Long-term Nutritional Intervention Study to Determine How Protein Affects Calcium Metabolism

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00671944
Recruitment Status : Completed
First Posted : May 5, 2008
Last Update Posted : July 1, 2010
United States Department of Agriculture (USDA)
Information provided by:
Yale University

Brief Summary:
Osteoporosis is a major health problem in men and women in this country and the incidence of this disease is rising. We think that environmental factors such as nutrition may play a role in the increasing prevalence of osteoporosis. In particular, we think that a diet that is too low in protein may be contributing to bone loss. The primary purpose of this study is to compare the long-term impact of a low protein diet on measures of bone and calcium metabolism.

Condition or disease Intervention/treatment Phase
Osteoporosis Other: Low protein diet Phase 1

Detailed Description:
The protocol is composed of a 9.5-week study, consisting of a 3-week adjustment period followed by a 6.5-week experimental period. During the adjustment period, subjects consume a well-balanced lead-in diet designed to stabilize baseline Ca homeostasis. In the subsequent experimental period, subjects will consume the experimental diet containing 0.7 g protein/kg, 800-1200 mg phosphorus, 800 mg calcium and 2300 mg sodium. During days -6 to -1 of the adjustment diet, 5-10 and days 40-45 of the experimental period, we will measure Ca absorption and kinetics. Weekly assessments of Ca homeostasis will be done using our standard measures of calcitropic hormones, markers of bone turnover, and urine and serum minerals.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 11 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Long-term Impact of Protein on Calcium Kinetics
Study Start Date : May 2003
Actual Primary Completion Date : October 2009
Actual Study Completion Date : April 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Calcium Osteoporosis
U.S. FDA Resources

Arm Intervention/treatment
Experimental: 1
Low protein diet
Other: Low protein diet
Low protein diet for 6.5 weeks

Primary Outcome Measures :
  1. Calcium absorption and kinetics [ Time Frame: Baseline, day 5 and week 6 ]

Secondary Outcome Measures :
  1. Serum Parathyroid hormone [ Time Frame: baseline and weekly ]
  2. Markers of bone turnover [ Time Frame: baseline and weekly ]

Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 40 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy Asian or Caucasian women between the ages of 20-40 years.

Exclusion Criteria:

  • Diseases or medical conditions: gastrointestinal diseases, osteoporosis, diabetes, hypertension, liver disease, thyroid disorders, kidney disease, kidney stones, cancer, heart disease, eating disorders, obesity, hypogonadism , amenorrhea, oligomenorrhea, abnormal serum FSH or estradiol levels, birth control medication, or other hormone-altering medications, pregnancy.
  • Lifestyle: smoking, excessive exercise (although moderate exercise is allowed), prescription medications known to influence vitamin D or calcium metabolism or gastric acid, excessive body weight change during the past 6 months, food allergies, unusual eating habits, or medically prescribed diets.
  • Also excluded are prisoners and individuals who are cognitively impaired.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00671944

United States, Connecticut
Yale New Haven Hospital Research Unit
New Haven, Connecticut, United States, 06510
Sponsors and Collaborators
Yale University
United States Department of Agriculture (USDA)
Principal Investigator: Karl L Insogna, MD Yale University

Responsible Party: Karl Insogna, MD, Yale University Identifier: NCT00671944     History of Changes
Other Study ID Numbers: 00-35200-9579
First Posted: May 5, 2008    Key Record Dates
Last Update Posted: July 1, 2010
Last Verified: June 2010

Keywords provided by Yale University:
parathyroid hormone
bone markers
calcium kinetics

Additional relevant MeSH terms:
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases
Calcium, Dietary
Bone Density Conservation Agents
Physiological Effects of Drugs