Comparison of the influence of low-dose supplementation with potassium citrate or potassium chloride on blood pressure, plasma and erythrocyte electrolyte concentrations and bone health biomarkers
It is hypothesised that a sustained supplementation (6 weeks) with low-dose potassium (30 mmol per day), equivalent to the amount present in five portions of fruit and vegetables, would decrease blood pressure and would improve bone metabolism, by reducing bone resorption and increasing bone formation.
It is also hypothesized that a non-chloride potassium salt (potassium citrate) when compared to the chloride salts, might promote a further decrease in blood pressure, reduce bone resorption and increase bone formation. Finally it is hypothesised that the potassium-induced decrease in blood pressure might be related to changes in plasma and erythrocyte concentration of sodium and potassium.
Ethics approval details not yet received as of 28/04/06
Randomised, double-blind, placebo-controlled trial with a parallel arm design
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Hypertension and osteoporosis
Patients will be randomised to receive one of three treatments:
2. Potassium citrate
3. Potassium chloride
Potassium citrate and potassium chloride
Primary outcome measure
1. Mean change in systolic and diastolic blood pressure after 6 weeks of treatment
2. Mean change in biomarkers of bone resorption and bone formation
3. Mean change in erythrocyte and plasma electrolytes concentrations
Secondary outcome measures
Mean change in mean arterial pressure
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
To take part in the study, participants will be aged between 22 and 65 years and will have a body mass index (BMI) between 19 and 35 kg/m^2 and alcohol consumption of no more than 21 units (women) or 28 units (men) per week. Volunteers eligible for the study will have the average self-measured systolic blood pressure <160 and average self-measured diastolic blood pressure <105 mmHg (an average of 20 readings for both systolic and diastolic blood pressure). Those with blood pressure levels higher than these values will be advised to contact their general practitioners.
Subjects taking medications for which potassium supplementation is not contraindicated, or mineral and vitamin supplements, will be allowed to participate in the study with the provision that they will not discontinue to use these products.
Target number of participants
120 healthy volunteers
Participant exclusion criteria
The main exclusion criteria will be diseases or conditions that might involve collateral effects from potassium supplementation or interfere with its metabolism. These will be insulin dependent diabetes mellitus, non-insulin dependent diabetes mellitus, diabetes insipidus, cardiovascular diseases (including events of cardiac arrhythmia and peripheral arterial disease) or previous cardiovascular events, any kind of renal diseases, metabolic acidosis, current peptic ulcers, dysphagia, general digestive problems, gastric surgery, pregnancy and lactation. Women planning to become pregnant will also be excluded.
Other exclusion criteria will be the use of antihypertensive drugs, changes in lifestyle (e.g. dieting, start of new medication), the use of drugs known to interfere with potassium metabolism (cyclosporin, heparin, digoxin, anticholinergics) and prolonged use of non-steroidal anti-inflammatory drugs.
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Deparment of Nutrition and Dietetics
All costs related to the running of the trial and are covered by a modest grant (less than £20,000) from the Food and Drink Federation, which is supported by contributions made by affiliated member companies. The study is also partially supported by King's College Enterprises (cost of manufacturing the supplements).
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
2008 results in https://doi.org/10.1017/S0007114507864853 (added 06/08/2020)