Protein Requirements in Male and Female Endurance Athletes

University of Toronto16 enrolled

Overview

Protein is an essential macronutrient for post-exercise recovery through its ability to provide the amino acid building blocks that support increased rates of muscle and whole body protein synthesis. Despite the growing understanding of the importance of post-exercise protein in endurance athlete populations, the impact of sex and female menstrual cycle phase on protein metabolism is not fully understood. To date, no studies have examined protein requirements in female endurance trained athletes. The aim of the proposed study is to utilize the well-established IAAO method to determine protein requirements in endurance trained female and male athletes in a "real-world" and at-home setting.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Increased Metabolic Requirement Healthy

Interventions

Participants will consume hourly (8 hours) isoenergetic, isonitrogenous beverages containing one of the three protein intakes (0.2g/kg/d, 1.2 g/kg/d, 2.0g/kg/d) assigned in a randomized order between the three metabolic trials. Drinks will be enriched with stable isotope \[13C\]phenylalanine. The use of stable isotope \[13C\]phenylalanine will allow for the determination of the fate of AA in the body (incorporation into body protein or oxidation) which can be used to determine protein (AA) requirements.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy endurance trained runners. Total weekly running distance of greater than 50km/week and perform endurance exercise for more than 5 hours/week. * Age 18-35 years old * Eumenorrheic over last 3 months (one cycle no longer than 42 days and no shorter than 20 days). * Not using hormonal contraceptives (the pill, implants and injections, hormonal intrauterine devices (IUDs), vaginal ring, skin patch). * Do not have polycystic ovarian syndrome (PCOS) or other conditions effecting ovarian hormone regularity. * Not pregnant within the past year. * Must meet the classification of 'superior' aerobic power for their respective age category based on the ACSM criteria; (women age 20-29 years VO2max \>50ml/kg/min and women age 30-35 years VO2max \>46ml/kg/min) (men age 20-29 years VO2max \>56ml/kg/min and men age 30-35 years VO2max \>54ml/kg/min). Exclusion Criteria: * Inability to meet health and physical activity guidelines according to the CSEP 'Get Active' Questionnaire (Appendix G). * Inability to adhere to study protocol requirements relating to diet and exercise (i.e. alcohol and caffeine consumption, training/exercise prior to beginning a study testing day). * Regular use of tobacco and/or other recreational drugs/banned substances (i.e. growth hormone, testosterone, marijuana). * Self-reported intentional or unintentional weight loss (past 6 months) or plan to lose weight (\>5-10kg). * Amenorrhea (self-reported) in the past 3 months. * Fewer than 6 menstrual cycles per year. * Answering yes to any questions asked within the COVID-19 screening questionnaire until 14 days of being symptom free and/or having a negative COVID-19 test

Outcomes

Primary Outcomes

Phenylalanine excretion

13CO2 production in umol/kg/h

Time frame: 8 hours

Secondary Outcomes

Phenylalanine Oxidation

\[13C\]phenylalanine oxidation in umol/kg/h

Time frame: 8 hours

Phenylalanine net balance

Difference between phenylalanine rate of appearance and disappearance

Time frame: 8 hours

Protein Requirements in Male and Female Endurance Athletes

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes