Salty Life 7 Study: Effect of High Salt Intake on Several Physiological Systems in Immobilisation (SL7)

July 7, 2011 updated by: DLR German Aerospace Center

Influence of a High Salt Intake on Sodium Retention, Bone Metabolism and Acid-base Balance in Immobilised Test Subjects

The Salty Life 7 study aimed to examine the effect of a high salt (sodium chloride, NaCl) intake on different forms of sodium retention, acid-base balance and bone metabolism and other influenced physiological systems. Because of the fact that astronauts are a vulnerable group in this context, they were of special interest. Astronauts have a high salt intake, probably because of a reduced sense of taste, as well as an increased bone resorption resulting from the lowered mechanical load in space. In which forms sodium could be retained even without fluid retention (osmotically inactive)- contrary to the argumentation of physiological text books - and if the acid-base balance is connected to sodium chloride induced bone loss is examined in a stationary bed rest study with 8 healthy, young, male test subjects. The study consisting of 2 x 21 days is carried out at the German Aerospace Center (DLR). After an adaptation period of 4 days, test subjects are immobilised in 6° head-down tilt bed rest (simulation model for some physiological changes in space) for 14 days during which they received a high (7.7 mmol NaCl/kgBW/d) and a low salt (0.7 mmol NaCl/kgBW/d) intake in cross-over design. The form of sodium retention is investigated by the calculation of daily metabolic sodium-, water- and potassium balances and by changes in body weight. The measurements of bone formation (bAP, PINP, Osteocalcin) markers as well as bone resorption markers (CTX, NTX) supply insight into the influences of a high salt intake on bone metabolism. Blood gas analysis and ph values of 24-h urine are used to gather information about accompanying changes in the acid-base balance. Further physiological systems like energy metabolism and circulation system are also under investigation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

8

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

  • Germany
    • NRW
      • Cologne, NRW, Germany, 51147
        • German Aerospace 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

20 years to 35 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  • Male
  • Age: 20-35 years
  • Weight: 65±85kg
  • Height:180±10cm.
  • Successfully completed medical & psychological screening

Exclusion Criteria:

  • Drugs- and alcohol abuse
  • Hyperlipidemia
  • Obesity
  • Renal diseases
  • Participant of another study in the same time frame and 3 months before starting the study
  • Blood donation within the last three months before starting the study
  • Risk for thrombosis
  • Smoking
  • Diabetes
  • Rheumatism
  • Bone Fracture

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: High salt intake
Other: Dietary salt intake
Placebo Comparator: Low salt intake
Other: Dietary salt intake

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
To determine the effect of salt intake on bone metabolism in bed rest
Time Frame: after 14 days of high and low salt intake
after 14 days of high and low salt intake

Secondary Outcome Measures

Outcome Measure
Time Frame
To determine the effect of salt intake on acid base metabolism in bed rest
Time Frame: after 14 days of high and low salt intake
after 14 days of high and low salt intake
To determine the effect of salt intake on electrolyte metabolism in bed rest
Time Frame: after 14 days of high and low salt intake
after 14 days of high and low salt intake
To determine the effect of salt intake on the circulation system in bed rest
Time Frame: after 14 days of high and low salt intake
after 14 days of high and low salt intake
To determine the effect of salt intake on energy metabolism in bed rest
Time Frame: after 14 days of high and low salt intake
after 14 days of high and low salt intake

Collaborators and Investigators

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

Sponsor

DLR German Aerospace Center

Collaborators

Charite University, Berlin, Germany
University of Erlangen-Nürnberg
University Hospital Tuebingen

Investigators

  • Principal Investigator: Francisca May, Dr, German Aerospace Center (DLR)

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

April 1, 2005

Study Completion

April 1, 2006

Study Registration Dates

First Submitted

June 17, 2010

First Submitted That Met QC Criteria

August 13, 2010

First Posted (Estimate)

August 17, 2010

Study Record Updates

Last Update Posted (Estimate)

July 8, 2011

Last Update Submitted That Met QC Criteria

July 7, 2011

Last Verified

July 1, 2011

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • DLR-2005049

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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