Clinical trial NCT01655953: Changes in Acid Base Status During High Salt Intake
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Low Grade Metabolic Acidosis
Lead sponsor: DLR German Aerospace Center
Sponsor class: OTHER
Collaborators: name: Charite University, Berlin, Germany
name: University of Erlangen-Nürnberg
First posted: 2012-08-02
Enrollment: 8
Sex: MALE
Minimum age (years): 19
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: The study aimed to examine the effects of an alkalinisation of a NaCl (sodium chloride, salt)-rich diet on acid base status, bone metabolism, protein turnover and other influenced physiological systems. Due to increased urinary calcium excretion and bone resorption a high NaCl-intake is considered as a risk factor for osteoporosis. On the contrary an alkaline diet is known to have a beneficial influence on bone metabolism. Therefore the investigators hypothesized that an alkaline diet can reduce NaCl-induced bone resorption.

8 healthy male volunteers took part in a stationary study carried out in the metabolic ward of the German Aerospace Center. The study consisted of 2 campaigns, each lasting 16 days. Both campaigns were divided into 5 days of adaptation, 10 days of intervention and 1.5 days of stationary recovery. During the intervention period the volunteers diet was NaCl-rich (7.7 mmol Na/kg body weight/day) and supplemented in one campaign by 90 mmol potassium bicarbonate (KHCO3) in a randomized cross-over design. The other campaign served as control.

Bone metabolism was studied by bone formation markers in the fasting morning blood and 24h-urinary bone resorption markers. Acid base status was assessed by blood gas analyses in the fasted and the postprandial state as well as urinary markers. Protein turnover was studied with stable isotopes. Further physiological systems like energy metabolism and the cardiovascular system are also under investigation.


Eligibility criteria: Inclusion Criteria:

* healthy males
* 19 - 35 years
* 65 - 85kg
* 170 - 190 cm
* successfully completed psychological and medical screening

Exclusion Criteria:

* athletes
* smoking
* drug- or alcohol abuse
* hyperlipidemia
* renal diseases
* obesity
* anemia
* bone diseases
* diabetes
* rheumatism
* blood donation within three month prior to study start
* participation in another clinical investigation three month prior to study start

Primary outcomes:
measure: Change in daily urinary C- and N-terminal bone collagen telopeptides (mmol/d)
timeFrame: Daily for a duration of 16 days
Secondary outcomes:
measure: Serum concentration of bone specific alkaline phosphatase (microg/L)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing the intervention
measure: Daily Nitrogen balance (g/d)
timeFrame: Daily for a duration of 16 days
measure: Free cortisol excretion in 24h urine (microg/d)
timeFrame: Baseline, after 3, 6, 10 days of intervention
measure: Phenylalanine hydroxylation (micromol/min)
timeFrame: Baseline, end of intervention
measure: Systolic blood pressure (bpm)
timeFrame: Daily for a duration of 16 days
measure: 24h urinary net acid excretion (mEq/d)
timeFrame: Baseline, end of intervention
measure: Serum concentration of N-terminal propeptide Type I (mmol/L)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
measure: Free cortisone excretion in 24h urine (microg/d)
timeFrame: Baseline, after 3, 6, 10 days of intervention
measure: Protein synthesis (micromol/min)
timeFrame: Baseline, end of intervention
measure: Protein degradation (micromol/min)
timeFrame: Baseline, end of intervention
measure: Diastolic blood pressure (bpm)
timeFrame: Daily for a duration of 16 days
measure: Capillary pH
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
measure: Capillary HCO3- Concentration (mmol/L)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
measure: Capillary Base excess (mmol/L)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
measure: Capillary pCO2 (mmHg)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
measure: Capillary pO2 (mmHg)
timeFrame: Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention
Other outcomes:
Locations:
city: Cologne
country: Germany
facility: German Aerospace Center (DLR)
Study officials:
References: