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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
17

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

  • United States
    • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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).
Other: Preflight
4-d controlled diet sessions will occur twice before flight.
Other: In-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.
Other: Preflight
4-d controlled diet sessions will occur twice before flight.
Other: In-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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National Aeronautics and Space Administration (NASA)

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.

General Publications

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

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2009

Primary Completion (ACTUAL)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2015

Study Completion (ACTUAL)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2015

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 19, 2012

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 24, 2012

First Posted (ESTIMATE)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 25, 2012

Study Record Updates

Last Update Posted (ESTIMATE)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 16, 2015

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 13, 2015

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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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