Effect of Dietary Protein Source on Calcium Metabolism

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.

Study Overview

• Status: Completed
• Conditions: Calcium Metabolism
• Intervention / Treatment: Behavioral: Dietary

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 Type: Interventional
• Enrollment (Actual): 183
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Baltimore, Maryland, United States, 21224
      • Johns Hopkins University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 55 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

Healthy postmenopausal women

Exclusion Criteria:

No meds affecting bone Normal renal, GI, hepatic function

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 2	Behavioral: Dietary; dietary
Active Comparator: 1	Behavioral: Dietary; dietary
Active Comparator: 3	Behavioral: Dietary; dietary
Active Comparator: 4	Behavioral: Dietary; dietary

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
calcium metabolism	after 8 weeks of diet

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Collaborators: National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
• Investigators: Principal Investigator: Deborah Sellmeyer, MD, Johns Hopkins University

Publications and helpful links

General Publications

• Gonciulea AR, Sellmeyer DE. The effect of dietary protein source on serum lipids: Secondary data analysis from a randomized clinical trial. J Clin Lipidol. 2017 Jan-Feb;11(1):46-54. doi: 10.1016/j.jacl.2016.09.014. Epub 2016 Oct 3.

Study record dates

Study Major Dates

• Study Start: February 1, 2002
• Primary Completion (Actual): December 1, 2012
• Study Completion (Actual): July 1, 2013

Study Registration Dates

• First Submitted: September 13, 2005
• First Submitted That Met QC Criteria: September 13, 2005
• First Posted (Estimate): September 16, 2005

Study Record Updates

• Last Update Posted (Estimate): August 21, 2014
• Last Update Submitted That Met QC Criteria: August 20, 2014
• Last Verified: August 1, 2014

More Information

Terms related to this study

• Other Study ID Numbers: H9291-19207-05