PP280-SUN: Outstanding abstract: Fat CO-Ingestion does not Impair Postprandial Protein Digestion and Absorption Kinetics or Whole-Body Net Protein Balance in Elderly Males

ABSTRACT Background Age-related decline in skeletal muscle mass is at least partly attributed to anabolic resistance to food intake. Resistance exercise sensitizes skeletal muscle tissue to the anabolic properties of amino acids. Objective The present study assessed protein digestion and amino acid absorption kinetics, whole-body protein balance, and the myofibrillar protein synthetic response to ingestion of different amounts of protein during recovery from resistance exercise in older men. Methods Forty-eight healthy older men [mean ± SEM age: 66 ± 1 y; body mass index (kg/m2): 25.4 ± 0.3] were randomly assigned to ingest 0, 15, 30, or 45 g milk protein concentrate after a single bout of resistance exercise consisting of 4 sets of 10 repetitions of leg press and leg extension and 2 sets of 10 repetitions of lateral pulldown and chest press performed at 75–80% 1-repetition maximum. Postprandial protein digestion and amino acid absorption kinetics, whole-body protein metabolism, and myofibrillar protein synthesis rates were assessed using primed, continuous infusions of l-[ring-2H5]-phenylalanine, l-[ring-2H2]-tyrosine, and l-[1-13C]-leucine combined with ingestion of intrinsically l-[1-13C]-phenylalanine and l-[1-13C]-leucine labeled protein. Results Whole-body net protein balance showed a dose-dependent increase after ingestion of 0, 15, 30, or 45 g of protein (0.015 ± 0.002, 0.108 ± 0.004, 0.162 ± 0.008, and 0.215 ± 0.009 μmol Phe · kg−1 · min−1, respectively; P < 0.001). Myofibrillar protein synthesis rates were higher after ingesting 30 (0.0951% ± 0.0062%/h, P = 0.07) or 45 g of protein (0.0970% ± 0.0062%/h, P < 0.05) than after 0 g (0.0746% ± 0.0051%/h). Incorporation of dietary protein–derived amino acids (l-[1-13C]-phenylalanine) into de novo myofibrillar protein showed a dose-dependent increase after ingestion of 15, 30, or 45 g protein (0.0171 ± 0.0017, 0.0296 ± 0.0030, and 0.0397 ± 0.0026 mole percentage excess, respectively; P < 0.05). Conclusions Dietary protein ingested during recovery from resistance exercise is rapidly digested and absorbed. Whole-body net protein balance and dietary protein-derived amino acid incorporation into myofibrillar protein show dose-dependent increases. Ingestion of ≥30 g protein increases postexercise myofibrillar protein synthesis rates in older men. This trial was registered at Nederlands Trial Register as NTR4492.

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Whole-body net protein balance plateaus in response to increasing protein intakes during post-exercise recovery in adults and adolescents

Nutrition & Metabolism ◽

10.1186/s12986-018-0301-z ◽

2018 ◽

Vol 15 (1) ◽

Cited By ~ 10

Author(s):

Michael Mazzulla ◽

Kimberly A. Volterman ◽

Jeff E. Packer ◽

Denise J. Wooding ◽

Jahmal C. Brooks ◽

...

Keyword(s):

Whole Body ◽

Exercise Recovery ◽

Protein Balance ◽

Post Exercise ◽

Post Exercise Recovery ◽

Net Protein

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Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00543.2003 ◽

2004 ◽

Vol 287 (4) ◽

pp. E712-E720 ◽

Cited By ~ 86

Author(s):

René Koopman ◽

Daphne L. E. Pannemans ◽

Asker E. Jeukendrup ◽

Annemie P. Gijsen ◽

Joan M. G. Senden ◽

...

Keyword(s):

Endurance Exercise ◽

Whole Body ◽

Protein Balance ◽

Entire Study ◽

Carbohydrate Ingestion ◽

Body Protein ◽

Exercise Period ◽

Postexercise Recovery ◽

Ultra Endurance ◽

Net Protein

The aims of this study were to compare different tracer methods to assess whole body protein turnover during 6 h of prolonged endurance exercise when carbohydrate was ingested throughout the exercise period and to investigate whether addition of protein can improve protein balance. Eight endurance-trained athletes were studied on two different occasions at rest (4 h), during 6 h of exercise at 50% of maximal O2 uptake (in sequential order: 2.5 h of cycling, 1 h of running, and 2.5 h of cycling), and during subsequent recovery (4 h). Subjects ingested carbohydrate (CHO trial; 0.7 g CHO·kg−1·h−1) or carbohydrate/protein beverages (CHO + PRO trial; 0.7 g CHO·kg−1·h−1 and 0.25 g PRO·kg−1·h−1) at 30-min intervals during the entire study. Whole body protein metabolism was determined by infusion of l-[1-13C]leucine, l-[2H5]phenylalanine, and [15N2]urea tracers with sampling of blood and expired breath. Leucine oxidation increased from rest to exercise [27 ± 2.5 vs. 74 ± 8.8 (CHO) and 85 ± 9.5 vs. 200 ± 16.3 mg protein·kg−1·h−1 (CHO + PRO), P < 0.05], whereas phenylalanine oxidation and urea production did not increase with exercise. Whole body protein balance during exercise with carbohydrate ingestion was negative (−74 ± 8.8, −17 ± 1.1, and −72 ± 5.7 mg protein·kg−1·h−1) when l-[1-13C]leucine, l-[2H5]phenylalanine, and [15N2]urea, respectively, were used as tracers. Addition of protein to the carbohydrate drinks resulted in a positive or less-negative protein balance (−32 ± 16.3, 165 ± 4.6, and 151 ± 13.4 mg protein·kg−1·h−1) when l-[1-13C]leucine, l-[2H5]phenylalanine, and [15N2]urea, respectively, were used as tracers. We conclude that, even during 6 h of exhaustive exercise in trained athletes using carbohydrate supplements, net protein oxidation does not increase compared with the resting state and/or postexercise recovery. Combined ingestion of protein and carbohydrate improves net protein balance at rest as well as during exercise and postexercise recovery.

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Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery

Journal of Applied Physiology ◽

10.1152/japplphysiol.00108.2009 ◽

2010 ◽

Vol 109 (2) ◽

pp. 431-438 ◽

Cited By ~ 63

Author(s):

Krista R. Howarth ◽

Stuart M. Phillips ◽

Maureen J. MacDonald ◽

Douglas Richards ◽

Natalie A. Moreau ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Protein Turnover ◽

Muscle Protein ◽

Whole Body ◽

Skeletal Muscle Protein ◽

Protein Balance ◽

Body Protein ◽

Muscle Protein Turnover ◽

Net Protein

We examined the effect of carbohydrate (CHO) availability on whole body and skeletal muscle protein utilization at rest, during exercise, and during recovery in humans. Six men cycled at ∼75% peak O2 uptake (V̇o2peak) to exhaustion to reduce body CHO stores and then consumed either a high-CHO (H-CHO; 71 ± 3% CHO) or low-CHO (L-CHO; 11 ± 1% CHO) diet for 2 days before the trial in random order. After each dietary intervention, subjects received a primed constant infusion of [1-13C]leucine and l-[ring-2H5]phenylalanine for measurements of the whole body net protein balance and skeletal muscle protein turnover. Muscle, breath, and arterial and venous blood samples were obtained at rest, during 2 h of two-legged kicking exercise at ∼45% of kicking V̇o2peak, and during 1 h of recovery. Biopsy samples confirmed that the muscle glycogen concentration was lower in the L-CHO group versus the H-CHO group at rest, after exercise, and after recovery. The net leg protein balance was decreased in the L-CHO group compared with at rest and compared with the H-CHO condition, which was primarily due to an increase in protein degradation (area under the curve of the phenylalanine rate of appearance: 1,331 ± 162 μmol in the L-CHO group vs. 786 ± 51 μmol in the H-CHO group, P < 0.05) but also due to a decrease in protein synthesis late in exercise. There were no changes during exercise in the rate of appearance compared with rest in the H-CHO group. Whole body leucine oxidation increased above rest in the L-CHO group only and was higher than in the H-CHO group. The whole body net protein balance was reduced in the L-CHO group, largely due to a decrease in whole body protein synthesis. These data extend previous findings by others and demonstrate, using contemporary stable isotope methodology, that CHO availability influences the rates of skeletal muscle and whole body protein synthesis, degradation, and net balance during prolonged exercise in humans.

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Intragastric protein administration stimulates overnight muscle protein synthesis in elderly men

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00321.2011 ◽

2012 ◽

Vol 302 (1) ◽

pp. E52-E60 ◽

Cited By ~ 70

Author(s):

Bart B. L. Groen ◽

Peter T. Res ◽

Bart Pennings ◽

Elisabeth Hertle ◽

Joan M. G. Senden ◽

...

Keyword(s):

Protein Synthesis ◽

Dietary Protein ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Whole Body ◽

Protein Digestion ◽

Absorption Kinetics ◽

Elderly Men ◽

Body Protein

The loss of skeletal muscle mass with aging has been attributed to an impaired muscle protein synthetic response to food intake. Therefore, nutritional strategies are targeted to modulate postprandial muscle protein accretion in the elderly. The purpose of this study was to assess the impact of protein administration during sleep on in vivo protein digestion and absorption kinetics and subsequent muscle protein synthesis rates in elderly men. Sixteen healthy elderly men were randomly assigned to an experiment during which they were administered a single bolus of intrinsically l-[1-13C]phenylalanine-labeled casein protein (PRO) or a placebo (PLA) during sleep. Continuous infusions with l-[ ring-2H5]phenylalanine and l-[ ring-2H2]tyrosine were applied to assess in vivo dietary protein digestion and absorption kinetics and subsequent muscle protein synthesis rates during sleep. We found that exogenous phenylalanine appearance rates increased following protein administration. The latter stimulated protein synthesis, resulting in a more positive overnight whole body protein balance (0.30 ± 0.1 vs. 11.8 ± 1.0 μmol phenylalanine·kg−1·h−1 in PLA and PRO, respectively; P < 0.05). In agreement, overnight muscle protein fractional synthesis rates were much greater in the PRO experiment (0.045 ± 0.002 vs. 0.029 ± 0.002%/h, respectively; P < 0.05) and showed abundant incorporation of the amino acids ingested via the intrinsically labeled protein (0.058 ± 0.006%/h). This is the first study to show that dietary protein administration during sleep is followed by normal digestion and absorption kinetics, thereby stimulating overnight muscle protein synthesis. Dietary protein administration during sleep stimulates muscle protein synthesis and improves overnight whole body protein balance. These findings may provide a basis for novel interventional strategies to attenuate muscle mass loss.

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Insulin resistance is a significant determinant of sarcopenia in advanced kidney disease

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00070.2018 ◽

2018 ◽

Vol 315 (6) ◽

pp. E1108-E1120 ◽

Cited By ~ 2

Author(s):

Serpil M. Deger ◽

Jennifer R. Hewlett ◽

Jorge Gamboa ◽

Charles D. Ellis ◽

Adriana M. Hung ◽

...

Keyword(s):

Protein Synthesis ◽

Kidney Disease ◽

Fat Free Mass ◽

Whole Body ◽

Protein Breakdown ◽

Protein Balance ◽

Breakdown Rates ◽

Phosphorylated Akt ◽

Sm Protein ◽

Net Protein

Maintenance hemodialysis (MHD) patients display significant nutritional abnormalities. Insulin is an anabolic hormone with direct effects on skeletal muscle (SM). We examined the anabolic actions of insulin, whole-body (WB), and SM protein turnover in 33 MHD patients and 17 participants without kidney disease using hyperinsulinemic-euglycemic-euaminoacidemic (dual) clamp. Gluteal muscle biopsies were obtained before and after the dual clamp. At baseline, WB protein synthesis and breakdown rates were similar in MHD patients. During dual clamp, controls had a higher increase in WB protein synthesis and a higher suppression of WB protein breakdown compared with MHD patients, resulting in statistically significantly more positive WB protein net balance [2.02 (interquartile range [IQR]: 1.79 and 2.36) vs. 1.68 (IQR: 1.46 and 1.91) mg·kg fat-free mass−1·min−1 for controls vs. for MHD patients, respectively, P < 0.001]. At baseline, SM protein synthesis and breakdown rates were higher in MHD patients versus controls, but SM net protein balance was similar between groups. During dual clamp, SM protein synthesis increased statistically significantly more in controls compared with MHD patients ( P = 0.03), whereas SM protein breakdown decreased comparably between groups. SM net protein balance was statistically significantly more positive in controls compared with MHD patients [67.3 (IQR: 46.4 and 97.1) vs. 15.4 (IQR: −83.7 and 64.7) μg·100 ml−1·min−1 for controls and MHD patients, respectively, P = 0.03]. Human SM biopsy showed a positive correlation between glucose and leucine disposal rates, phosphorylated AKT to AKT ratio, and muscle mitochondrial markers in controls but not in MHD patients. Diminished response to anabolic actions of insulin in the stimulated setting could lead to muscle wasting in MHD patients.

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Higher Net Protein Balance Following the Ingestion of Free Range Reindeer Compared to Commercial Beef

10.20944/preprints202002.0284.v1 ◽

2020 ◽

Author(s):

Melynda S. Coker ◽

Kaylee R. Ladd ◽

Scott E. Schutzler ◽

Sanghee Park ◽

Rick H. Williams ◽

...

Keyword(s):

Mass Spectrometry ◽

Amino Acid ◽

Protein Metabolism ◽

Essential Amino Acid ◽

Whole Body ◽

Induced Response ◽

Protein Balance ◽

Body Protein ◽

Wild Game ◽

Net Protein

Wild game consumption has been associated with health benefits, but the influence on protein metabolism remains unknown. We compared the feeding-induced response to 2 oz of free-range reindeer (FR) versus commercial beef (CB) using stable isotope methodology. Seven male and female participants (age: 38±12 years; body mass index: 24±3 kg/m2) completed two studies using a randomized, crossover design in which they ingested 2 oz of FR or CB. L-[ring 2H5]phenylalanine & L-[ring 2H2]tyrosine were delivered via primed, continuous intravenous infusion. Blood samples were collected during the basal period and following consumption of FR or CB. Feeding-induced changes in whole body protein synthesis (PS), protein breakdown (PB), and net protein balance (NB) were determined via analysis of plasma samples for phenyalanine and tyrosine enrichment by gas chromatography mass spectrometry; plasma essential amino acid concentrations were determined by liquid chromatography-electrospray ionization-mass spectrometry. Plasma post-prandial essential amino acid (EAA) concentrations were higher with the ingestion of FR compared to CB (P=0.02). The acute feeding-induced response in PS was not different in either trial, but PB was reduced with the ingestion of FR compared to CB (P<0.0001). The difference in PB contributed to a superior level of NB (P<0.0001). When protein kinetics were normalized relative to the amino acids ingested, PB/EAAs and total amino acids ingested were reduced (P<0.01 and 0.001, respectively) in FR compared to CB; contributing to greater NB/total amino acid ingested (P<0.0001) between FR and CB. We conclude that the nutrient profiles of FR may have a more favorable benefit on protein metabolism compared to CB. These data support the potential health benefits of wild game in the preservation of whole-body protein.

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Postexercise protein ingestion increases whole body net protein balance in healthy children

Journal of Applied Physiology ◽

10.1152/japplphysiol.00224.2014 ◽

2014 ◽

Vol 117 (12) ◽

pp. 1493-1501 ◽

Cited By ~ 9

Author(s):

Daniel R. Moore ◽

Kimberly A. Volterman ◽

Joyce Obeid ◽

Elizabeth A. Offord ◽

Brian W. Timmons

Keyword(s):

Recovery Period ◽

Whole Body ◽

Dietary Control ◽

Healthy Children ◽

Dependent Manner ◽

Protein Balance ◽

Main Effect ◽

Protein Ingestion ◽

Effect Time ◽

Net Protein

Postexercise protein ingestion increases whole body and muscle protein anabolism in adults. No study has specifically investigated the combined effects of exercise and protein ingestion on protein metabolism in healthy, physically active children. Under 24-h dietary control, 13 (seven males, six females) active children (∼11 yr old; 39.3 ± 5.9 kg) consumed an oral dose of [15N]glycine prior to performing a bout of exercise. Immediately after exercise, participants consumed isoenergetic mixed macronutrient beverages containing a variable amount of protein [0, 0.75, and 1.5 g/100 ml for control (CON), low protein (LP), and high protein (HP), respectively] according to fluid losses. Whole body nitrogen turnover (Q), protein synthesis (S), protein breakdown (B), and protein balance (WBPB) were measured throughout exercise and the early acute recovery period (9 h combined) as well as over 24 h. Postexercise protein intake from the beverage was ∼0.18 and ∼0.32 g/kg body mass for LP and HP, respectively. Q, S, and B were significantly greater (main effect time, all P < 0.001) over 9 h compared with 24 h with no differences between conditions. WBPB was also greater over 9 h compared with 24 h in all conditions (main effect time, P < 0.001). Over 9 h, WBPB was greater in HP ( P < 0.05) than LP and CON with a trend ( P = 0.075) toward LP being greater than CON. WBPB was positive over 9 h for all conditions but only over 24 h for HP. Postexercise protein ingestion acutely increases net protein balance in healthy children early in recovery in a dose-dependent manner with larger protein intakes (∼0.32 g/kg) required to sustain a net anabolic environment over an entire 24 h period.

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Whole Body Protein Turnover and Net Protein Balance After Pediatric Thoracic Surgery

Journal of Parenteral and Enteral Nutrition ◽

10.1177/0148607116678831 ◽

2016 ◽

pp. 014860711667883 ◽

Cited By ~ 1

Author(s):

Brenna S. Fullerton ◽

Eric A. Sparks ◽

Faraz A. Khan ◽

Jeremy G. Fisher ◽

Rocco Anzaldi ◽

...

Keyword(s):

Thoracic Surgery ◽

Protein Turnover ◽

Whole Body ◽

Protein Balance ◽

Body Protein ◽

Net Protein

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Amino acid absorption and subsequent muscle protein accretion following graded intakes of whey protein in elderly men

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00517.2011 ◽

2012 ◽

Vol 302 (8) ◽

pp. E992-E999 ◽

Cited By ~ 188

Author(s):

Bart Pennings ◽

Bart Groen ◽

Anneke de Lange ◽

Annemie P. Gijsen ◽

Antoine H. Zorenc ◽

...

Keyword(s):

Amino Acid ◽

Whey Protein ◽

Muscle Protein ◽

Older Men ◽

Whole Body ◽

Protein Digestion ◽

Protein Balance ◽

Acid Absorption ◽

Amino Acid Absorption ◽

The Impact

Whey protein ingestion has been shown to effectively stimulate postprandial muscle protein accretion in older adults. However, the impact of the amount of whey protein ingested on protein digestion and absorption kinetics, whole body protein balance, and postprandial muscle protein accretion remains to be established. We aimed to fill this gap by including 33 healthy, older men (73 ± 2 yr) who were randomly assigned to ingest 10, 20, or 35 g of intrinsically l-[1-13C]phenylalanine-labeled whey protein ( n = 11/treatment). Ingestion of labeled whey protein was combined with continuous intravenous l-[ ring-2H5]phenylalanine and l-[ ring-2H2]tyrosine infusion to assess the metabolic fate of whey protein-derived amino acids. Dietary protein digestion and absorption rapidly increased following ingestion of 10, 20, and 35 g whey protein, with the lowest and highest (peak) values observed following 10 and 35 g, respectively ( P < 0.05). Whole body net protein balance was positive in all groups (19 ± 1, 37 ± 2, and 58 ± 2 μmol/kg), with the lowest and highest values observed following ingestion of 10 and 35 g, respectively ( P < 0.05). Postprandial muscle protein accretion, assessed by l-[1-13C]phenylalanine incorporation in muscle protein, was higher following ingestion of 35 g when compared with 10 ( P < 0.01) or 20 ( P < 0.05) g. We conclude that ingestion of 35 g whey protein results in greater amino acid absorption and subsequent stimulation of de novo muscle protein synthesis compared with the ingestion of 10 or 20 g whey protein in healthy, older men.

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