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Effect of Dietary Protein Source on Calcium Metabolism

This study is ongoing, but not recruiting participants.
Study NCT00187538.   Last updated on March 5, 2008.   Information provided by University of California, San Francisco

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Descriptive Information Fields
Brief Title  Effect of Dietary Protein Source on Calcium Metabolism
Official Title  Effect of Dietary Protein Source on Calcium Metabolism
Brief Summary

Osteoporosis is a major health concern worldwide. While there are drugs available for the treatment and prevention of osteoporosis, they are not practical for population-wide prevention efforts. Demonstrating the effectiveness of safe and widely available dietary interventions to prevent osteoporosis could have important public health ramifications. Different food sources of dietary protein may have different effects on bone metabolism. Animal foods provide a dietary acid load that may lead to negative calcium balance and increased bone resorption. In contrast, vegetable sources of protein, while providing some acid due to their protein content, provide proportionally more base that counters the dietary acid load. The effect of dairy products, which are rich in animal protein but also contain potential base precursors not found in vegetable foods, has not been established. Finally, soy protein sources may have a dual benefit: soy foods provide base precursors as well as plant estrogens that may have a beneficial effect on bone. We are resubmitting this proposal to randomize postmenopausal women to one of four diets equal in calories, protein, calcium, and sodium. The diets will differ by having 80 percent of the protein from one of four sources: non-dairy animal, vegetable, dairy, or soy foods, resulting in significant differences among the diets in acid, base, and isoflavone content. All food will be prepared and provided by the General Clinical Research Center. The subjects will consume the diets for 6 weeks with measurements of acid-base status, isoflavone excretion, and calcium metabolism. This will be the first intervention study to examine the effect of different sources of dietary protein in whole foods on calcium metabolism. Eventually our findings could have substantial public health implications and provide a widely available and low risk means to help prevent osteoporosis.

Detailed Description

Demonstrating the effectiveness of safe and widely available dietary interventions to prevent osteoporosis could have important public health ramifications. Different food sources of dietary protein may have different effects on bone metabolism. Animal foods provide a dietary acid load that may lead to negative calcium balance and increased bone resorption. In contrast, vegetable sources of protein, while providing some acid due to their protein content, provide proportionally more base that counters the dietary acid load. The effect of dairy products, which are rich in animal protein but also contain potential base precursors not found in vegetable foods, has not been established. Finally, soy protein sources may have a dual benefit: soy foods provide base precursors as well as plant estrogens that may have a beneficial effect on bone. We are resubmitting this proposal to randomize postmenopausal women to one of four diets equal in calories, protein, calcium, and sodium. The diets will differ by having 80 percent of the protein from one of four sources: non-dairy animal, vegetable, dairy, or soy foods, resulting in significant differences among the diets in acid, base, and isoflavone content. All food will be prepared and provided by the General Clinical Research Center. The subjects will consume the diets for 6 weeks with measurements of acid-base status, isoflavone excretion, and calcium metabolism. This will be the first intervention study to examine the effect of different sources of dietary protein in whole foods on calcium metabolism. Eventually our findings could have substantial public health implications and provide a widely available and low risk means to help prevent osteoporosis.

Study Phase
Study Type  Interventional
Study Design  Prevention, Randomized, Open Label, Active Control, Single Group Assignment, Efficacy Study
Primary Outcome Measure  calcium metabolism [ Time Frame: after 8 weeks of diet ] [ Designated as safety issue: No ]
Secondary Outcome Measure 
Condition  Calcium Metabolism
Intervention  Behavioral: Dietary
MEDLINE PMIDs
Links
Recruitment Information Fields
Recruitment Status  Active, not recruiting
Enrollment  183
Start Date  February 2002
Completion Date July 2008
Eligibility Criteria 

Inclusion Criteria:

Healthy postmenopausal women

Exclusion Criteria:

No meds affecting bone Normal renal, GI, hepatic function

Gender Female
Ages 55 Years and older
Accepts Healthy Volunteers Yes
Contacts ††
Location Countries  United States
Administrative Information Fields
NCT ID  NCT00187538
Organization ID H9291-19207-05
Secondary IDs ††
Study Sponsor  University of California, San Francisco
Collaborators †† National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Investigators 
Principal Investigator:     Deborah Sellmeyer, MD     University of California, San Francisco    
Information Provided By University of California, San Francisco
Verification Date March 2008
First Received Date  September 13, 2005
Last Updated Date March 5, 2008

 †    Required WHO trial registration data element.
††   WHO trial registration data element that is required only if it exists.




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