Effect of amino acid supplementation on muscle mass, strength and physical function in elderly.
OBJECTIVE
With advancing age there is a gradual decline in muscle mass, strength and function. The aim of this study was to determine if regular intake of a nutritional supplement containing essential amino acids (EAA)+arginine could reverse these responses in elderly subjects.


METHODS
Twelve glucose intolerant subjects (67.0+/-5.6 (SD) years, 7 females, 5 males) ingested 11 g of EAA+arginine two times a day, between meals for 16 weeks. Diet and activity were not otherwise modified. Lean body mass (DEXA) was measured every fourth week. Maximal leg strength was tested and functional tests were performed at week 0, 8, 12, and 16.


RESULTS
Lean body mass (LBM) increased during the study (p=0.038). At week 12, the average increase in LBM was 1.14+/-0.36 (SE) kg (p<0.05 vs baseline), whereas at week 16, the increase was 0.60+/-0.38 kg (NS vs baseline). The lower extremity strength measure score (sum of individual knee flexors and extensors' one repetition maximum, n=10) was 127.5+/-21.8 kg at baseline, and average increase during the study was 22.2+/-6.1% (p<0.001). Improvements were also observed in usual gait speed (p=0.002), timed 5-step test (p=0.007), and timed floor-transfer test (p=0.022).


CONCLUSIONS
Supplementation of the diet with EAA+arginine improves lean body mass, strength and physical function compared to baseline values in glucose intolerant elderly individuals.
Børsheim
Elisabet
E
Department of Surgery, University of Texas Medical Branch, 815 Market Street, Galveston, TX 77550, USA. elborshe@utmb.edu
Bui
Quynh-Uyen T
QU
Tissier
Sandrine
S
Kobayashi
Hisamine
H
Ferrando
Arny A
AA
Wolfe
Robert R
RR
D015502:Absorptiometry, Photon; D000368:Aged; D000375:Aging / Q000502:physiology; D000601:Amino Acids, Essential / Q000008:administration & dosage* / Q000494:pharmacology; D001120:Arginine / Q000008:administration & dosage* / Q000494:pharmacology; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D019587:Dietary Supplements; D005260:Female; D005684:Gait / Q000502:physiology; D018149:Glucose Intolerance / Q000378:metabolism; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome
D000601:Amino Acids, Essential; D001120:Arginine