Calcium Metabolism in Asian Adolescents

Study Overview
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Brief Summary
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Maximizing calcium retention by the skeleton within the genetic potential is a key strategy to prevent osteoporosis. It has been shown that calcium retention varies between blacks and whites and between gender within race. This study is designed to study the relationship between calcium intakes and calcium retention in Asian adolescent girls and boys. It is hypothesized that calcium intakes which maximize calcium retention will be lower in Asians than for whites studies under the same conditions. In addition it is thought that the differences between races in the physiological mechanisms involved in calcium metabolism will result in a lower calcium intake required to observe a plateau in calcium retention. This is turn could be translated into lower calcium requirements in Asians relative to Caucasians for achieving optimal peak bone mass.

Detailed Description
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Adolescent Asian boys and girls will consume a controlled diet for two three-week periods. The basal diet will contain 600 mg/d calcium and will be supplemented with beverages fortified with calcium citrate malate to achieve a range of intakes from 600-2100 mg Ca/d. Each participant will be studied on one of four combinations of a lower and a higher calcium intake within that range in a cross-over design.

Official Title
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Calcium Metabolism in Asian Adolescents

Conditions
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Bone Mineralization, Adolescent Development

Intervention / Treatment
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* Dietary Supplement: Beverage containing calcium citrate malate
* Dietary Supplement: Beverage fortified with calcium citrate malate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy teens of Asian descent Exclusion Criteria: malabsorptive disorders anemia smoking, illegal drugs oral contraceptives pregnancy drugs that influence calcium metabolism body weight for height greater than 85 percentile

Ages Eligible for Study
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Minimum Age: 11 Years
Maximum Age: 15 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: B<br>Supplementation of a higher level of calcium (500-1300 mg/d) via calcium fortified beverages (calcium citrate malate) to a basal diet of 600 mg/d for 21 consecutive days. All excreta will be collected. | Dietary Supplement: Beverage fortified with calcium citrate malate<br>* Beverages containing a higher amount of calcium (500-1300 mg/d) will be supplemented to a basal diet containing 600 mg/d Ca. The controlled diet will be consumed for 21 consecutive days.<br>|
| Experimental: A<br>Supplementation of a lower level of calcium (0-400 mg/d) via calcium fortified beverages (calcium citrate malate) to a basal diet of 600 mg/d for 21 consecutive days. All excreta will be collected. | Dietary Supplement: Beverage containing calcium citrate malate<br>* Beverages containing a lower amount of calcium (0-400 mg/d) will be supplemented to a basal diet containing 600 mg/d Ca. The controlled diet will be consumed for 21 consecutive days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calcium retention (mg/d) |  | Metabolic balance will be determined over a two week period on a controlled diet after equilibration for one week on the same diet. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serial serum biochemistry profiles (PTH, 1,25 dihydroxy-vitamin D, calcium) |  | Six serial measurements in 10 hours after ingestion of a calcium load representing one third of the daily consumption | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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calcium, bone, bone density, adolescence