Low Grade Metabolic Acidosis
Conditions
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.
Interventions
DIETARY_SUPPLEMENTHigh NaCl + KHCO3
7.7 mmol Na/kgBW/d + 90 mmol KHCO3
OTHERControl: high NaCl
7.7 mmol Na/kgBW/d
Sponsors
Charite University, Berlin, Germany
University of Erlangen-Nürnberg
DLR German Aerospace Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
19 Years to 35 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Change in daily urinary C- and N-terminal bone collagen telopeptides (mmol/d) | Daily for a duration of 16 days |
Secondary
| Measure | Time frame |
|---|---|
| Systolic blood pressure (bpm) | Daily for a duration of 16 days |
| 24h urinary net acid excretion (mEq/d) | Baseline, end of intervention |
| Serum concentration of bone specific alkaline phosphatase (microg/L) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing the intervention |
| Daily Nitrogen balance (g/d) | Daily for a duration of 16 days |
| Free cortisol excretion in 24h urine (microg/d) | Baseline, after 3, 6, 10 days of intervention |
| Serum concentration of N-terminal propeptide Type I (mmol/L) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Free cortisone excretion in 24h urine (microg/d) | Baseline, after 3, 6, 10 days of intervention |
| Phenylalanine hydroxylation (micromol/min) | Baseline, end of intervention |
| Protein degradation (micromol/min) | Baseline, end of intervention |
| Diastolic blood pressure (bpm) | Daily for a duration of 16 days |
| Capillary pH | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Capillary HCO3- Concentration (mmol/L) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Capillary Base excess (mmol/L) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Capillary pCO2 (mmHg) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Capillary pO2 (mmHg) | Baseline, after 3, 6, 8, 10 days of intervention, 2 days after finishing intervention |
| Protein synthesis (micromol/min) | Baseline, end of intervention |
Countries
Germany
Outcome results
None listed