The Role of Diet in Supporting Bone and Muscle Health in Older Adults (Poster Theater Flash Session 9)

(PTFS09-02-25) The Role of (Pre) Frailty in Muscle Health and Related Amino Acid Metabolism Measured by Stable Isotope Tracers

Monday, June 2, 2025

10:04 AM – 10:08 AM ET

Location: South Hall B (The Hub) - Poster Theater / Poster Board Number PT-1

Presenting Author(s)

Minchae Chloe Kang, BS (she/her/hers)

Graduate Research Assistant
Center for Translational Research in Aging & Longevity, Texas A&M University
College Station, Texas, United States

Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

Co-Author(s)

ND

Nicolaas E.P. Deutz, MD, PhD

Professor
Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University; and Department of Geriatrics, University of Arkansas for Medical Sciences
College Station, Texas, United States
TS

Tanja Stoll

N/A, Germany
SD

Sofie De Wandel

Texas A&M Health, United States
RM

Raven A. McNew, Ph.D., RN

Center for Translational Research in Aging & Longevity, Texas A&M University
College Station, Texas, United States
KC

Kimberly Coyle, NP

Center for Translational Research in Aging & Longevity, Texas A&M University
College Station, Texas, United States
AC

Adonnela Contreras

Texas A&M University, Texas, United States
JT

John J. Thaden, PhD

Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University
College Station, Texas, United States
ME

Marielle P.K.J. PKJ. Engelen, PhD

Professor
Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, and Department of Geriatrics, University of Arkansas for Medical Sciences
College Station, Texas, United States

Objectives: Previous studies found disturbances in plasma amino acid profiles in frail older adults with muscle loss. We investigated whether pre-frail older adults already have evidence of perturbations in protein/amino acid kinetics that may precede poor muscle health and physical function in these older adults.

Methods: We stratified 127 subjects (age >60) into three groups based on Fried frailty phenotype (FP). In total, 18 non-frail (13m/5f), 76 pre-frail (39m/37f), and 33 frail (10m/23f) older participants were studied. Body composition and bone density were measured by DXA, skeletal and respiratory (inspiratory) muscle strength by handgrip dynamometry and mouth pressure device, respectively, and functional capacity by 6-minute walking test (6MWT). Whole body amino acid kinetics in the postabsorptive state were measured by pulse administration of a cocktail of amino acid stable isotopes. Plasma enrichments of these amino acids were measured by LC-MS/MS to calculate their whole-body production (WBP) rates. Statistics: GLM with sex, age, and Charlson comorbidity index score as covariates. Metabolic data were corrected for lean mass.

Results: BMI and fat mass were comparable among the three groups. Frail older adults had lower lean soft tissue, respiratory and skeletal muscle strength, 6MWT distance, and physical activity (all p< 0.05) as well as lower WBP of leucine, valine, and phenylalanine (marker of whole body protein breakdown) (p < 0.03) compared to non-frail older adults. The pre-frail older adults had lower values for skeletal muscle strength, bone mineral density in the hip, and WBP of arginine and valine than those who were non-frail (p < 0.05). We also observed lower values for skeletal and respiratory muscle strength, and physical activity in frailty compared to pre-frailty (p < 0.001) as well as lower WBP of phenylalanine (p=0.035).

Conclusions: Presence of pre-frailty in older adults is already associated with muscle weakness and bone mineral loss, which get more severe with frailty. Decline in lean mass and functional capacity is specific to frailty and in part related to physical inactivity and suppressed protein turnover. Whether the specific metabolic perturbations seen in different stages of frailty warrant targeted nutritional approaches to prevent further muscle health decline needs further investigation.

Funding Sources: N/A