Effect of Potassium Bicarbonate Supplementation on Bone and Muscle in Older Adults

Not Applicable

Completed

Conditions: Osteoporosis
Sarcopenia

Interventions: Dietary Supplement: Potassium Bicarbonate
Dietary Supplement: placebo (microcrystalline cellulose)
Dietary Supplement: Sodium Bicarbonate
Dietary Supplement: Potassium Chloride

Registration Number: NCT00357214

Lead Sponsor: Tufts University

Brief Summary: There is increasing evidence that the acid-base balance of diet plays an important role in the health of bones and muscles. An excess of acid in the body can result in calcium loss and muscle breakdown. Potassium bicarbonate, a base supplement, can neutralize acid within the body. The purpose of this study is to determine the effectiveness of potassium and bicarbonate, alone and combined, at reducing bone loss and preventing muscle wasting in older adults.

Detailed Description: The typical American diet of dairy products, grains, and meats results in excess acid build-up in the body. The kidney is often unable to remove this excess acid quickly enough, resulting in mildly elevated blood acidity. In an attempt to neutralize the acidity, the body releases calcium from its bones. Over time, however, this calcium loss can lead to decreased bone density and possibly osteoporosis. Excess acid in the body also stimulates the breakdown of muscle. The combination of osteoporosis and reduced muscle strength sets the stage for falls, fractures, and ultimately functional decline. At least 30% of older adults fall once a year and, of those falls, 5% result in fractures. Preserving muscle mass and strength is an effective way to lower the risk of falling and to maintain independence among older people. Potassium bicarbonate is a base supplement that can neutralize acid. The purpose of this study is to determine the effectiveness of potassium and bicarbonate, alone and combined, at reducing bone loss and preventing muscle wasting in older adults.

This study will last 3 months. Participants will be randomly assigned to one of four treatment groups:

* Group 1 will receive potassium bicarbonate supplements

* Group 2 will receive potassium chloride supplements

* Group 3 will receive sodium bicarbonate supplements

* Group 4 will receive placebo supplements

All participants will take three pills of their assigned supplement after each meal; this will occur on a daily basis throughout the study. Participants will also take a multivitamin and a 600-mg calcium tablet daily. Participants will not be required to alter their usual diet in any way, but they will be requested to not take their usual calcium and vitamin D supplements during the study. Study visits will occur on Days 1, 21, 49, and 84. Days 1 and 84 study visits will include a review of medical history and physical activity, blood collection, and evaluation of weight, blood pressure, calcium absorption, and muscle function. Collection of both a 24-hour urine sample and a calendar depicting compliance with the supplement schedule will also occur at these two visits. The other study visits, on Days 21 and 49, may include blood collection, calendar compliance checking, and weight and blood pressure measurements. Supplements will be handed out on Days 1, 21, and 49.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 171

Inclusion Criteria

Body mass idex less than 35
Not currently on a weight gain or weight loss diet
Willing to maintain usual level of physical activity
Willing to refrain from taking own calcium supplements, antacids, or salt substitutes

Exclusion Criteria

Vegetarian
Use of glucocorticoids for more than 10 days in the 3 months prior to study entry
Use of estrogen, raloxifene, or calcitonin in the 6 months prior to study entry
Use of bisphosphonate or teriparatide in the 2 years prior to study entry
Current use of diuretics, nonsteroidal anti-inflammatory drugs (NSAIDS), beta-blockers, anabolic drugs (steroids or other), angiotensin converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs)
Renal disease, including kidney stones in the 5 years prior to study entry or creatinine clearance less than 50 ml/min/1.73 m2 of body surface area
Hyperparathyroidism
Untreated thyroid disease
Significant immune disorder
Current unstable heart disease
Active malignancy or cancer therapy in the year prior to study entry
24-hour urine calcium levels greater than 300 mg/d after 1 week of being off calcium supplements
Hypertension, congestive heart failure, arrythmias, or myocardial infarction in the 12 months prior to study entry
On a salt-restricted diet
Bone density total hip T score of less than -2.5
Abnormal serum calcium
Alkaline phosphatase levels greater than 10% above the upper end of the reference range
Adrenal insufficiency, primary aldosteronism, or Bartter's syndrome
Diabetes mellitus
Alcohol use exceeding two drinks/day
Peptic ulcers or esophageal stricture
Screening serum 25(OH)D levels below 16 ng/ml

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
potassium bicarbonate	Potassium Bicarbonate	Participants will receive potassium bicarbonate in dosage of 67.5 mmol/d. This compound has no other name.
microcrystalline cellulose	placebo (microcrystalline cellulose)	Participants will receive placebo is microcrystalline cellulose. This compound has no other name.
Sodium bicarbonate	Sodium Bicarbonate	Participants will receive sodium bicarbonate in dosage of 67.5 mmol/d. This compound has no other name.
Potassium chloride	Potassium Chloride	Participants will receive potassium chloride in dosage of 67.5 mmol/d. This compound has no other name.

Primary Outcome Measures

Name	Time	Method
Biochemical Markers of Bone Turnover	3 month change in 24-hr urine values	Change in 24-hr urinary N-telopeptide/creatinine measured at baseline and 3 months

Secondary Outcome Measures