Skeletal Muscle Growth
Conditions
Brief summary
Soy and whey protein have different concentrations of leucine, an amino acid known to be a particularly potent simulator of muscle protein synthesis. The purpose of this study is to determine whether matching soy and whey protein supplements for leucine content instead of by total protein content would contribute to differences in strength increases and muscle growth in response to 12 wk of resistance training.
Interventions
DIETARY_SUPPLEMENTWhey protein supplement
19 g whey protein isolate (contains 2 g leucine) was consumed daily by one intervention group.
DIETARY_SUPPLEMENTSoy protein supplement
26 g soy protein isolate (contains 2 g leucine) was consumed daily by the other intervention group.
Sponsors
Point Loma Nazarene University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* non-smoking * body mass index (BMI) 18.5-24.9 * recreationally active
Exclusion criteria
* participated in structured weight training during the previous 12 month * vegetarian or vegan * presence of chronic disease * pregnant, postpartum up to six months, lactating, or intention to become pregnant * allergy to whey or soy * changes in body weight more than 10 pounds in the past three months
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Lean Body Mass Change | Post-12 week intervention | assessed using dual energy x-ray absorptiometry (DEXA) scan for changes in lean body mass (kg) |
| Muscle Tissue Thickness Change | Post-12 week intervention | assessed using changes in muscle thickness assessed by ultrasound (cm) |
| Leg Girth Changes | Post-12 week intervention | assessed using circumference measurements (cm) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Peak Torque When Doing Leg Extensions | Post-12 week intervention | Assessed using an isokinetic dynamometer set at 60 degrees of motion per second (d/s) |
Countries
United States
Participant flow
Recruitment details
282 people responded to the screening survey online from August 2016 through January 2017. Data collection was completed by May 2017. 61 participants were randomized for study participation. Recruitment emails were sent to students at Arizona State University and others were contacted via word of mouth.
Participants by arm
| Arm | Count |
|---|---|
| Soy Protein Group Soy protein supplement: 26 g soy protein isolate (contains 2 g leucine) was consumed daily by the other intervention group. | 30 |
| Whey Protein Group Whey protein supplement: 19 g whey protein isolate (contains 2 g leucine) was consumed daily by one intervention group. | 31 |
| Total | 61 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Baseline to Week 6 | Adverse Event | 0 | 3 |
| Baseline to Week 6 | Protocol Violation | 1 | 1 |
| Baseline to Week 6 | Withdrawal by Subject | 3 | 0 |
| Week 6 to Week 12 (Study Completion) | Adverse Event | 2 | 0 |
| Week 6 to Week 12 (Study Completion) | Protocol Violation | 1 | 0 |
| Week 6 to Week 12 (Study Completion) | Withdrawal by Subject | 1 | 1 |
Baseline characteristics
| Characteristic | Whey Protein Group | Total | Soy Protein Group |
|---|---|---|---|
| Age, Continuous | 22.22 years STANDARD_DEVIATION 3.38 | 22.03 years STANDARD_DEVIATION 3.81 | 21.83 years STANDARD_DEVIATION 4.27 |
| Appendicular lean body mass | 20.32806 kilograms STANDARD_DEVIATION 5.096195 | 20.09263 kilograms STANDARD_DEVIATION 5.171179 | 19.81796 kilograms STANDARD_DEVIATION 5.353628 |
| Body fat percent | 31.38214 percent body fat STANDARD_DEVIATION 8.163188 | 31.16923 percent body fat STANDARD_DEVIATION 8.115504 | 30.92083 percent body fat STANDARD_DEVIATION 8.227645 |
| Fat mass | 20.21259 kilograms STANDARD_DEVIATION 6.261987 | 19.97825 kilograms STANDARD_DEVIATION 6.468543 | 19.71463 kilograms STANDARD_DEVIATION 6.818858 |
| Height | 168.20 centimeters STANDARD_DEVIATION 7.04 | 167.57 centimeters STANDARD_DEVIATION 8.59 | 166.93 centimeters STANDARD_DEVIATION 10.03 |
| Lean body mass | 44.486 kilograms STANDARD_DEVIATION 8.7167 | 44.301 kilograms STANDARD_DEVIATION 9.3816 | 44.084 kilograms STANDARD_DEVIATION 10.2896 |
| Peak torque doing leg extensions (60 d/s) | 124.3479 Newton-meters STANDARD_DEVIATION 39.91502 | 127.8901 Newton-meters STANDARD_DEVIATION 42.03202 | 132.0228 Newton-meters STANDARD_DEVIATION 44.87827 |
| Peak torque doing leg flexions (60 d/s) | 60.4792 Newton-meters STANDARD_DEVIATION 15.85495 | 62.2373 Newton-meters STANDARD_DEVIATION 15.4526 | 64.2884 Newton-meters STANDARD_DEVIATION 15.04077 |
| Race/Ethnicity, Customized Ethnicity Non-white | 13 Participants | 22 Participants | 9 Participants |
| Race/Ethnicity, Customized Ethnicity White | 18 Participants | 39 Participants | 21 Participants |
| Region of Enrollment United States | 31 Participants | 61 Participants | 30 Participants |
| Sex: Female, Male Female | 21 Participants | 42 Participants | 21 Participants |
| Sex: Female, Male Male | 10 Participants | 19 Participants | 9 Participants |
| Vastus intermedius thickness | 1.572045 centimeters STANDARD_DEVIATION 0.4095149 | 1.568222 centimeters STANDARD_DEVIATION 0.3761121 | 1.563921 centimeters STANDARD_DEVIATION 0.3433793 |
| Vastus lateralis thickness | 2.330765 centimeters STANDARD_DEVIATION 0.5032904 | 2.253989 centimeters STANDARD_DEVIATION 0.4286374 | 2.167615 centimeters STANDARD_DEVIATION 0.3136369 |
| Weight | 66.9 kilograms STANDARD_DEVIATION 10.1 | 66.26 kilograms STANDARD_DEVIATION 11.61 | 65.5 kilograms STANDARD_DEVIATION 13.3 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 30 | 0 / 31 |
| other Total, other adverse events | 2 / 30 | 3 / 31 |
| serious Total, serious adverse events | 0 / 30 | 0 / 31 |
Outcome results
Primary
Lean Body Mass Change
assessed using dual energy x-ray absorptiometry (DEXA) scan for changes in lean body mass (kg)
Time frame: Post-12 week intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Soy Protein Group | Lean Body Mass Change | 1.5 kilogram | Standard Deviation 0.4 |
| Whey Protein Group | Lean Body Mass Change | 1.3 kilogram | Standard Deviation 0.3 |
Comparison: Between-group differences at baseline were compared using independent t-tests. Multilevel models for change (MLM) were used to determine differences between groups over time for study outcomes. Age, sex, and number of sessions missed were included as covariates. Time and time by group interactions were examined. Analyses were conducted using IBM SPSS Statistics version 23. Significance was set at p\<0.05.p-value: <0.05multilevel models for change
Primary
Leg Girth Changes
assessed using circumference measurements (cm)
Time frame: Post-12 week intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Soy Protein Group | Leg Girth Changes | -0.1865 centimeter | Standard Deviation 0.05254 |
| Whey Protein Group | Leg Girth Changes | -0.0084 centimeter | Standard Deviation 0.06227 |
Primary
Muscle Tissue Thickness Change
assessed using changes in muscle thickness assessed by ultrasound (cm)
Time frame: Post-12 week intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Soy Protein Group | Muscle Tissue Thickness Change | 0.12 centimeter | Standard Deviation 0.16 |
| Whey Protein Group | Muscle Tissue Thickness Change | 0.05 centimeter | Standard Deviation 0.41 |
Secondary
Change in Peak Torque When Doing Leg Extensions
Assessed using an isokinetic dynamometer set at 60 degrees of motion per second (d/s)
Time frame: Post-12 week intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Soy Protein Group | Change in Peak Torque When Doing Leg Extensions | 12.1 Newton-meters | Standard Deviation 13.5 |
| Whey Protein Group | Change in Peak Torque When Doing Leg Extensions | 18.0 Newton-meters | Standard Deviation 16.1 |