The Effect of Protein on Calcium Absorption and Gastric Acid Production

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Karl Insogna, Yale University
ClinicalTrials.gov Identifier:
NCT00719160
First received: July 17, 2008
Last updated: November 30, 2012
Last verified: November 2012
  Purpose

We have established that dietary protein is an important regulator of intestinal calcium absorption in humans. However, we do not understand the mechanism by which dietary protein is affecting calcium absorption. Therefore, the purpose of this research is to evaluate whether dietary protein-induced changes in gastric acid secretion explain the observed changes in intestinal calcium absorption.


Condition Intervention Phase
Osteoporosis
Drug: esomeprazole
Drug: Placebo
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Primary Purpose: Treatment
Official Title: Dietary Protein's Effect on Gastric pH and Calcium Absorption

Resource links provided by NLM:


Further study details as provided by Yale University:

Primary Outcome Measures:
  • Percent Change in Intestinal Calcium Absorption [ Time Frame: Day 5 of a high protein diet ] [ Designated as safety issue: No ]
    This is completed by measuring the amount of calcium absorbed by utilizing dual stable calcium isotopes. It was hypothesized that we would see a percent decrease as a result of the proton pump inhibitor. Previous published data indicated a decline in calcium absorption of 6.6 +/- 5.5% when gastric pH is blocked.


Secondary Outcome Measures:
  • Gastric pH [ Time Frame: Day 5 of a high protein diet ] [ Designated as safety issue: No ]
    The American Heritage Dictionary defines pH as "a measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14." The normal pH range for stomach acid is between 1.5 and 3.5.


Enrollment: 12
Study Start Date: January 2005
Study Completion Date: May 2008
Primary Completion Date: May 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Esomeprazole Drug: esomeprazole
2 Interventions with esomeprazole 20 mg twice a day for 9 days vs. a placebo for 9 days while on a high protein diet
Drug: Placebo
Placebo 20 mg twice a day for 9 days
Active Comparator: Placebo Drug: esomeprazole
2 Interventions with esomeprazole 20 mg twice a day for 9 days vs. a placebo for 9 days while on a high protein diet
Drug: Placebo
Placebo 20 mg twice a day for 9 days

Detailed Description:

We have established that dietary protein is an important regulator of intestinal calcium absorption in humans. However, we do not understand the mechanism by which dietary protein is affecting calcium absorption. Therefore, the purpose of this research is to evaluate whether dietary protein-induced changes in gastric acid secretion explain the observed changes in intestinal calcium absorption. We have compelling in vitro data that amino acids can stimulate gastric acid secretion. We have found that this occurs via allosteric activation of the calcium sensing receptor expressed on the gastric acid-secreting parietal cells. At a fixed concentration of extracellular calcium, addition of L but not D isomers of specific amino acids activates the calcium sensing receptor and stimulates parietal cell acid production. We hypothesize that dietary protein induced gastric acid production increases calcium solubility and bioavailability thereby increasing its absorption. We will test this hypothesis in humans by quantifying the impact of dietary protein on intestinal calcium absorption in subjects who cannot make gastric acid. We will measure intestinal calcium absorption in healthy adults as they consume either a high protein diet with concomitant administration of a proton pump inhibiting (PPI) drug or the same high protein diet with a placebo instead of a PPI. The order of the 2 interventions will be randomized, and study will be double-blind and placebo controlled. If our hypothesis is correct, then intestinal calcium absorption will be highest during the high protein diet with placebo, and lowest during the drug intervention.

  Eligibility

Ages Eligible for Study:   18 Years to 45 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Healthy men and women age 18-45 years
  • Caucasian or Asian descent due to increased risk of Osteoporosis

Exclusion Criteria:

  • 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 factors such as:

    • 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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00719160

Locations
United States, Connecticut
Yale New Haven Hospital Hospital Research Unit
New Haven, Connecticut, United States, 06510
Sponsors and Collaborators
Yale University
Investigators
Principal Investigator: Karl Insogna, MD Yale University
  More Information

No publications provided

Responsible Party: Karl Insogna, Professor of Medicine, Yale University
ClinicalTrials.gov Identifier: NCT00719160     History of Changes
Other Study ID Numbers: 0408026977
Study First Received: July 17, 2008
Results First Received: January 26, 2012
Last Updated: November 30, 2012
Health Authority: United States: Institutional Review Board

Keywords provided by Yale University:
Gastric acid
Dietary protein
Calcium
Intestinal absorption
Calcium sensing receptor

Additional relevant MeSH terms:
Osteoporosis
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Esomeprazole
Anti-Ulcer Agents
Gastrointestinal Agents
Therapeutic Uses
Pharmacologic Actions
Proton Pump Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action

ClinicalTrials.gov processed this record on August 25, 2014