An interventional study of Dietary salt intake in Bone Metabolism, Electrolyte Metabolism and Acid-Base Metabolism, sponsored by DLR German Aerospace Center. Completed at 1 site in Germany. Open to male participants aged 20 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2011-07-08.
Sponsored by DLR German Aerospace Center · Not applicable, Interventional, and Basic science
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.
DLR German Aerospace Center is the lead sponsor of 9 studies on the registry; none are open to participants now.
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Exclusion Criteria:
Other: Dietary salt intake
Other: Dietary salt intake
To determine the effect of salt intake on bone metabolism in bed rest
Time frame: after 14 days of high and low salt intake
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
To determine the effect of salt intake on electrolyte metabolism in bed rest
Time frame: 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
To determine the effect of salt intake on energy metabolism in bed rest
Time frame: after 14 days of high and low salt intake
This study is completed, as verified in Jul 2011. You cannot join it, but the record below documents what was studied.
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DLR German Aerospace Center