See if the IAAO method reflects muscle protein responses
Validating the Indicator Amino Acid Oxidation Technique for Muscle Outcomes
This study will test whether a noninvasive indicator amino acid oxidation (IAAO) method can estimate muscle protein synthesis in healthy adults aged 18–35.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 8 (estimated) |
| Ages | 18 Years to 35 Years |
| Sex | All |
| Sponsor | University of Toronto Academic / other |
| Locations | 1 site (Toronto, Ontario) |
| Trial ID | NCT07317921 on ClinicalTrials.gov |
What this trial studies
Researchers will give participants a protein beverage labeled with stable isotope tracers and measure whole-body indicator amino acid oxidation (IAAO) alongside gold-standard, biopsy-derived measures of muscle protein synthesis using established infusion and biopsy techniques. The study enrolls healthy, normally weighted adults who meet specific activity and menstrual-cycle criteria and excludes people on hormonal contraception or with contraindications to biopsies. Participants must follow standardized activity and dietary restraints before testing sessions to reduce variability. Results will compare IAAO outcomes, which reflect hepatic and whole-body metabolism, to direct muscle measurements to determine how well IAAO represents skeletal muscle protein synthesis.
Who should consider this trial
Good fit: Healthy adults aged 18–35 with a BMI of 18.5–24.9, regular physical activity, and for women a regular menstrual cycle who can comply with study rules and tolerate isotope procedures and muscle biopsy.
Not a fit: People outside the 18–35 age range, with overweight/obesity, irregular menstrual cycles, using hormonal contraceptives, tobacco or illicit drugs, or with conditions affecting protein metabolism may not get applicable results from this study.
Why it matters
Potential benefit: If successful, the IAAO method could allow researchers to estimate muscle protein responses without invasive muscle biopsies, making nutrition and muscle metabolism studies easier and less risky for participants.
How similar studies have performed: IAAO has been used successfully to estimate whole-body protein requirements in prior nutrition studies, but direct validation against biopsy-derived muscle protein synthesis is limited and this application is relatively novel.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Participants will be aged 18-35 years old * Participants will have a BMI within the normal range (i.e., 18.5-24.9) and waist-to-hip circumference ratio of \<0.95 for males and \<0.8 for circumference for females to ensure homogeneity of the sample population * Participants are willing to abide by the compliance rules of this study (e.g., abstain from extraneous physical activity 48h prior to session 4 * Self-reported regular menstrual cycle (25-35d) within the last 3 months (female participants) * Physical activity score of ≥24 units as measured by the Godin leisure time exercise questionnaire Exclusion Criteria: * Inability to adhere to any of the compliance rules judged by principal investigator * Self-reported regular tobacco or illicit drug use (e.g., growth hormone or testosterone) * Current use of hormonal contraceptives * Individuals with a history of allergy to local anesthetics (e.g., lidocaine)
Where this trial is running
Toronto, Ontario
- Kinesiology & Physical Education — Toronto, Ontario, Canada (Recruiting)
Study contacts
- Principal investigator: Daniel Moore, Ph.D — University of Toronto, Faculty of KPE
- Study coordinator: Sabrina T Barsky, Ph.D.
- Email: sabrina.barsky@utoronto.ca
- Phone: 16475400115
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.