Body Composition, Cardiovascular Risk Factors
Conditions
Keywords
Resistance training, Body Composition, Cardiovascular Risk factors, Dairy
Brief summary
The investigators primary objective is to evaluate the effect of a 6 month (3 days/wk) supervised, progressive RT program with increased daily milk intake in untrained adolescents on measures of body composition and cardiovascular risk factors. The investigators hypothesize that milk supplementation will produce significantly greater favorable changes in all body composition measures compared with RT + carbohydrate and control.
Detailed description
We will recruit 150 healthy, adolescent middle school boys and girls (grades 7 through 9), BMI \> 50th percentile \< 98th percentile, who will participate in 6 months of supervised resistance training (3 days/wk) and will be randomized to one of 3 groups: RT + milk, RT + isocaloric carbohydrate, RT only (control). Both physical activity and diet outside the study protocol will be carefully monitored. Measurements will be completed at baseline 3 months and upon completion of the training protocol at 6 months.
Interventions
OTHERResistance Training with Milk Supplementation in Adolescents
On resistance training days, the RT+ milk group will receive milk (280kcals) immediately following exercise and milk at another time during the day. The RT+ juice group will receive fruit juice immediately following resistance exercise and juice again another time during the day. The RT+ water group will receive water following resistance exercise and water at another time during the day. On non training days, students in the RT+ milk group will receive milk. Students in the RT+ juice group will receive juice. The RT+ water group will receive water during the school day. On non-RT days, the total volume of milk, juice, or water will be split into two administration times during the school day.
Sponsors
Dairy Management Inc.
University of Kansas
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
12 Years to 14 Years
Healthy volunteers
Yes
Inclusion criteria
1. Middle school student (Grades 7-9) 2. BMI \> 50th percentile - \< 98th percentile 3. No resistance training in the past 6 months. 4. Endurance training (running, cycling, swimming, walking for exercise etc) not more than 3 hr per week, as assessed by screening questionnaire. 5. Weight stable (+/- 4.5kg) for 3 months prior to intake. 6. Willing to be randomized to one of the 3 study groups.
Exclusion criteria
1. Individuals with contraindications based on review of health history by the investigators, including blood pressure, lipid profile, glucose, and insulin, and abnormal values obtained in a 24 item blood panel, such as electrolytes, liver function, etc. These individuals will be referred to their primary care physician for further evaluation and to obtain permission to participate. The following cut-points will be used for cardiovascular and metabolic parameters: dyslipidemia- lipids (cholesterol \> 240 mg/L; triglycerides \>500 mg/L), hypertension- systolic blood pressure \> 140 mmHG or diastolic blood pressure \> 90 mmHG, diabetes - fasting glucose from venous plasma fasting glucose \> 126 mg/dL. 2. Medications that could affect metabolism such as cardiac drugs, thyroid, steroids, insulin, beta blockers, SSRI's, birth control pills, etc. 3. Current use of smoking/tobacco products or initiation of smoking/tobacco during the study. 4. Eating disorders as determined by screening questionnaire 5. Adherence to specialized diet regimes, vegetarian, macrobiotic, etc. 6. Food allergies, particularly lactose intolerance. 7. Treatment for psychiatric illness of chemical dependency within the previous 6 months. 8. Pregnancy or lactation. 9. Dietary intake of ≤800 mg calcium and ≤1 servings of milk per day as assessed from 3 -24 hr diet recalls (2 week-days, 1 week-end day) conducted at baseline.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Body Composition | 6 months | Changes in body composition will be evaluated by measuring the change in percent body fat, total fat mass, and total lean mass by DEXA |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Blood lipids, glucose, and insulin | 6 months | Blood samples will be collected for the purpose of measuring triglycerides, total cholesterol, HDL-cholesterol, glucose and insulin. |
Countries
United States
Outcome results
None listed