None listed
Conditions
Brief summary
Previous studies have shown that nutritional supplementation with potassium bicarbonate causes older adults to excrete less nitrogen (protein) in their urine. As a major source of protein in our body is muscle, these previous studies suggest that supplementation with potassium bicarbonate may have a muscle-preserving effect. This study will test whether potassium bicarbonate supplementation improves muscle protein synthesis rates in older women. In addition, we will examine whether potassium bicarbonate has beneficial impacts on markers on bone turnover, as there is also some evidence that potassium bicarbonate supplementation may favourably affect bone health in ageing. To do this we will recruit 20 women aged between 65 and 90 years who will take part in two 21-day study phases. During Phase 1, the participants will be randomly allocated to receive either potassium bicarbonate supplements or placebo supplements. After Phase 1, participants will have a 3-week “wash-out” period during which they do not take any supplements. Following this, participants will complete Phase 2. This study phase will be identical to Phase 1 with the exception that participants will take the alternate study supplement. At the end of each study phase, we will measure the rate of muscle protein synthesis. To do this, participants will consume a dose of deuterated water and trained personnel will collect thigh muscle samples and blood samples from each participant. Participants will also collect 24-h urine samples at the beginning and end of each phase. In the blood and urine samples, we will measure markers of bone health and acid-base status.
Interventions
Participants will consume a potassium bicarbonate nutritional supplement at a dose of 1.5 mmol/kg body mass/day, split into three separate doses consumed with meals, for 21 days. The potassium bicarbonate will be administered via oral capsules. The supplementation dose will be increased gradually over the first 3 days to minimise the risk of gastrointestinal disturbances. On day 1, participants will consume 0.5 mmol/kg body mass (split into two separate doses), 1 mmol/kg body mass on day 2 (spli
Participants will consume a potassium bicarbonate nutritional supplement at a dose of 1.5 mmol/kg body mass/day, split into three separate doses consumed with meals, for 21 days. The potassium bicarbonate will be administered via oral capsules. The supplementation dose will be increased gradually over the first 3 days to minimise the risk of gastrointestinal disturbances. On day 1, participants will consume 0.5 mmol/kg body mass (split into two separate doses), 1 mmol/kg body mass on day 2 (split into three separate doses), and 1.5 mmol/kg body mass (split into three separate doses) from day 3 onwards. Adherence will be monitored via the pill count tracking method. Each week participants will be provided with more capsules than required and asked to return any capsules not taken. The number of returned capsules will then be cross referenced against the number prescribed. Participants will be informed about the pill count tracking method to encourage them to comply. This is a crossover trial and there will be a 21-day wash-out period between the active (potassium bicarbonate) and placebo treatments. The order of treatment will be randomised.
Sponsors
Dr Caoileann Murphy
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
65 Years to 90 Years
Healthy volunteers
Yes
Inclusion criteria
- Women aged between 65 and 90 y - 24-h urine pH of less than or equal to 6.7 at screening
Exclusion criteria
• Self-reported history of conditions impacting acid-base balance (i.e. renal disease, addison’s disease, severe COPD with CO2 retention, kidney stones in last 2 years, liver cirrhosis), active hyperparathyroidism, untreated thyroid disease, significant immune disorders, unstable heart disease, primary aldosteronism, active malignancy, type 1 diabetes mellitus, active inflammatory bowel disease, neuromuscular disease (e.g. Myasthenia gravis, MS, muscular dystrophies, MND), Parkinson’s disease • Medications that can impact acid-base balance, skeletal muscle / bone turnover (i.e. current use of diuretics, antacids containing aluminum hydroxide or magnesium hydroxide), HRT, insulin, drugs affecting bone turnover (bisphosphonates or denosumab in the last year, other osteoporosis medications [Tamoxifen/raloxifene, calcitonin, oestrogen] in the last 3 months, glucocorticoids for >10 days in the last 3 months), simvastatin / zocor, oestrogen suppressants , warfarin, anticoagulants other than aspirin (will be stopped 3 days prior to each biopsy) • Glomerular filtration rate (GFR) <51 mL/min/1.73m2 and a serum potassium >5.3 mmol/L (assessed during participant screening) • Regular resistance structured training (> 1 sessions of structured training / week) • Participants taking nutritional supplements will be asked to cease taking these 2 weeks prior to, and for the duration of the study, including potassium-containing salt substitutes • Total walking incapacity • Women must be at least 1 year since last menses • Smokers • Bone mineral density (BMD) T-score below -2.5 at the lumbar spine or total hip • Cachexia – defined as unintentional weight loss > 5% in last 6 months or, in persons with BMI < 20 kg/m2 weight loss > 2%, or low muscle mass (ASMI < 7 kg/m2 in men, < 5.5 kg/m2 in women) plus > 2% weight loss in individuals with an underlying condition associated with cachexia • Current infectious disease or diagnosis of bloodborne disease • Allergy to local anaesthesia • Mini Mental State Examination (MMSE) score < 24 • If participant’s GP reports they have an excluded condition or are taking an excluded medication
Outcome results
None listed