Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein

Shanon L. Casperson, Melinda Sheffield-Moore, Susan J. Hewlings, Douglas Paddon-Jones

Research output: Contribution to journalArticle

87 Citations (Scopus)

Abstract

Background & aim: Protein-energy supplementation is routinely employed to combat muscle loss. However, success is often compromised by increased satiety, poor palatability, high costs and low compliance. Methods: For 2-weeks we supplemented meals of older individuals with leucine (4 g/meal; 3 meals/day; days 2-14). Metabolic studies were performed prior to (Day 1) and following (Day 15) supplementation. Leucine was not provided on metabolic study days. Venous blood and vastus lateralis muscle biopsies were obtained during a primed constant infusion of L-[ring-13C6] phenylalanine. Mixed muscle fractional synthesis rate (FSR), body composition and markers of nutrient signaling (mTOR, 4E-BP1 and p70S6K1 phosphorylation) were measured before and after a low protein/carbohydrate simulated meal. Results: The meal modestly increased FSR on Day 1 (postabsorptive: 0.063 ± 0.004 vs. postprandial: 0.075 ± 0.006%/h; p = 0.03), however, two weeks of leucine supplementation increased postabsorptive FSR (p = 0.004) and the response to the meal (p = 0.01) (postabsorptive: 0.074 ± 0.007 vs. postprandial: 0.10 ± 0.007%/h). Changes in FSR were mirrored by increased phosphorylation of mTOR, 4E-BP1 and p70S6K1 (p ≤ 0.1). No change in fat free mass was observed (p > 0.05). Conclusions: In older adults, leucine supplementation may improve muscle protein synthesis in response to lower protein meals.

Original languageEnglish (US)
Pages (from-to)512-519
Number of pages8
JournalClinical Nutrition
Volume31
Issue number4
DOIs
StatePublished - Aug 2012

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Muscle Proteins
Leucine
Meals
Proteins
Muscles
Phosphorylation
Quadriceps Muscle
Body Composition
Phenylalanine
Compliance
Fats
Carbohydrates
Biopsy
Costs and Cost Analysis
Food

Keywords

  • Aging
  • Nutrition
  • Protein requirements
  • Sarcopenia

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Nutrition and Dietetics

Cite this

Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein. / Casperson, Shanon L.; Sheffield-Moore, Melinda; Hewlings, Susan J.; Paddon-Jones, Douglas.

In: Clinical Nutrition, Vol. 31, No. 4, 08.2012, p. 512-519.

Research output: Contribution to journalArticle

Casperson, Shanon L. ; Sheffield-Moore, Melinda ; Hewlings, Susan J. ; Paddon-Jones, Douglas. / Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein. In: Clinical Nutrition. 2012 ; Vol. 31, No. 4. pp. 512-519.
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