Clinical trial NCT03845569: Influence of Habitual Protein Intake on AA Tracer Oxidation
Official title: Impact of Habitual Protein Intake on Estimates of Dietary Protein Requirements in Resistance Trained Athletes
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Protein/Amino Acid Metabolism
Indicator Amino Acid Oxidation Method
Keywords: Amino acids
Protein
metabolism
IAAO
Tracer
Indicator amino acid
Resistance trained
Lead sponsor: University of Toronto
Sponsor class: OTHER
First posted: 2019-02-19
Enrollment: 5
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Randomized crossover trial.
Primary purpose: OTHER

Brief summary: Protein is an essential nutrient that one's diet to maintain important bodily functions and to recover from exercise. Currently, the Indicator Amino Acid Oxidation method (IAAO) has been used to determine protein requirements in a variety of populations including children, neonates, the elderly and recently, resistance trained populations. This study serves to test the robustness of the IAAO method and to determine if high habitual dietary protein intake, as seen in resistance trained males, has the potential to influence the protein requirements determined by the IAAO method. Further, the current study also aims to determine how the body metabolizes or uses dietary protein and how it might change when consuming a protein intake that is less than what is habitually consumed.

Detailed description: This study employed a two-phase randomized crossover design, where participants performed both a High/Habitual protein phase and a moderate protein phase. The Habitual protein phase is designed to model resistance trained individual's habitual protein consumption by providing 2.2g/kg/d in a controlled diet. The Moderate protein phase is designed to investigate the impact of decreasing dietary protein intake to a moderate amount (1.2g/kg/d) over five days on protein metabolism. Both phases used the stable isotope L-\[1-13C\]Phenylalanine and metabolic trails were modelled after the indicator amino acid oxidation (IAAO) technique.

High Protein Phase The high protein phase is three days in length, with diet-controlled throughout, and a metabolic trail on day 3. Participants will perform whole-body resistance exercise on days one and three.

Moderate protein phase The Moderate protein phase is seven days in length, with MT on days three, five and seven. Dietary intake will be controlled throughout the whole phase providing either 2.2 g/kg/d of protein (days one and two), or 1.2 g/kg/d (days three through seven). Full body resistance exercise will be performed performed on days one, three, five and seven.

This phase will allow measurement of protein metabolism over five days following a decrease in dietary protein intake, and to determine the effect of dietary changes on the IAAO method.

Eligibility criteria: Inclusion Criteria:

* Healthy, weight-trained individuals that have trained consistently for \> 1 year
* Habitually dietary protein consumption of 1.9 to 3.0g/kg/d
* Train each muscle group (i.e. chest, back, legs) at least twice a week
* Body mass stable in the last month
* Meets strength relative-to-weight guidelines (adapted from Morton et al., 2016; Chilibeck et -al., 1997)

  * Bench Press: - Bodyweight (kg) \* 1.25
  * Leg Press: - Bodyweight (kg) \*4.0

Exclusion Criteria:

* Inability to meet health and PA guidelines according to the PAR-Q+
* Inability to adhere to any of the protocol guidelines (e.g. alcohol and caffeine consumption)
* Regular tobacco use, screened by questionnaire
* Illicit drug use (e.g. growth hormone, testosterone, etc.), screened by a survey in training log

  * 1 month sedentary in the last 6 months prior to study participation
  * 30 minutes of continuous cardio per exercise session
* BMI \> or equal to 35
* Individual plans to increase or decrease body mass in the next 3 months
* Use of supplements (excluding whey protein), such as creatine and beta-alanine, in the last 30 days

Primary outcomes:
measure: Phenylalanine excretion (F13CO2)
timeFrame: Through study completion, an average of 3 months
measure: Phenylalanine oxidation (PheOX)
timeFrame: Through study completion, an average of 3 months
Secondary outcomes:
measure: Phenylalanine Rate of Appearance (PheRa/Flux)
timeFrame: Through study completion, an average of 3 months
measure: Net Protein Balance
timeFrame: Through study completion, an average of 3 months
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Goldring Centre for High Performance Sport
state: Ontario
Study officials:
affiliation: University of Toronto
name: Daniel R Moore, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Tinline-Goodfellow CT, West DWD, Malowany JM, Gillen JB, Moore DR. An Acute Reduction in Habitual Protein Intake Attenuates Post Exercise Anabolism and May Bias Oxidation-Derived Protein Requirements in Resistance Trained Men. Front Nutr. 2020 Apr 22;7:55. doi: 10.3389/fnut.2020.00055. eCollection 2020.