Essential Amino Acids Supplementation and Muscle Protein Synthesis

The modern warfighter faces numerous physiological challenges including sleep deprivation, sustained intense physical activity, and caloric restriction, the combined effects of which may result in the loss of lean body mass and decreased physical performance. Dietary interventions may help preserve lean body mass and facilitate recovery from periods of intense physical demand. For example, dietary strategies that increase amino acid availability have been shown to stimulate protein synthesis in skeletal muscle following resistance exercise. Because military tasks also incorporate endurance exercise components, studies regarding the effects of increasing dietary amino acids following endurance exercise are warranted. The objectives of this study are to characterize the effect of endurance exercise on protein synthesis and breakdown as well as the ability of an essential amino acid supplement to influence skeletal muscle protein metabolism and its cellular and molecular regulation following endurance exercise.

• Muscle Loss
• Muscle Anabolism

• Dietary Supplement: Essential Amino Acids
  10 Gram Essential Amino Acid solutions with different leucine contents consumed during two identical endurance exercise trials
• Other: Endurance exercise
  60 minute endurance exercise session

• No Intervention: Muscle protein turnover and intracellular signaling at rest
  Muscle protein turnover and intracellular signaling are measured at rest for comparison to post-exercise muscle metabolism.
• Active Comparator: Muscle metabolism after endurance exercise
  Post-exercise muscle protein metabolism was measured to determine if endurance exercise affects muscle metabolism compared to rest.
  Interventions:

  • Dietary Supplement: Essential Amino Acids
  • Other: Endurance exercise
• Experimental: Muscle Metabolism after endurance exercise
  Muscle metabolism response to endurance exercise with essential amino acid supplementation
  Intervention: Dietary Supplement: Essential Amino Acids
• Experimental: Muscle anabolism after endurance exercise
  Muscle anabolism after endurance exercise with essential amino acid supplementation.
  Intervention: Dietary Supplement: Essential Amino Acids

• Pasiakos SM, McClung HL, McClung JP, Urso ML, Pikosky MA, Cloutier GJ, Fielding RA, Young AJ. Molecular responses to moderate endurance exercise in skeletal muscle. Int J Sport Nutr Exerc Metab. 2010 Aug;20(4):282-90.
• Scofield DE, McClung HL, McClung JP, Kraemer WJ, Rarick KR, Pierce JR, Cloutier GJ, Fielding RA, Matheny RW Jr, Young AJ, Nindl BC. A NOVEL, NON-INVASIVE TRANSDERMAL FLUID SAMPLING METHODOLOGY: IGF-I MEASUREMENT FOLLOWING EXERCISE. Am J Physiol Regul Integr Comp Physiol. 2011 Mar 9; [Epub ahead of print]
• Pasiakos SM, McClung HL, McClung JP, Margolis LM, Andersen NE, Cloutier GJ, Pikosky MA, Rood JC, Fielding RA, Young AJ. Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis. Am J Clin Nutr. 2011 Sep;94(3):809-18. Epub 2011 Jul 20.

Inclusion Criteria:

• Men and women aged 18 - 35 years
• Weight stable
• Recreationally active with VO2max of 40 - 50 ml/kg/min
• Refrain from taking any NSAIDS or any aspirin-containing medications
• Supervisor approval if a federal employee

Exclusion Criteria:

• Disease or medication that affects macronutrient metabolism and/or the ability to participate in strenuous exercise
• Allergies to foods or medications (including, but not limited to, lidocaine or phenylalanine) to be utilized in the study
• Abnormal PT/PTT test or problems with blood clotting
• Present condition of alcoholism or other substance abuse that compromises exercise capacity
• Musculoskeletal injuries that compromise the ability to exercise
• Pregnancy