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

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

Research output: Contribution to journalArticle

164 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)451-456
Number of pages6
JournalAmerican Journal of Clinical Nutrition
Volume86
Issue number2
StatePublished - Aug 1 2007

Fingerprint

Meals
ingestion
muscle protein
beef
Eating
fractional synthesis rate
Muscle Proteins
amino acids
Amino Acids
Proteins
proteins
muscles
Muscles
protein synthesis
sarcopenia
Sarcopenia
Food
Essential Amino Acids
essential amino acids
Dietary Proteins

Keywords

  • Amino acids
  • Beef
  • Diet
  • Nutrition
  • Sarcopenia
  • Stable isotopes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

Symons, T. B., Schutzler, S. E., Cocke, T. L., Chinkes, D. L., Wolfe, R. R., & Paddon-Jones, D. (2007). Aging does not impair the anabolic response to a protein-rich meal. American Journal of Clinical Nutrition, 86(2), 451-456.

Aging does not impair the anabolic response to a protein-rich meal. / Symons, T. Brock; Schutzler, Scott E.; Cocke, Tara L.; Chinkes, David L.; Wolfe, Robert R.; Paddon-Jones, Douglas.

In: American Journal of Clinical Nutrition, Vol. 86, No. 2, 01.08.2007, p. 451-456.

Research output: Contribution to journalArticle

Symons, TB, Schutzler, SE, Cocke, TL, Chinkes, DL, Wolfe, RR & Paddon-Jones, D 2007, 'Aging does not impair the anabolic response to a protein-rich meal', American Journal of Clinical Nutrition, vol. 86, no. 2, pp. 451-456.
Symons TB, Schutzler SE, Cocke TL, Chinkes DL, Wolfe RR, Paddon-Jones D. Aging does not impair the anabolic response to a protein-rich meal. American Journal of Clinical Nutrition. 2007 Aug 1;86(2):451-456.
Symons, T. Brock ; Schutzler, Scott E. ; Cocke, Tara L. ; Chinkes, David L. ; Wolfe, Robert R. ; Paddon-Jones, Douglas. / Aging does not impair the anabolic response to a protein-rich meal. In: American Journal of Clinical Nutrition. 2007 ; Vol. 86, No. 2. pp. 451-456.
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abstract = "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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AU - Symons, T. Brock

AU - Schutzler, Scott E.

AU - Cocke, Tara L.

AU - Chinkes, David L.

AU - Wolfe, Robert R.

AU - Paddon-Jones, Douglas

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