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

This study has been completed.
Sponsor:
Collaborators:
Charite University, Berlin, Germany
University of Erlangen-Nürnberg
University Hospital Tuebingen
Information provided by:
DLR German Aerospace Center
ClinicalTrials.gov Identifier:
NCT01183299
First received: June 17, 2010
Last updated: July 7, 2011
Last verified: July 2011
  Purpose

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.


Condition Intervention
Bone Metabolism
Electrolyte Metabolism
Acid-Base Metabolism
Energy Metabolism
Circulation System
Other: Dietary salt intake

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Influence of a High Salt Intake on Sodium Retention, Bone Metabolism and Acid-base Balance in Immobilised Test Subjects

Resource links provided by NLM:


Further study details as provided by DLR German Aerospace Center:

Primary Outcome Measures:
  • To determine the effect of salt intake on bone metabolism in bed rest [ Time Frame: after 14 days of high and low salt intake ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]
  • To determine the effect of salt intake on electrolyte metabolism in bed rest [ Time Frame: after 14 days of high and low salt intake ] [ Designated as safety issue: No ]
  • 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 ] [ Designated as safety issue: No ]
  • To determine the effect of salt intake on energy metabolism in bed rest [ Time Frame: after 14 days of high and low salt intake ] [ Designated as safety issue: No ]

Enrollment: 8
Study Start Date: April 2005
Estimated Study Completion Date: April 2006
Arms Assigned Interventions
Active Comparator: High salt intake Other: Dietary salt intake
Placebo Comparator: Low salt intake Other: Dietary salt intake

  Eligibility

Ages Eligible for Study:   20 Years to 35 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

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
  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: NCT01183299

Locations
Germany
German Aerospace Center
Cologne, NRW, Germany, 51147
Sponsors and Collaborators
DLR German Aerospace Center
Charite University, Berlin, Germany
University of Erlangen-Nürnberg
University Hospital Tuebingen
Investigators
Principal Investigator: Francisca May, Dr German Aerospace Center (DLR)
  More Information

No publications provided

ClinicalTrials.gov Identifier: NCT01183299     History of Changes
Other Study ID Numbers: DLR-2005049
Study First Received: June 17, 2010
Last Updated: July 7, 2011
Health Authority: Germany: Ethics Commission

Keywords provided by DLR German Aerospace Center:
bone metabolism
salt intake
acid base balance
bed rest

ClinicalTrials.gov processed this record on November 20, 2014