Aging does not impair the anabolic response to a protein-rich meal  

Oleh:

Symons, T. Brock ; Schutzler, Scott E. ; Cocke, Tara L ; Chinkes, David L. ; Wolfe, Robert R. ; Paddon-Jones, Douglas

Jenis: Article from Journal - ilmiah internasional
Dalam koleksi: The American Journal of Clinical Nutrition vol. 86 no. 02 (Aug. 2007), page 451.
Topik: Nutrition • stable isotopes • sarcopenia • diet • beef • amino acids

Ketersediaan

Perpustakaan FK Nomor Panggil: A07.K.2007.03 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

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Background: Sarcopenia is a debilitating condition afflicting the elderly that may be facilitated by insufficient or ineffectual intake of dietary protein. We previously showed that free-form essential amino acids acutely stimulate muscle protein synthesis in both the young and the elderly. However, the ability of an actual protein-rich food to stimulate anabolism in the young and the elderly has not been explored. Objective: We aimed to characterize changes in plasma amino acid concentrations and to quantify muscle protein synthesis in healthy young (41 ± 8 y old; n = 10) and elderly (70 ± 5 y old; n = 10) persons after ingestion of a 113-g (4-oz) serving of lean beef. Design: Venous blood samples and vastus lateralis muscle biopsy samples were obtained during a primed (2.0 µmol/kg) constant infusion (0.08 µmol·kg–1·min–1) of L-[ring-13C6] phenylalanine. Plasma amino acid concentrations were measured and a mixed-muscle fractional synthesis rate (FSR) was calculated during the premeal period and for 5 h after beef ingestion. Results: Mixed-muscle FSR increased by 51% in both the elderly (mean ± SE measurements: 0.072 ± 0.004%/h and 0.108 ± 0.006%/h before and after the meal, respectively) and the young (0.074 ± 0.005%/h and 0.113 ± 0.005%/h before and after the meal, respectively) after beef ingestion (P < 0.001). Plasma amino acid concentrations peaked at 100 min after beef ingestion in both age groups but were substantially higher in the elderly (2185 ± 134 nmol/mL compared with 1403 ± 96 nmol/mL; P < 0.001). Conclusion: Despite differences in the concentration of amino acids in the plasma precursor pool, aging does not impair the ability to acutely synthesize muscle protein after ingestion of a common protein-rich food.

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