Symbiotic Yogurt, Calcium Absorption and Bone Health in Young Adult Women

Study Overview
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Brief Summary
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Prebiotics have been linked to increased calcium absorption in animal and human studies (particularly in adolescents and in premenopausal women). Similarly, probiotics have been found to benefit calcium homeostasis in pregnant women, and to promote bio-mineralization in animal models. The effect of symbiotic on calcium absorption has been tested in rats, but not in human studies. The primary objective of this study is to investigate the effect of daily consumption of a functional symbiotic yogurt containing inulin and Lactobacillus rhamnosus compared to a control yogurt, on calcium absorption in young adult women. A secondary objective is to relate changes in calcium absorption following yogurt consumption, with calcium metabolism, vitamin D status, bone mass, calcium intake and overall composition of habitual diet.

Detailed Description
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A potential strategy to reduce the risk of osteoporosis later in life is to promote optimal bone mass during early adulthood by including in the diet functional foods that maximize the efficiency of calcium absorption. This approach is specially important in women because of their greater risk for osteoporosis than men. In this study, we hypothesized that the daily consumption of a yogurt containing inulin and Lactobacillus rhamnosus (symbiotic yogurt) increases the efficiency of calcium absorption in young adult women when compared to daily consumption of a yogurt of similar composition but without prebiotic or probiotic (control yogurt). Subjects in this study will be randomly assigned to consume daily the symbiotic yogurt or the control yogurt during two 3-week periods with a wash-out period of 3-weeks, in a cross-over design. Calcium absorption will be measured by stable calcium isotope methodology. Bone mass (BMD, BMC) will be measured by dual-Y ray absorptiometry. Serum intact parathyroid hormone, 25-hydroxyvitamin D and dietary intake will be measured by conventional methods.

Official Title
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Effect of Regular Consumption of a Symbiotic Yogurt on Calcium Absorption and Bone Health in Young Adult Women

Conditions
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Osteoporosis

Intervention / Treatment
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* Dietary Supplement: yogurt


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ages 18 to 35 years generally healthy Exclusion Criteria: pregnancy/lactation BMI <18,5 kg/m2 BMI> 29 kg/m2 metabolic disorders, bone, liver or kidney disease that may affect calcium metabolism smoking

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: 3 weeks on symbiotic yogurt or control yogurt, with a 3 week wash out period in between. Type of yougurt consumed first is randomized.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: functional yogurt<br>Participants are given the symbiotic yogurt daily (180 ml) | Dietary Supplement: yogurt<br> <br> |
| Experimental: control yogurt<br>Participants are given the control yogurt daily (180 ml) | Dietary Supplement: yogurt<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in calcium absorption | Fractional calcium absorption measured with stable isotopes | Day 21 and Day 63 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum 25(OH) vitamin D | Serum 25 (OH) vitamin D values expressed in nmol/liter | Day 1 | 
| Bone mineral content and bone mineral density | Bone mineral content and bone mineral density values expressed as Z scores. | Day 1 | 
| Dietary calcium intake | Values expressed in mg/d | Day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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functional foods, dairy foods, calcium absorption, prebiotics and probiotics, young women, bone health