Association of postprandial postexercise muscle protein synthesis rates with dietary leucine: A systematic review.
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ABSTRACT: Background
Dietary protein ingestion augments post (resistance) exercise muscle protein synthesis (MPS) rates. It is thought that the dose of leucine ingested within the protein (leucine threshold hypothesis) and the subsequent plasma leucine variables (leucine trigger hypothesis; peak magnitude, rate of rise, and total availability) determine the magnitude of the postprandial postexercise MPS response.Methods
A quantitative systematic review was performed extracting data from studies that recruited healthy adults, applied a bout of resistance exercise, ingested a bolus of protein within an hour of exercise, and measured plasma leucine concentrations and MPS rates (delta change from basal).Results
Ingested leucine dose was associated with the magnitude of the MPS response in older, but not younger, adults over acute (0-2 h, r2 = 0.64, p = 0.02) and the entire postprandial (>2 h, r2 = 0.18, p = 0.01) period. However, no single plasma leucine variable possessed substantial predictive capacity over the magnitude of MPS rates in younger or older adults.Conclusion
Our data provide support that leucine dose provides predictive capacity over postprandial postexercise MPS responses in older adults. However, no threshold in older adults and no plasma leucine variable was correlated with the magnitude of the postexercise anabolic response.
SUBMITTER: Wilkinson K
PROVIDER: S-EPMC10400406 | biostudies-literature | 2023 Aug
REPOSITORIES: biostudies-literature
Publications
Association of postprandial postexercise muscle protein synthesis rates with dietary leucine: A systematic review.
Wilkinson Kiera K Koscien Christopher P CP Monteyne Alistair J AJ Wall Benjamin T BT Stephens Francis B FB
Physiological reports 20230801 15
<h4>Background</h4>Dietary protein ingestion augments post (resistance) exercise muscle protein synthesis (MPS) rates. It is thought that the dose of leucine ingested within the protein (leucine threshold hypothesis) and the subsequent plasma leucine variables (leucine trigger hypothesis; peak magnitude, rate of rise, and total availability) determine the magnitude of the postprandial postexercise MPS response.<h4>Methods</h4>A quantitative systematic review was performed extracting data from st ...[more]
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Project description:Key pointsProtein ingestion and cooling are strategies employed by athletes to improve postexercise recovery and, as such, to facilitate muscle conditioning. However, whether cooling affects postprandial protein handling and subsequent muscle protein synthesis rates during recovery from exercise has not been assessed. We investigated the effect of postexercise cooling on the incorporation of dietary protein-derived amino acids into muscle protein and acute postprandial (hourly) as well as prolonged (daily) myofibrillar protein synthesis rates during recovery from resistance-type exercise over 2 weeks. Cold-water immersion during recovery from resistance-type exercise lowers the capacity of the muscle to take up and/or direct dietary protein-derived amino acids towards de novo myofibrillar protein accretion. In addition, cold-water immersion during recovery from resistance-type exercise lowers myofibrillar protein synthesis rates during prolonged resistance-type exercise training. Individuals aiming to improve skeletal muscle conditioning should reconsider applying cooling as a part of their postexercise recovery strategy.AbstractWe measured the impact of postexercise cooling on acute postprandial (hourly) as well as prolonged (daily) myofibrillar protein synthesis rates during adaptation to resistance-type exercise over 2 weeks. Twelve healthy males (aged 21 ± 2 years) performed a single resistance-type exercise session followed by water immersion of both legs for 20 min. One leg was immersed in cold water (8°C: CWI), whereas the other leg was immersed in thermoneutral water (30°C: CON). After water immersion, a beverage was ingested containing 20 g of intrinsically (l-[1-13 C]-phenylalanine and l-[1-13 C]-leucine) labelled milk protein with 45 g of carbohydrates. In addition, primed continuous l-[ring-2 H5 ]-phenylalanine and l-[1-13 C]-leucine infusions were applied, with frequent collection of blood and muscle samples to assess myofibrillar protein synthesis rates in vivo over a 5 h recovery period. In addition, deuterated water (2 H2 O) was applied with the collection of saliva, blood and muscle biopsies over 2 weeks to assess the effects of postexercise cooling with protein intake on myofibrillar protein synthesis rates during more prolonged resistance-type exercise training (thereby reflecting short-term training adaptation). Incorporation of dietary protein-derived l-[1-13 C]-phenylalanine into myofibrillar protein was significantly lower in CWI compared to CON (0.016 ± 0.006 vs. 0.021 ± 0.007 MPE; P = 0.016). Postexercise myofibrillar protein synthesis rates were lower in CWI compared to CON based upon l-[1-13 C]-leucine (0.058 ± 0.011 vs. 0.072 ± 0.017% h-1 , respectively; P = 0.024) and l-[ring-2 H5 ]-phenylalanine (0.042 ± 0.009 vs. 0.053 ± 0.013% h-1 , respectively; P = 0.025). Daily myofibrillar protein synthesis rates assessed over 2 weeks were significantly lower in CWI compared to CON (1.48 ± 0.17 vs. 1.67 ± 0.36% day-1 , respectively; P = 0.042). Cold-water immersion during recovery from resistance-type exercise reduces myofibrillar protein synthesis rates and, as such, probably impairs muscle conditioning.
| S-EPMC7028023 | biostudies-literature
Project description:Ingested galactose can enhance postexercise liver glycogen repletion when combined with glucose but effects on muscle glycogen synthesis are unknown. In this double-blind randomized study participants [7 men and 2 women; V̇o2max: 51.1 (8.7) mL·kg-1·min-1] completed three trials of exhaustive cycling exercise followed by a 4-h recovery period, during which carbohydrates were ingested at the rate of 1.2 g·kg-1·h-1 comprising glucose (GLU), galactose (GAL) or galactose + glucose (GAL + GLU; 1:2 ratio). The increase in vastus lateralis skeletal-muscle glycogen concentration during recovery was higher with GLU relative to GAL + GLU [contrast: +50 mmol·(kg DM)-1; 95%CL 10, 89; P = 0.021] and GAL [+46 mmol·(kg DM)-1; 95%CL 8, 84; P = 0.024] with no difference between GAL + GLU and GAL [-3 mmol·(kg DM)-1; 95%CL -44, 37; P = 0.843]. Plasma glucose concentration in GLU was not significantly different vs. GAL + GLU (+ 0.41 mmol·L-1; 95%CL 0.13, 0.94) but was significantly lower than GAL (-0.75 mmol·L-1; 95%CL -1.34, -0.17) and also lower in GAL vs. GAL + GLU (-1.16 mmol·-1; 95%CL -1.80, -0.53). Plasma insulin was higher in GLU + GAL and GLU compared with GAL but not different between GLU + GAL and GLU. Plasma galactose concentration was higher in GAL compared with GLU (3.35 mmol·L-1; 95%CL 3.07, 3.63) and GAL + GLU (3.22 mmol·L-1; 95%CL 3.54, 2.90) with no difference between GLU + GAL (0.13 mmol·L-1; 95%CL -0.11, 0.37) and GLU. Compared with galactose or a galactose + glucose blend, glucose feeding was more effective in postexercise muscle glycogen synthesis. Comparable muscle glycogen synthesis was observed with galactose-glucose coingestion and exclusive galactose-only ingestion.NEW & NOTEWORTHY Postexercise galactose-glucose coingestion or exclusive galactose-only ingestion resulted in a lower rate of skeletal-muscle glycogen replenishment compared with exclusive glucose-only ingestion. Comparable muscle glycogen synthesis was observed with galactose-glucose coingestion and exclusive galactose-only ingestion.
| S-EPMC10864004 | biostudies-literature
Project description:Prolonged passive heat treatment (PHT) has been suggested to trigger skeletal muscle adaptations that may improve muscle maintenance in older individuals. To assess the effects of PHT on skeletal muscle tissue capillarization, perfusion capacity, protein synthesis rates, hypertrophy and leg strength, 14 older adults (9 males, 5 females; 73 ± 6 years) underwent 8 weeks of PHT (infrared sauna: 3× per week, 45 min at ∼60°C). Before and after PHT we collected muscle biopsies to assess skeletal muscle capillarization and fibre cross-sectional area (CSA). Basal and postprandial muscle tissue perfusion kinetics and protein synthesis rates were assessed using contrast-enhanced ultrasound and primed continuous l-[ring-13C6]phenylalanine infusions, respectively. One-repetition maximum (1RM) leg strength and vastus lateralis muscle CSA were assessed. Type I and type II muscle fibre capillarization strongly increased following PHT (capillary-to-fibre perimeter exchange index: +31 ± 18 and +33 ± 30%, respectively; P < 0.001). No changes were observed in basal (0.24 ± 0.27 vs. 0.18 ± 0.11 AU; P = 0.266) or postprandial (0.20 ± 0.12 vs. 0.18 ± 0.14 AU; P = 0.717) microvascular blood flow following PHT. Basal (0.048 ± 0.014 vs. 0.051 ± 0.019%/h; P = 0.630) and postprandial (0.041 ± 0.012 vs. 0.051 ± 0.024%/h; P = 0.199) muscle protein synthesis rates did not change in response to prolonged PHT. Furthermore, no changes in vastus lateralis muscle CSA (15.3 ± 4.6 vs. 15.2 ± 4.6 cm2; P = 0.768) or 1RM leg strength (46 ± 12 vs. 47 ± 12 kg; P = 0.087) were observed over time. In conclusion, prolonged PHT increases muscle tissue capillarization but this does not improve muscle microvascular blood flow or increase muscle protein synthesis rates in healthy, older adults. Prolonged PHT does not induce skeletal muscle hypertrophy or increase leg strength in healthy, older adults. KEY POINTS: Repeated exposure to heat has been suggested to trigger skeletal muscle adaptive responses. We investigated the effect of 8 weeks of whole-body passive heat treatment (PHT; infrared sauna: 3× per week for 45 min at ∼60°C) on skeletal muscle tissue capillarization, perfusion capacity, basal, and postprandial muscle protein synthesis rates, muscle (fibre) hypertrophy, and leg strength in healthy, older adults. Prolonged PHT increases muscle tissue capillarization, but this does not improve muscle microvascular blood flow or increase muscle protein synthesis rates. Despite increases in muscle tissue capillarization, prolonged PHT does not suffice to induce skeletal muscle hypertrophy or increase leg strength in healthy, older adults.
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Project description:Postexercise protein ingestion can elevate rates of myofibrillar protein synthesis (MyoPS), mTORC1 activity, and mTOR translocation/protein-protein interactions. However, it is unclear if leucine-enriched essential amino acids (LEAA) can similarly facilitate intracellular mTOR trafficking in humans after exercise. The purpose of this study was to determine the effect of postexercise LEAA (4 g total EAAs, 1.6 g leucine) on acute MyoPS and mTORC1 translocation and signaling. Recreationally active men performed lower-body resistance exercise (5 × 8-10 leg press and leg extension) to volitional failure. Following exercise participants consumed LEAA (n = 8) or an isocaloric carbohydrate drink (PLA; n = 10). MyoPS was measured over 1.5-4 h of recovery by oral pulse of l-[ring-2H5]-phenylalanine. Phosphorylation of proteins in the mTORC1 pathway were analyzed via immunoblotting and mTORC1-LAMP2/WGA/Rheb colocalization via immunofluorescence microscopy. There was no difference in MyoPS between groups (LEAA = 0.098 ± 0.01%/h; PL = 0.090 ± 0.01%/h; P > 0.05). Exercise increased (P < 0.05) rpS6Ser240/244(LEAA = 35.3-fold; PLA = 20.6-fold), mTORSer2448(LEAA = 1.8-fold; PLA = 1.2-fold) and 4EBP1Thr37/46(LEAA = 1.5-fold; PLA = 1.4-fold) phosphorylation irrespective of nutrition (P > 0.05). LAT1 and SNAT2 protein expression were not affected by exercise or nutrient ingestion. mTOR-LAMP2 colocalization was greater in LEAA preexercise and decreased following exercise and supplement ingestion (P < 0.05), yet was unchanged in PLA. mTOR-WGA (cell periphery marker) and mTOR-Rheb colocalization was greater in LEAA compared with PLA irrespective of time-point (P < 0.05). In conclusion, the postexercise consumption of 4 g of LEAA maintains mTOR in peripheral regions of muscle fibers, in closer proximity to its direct activator Rheb, during prolonged recovery independent of differences in MyoPS or mTORC1 signaling compared with PLA ingestion. This intracellular localization of mTOR may serve to "prime" the kinase for future anabolic stimuli.NEW & NOTEWORTHY This is the first study to investigate whether postexercise leucine-enriched amino acid (LEAA) ingestion elevates mTORC1 translocation and protein-protein interactions in human skeletal muscle. Here, we observed that although LEAA ingestion did not further elevate postexercise MyoPS or mTORC1 signaling compared with placebo, mTORC1 peripheral location and interaction with Rheb were maintained. This may serve to "prime" mTORC1 for subsequent anabolic stimuli.
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Project description:Physical endurance can be limited by muscle glycogen stores, in that glycogen depletion markedly reduces external work. During carbohydrate restriction, the liver synthesizes the ketone bodies, D-β-hydroxybutyrate, and acetoacetate from fatty acids. In animals and in the presence of glucose, D-β-hydroxybutyrate promotes insulin secretion and increases glycogen synthesis. Here we determined whether a dietary ketone ester, combined with plentiful glucose, can increase postexercise glycogen synthesis in human skeletal muscle.After an interval-based glycogen depletion exercise protocol, 12 well-trained male athletes completed a randomized, three-arm, blinded crossover recovery study that consisted of consumption of either a taste-matched, zero-calorie control or a ketone monoester drink, followed by a 10-mM glucose clamp or saline infusion for 2 h. The three postexercise conditions were control drink then saline infusion, control drink then hyperglycemic clamp, or ketone ester drink then hyperglycemic clamp. Skeletal muscle glycogen content was determined in muscle biopsies of vastus lateralis taken before and after the 2-h clamps.The ketone ester drink increased blood D-β-hydroxybutyrate concentrations to a maximum of 5.3 versus 0.7 mM for the control drink (P < 0.0001). During the 2-h glucose clamps, insulin levels were twofold higher (31 vs 16 mU·L, P < 0.01) and glucose uptake 32% faster (1.66 vs 1.26 g·kg, P < 0.001). The ketone drink increased by 61 g, the total glucose infused for 2 h, from 197 to 258 g, and muscle glycogen was 50% higher (246 vs 164 mmol glycosyl units per kilogram dry weight, P < 0.05) than after the control drink.In the presence of constant high glucose concentrations, a ketone ester drink increased endogenous insulin levels, glucose uptake, and muscle glycogen synthesis.
| S-EPMC5556006 | biostudies-other
Project description:Aged skeletal muscle has an attenuated and delayed ability to proliferate satellite cells in response to resistance exercise. The mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is a focal point for cell growth, however, the effect of postexercise mTORC1 activation on human skeletal muscle satellite cell (SC) proliferation is unknown. To test the proliferative capacity of skeletal muscle SC in aging muscle to a potent mTORC1 activator (i.e., EAA; essential amino acids) we recruited older (~72y) men to conduct leg resistance exercise (8setsx10reps) without (-EAA; n = 8) and with (+EAA: n = 11) ingestion of 10 g of EAA 1 h postexercise. Muscle biopsies were taken before exercise (Pre) and 24 h postexercise (Post) for assessment of expression and fiber type-specific Pax7+ SC, Ki67+Pax7+ SC and MyoD+ SC -EAA did not show an increase in Pax7+ satellite cells at Post(P > 0.82). Although statistical significance for an increase in Pax7 + SC at 24 h post-RE was not observed in +EAA versus -EAA, we observed trends for a treatment difference (P < 0.1). When examining the change from Pre to Post trends were demonstrated (#/myofiber: P = 0.076; and %/myonuclei: P = 0.065) for a greater increase in +EAA versus -EAA Notably, we found an increase SC proliferation in +EAA, but not -EAA with increase in Ki67+ SC and MyoD+ cells (P < 0.05). Ki67+ SC also exhibited a significant group difference Post (P < 0.010). Pax7+ SC in fast twitch myofibers did not change and were not different between groups (P > 0.10). CDK2, MEF2C, RB1 mRNA only increased in +EAA (P < 0.05). Acute muscle satellite cell proliferative capacity may be partially rescued with postexercise EAA ingestion in older men.
| S-EPMC5471431 | biostudies-literature
Project description:Pea protein is an attractive nonanimal-derived protein source to support dietary protein requirements. However, although high in leucine, a low methionine content has been suggested to limit its anabolic potential. Mycoprotein has a complete amino acid profile which, at least in part, may explain its ability to robustly stimulate myofibrillar protein synthesis (MyoPS) rates. We hypothesized that an inferior postexercise MyoPS response would be seen following ingestion of pea protein compared with mycoprotein, which would be (partially) rescued by blending the two sources. Thirty-three healthy, young [age: 21 ± 1 yr, body mass index (BMI): 24 ± 1 kg·m-2] and resistance-trained participants received primed, continuous infusions of l-[ring-2H5]phenylalanine and completed a bout of whole body resistance exercise before ingesting 25 g of protein from mycoprotein (MYC, n = 11), pea protein (PEA, n = 11), or a blend (39% MYC, 61% PEA) of the two (BLEND, n = 11). Blood and muscle samples were taken pre-, 2 h, and 4 h postexercise/protein ingestion to assess postabsorptive and postprandial postexercise myofibrillar protein fractional synthetic rates (FSRs). Protein ingestion increased plasma essential amino acid and leucine concentrations (time effect; P < 0.0001), but more rapidly in BLEND and PEA compared with MYC (time × condition interaction; P < 0.0001). From similar postabsorptive values (MYC, 0.026 ± 0.008%·h-1; PEA, 0.028 ± 0.007%·h-1; BLEND, 0.026 ± 0.006%·h-1), resistance exercise and protein ingestion increased myofibrillar FSRs (time effect; P < 0.0001) over a 4-h postprandial period (MYC, 0.076 ± 0.004%·h-1; PEA, 0.087 ± 0.01%·h-1; BLEND, 0.085 ± 0.01%·h-1), with no differences between groups (all; P > 0.05). These data show that all three nonanimal-derived protein sources have utility in supporting postexercise muscle reconditioning.NEW & NOTEWORTHY This study provides evidence that pea protein (PEA), mycoprotein (MYC), and their blend (BLEND) can support postexercise myofibrillar protein synthesis rates following a bout of whole body resistance exercise. Furthermore, these data suggest that a methionine deficiency in pea may not limit its capacity to stimulate an acute increase in muscle protein synthesis (MPS).
| S-EPMC10655824 | biostudies-literature
Project description:BackgroundThe decline in postabsorptive and postprandial muscle protein fractional synthesis rates (FSR) does not quantitatively account for muscle atrophy during uncomplicated, short-term disuse, when atrophy rates are the highest. We sought to determine whether 2 days of unilateral knee immobilization affects mixed muscle protein fractional breakdown rates (FBR) during postabsorptive and simulated postprandial conditions.MethodsTwenty-three healthy, male participants (age: 22 ± 1 year; height: 179 ± 1 cm; body mass: 73.4 ± 1.5 kg; body mass index 22.8 ± 0.5 kg·m-2 ) took part in this randomized, controlled study. After 48 h of unilateral knee immobilization, primed continuous intravenous l-[15 N]-phenylalanine and l-[ring-2 H5 ]-phenylalanine infusions were used for parallel determinations of FBR and FSR, respectively, in a postabsorptive (saline infusion; FAST) or simulated postprandial state (67.5 mg·kg body mass-1 ·h-1 amino acid infusion; FED). Bilateral m. vastus lateralis biopsies from the control (CON) and immobilized (IMM) legs, and arterialized-venous blood samples, were collected throughout.ResultsAmino acid infusion rapidly increased plasma phenylalanine (59 ± 9%), leucine (76 ± 5%), isoleucine (109 ± 7%) and valine (42 ± 4%) concentrations in FED only (all P < 0.001), which was sustained for the remainder of infusion. Serum insulin concentrations peaked at 21.8 ± 2.2 mU·L-1 at 15 min in FED only (P < 0.001) and were 60% greater in FED than FAST (P < 0.01). Immobilization did not influence FBR in either FAST (CON: 0.150 ± 0.018; IMM: 0.143 ± 0.017%·h-1 ) or FED (CON: 0.134 ± 0.012; IMM: 0.160 ± 0.018%·h-1 ; all effects P > 0.05). However, immobilization decreased FSR (P < 0.05) in both FAST (0.071 ± 0.004 vs. 0.086 ± 0.007%·h-1 ; IMM vs CON, respectively) and FED (0.066 ± 0.016 vs. 0.119 ± 0.016%·h-1 ; IMM vs CON, respectively). Consequently, immobilization decreased net muscle protein balance (P < 0.05) and to a greater extent in FED (CON: -0.012 ± 0.025; IMM: -0.095 ± 0.023%·h-1 ; P < 0.05) than FAST (CON: -0.064 ± 0.020; IMM: -0.072 ± 0.017%·h-1 ).ConclusionsWe conclude that merely 2 days of leg immobilization does not modulate postabsorptive and simulated postprandial muscle protein breakdown rates. Instead, under these conditions the muscle negative muscle protein balance associated with brief periods of experimental disuse is driven near exclusively by reduced basal muscle protein synthesis rates and anabolic resistance to amino acid administration.
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Project description:Dietary interventions such as sulfur amino acid restriction (SAAR) target multiple drivers of aging, and show promise for preventing or delaying the onset of chronic diseases. SAAR promotes metabolic health and longevity in laboratory animals. The effects of SAAR on proteostasis remain relatively unexplored. We previously reported that SAAR promotes mitochondrial proteostatic maintenance, despite suppression of global protein synthesis, in two peripheral tissues, the liver and skeletal muscle. However, the brain, a tissue vulnerable to age-related neurodegenerative diseases due to the loss of proteostasis, has not been thoroughly studied. Therefore, we sought to reveal proteostatic responses in the brains of mice fed SAAR for 35 days. Here, we demonstrate that male C57Bl/6J mice fed two levels of SAAR maintained rates of protein synthesis in all sub-cellular fractions of the pre-frontal cortex. In comparison, rates of skeletal muscle protein synthesis in SAAR fed mice were slower than control-fed mice. To gain mechanistic insight, we examined several key nutrient/energy sensitive signaling proteins: AMP-activated protein kinase (AMPK), eukaryotic initiation factor 2 (eIF2), and ribosomal protein S6 (rpS6). SAAR had minimal to modest effects on the total abundance and phosphorylation of these proteins in both tissues. Our results indicate that the pre-frontal cortex in brain is resistant to perturbations in protein synthesis in mice fed SAAR, unlike skeletal muscle, which had a reduction in global protein synthesis. The results from this study demonstrate that proteostatic control in brain is of higher priority than skeletal muscle during dietary SAAR.
| S-EPMC9450999 | biostudies-literature
Project description:This study investigated the hypothesis that dietary supplementation of leucine (Leu) above actual recommendations activates protein synthesis and inhibits protein degradation pathways on the molecular level and supports higher muscle growth in broilers. Day-old male Cobb-500 broilers (n = 180) were allotted to 3 groups and phase-fed 3 different corn-wheat-soybean meal-based basal diets during periods 1 to 10, 11 to 21, and 22 to 35 D. The control group (L0) received the basal diet which met the broiler's requirements of nutrients and amino acids for maintenance and growth. Groups L1 and L2 received basal diets supplemented with Leu to exceed recommendations by 35 and 60%, respectively, and isoleucine (Ile) and valine (Val) were supplemented to keep Leu: Ile and Leu: Val ratios fixed. Samples of liver and breast muscle and pancreas were collected on days 10, 21, and 35. The gene expression and abundance of total and phosphorylated proteins involved in the mammalian target of rapamycin pathway of protein synthesis, in the ubiquitin-proteasome pathway and autophagy-lysosomal pathway of protein degradation, in the general control nonderepressible 2/eukaryotic translation initiation factor 2A pathway involved in the inhibition of protein synthesis, and in the myostatin-Smad2/3 pathway involved in myogenesis were evaluated in the muscle, as well as expression of genes involved in the growth hormone axis. Growth performance, feed intake, the feed conversion ratio, and carcass weights did not differ between the 3 groups (P > 0.05). Plasma concentrations of Leu, Ile, and Val and of their keto acids, and the activity of the branched-chain α-keto acid dehydrogenase in the pancreas increased dose dependently with increasing dietary Leu concentrations. In the breast muscle, relative mRNA abundances of genes and phosphorylation of selected proteins involved in all investigated pathways were largely uninfluenced by dietary Leu supplementation (P > 0.05). In summary, these data indicate that excess dietary Leu concentrations do not influence protein synthesis or degradation pathways, and subsequently do not increase muscle growth in broilers at fixed ratios to Ile and Val.
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