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

Energy Metabolism Clinical Trial

— SL7  

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01183299
• Other study ID #: DLR-2005049
• Status: Completed
• Phase: N/A
• First received: June 17, 2010
• Last updated: July 7, 2011
• Start date: April 2005
• Est. completion date: April 2006

Study information

• Verified date: July 2011
• Source: DLR German Aerospace Center
• Contact: n/a
• Is FDA regulated: No
• Health authority: Germany: Ethics Commission
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 8
• Est. completion date: April 2006
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 20 Years to 35 Years

Eligibility

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 Design

Allocation: Randomized, Intervention Model: Crossover Assignment, Masking: Open Label, Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Acid-Base Metabolism
• Bone Metabolism
• Circulation System
• Electrolyte Metabolism
• Energy Metabolism

Intervention

Other:
• Dietary salt intake

Locations

Country	Name	City	State
Germany	German Aerospace Center	Cologne	NRW

Sponsors (4)

Lead Sponsor	Collaborator
DLR German Aerospace Center	Charite University, Berlin, Germany, University Hospital Tuebingen, University of Erlangen-Nürnberg

Country where clinical trial is conducted

Germany, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	To determine the effect of salt intake on bone metabolism in bed rest		after 14 days of high and low salt intake	No
Secondary	To determine the effect of salt intake on acid base metabolism in bed rest		after 14 days of high and low salt intake	No
Secondary	To determine the effect of salt intake on electrolyte metabolism in bed rest		after 14 days of high and low salt intake	No
Secondary	To determine the effect of salt intake on the circulation system in bed rest		after 14 days of high and low salt intake	No
Secondary	To determine the effect of salt intake on energy metabolism in bed rest		after 14 days of high and low salt intake	No