Meat Protein and Calcium: Do They Interact Synergistically or Antagonistically?

Study Overview
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Brief Summary
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The primary objective is to determine whether meat interacts positively with calcium to improve calcium retention. The secondary objective is to determine whether any interaction between dietary protein and calcium affects biomarkers of bone metabolism.

Detailed Description
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This study tests the effects of dietary protein and calcium on calcium retention and indices of bone metabolism. It is a controlled feeding trial with a randomized crossover design (2x2 Factorial), studying 34 healthy post-menopausal women. The women are blocked on Body Mass Index (weight in kilograms divided by height in meters squared)and randomly assigned to a high calcium (HC,1500 milligrams per day) or low calcium (LC, 600 milligrams per day) group, and consume both low protein (LP,10% protein) and high protein (HP, 20% protein) diets for 7 weeks each. There is a 3-week washout between dietary periods, during which the subjects consume self-selected diets. After 3 week equilibration to each diet, the 2-day rotating menu is extrinsically labeled with a Calcium-47 radiotracer and retention is monitored for 28 days by whole body scintillation counting. In addition to Calcium retention, other endpoints include urinary indices of acid excretion and urine serum indices of bone resorption.

Official Title
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Meat Protein and Calcium: Do They Interact Synergistically or Antagonistically?

Conditions
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Dietary Proteins

Intervention / Treatment
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* Behavioral: High Protein Diet
* Behavioral: Low Protein Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: at least 3 years since last menses bone mineral density equal to or greater than 2.5 standard deviations from average bone mineral density for young adults, body mass index equal to or less than 35 kilograms/meter squared Exclusion Criteria: taking prescription medication other than hormone replacement therapy

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 80 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: Basic Science
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Calcium Diet<br> | Behavioral: High Protein Diet<br>* High and low protein diets with meat as a primary protein source, tested in a cross-over design for each arm<br>|
| Experimental: Low Calcium Diet<br> | Behavioral: Low Protein Diet<br>* High and low protein diets with meat as a primary protein source, tested in a cross-over design for each arm<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calcium Absorption | Retention of Calcium-47 was monitored for 28 days by whole body scintillation counting. The percentage of Calcium-47 absorbed was estimated from the y-intercept of the linear portion of a semilogarithmic retention plot of percent Calcium-47 retained vs time | 17 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum Insulin-like Growth Factor 1 (IGF-1) |  | 7 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Calcium retention, dietary protein, dietary calcium