An oral essential amino acid-carbohydrate supplement  enhances muscle protein anabolism after resistance exercise

This study was designed to determine the response of muscle protein to the bolus ingestion of a drink containing essential amino acids and carbohydrate after resistance exercise. Six subjects (3 men, 3 women) randomly consumed a treatment drink (6 g essential amino acids, 35 g sucrose) or a flavored placebo drink 1 h or 3 h after a bout of resistance exercise on two separate occasions. We used a three-compartment model for determination of leg muscle protein kinetics. The model involves the infusion of ring-2H5-phenylalanine, femoral arterial and venous blood sampling, and muscle biopsies. Phenylalanine net balance and muscle protein synthesis were significantly increased above the predrink and corresponding placebo value ( P < 0.05) when the drink was taken 1 or 3 h after exercise but not when the placebo was ingested at 1 or 3 h. The response to the amino acid-carbohydrate drink produced similar anabolic responses at 1 and 3 h. Muscle protein breakdown did not change in response to the drink. We conclude that essential amino acids with carbohydrates stimulate muscle protein anabolism by increasing muscle protein synthesis when ingested 1 or 3 h after resistance exercise.

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Postexercise net protein synthesis in human muscle from orally administered amino acids

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1999.276.4.e628 ◽

1999 ◽

Vol 276 (4) ◽

pp. E628-E634 ◽

Cited By ~ 124

Author(s):

Kevin D. Tipton ◽

Arny A. Ferrando ◽

Stuart M. Phillips ◽

David Doyle ◽

Robert R. Wolfe

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Resistance Exercise ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Random Order ◽

Essential Amino Acids ◽

Constant Infusion ◽

Protein Balance

We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion ofl-[ ring-2H5]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions. Subjects consumed in random order 1 liter of 1) a mixed amino acid (40 g) solution (MAA), 2) an essential amino acid (40 g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased ∼150–640% above baseline during ingestion of MAA and EAA. Net muscle protein balance was significantly increased from negative during PLA ingestion (−50 ± 23 nmol ⋅ min−1 ⋅ 100 ml leg volume−1) to positive during MAA ingestion (17 ± 13 nmol ⋅ min−1 ⋅ 100 ml leg volume−1) and EAA (29 ± 14 nmol ⋅ min−1 ⋅ 100 ml leg volume−1; P < 0.05). Because net balance was similar for MAA and EAA, it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise. We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused.

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Combined effects of hyperaminoacidemia and oxandrolone on skeletal muscle protein synthesis

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.278.2.e273 ◽

2000 ◽

Vol 278 (2) ◽

pp. E273-E279 ◽

Cited By ~ 21

Author(s):

Melinda Sheffield-Moore ◽

Robert R. Wolfe ◽

Dennis C. Gore ◽

Steven E. Wolf ◽

Dennis M. Ferrer ◽

...

Keyword(s):

Skeletal Muscle ◽

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Compartment Model ◽

Acid Mixture ◽

Skeletal Muscle Protein ◽

Amino Acid Infusion

We investigated whether the normal anabolic effects of acute hyperaminoacidemia were maintained after 5 days of oxandrolone (Oxandrin, Ox)-induced anabolism. Five healthy men [22 ± 3 (SD) yr] were studied before and after 5 days of oral Ox (15 mg/day). In each study, a 5-h basal period was followed by a 3-h primed-continuous infusion of a commercial amino acid mixture (10% Travasol). Stable isotopic data from blood and muscle sampling were analyzed using a three-compartment model to calculate muscle protein synthesis and breakdown. Model-derived muscle protein synthesis increased after amino acid infusion in both the control [basal control (BC) vs. control + amino acids (C+AA); P < 0.001] and Ox study [basal Ox (BOx) vs. Ox + amino acids (Ox+AA); P < 0.01], whereas protein breakdown was unchanged. Fractional synthetic rates of muscle protein increased 94% (BC vs. C+AA; P = 0.01) and 53% (BOx vs. Ox+AA; P < 0.01), respectively. We conclude that the normal anabolic effects of acute hyperaminoacidemia are maintained in skeletal muscle undergoing oxandrolone-induced anabolism.

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The Role of the Anabolic Properties of Plant- versus Animal-Based Protein Sources in Supporting Muscle Mass Maintenance: A Critical Review

Nutrients ◽

10.3390/nu11081825 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1825 ◽

Cited By ~ 34

Author(s):

Insaf Berrazaga ◽

Valérie Micard ◽

Marine Gueugneau ◽

Stéphane Walrand

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Amino Acid Composition ◽

Protein Intake ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Essential Amino Acids ◽

Protein Sources ◽

Nutritional Strategies

Plant-sourced proteins offer environmental and health benefits, and research increasingly includes them in study formulas. However, plant-based proteins have less of an anabolic effect than animal proteins due to their lower digestibility, lower essential amino acid content (especially leucine), and deficiency in other essential amino acids, such as sulfur amino acids or lysine. Thus, plant amino acids are directed toward oxidation rather than used for muscle protein synthesis. In this review, we evaluate the ability of plant- versus animal-based proteins to help maintain skeletal muscle mass in healthy and especially older people and examine different nutritional strategies for improving the anabolic properties of plant-based proteins. Among these strategies, increasing protein intake has led to a positive acute postprandial muscle protein synthesis response and even positive long-term improvement in lean mass. Increasing the quality of protein intake by improving amino acid composition could also compensate for the lower anabolic potential of plant-based proteins. We evaluated and discussed four nutritional strategies for improving the amino acid composition of plant-based proteins: fortifying plant-based proteins with specific essential amino acids, selective breeding, blending several plant protein sources, and blending plant with animal-based protein sources. These nutritional approaches need to be profoundly examined in older individuals in order to optimize protein intake for this population who require a high-quality food protein intake to mitigate age-related muscle loss.

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Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling

Journal of Applied Physiology ◽

10.1152/japplphysiol.91397.2008 ◽

2009 ◽

Vol 106 (4) ◽

pp. 1374-1384 ◽

Cited By ~ 175

Author(s):

Micah J. Drummond ◽

Hans C. Dreyer ◽

Christopher S. Fry ◽

Erin L. Glynn ◽

Blake B. Rasmussen

Keyword(s):

Skeletal Muscle ◽

Amino Acids ◽

Protein Synthesis ◽

Resistance Exercise ◽

Human Skeletal Muscle ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Essential Amino Acids ◽

Skeletal Muscle Protein ◽

Mtorc1 Signaling

In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.

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Role of specific dietary amino acids in clinical conditions

British Journal Of Nutrition ◽

10.1017/s0007114512002358 ◽

2012 ◽

Vol 108 (S2) ◽

pp. S139-S148 ◽

Cited By ~ 34

Author(s):

Renate Jonker ◽

Mariëlle P. K. J. Engelen ◽

Nicolaas E. P. Deutz

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Muscle Wasting ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Essential Amino Acids ◽

Dietary Proteins ◽

Disease States ◽

Stimulation Of

In a variety of chronic and acute disease states, alterations in protein synthesis, breakdown and protein turnover rates occur that are related to the loss of body protein and skeletal muscle wasting. A key observation is the stimulation of protein breakdown in muscle and the stimulation of protein synthesis in the splanchnic area; mainly liver. An altered splanchnic extraction of amino acids as well as an anabolic resistance to dietary protein, related to stress, disuse and aging play a key role in the pathogenesis of muscle wasting in these conditions. To overcome these factors, specific dietary protein and amino acid diets have been introduced. The main focus of these diets is the quantity and quality of dietary proteins and whether a balanced mixture or solely dietary essential amino acids are required with or without higher intake levels of specific amino acids. Specifically in cancer patients, stimulated muscle protein synthesis has been obtained by increasing the amount of protein in a meal and by providing additional leucine. Also in other chronic diseases such as chronic obstructive pulmonary disease and cystic fibrosis, meals with specific dietary proteins and specific combinations of dietary essential amino acids are able to stimulate anabolism. In acute diseases, a special role for the amino acid arginine and its precursor citrulline as anabolic drivers has been observed. Thus, there is growing evidence that modifying the dietary amino acid composition of a meal will positively influence the net balance between muscle protein synthesis and breakdown, leading to muscle protein anabolism in a variety of chronic and acute disease states. Specific amino acids with anabolic potential are leucine, arginine and citrulline.

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Effects of Amino Acid Intake on Anabolic Processes

Canadian Journal of Applied Physiology ◽

10.1139/h2001-056 ◽

2001 ◽

Vol 26 (S1) ◽

pp. S220-S227 ◽

Cited By ~ 28

Author(s):

Robert R. Wolfe

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Essential Amino Acids ◽

Negative Resistance ◽

Static Concentration ◽

Amino Acid Intake ◽

Modest Effect

In the resting state muscle protein breakdown exceeds the rate of muscle protein synthesis, meaning that the balance between synthesis and breakdown is negative. Resistance exercise improves the net balance by stimulating muscle protein synthesis, but nutrient intake is requiredfor synthesis to exceed breakdown (i.e., an anabolic response). Exercise and exogenous amino acids have an additive effect on muscle protein synthesis. There is a timecourse of the response to a steady-state change in amino acid concentration. The signal for stimulation of muscle protein synthesis appears to be the extracellular concentrations of one or more of the essential amino acids (EAAs). Further, the rate , and direction, of change in extracellular concentrations (rather than the static concentration, per se) may be the important. Ingestion of non-essential AAs is not needed to stimulate muscle protein synthesis. Carbohydrate has, at most, a modest effect to enhance the response to amino acid ingestion after exercise. Finally, a mixture of EAAs + CRO more effectively stimulates muscle protein synthesis when taken before as opposed to after exercise.

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Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2001.281.2.e197 ◽

2001 ◽

Vol 281 (2) ◽

pp. E197-E206 ◽

Cited By ~ 282

Author(s):

Kevin D. Tipton ◽

Blake B. Rasmussen ◽

Sharon L. Miller ◽

Steven E. Wolf ◽

Sharla K. Owens-Stovall ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Resistance Exercise ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Vastus Lateralis ◽

Healthy Human ◽

Anabolic Response ◽

Carbohydrate Ingestion

The present study was designed to determine whether consumption of an oral essential amino acid-carbohydrate supplement (EAC) before exercise results in a greater anabolic response than supplementation after resistance exercise. Six healthy human subjects participated in two trials in random order, PRE (EAC consumed immediately before exercise), and POST (EAC consumed immediately after exercise). A primed, continuous infusion ofl-[ ring-2H5]phenylalanine, femoral arteriovenous catheterization, and muscle biopsies from the vastus lateralis were used to determine phenylalanine concentrations, enrichments, and net uptake across the leg. Blood and muscle phenylalanine concentrations were increased by ∼130% after drink consumption in both trials. Amino acid delivery to the leg was increased during exercise and remained elevated for the 2 h after exercise in both trials. Delivery of amino acids (amino acid concentration times blood flow) was significantly greater in PRE than in POST during the exercise bout and in the 1st h after exercise ( P < 0.05). Total net phenylalanine uptake across the leg was greater ( P = 0.0002) during PRE (209 ± 42 mg) than during POST (81 ± 19). Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, increased after EAC consumption in both trials. These results indicate that the response of net muscle protein synthesis to consumption of an EAC solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.

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An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1997.273.1.e122 ◽

1997 ◽

Vol 273 (1) ◽

pp. E122-E129 ◽

Cited By ~ 168

Author(s):

G. Biolo ◽

K. D. Tipton ◽

S. Klein ◽

R. R. Wolfe

Keyword(s):

Amino Acids ◽

Blood Flow ◽

Protein Synthesis ◽

Amino Acid ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Protein Kinetics ◽

Amino Acid Infusion

Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (approximately 0.15 g.kg-1.h-1 for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle protein synthesis were also greater after exercise than at rest (291 +/- 42% vs. 141 +/- 45%). Muscle protein breakdown was not significantly affected by hyperminoacidemia either at rest or after exercise. We conclude that the stimulatory effect of exogenous amino acids on muscle protein synthesis is enhanced by prior exercise, perhaps in part because of enhanced blood flow. Our results imply that protein intake immediately after exercise may be more anabolic than when ingested at some later time.

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