Dietary Intake Modifications to Protect Against Changes in Bone Metabolism (ProK)

November 13, 2015 updated by: Scott M. Smith, National Aeronautics and Space Administration (NASA)

Dietary Intake Can Predict and Protect Against Changes in Bone Metabolism During Spaceflight and Recovery

Bone loss is not only a well-documented effect of spaceflight on astronauts, but also a condition that affects millions of men and women on Earth each year. Many countermeasures to bone loss have been proposed, and many have been evaluated to some degree. To date, those showing potential have focused on either exercise or pharmacological interventions, but none have targeted dietary intake alone as a factor to predict or minimize bone loss during spaceflight. The investigators proposed to document how the ratio of acid precursors to base precursors in the diet is related to directional changes in markers of bone resorption and formation during flight and recovery from flight. There is a high likelihood for success in predicting the extent of bone loss from dietary intake patterns of astronauts during spaceflight, given that this concept is strongly anchored in data obtained from ground-based experiments in our laboratory and others. The notion of manipulating diet to minimize bone loss could also have significant social and economic impacts for NASA and for the general public - especially given the increasing trends for diets that are high in animal protein and low in fruits and vegetables. The results of the proposed experiments will lead to development of a dietary countermeasure for bone loss consisting of a balanced diet with no associated risks for side effects that might be present with pharmaceuticals or supplements, no requirement for payload mass, and no additional crew time necessary during flight.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

17

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Texas
      • Houston, Texas, United States, 77058
        • Johnson Space Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • ADULT
  • OLDER_ADULT
  • CHILD

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Astronauts flying on long-duration (3-6 months) spaceflights

Exclusion Criteria:

  • Non-astronauts

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: PREVENTION
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: Low Apro/K Diet
Subjects consume a prescribed diet for 4 days with a low ratio of animal protein to potassium (0.3-0.6 g/mEq).
4-d controlled diet sessions will occur twice before flight.
4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)
EXPERIMENTAL: High Apro/K Diet
Subjects consume a prescribed diet that has a high ratio of animal protein to potassium (1.0-1.3 g/mEq) for 4 days.
4-d controlled diet sessions will occur twice before flight.
4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in urinary n-telopeptide after 15 days of space flight compared to preflight
Time Frame: 15 days
24-h NTX will be used as an indicator of bone resorption
15 days
Change in urinary n-telopeptide after 30 days of space flight compared to preflight
Time Frame: 30 days
30 days
Change in urinary n-telopeptide after 60 days of space flight compared to preflight
Time Frame: 60 days
60 days
Change in urinary n-telopeptide after 120 days of space flight compared to preflight
Time Frame: 120 days
120 days
Change in urinary n-telopeptide after 180 days of space flight compared to preflight
Time Frame: 180 days
180 days
Change in urinary calcium after 15 days of space flight compared to preflight
Time Frame: 15 days
15 days
Change in urinary calcium after 60 days of space flight compared to preflight
Time Frame: 60 days
60 days
Change in urinary calcium after 120 days of space flight compared to preflight
Time Frame: 120 days
120 days
Change in urinary calcium after 180 days of space flight compared to preflight
Time Frame: 180 days
180 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in urinary calcium after 30 days of space flight compared to preflight
Time Frame: 30 days
24-h urinary calcium
30 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2009

Primary Completion (ACTUAL)

November 1, 2015

Study Completion (ACTUAL)

November 1, 2015

Study Registration Dates

First Submitted

October 19, 2012

First Submitted That Met QC Criteria

October 24, 2012

First Posted (ESTIMATE)

October 25, 2012

Study Record Updates

Last Update Posted (ESTIMATE)

November 16, 2015

Last Update Submitted That Met QC Criteria

November 13, 2015

Last Verified

November 1, 2015

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro0225

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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