TY - JOUR
T1 - Differential stimulation of muscle protein synthesis in elderly humans following isocaloric ingestion of amino acids or whey protein
AU - Paddon-Jones, Douglas
AU - Sheffield-Moore, Melinda
AU - Katsanos, Christos S.
AU - Zhang, Xiao Jun
AU - Wolfe, Robert R.
N1 - Funding Information:
We gratefully acknowledge the assistance of Melissa Bailey, Stephaine Blasé, David Chinkes, Dan Creson, Christopher Danesi, Dessa Gemar, Guy Jones, Hisamine Kobayashi and Elena Volpi for their assistance with data collection and analysis. This project was supported by NIH 5 RO1 GM 57295. Studies were conducted on the General Clinical Research Center (GCRC) at The University of Texas Medical Branch at Galveston and funded by grant M01 RR 00073 from the National Center for Research Resources, NIH, USPHS.
PY - 2006/2
Y1 - 2006/2
N2 - To counteract the debilitating progression of sarcopenia, a protein supplement should provide an energetically efficient anabolic stimulus. We quantified net muscle protein synthesis in healthy elderly individuals (65-79 yrs) following ingestion of an isocaloric intact whey protein supplement (WY; n=8) or an essential amino acid supplement (EAA; n=7). Femoral arterio-venous blood samples and vastus lateralis muscle biopsy samples were obtained during a primed, constant infusion of L-[ring-2H5]phenylalanine. Net phenylalanine uptake and mixed muscle fractional synthetic rate (FSR) were calculated during the post-absorptive period and for 3.5 h following ingestion of 15 g EAA or 15 g whey. After accounting for the residual increase in the intracellular phenylalanine pool, net post-prandial phenylalanine uptake was 53.4±9.7 mg phe leg-1 (EAA) and 21.7±4.6 mg phe leg-1 (WY), (P<0.05). Postabsorptive FSR values were 0.056±0.004% h-1 (EAA) and 0.049±0.006% h-1 (WY), (P>0.05). Both supplements stimulated FSR (P<0.05), but the increase was greatest in the EAA group with values of 0.088±0.011% h-1 (EAA) and 0.066±0.004% h-1 (WY), (P<0.05). While both EAA and WY supplements stimulated muscle protein synthesis, EAAs may provide a more energetically efficient nutritional supplement for elderly individuals.
AB - To counteract the debilitating progression of sarcopenia, a protein supplement should provide an energetically efficient anabolic stimulus. We quantified net muscle protein synthesis in healthy elderly individuals (65-79 yrs) following ingestion of an isocaloric intact whey protein supplement (WY; n=8) or an essential amino acid supplement (EAA; n=7). Femoral arterio-venous blood samples and vastus lateralis muscle biopsy samples were obtained during a primed, constant infusion of L-[ring-2H5]phenylalanine. Net phenylalanine uptake and mixed muscle fractional synthetic rate (FSR) were calculated during the post-absorptive period and for 3.5 h following ingestion of 15 g EAA or 15 g whey. After accounting for the residual increase in the intracellular phenylalanine pool, net post-prandial phenylalanine uptake was 53.4±9.7 mg phe leg-1 (EAA) and 21.7±4.6 mg phe leg-1 (WY), (P<0.05). Postabsorptive FSR values were 0.056±0.004% h-1 (EAA) and 0.049±0.006% h-1 (WY), (P>0.05). Both supplements stimulated FSR (P<0.05), but the increase was greatest in the EAA group with values of 0.088±0.011% h-1 (EAA) and 0.066±0.004% h-1 (WY), (P<0.05). While both EAA and WY supplements stimulated muscle protein synthesis, EAAs may provide a more energetically efficient nutritional supplement for elderly individuals.
KW - Aging
KW - Metabolism
KW - Nutrition
KW - Sarcopenia
KW - Supplements
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U2 - 10.1016/j.exger.2005.10.006
DO - 10.1016/j.exger.2005.10.006
M3 - Article
C2 - 16310330
AN - SCOPUS:31544472848
SN - 0531-5565
VL - 41
SP - 215
EP - 219
JO - Experimental Gerontology
JF - Experimental Gerontology
IS - 2
ER -