detect whether different populations are sensitive to dietary amino acids and in a position to gain or lose lean body mass.

Detailed Description

The objective of the present study is to validate the use of an oral L-[13C]-leucine stable isotope tracer, preferentially metabolized within skeletal muscle, to detect an exercise-induced increase in anabolic sensitivity (i.e., reduction in oxidation) in females. It is hypothesized that since resistance exercise enhances skeletal muscle protein synthesis, anabolic sensitivity measured through leucine retention would be greater with feeding after resistance exercise compared to feeding at rest.

Conditions

Dietary Protein; Female Protein Metabolism; Anabolic Sensitivity; Resistance Exercise; Young Adult Females

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Mid-Follicular Phase

7-10 days after the onset of menses, determined by self-reports and confirmed with ovulation test kits.

Group Type: EXPERIMENTAL

Fed

Intervention Type: BEHAVIORAL

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with \[13C\]-leucine.

Ex-Fed

Intervention Type: BEHAVIORAL

Participants will be subjected to a full-body resistance exercise protocol, consisting of an upper and lower body circuit. The upper body circuit will be a chest press and dumbbell row superset, whereas the lower body circuit will be leg press and leg extension (4 sets of 10 repetitions @ 75% of their 1 repetition max, respectively). The inter-set rest period will be 90 seconds.

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with [13C]-leucine.

Mid-Luteal Phase

5-7 days after ovulation, determined by self-reports and confirmed with ovulation test kits.

Group Type: EXPERIMENTAL

Fed

Intervention Type: BEHAVIORAL

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with \[13C\]-leucine.

Ex-Fed

Intervention Type: BEHAVIORAL

Participants will be subjected to a full-body resistance exercise protocol, consisting of an upper and lower body circuit. The upper body circuit will be a chest press and dumbbell row superset, whereas the lower body circuit will be leg press and leg extension (4 sets of 10 repetitions @ 75% of their 1 repetition max, respectively). The inter-set rest period will be 90 seconds.

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with [13C]-leucine.

Interventions

Fed

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with \[13C\]-leucine.

Intervention Type: BEHAVIORAL

Ex-Fed

Participants will be subjected to a full-body resistance exercise protocol, consisting of an upper and lower body circuit. The upper body circuit will be a chest press and dumbbell row superset, whereas the lower body circuit will be leg press and leg extension (4 sets of 10 repetitions @ 75% of their 1 repetition max, respectively). The inter-set rest period will be 90 seconds.

Subjects will be fed a mixed-macronutrient beverage at rest (0.75g/kg lean body mass of carbohydrates; 0.25g/kg lean body mass of protein). Amino acid composition of the protein will be modelled off the composition of egg. Leucine content will be enriched to 5% with [13C]-leucine.

Intervention Type: BEHAVIORAL

Other Intervention Names

Feeding at Rest; Exercise with Feeding

Eligibility Criteria

Inclusion Criteria

• Female sex
• 18-35 years of age
• BMI ≥18.5 kg/m2 and ≤ 30 kg/m2
• Eumenorrheic (self-reported menstruation for prior 3 consecutive months)
• Recreationally active; currently performing structured exercise (e.g. running, weightlifting, team-sport activity) at least once per week for ≥ 6 months before enrolment

Exclusion Criteria

• Use of oral contraceptives
• Inability to perform physical activity as determined by the PAR-Q+
• Inability to adhere to protocol guidelines (e.g. alcohol, caffeine, habitual diet)
• Regular tobacco use
• Illicit drug use (e.g. growth hormone, testosterone, etc...)
• Diagnosed medical condition under the care of a physician (e.g. type 2 diabetes)
• Inability to abstain from supplements (e.g. protein, creatine, HMB, BCAA, phosphatidic acid, etc...) at least three weeks before the trial
• Individuals on any medications known to affect protein metabolism (e.g. corticosteroids, non-steroidal anti-inflammatories, and/or prescription-strength acne medications)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of Toronto

OTHER

Sponsor Role: lead

Responsible Party

Daniel Moore

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Nicki Pourhashemi, MSc Student

Role: STUDY_DIRECTOR

Faculty of Kinesiology and Physical Education

Hugo JW Fung, PhD (c)

Role: STUDY_DIRECTOR

Faculty of Kinesiology and Physical Education

Jonathan Aguilera, PhD Student

Role: STUDY_DIRECTOR

Faculty of Kinesiology and Physical Education

Locations

University of Toronto

Toronto, Ontario, Canada

Site Status: RECRUITING

Countries

Canada

Central Contacts

Daniel R Moore, PhD

Role: CONTACT

dr.moore@utoronto.ca

4169464088

Michael Mazzulla, PhD

Role: CONTACT

m.mazzulla@mail.utoronto.ca

Facility Contacts

Daniel R Moore, PhD

Role: primary

dr.moore@utoronto.ca

416-946-4088

Nicki Pourhashemi, MSc Student

Role: backup

Other Identifiers

FBT

Identifier Type: -

Identifier Source: org_study_id