Impact of Protein and Alkali Supplementation on Skeletal Muscle in Older Adults

Muscle Loss Clinical Trial

Official title:

Impact of Protein and Alkali Supplementation on Skeletal Muscle in Older Adults

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04048616
• Other study ID #: 3010
• Secondary ID: 1R01AG055443-01A
• Status: Completed
• Phase: N/A
• Start date: November 1, 2019
• Est. completion date: December 21, 2023

Study information

• Verified date: January 2024
• Source: Tufts University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Whether higher dietary protein benefits skeletal muscle health in older adults remains an ongoing area of investigation. This study will determine whether adding an alkaline salt supplement, potassium bicarbonate, to reduce the dietary acid load of a high protein diet can further enhance the beneficial impact of a high protein diet alone on muscle performance and mass in older underactive adults on baseline low protein diet.

Description:

With aging, skeletal muscle mass and performance decline leading to an increased risk of falls and physical disability. There is ongoing research on whether increasing dietary protein intake in older adults improves indices of muscle health and thus translates to a reduction in physical disability. A main concern is that high protein results in a large dietary acid load from the breakdown of protein to acidogenic byproducts, which could in turn promote muscle degradation particularly in older adults with age-related declines in renal excretion of acid. The scientific premise of this project is that the balance between the amount of protein in the diet (anabolic component) and the net acid load of the diet (catabolic component) in part determines whether the diet as a whole has a net anabolic or catabolic effect on muscle. Preliminary data have suggested that a daily alkaline salt supplement (potassium bicarbonate, KHCO3) lowered the dietary acid load and improved lower extremity muscle power in postmenopausal women. The investigator's central hypothesis is that higher protein intake plus a neutralizing alkaline salt will have additive effects on muscle performance and mass in older adults to either intervention alone. To test the hypothesis, the investigators will conduct a randomized, double-blind, placebo-controlled, 2x2 factorial study in which underactive men and women age 65 and older on baseline lower protein diets will be enrolled. Participants will assigned to one of four groups: either a whey protein supplement (to raise protein intake to 1.5 g/kg/d) with or without KHCO3 81 mmol/d or an isocaloric placebo supplement with or without KHCO3 81 mmol/d for 24 wks. The primary outcome is lower extremity muscle power at 24 weeks. Secondary outcomes are lower extremity muscle power at 12 weeks, muscle endurance at 12 and 24 weeks, physical performance at 24 weeks, lean mass at 24 weeks, and 24-hr urinary nitrogen excretion adjusted for nitrogen intake at 24 weeks. Exploratory outcomes will include a measure of muscle mass - D3-creatine dilution - and how it correlates with lean mass. Changes in these outcomes will be compared in the 4 groups. If successful, this research would represent a meaningful step in defining the circumstances under which protein has its greatest anabolic benefit.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 141
• Est. completion date: December 21, 2023
• Est. primary completion date: December 21, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 65 Years and older

Eligibility

Inclusion Criteria:

1. ability to sign informed consent form

2. ambulatory community-dwelling men and women

3. age 65 years and over

4. habitual dietary intake of protein of =0.8 g/kg/d

5. underactive

6. estimated glomerular filtration rate = 50 ml/min/1.73 m2

Exclusion Criteria:

1. participation in a diet or intensive exercise program during the study

2. vegetarian (no animal protein)

3. oral glucocorticoid use for > 10 days in the last 3 months

4. anabolic and gonadal hormones in the last 6 months

5. Tamoxifen/raloxifene in the last 6 months

6. regular use of alkali-producing antacids (> 3 times per week)

7. potassium-containing supplements or products

8. non-steroidal anti-inflammatory medications >3 times per week

9. antacids containing calcium carbonate, aluminum hydroxide, magnesium hydroxide, or calcium acetate

10. insulin

11. sulfonylureas

12. SGLT2 inhibitors

13. a lower extremity fracture in the last year

14. kidney stones in the past 5 years

15. hyperkalemia

16. elevated serum bicarbonate

17. hypercalcemia

18. uncontrolled diabetes mellitus defined as having fasting blood >150 or hemoglobin A1c >8%

19. untreated thyroid or parathyroid disease

20. significant immune disorder

21. current unstable heart disease

22. Crohn's disease

23. active malignancy or cancer therapy in the last year

24. alcohol use exceeding 2 drinks/day

25. current peptic ulcers or esophageal stricture

26. other condition or abnormality in screening labs, at discretion of the study physician

Related Conditions & MeSH terms

• Age-Related Sarcopenia
• Muscle Loss
• Sarcopenia

Intervention

Dietary Supplement:
• whey protein isolate
one 15-25 gm (based on body weight) protein packet three times a day with each meal
• potassium bicarbonate (KHCO3)
two 13.5 mmol capsules three times a day with each meal

Other:
• microcrystalline cellulose
identical placebo capsule
• maltodextrin powder
isocaloric placebo powder

Locations

Country	Name	City	State
United States	Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University	Boston	Massachusetts

Sponsors (2)

Lead Sponsor	Collaborator
Tufts University	National Institute on Aging (NIA)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	D3-creatine dilution (exploratory)	measure of total body muscle mass	24 weeks
Primary	lower extremity muscle power	measure of muscle power using a double leg press	24 weeks
Secondary	lower extremity muscle power	measure muscle power using double leg press	12 weeks
Secondary	isokinetic leg extension strength and endurance	measure knee extension strength, torque and fatigability using Biodex Isokinetic Dynamometer	12 and 24 weeks
Secondary	handgrip strength	measure strength using grip strength dynamometer	24 weeks
Secondary	appendicular lean body mass	Dual energy X-ray absorptiometry (DXA) lean mass of arms plus legs divided by height squared	24 weeks
Secondary	physical performance battery	measure performance based on Health Aging and Body Composition-Physical Performance Battery	24 weeks
Secondary	24 hour urinary nitrogen excretion to nitrogen intake	measure based on 24 hour urine and 24 hour diet recall	24 weeks