Soy and Isoflavones Effect on Bone

Study Overview
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Brief Summary
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The purpose of this study is to test the effect of 1 year of added dietary soy protein and/or soy isoflavones on bone mineral density in late postmenopausal women.

Detailed Description
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Although soy foods contain several components (isoflavones and amino acids) that could potentially have positive effects on bone health, there are few long term, large, clinical trials using soy as a means of improving bone mineral density. The objective of this study is to provide daily soy protein and isoflavones to healthy older women in order to answer three major questions: Does soy protein alone affect bone metabolism? Do isoflavones, given with soy protein, affect bone metabolism? What dose of isoflavones affects bone in older women? We hypothesize that soy protein will have a beneficial effect on bone in older women compared to control protein. Further, we hypothesize that there will be an additional benefit to bone in women who receive soy protein plus isoflavones (at both doses) compared to soy protein alone. Both control and soy proteins used in the study were isolates, meaning they were the highest concentration of protein (85-90% by weight) in order to minimize the volume of protein supplement that each woman was asked to ingest on a daily basis. The soy protein was an alcohol-washed, soy protein isolate containing 90% protein and negligible isoflavone (0.2 mg/g product). The control protein was a mix consisting of 50% protein from sodium caseinate, 25% protein from whey protein and 25% from egg white protein. The use of a mix of proteins as a control provides a more balanced level of amino acids, mimics the real life mix of proteins that humans typically consume, and avoids the unique characteristics of one source of protein. In order to maintain the dietary protein intake constant, the participant was counseled to decrease her intake of other sources of protein from primarily animal sources by approximately 3 ounces per day (the approximate equivalent of the protein powders). The isoflavones tablets each contained 57 mg of total isoflavone from primarily genistein, glycitein, and daidzein and their beta-glycosides.

Official Title
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Soy Proteins and Isoflavones Impact Bone Mineral Density in Older Women

Conditions
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Osteoporosis

Intervention / Treatment
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* Dietary Supplement: Soy Isolate
* Dietary Supplement: Control protein
* Dietary Supplement: Novasoy isoflavones
* Dietary Supplement: Placebo tablets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Postmenopausal women 65 years old or older Able to travel to the clinical sites for follow-up visits Exclusion Criteria: History of disease that may affect bone metabolism (including Paget's disease, primary hyperparathyroidism, osteomalacia, untreated hyperthyroidism, or multiple myeloma) Cancer of any kind (except basal or squamous cell of skin) in past 5 years Use of any of the following medications within the past 2 years: calcitonin, calcitriol, heparin, phenytoin, phenobarbital Use at any time of bisphosphonates, long-term corticosteroids (over 6 months), methotrexate, or fluoride Estimated creatinine clearance less than 50 ml/min History of chronic liver disease or evidence of liver disease on screening History of hip fracture Known vertebral fracture within the past year Vegans

Ages Eligible for Study
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Minimum Age: 65 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: Factorial Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>Soy protein and isoflavone tablets | Dietary Supplement: Soy Isolate<br>* 20 grams of powder mixed in beverages or food daily for one year<br>* Other names: Pro Fam 930, 066-930;Dietary Supplement: Novasoy isoflavones<br>* 3 tablets daily for one year<br>|
| Active Comparator: 2<br>Soy protein and placebo tablets | Dietary Supplement: Soy Isolate<br>* 20 grams of powder mixed in beverages or food daily for one year<br>* Other names: Pro Fam 930, 066-930;Dietary Supplement: Placebo tablets<br>* 3 tablets daily for one year<br>|
| Active Comparator: 3<br>control protein and Isoflavone tablets | Dietary Supplement: Control protein<br>* 20 grams of powder mixed in beverages or food daily for one year<br>Dietary Supplement: Novasoy isoflavones<br>* 3 tablets daily for one year<br>|
| Placebo Comparator: 4<br>control protein and placebo tablets | Dietary Supplement: Control protein<br>* 20 grams of powder mixed in beverages or food daily for one year<br>Dietary Supplement: Placebo tablets<br>* 3 tablets daily for one year<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone turnover markers |  | baseline, 3 months, and 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone Mineral Density |  | Baseline, 6 and 12 months | 
| Quality of life measured by Medical Outcomes Short Form |  | Baseline, 6 and 12 months | 
| Medication Side Effects |  | 3 , 6, 9, and 12 months | 
| Adherence to dietary intervention through the use of 24-hour recall |  | 3, 6, 9, and 12 months | 
| Long-term medication behavior self-efficacy scale |  | 3, 6, 9, and 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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bone density, bone loss, postmenopausal