The Effect of Weight Loss and Dietary Protein Intake on Bone

Study Overview
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Brief Summary
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The purpose of this study is to learn how the amount of protein during moderate weight loss influences bone health. We will also examine how two levels of protein intake affects diet quality.

Detailed Description
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It is unclear whether protein intake during dieting influences bone density. This information is important for determining optimal nutrient requirements during weight loss. This study will compare the effects of weight loss with a lower-carbohydrate, high-protein (HP) diet to a high-carbohydrate, moderate protein (HC) diet on bone mass and quality in postmenopausal women (ages 50-70 years) with the hypothesis that bone turnover and loss of bone will be reduced on the HP compared to the HC weight loss diet. In a secondary aim, we will examine bone markers, hormones and the impact of protein intake on diet quality. Participants will be randomly assigned to one of 2 groups: A) weight loss with recommended level of protein intake, and B) weight loss with higher protein intake. All participants will attend regular counseling sessions (about 50 minutes per session) with a dietitian for approximately 1 year, and will be asked to take a daily vitamin/mineral supplement. Also, depending on their usual food intake, they may be asked to take a calcium tablet to meet the recommended intake throughout the study period. Bone, mineral, protein and lipid markers, and hormones that influence bones will be measured. These measurements will provide information about body composition (fat, muscle mass, and bone mineral density). Participants will be asked to attend 8 diet counseling sessions, with the opportunity to attend a total of approximately 28 diet counseling sessions during the year.

Official Title
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Nutritional Regulation of Bone - Aim 1

Conditions
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Weight Loss, Bone Density

Intervention / Treatment
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* Behavioral: Caloric restriction, high protein
* Behavioral: Caloric restriction; normal protein
* Behavioral: Counseling


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Postmenopausal women who are more than 2 years since last menses Obese or overweight Must live in the geographic vicinity of Rutgers University Exclusion Criteria: Currently on any medication known to influence calcium or bone metabolism, including HRT, or with evidence of diseases known to influence calcium metabolism (i.e. metabolic bone disease, hyperparathyroidism, untreated thyroid disease, significant immune, hepatic, or renal disease, significant cardiac disease [i.e., heart attack or stroke in the past 6 months., abnormal EKG], active malignancy or cancer therapy within the past year) History of kidney stones Weight gain or weight loss (5% of body wt) within 3 months prior to recruitment Participation in other investigational studies during the 12-month study period Usually have a very high or low intake of calcium (more than 1500 or less than 500 mg per day)

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>High Protein | Behavioral: Caloric restriction, high protein<br>* Weight loss with higher protein (35%) intake<br>Behavioral: Counseling<br>* Participants will be asked to attend eight 50-minute diet counseling sessions, with the opportunity to attend a total of approximately 28 diet counseling sessions, during the year.<br>|
| Active Comparator: 2<br>Normal Protein | Behavioral: Caloric restriction; normal protein<br>* Weight loss with recommended level of protein (18%)intake<br>Behavioral: Counseling<br>* Participants will be asked to attend eight 50-minute diet counseling sessions, with the opportunity to attend a total of approximately 28 diet counseling sessions, during the year.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Bone density and quality |  | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in serum and urine bone markers, hormones, and proteins |  | one year | 
| Nutrient Adequacy & Diet Quality with normal & higher protein intake | healthy eating index score | one year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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bone mass, calcium absorption, bone quality, fracture risk