The Effects of PeptiStrong and Whey on Muscle Function In Older Adults

The aim of this study is to compare two protein drinks containing whey protein (derived from milk) in healthy adults aged 60 to 85 years. One group will consume a standard whey protein drink (20g), while the other group will consume a drink with half the total protein dose (10g) made of whey protein and PeptiStrong, a fava bean hydrolysate containing bioactive peptides.

The study will assess whether the lower protein drink containing PeptiStrong will lead to equal or greater improvements than the standard drink in physical function, such as the ability to stand up from a chair, walk at a normal pace, maintain balance, and grip strength. The study will also examine markers related to inflammation, fatigue, and quality of life.

The intended value of this research is to improve understanding of how targeted nutritional strategies may help maintain or improve muscle function in older adults. The findings may help inform future nutritional recommendations and the development of practical dietary interventions aimed at supporting healthy ageing and independence.

• PeptiStrong + whey protein (Dietary supplement): Fava bean protein hydrolysate containing bioactive peptides mixed with whey protein as dry powder for drinkable protein shake
• Whey protein (Dietary supplement): Whey protein as dry powder for drinkable protein shake

Primary outcomes

• Hand Grip Strength via hand held dynamometer [Baseline to Week 4]: Change from baseline to end of study in grip strength as assessed via hand held dynamometer

Secondary outcomes

• Chair Stand Test - Part of short performance physical battery [Baseline to week 4]: Change from baseline to end of study in physical function assessment via chair stands. This test measures the time taken to complete 5 sit-to-stand repetitions in seconds. A lower time (fewer seconds) = better performance. As part of the full short performance physical battery it is converted to a subscore of 0-4, where a higher score = better performance
• Gait Speed as part of short performance physical battery [Baseline to week 4]: Change from baseline to end of study in physical function assessment assessed as time to walk a fixed distance in seconds and reporting in meters per second. Higher speeds indicate better performance. This is converted to a subscore of 0-4 within the full short performance physical battery
• 6 Minute Walking Endurance Test [Baseline to week 4]: Change from baseline to end of study in physical function and endurance assessed as the total distance walked in 6 minutes in meters. A greater distance reflects better walking endurance and functional capacity.
• Balance test as part of short performance physical battery [Baseline to week 4]: Change from baseline to end of study in balance as assessed by the ability to hold three standing positions of increasing difficulty: side-by-side, semi-tandem, and tandem stance in seconds. Higher scores indicate better balance. The overall score is converted to a a sub-score of 0-4 within the full short performance physical battery.
• Balance assessment via force plates [Baseline to week 4]: Change from baseline to end of study in balance as assessed via force plates
• Quality of Life via the Sarcopenia Quality of Life (SarQoL®) Questionnaire [Baseline to week 4]: Change from baseline to end of study in quality of life as measured via subjective SarQOL questionnaire. The total score ranges from 0 to 100, with higher scores reflecting a higher quality of life.
• Fatigue via Multidimensional Fatigue Inventory Questionnaire [Baseline to week 4]: Change from baseline to end of study in self-reported fatigue as assessed via multidimensional fatigue inventory questionnaire. This 20-item questionnaire covers five dimensions: General Fatigue, Physical Fatigue, Mental Fatigue, Reduced Motivation, and Reduced Activity. Each subscale score ranges from 4 to 20, with higher scores indicating greater fatigue
• C-reactive protein (CRP) via blood test [Baseline to week 4]: Change from baseline to the end of study in inflammatory marker C-reactive protein (CRP) in serum as mg/L
• Interleukins via blood test [Baseline to week 4]: Change from baseline to the end of study in Interleukin inflammatory markers in serum as pg/mL
• Body composition: Muscle mass and body fat via bioelectrical impedance analysis [Baseline to week 4]: Change from baseline to end of study in muscle mass and body fat as measured by bioelectrical impedance analysis in kilograms and % of total body weight

Sex: All, ages: 60 Years to 85 Years, accepts healthy volunteers

Inclusion Criteria:

* Men and women aged 60 to 85 years at the time of enrolment
* Community-dwelling (living independently or with minimal assistance)
* Able to walk independently (with or without a walking aid) and complete simple physical function tests (such as standing up from a chair and walking short distances)
* Willing and able to attend two study visits at the research facility (baseline and end of study)
* Willing and able to consume a protein drink containing whey protein (derived from milk) once daily for 30 days
* Able to understand the study information and provide written informed consent

Exclusion Criteria:

* Any known food allergy or intolerance to fava bean protein or milk protein
* Diagnosed kidney disease or any medical condition where increased protein intake is contraindicated
* Yes to any of the answers on the "Older Adult Functional Assessment Screening Questionnaire"
* Individuals with implanted electronic devices
* Current or recent (within the past 3 months) participation in another clinical research study involving a nutritional or exercise intervention
* Conditions that significantly impair mobility or balance such that safe completion of the physical function tests is not possible

• Graeme Close, Professor, Principal investigator, Liverpool John Moore University