scholarly journals Impact of dairy protein during limb immobilization and recovery on muscle size and protein synthesis; a randomized controlled trial

2018 ◽  
Vol 124 (3) ◽  
pp. 717-728 ◽  
Author(s):  
Cameron J. Mitchell ◽  
Randall F. D’Souza ◽  
Sarah M. Mitchell ◽  
Vandre C. Figueiredo ◽  
Benjamin F. Miller ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Controlled Trial ◽  
Protein Supplementation ◽  
Muscle Size ◽  
Thigh Muscle ◽  
Muscle Disuse ◽  
And Function ◽  
Dairy Protein

Muscle disuse results in the loss of muscular strength and size, due to an imbalance between protein synthesis (MPS) and breakdown (MPB). Protein ingestion stimulates MPS, although it is not established if protein is able to attenuate muscle loss with immobilization (IM) or influence the recovery consisting of ambulatory movement followed by resistance training (RT). Thirty men (49.9 ± 0.6 yr) underwent 14 days of unilateral leg IM, 14 days of ambulatory recovery (AR), and a further six RT sessions over 14 days. Participants were randomized to consume an additional 20 g of dairy protein or placebo with a meal during the intervention. Isometric knee extension strength was reduced following IM (−24.7 ± 2.7%), partially recovered with AR (−8.6 ± 2.6%), and fully recovered after RT (−0.6 ± 3.4%), with no effect of supplementation. Thigh muscle cross-sectional area decreased with IM (−4.1 ± 0.5%), partially recovered with AR (−2.1 ± 0.5%), and increased above baseline with RT (+2.2 ± 0.5%), with no treatment effect. Myofibrillar MPS, measured using deuterated water, was unaltered by IM, with no effect of protein. During AR, MPS was increased only with protein supplementation. Protein supplementation did not attenuate the loss of muscle size and function with disuse or potentiate recovery but enhanced myofibrillar MPS during AR. NEW & NOTEWORTHY Twenty grams of daily protein supplementation does not attenuate the loss of muscle size and function induced by 2 wk of muscle disuse or potentiate recovery in middle-age men. Average mitochondrial but not myofibrillar muscle protein synthesis was attenuated during immobilization with no effect of supplementation. Protein supplementation increased myofibrillar protein synthesis during a 2-wk period of ambulatory recovery following disuse but without group differences in phenotype recovery.

scholarly journals A randomized controlled trial of the impact of protein supplementation on leg lean mass and integrated muscle protein synthesis during inactivity and energy restriction in older persons

2018 ◽  
Vol 108 (5) ◽  
pp. 1060-1068 ◽  
Author(s):  
Sara Y Oikawa ◽  
Chris McGlory ◽  
Lisa K D'Souza ◽  
Adrienne K Morgan ◽  
Nelson I Saddler ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Lean Mass ◽  
Older Persons ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Controlled Trial ◽  
Protein Supplementation ◽  
Energy Restriction ◽  
Habitual Activity ◽  
The Impact

ABSTRACT Background In older persons, muscle loss is accelerated during physical inactivity and hypoenergetic states, both of which are features of hospitalization. Protein supplementation may represent a strategy to offset the loss of muscle during inactivity, and enhance recovery on resumption of activity. Objective We aimed to determine if protein supplementation, with proteins of substantially different quality, would alleviate the loss of lean mass by augmenting muscle protein synthesis (MPS) while inactive during a hypoenergetic state. Design Participants (16 men, mean ± SD age: 69 ± 3 y; 15 women, mean ± SD age: 68 ± 4 y) consumed a diet containing 1.6 g protein · kg–1 · d–1, with 55% ± 9% of protein from foods and 45% ± 9% from supplements, namely, whey protein (WP) or collagen peptides (CP): 30 g each, consumed 2 times/d. Participants were in energy balance (EB) for 1 wk, then began a period of energy restriction (ER; –500 kcal/d) for 1 wk, followed by ER with step reduction (ER + SR; <750 steps/d) for 2 wk, before a return to habitual activity in recovery (RC) for 1 wk. Results There were significant reductions in leg lean mass (LLM) from EB to ER, and from ER to ER + SR in both groups (P < 0.001) with no differences between WP and CP or when comparing the change from phase to phase. During RC, LLM increased from ER + SR, but in the WP group only. Rates of integrated muscle protein synthesis decreased during ER and ER + SR in both groups (P < 0.01), but increased during RC only in the WP group (P = 0.05). Conclusions Protein supplementation did not confer a benefit in protecting LLM, but only supplemental WP augmented LLM and muscle protein synthesis during recovery from inactivity and a hypoenergetic state. This trial was registered at http://www.clinicaltrials.gov as NCT03285737.

Understanding the sensitivity of muscle protein synthesis to dairy protein in middle-aged men

2016 ◽  
Vol 63 ◽  
pp. 35-41 ◽  
Author(s):  
Cameron J. Mitchell ◽  
Randall F. D'Souza ◽  
Nina Zeng ◽  
Robin A. McGregor ◽  
Aaron C. Fanning ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Middle Aged ◽  
Dairy Protein

scholarly journals Dileucine ingestion is more effective than leucine in stimulating muscle protein turnover in young males: a double blind randomized controlled trial

2021 ◽  
Author(s):  
Kevin J. M. Paulussen ◽  
Rafael A. Alamilla ◽  
Amadeo F. Salvador ◽  
Colleen F. McKenna ◽  
Andrew T. Askow ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Controlled Trial ◽  
Young Men ◽  
Double Blind ◽  
Muscle Protein Turnover ◽  
Breakdown Rates ◽  
Over Time

Leucine is regarded as an anabolic trigger for the mTORC1 pathway and the stimulation muscle protein synthesis rates. More recently, there has been an interest in underpinning the relevance of BCAA-containing dipeptides and their intact absorption into circulation to regulate muscle anabolic responses. We investigated the effects of dileucine and leucine ingestion on postprandial muscle protein turnover. Ten healthy young men (age: 23±3 y) consumed either 2 g of leucine (LEU) or 2 g of dileucine (DILEU) in a randomized crossover design. The participants underwent repeated blood and muscle biopsy sampling during primed continuous infusions of L-[ring-13C6]phenylalanine and L-[15N]phenylalanine to determine myofibrillar protein synthesis (MPS) and mixed muscle protein breakdown rates (MPB), respectively. LEU and DILEU similarly increased plasma leucine net area under the curve (AUC; P = 0.396). DILEU increased plasma dileucine AUC to a greater extent than LEU (P = 0.013). Phosphorylation of Akt (P = 0.002), rpS6 (P <0.001) and p70S6K (P < 0.001) increased over time in both LEU and DILEU conditions. Phosphorylation of 4E-BP1 (P = 0.229) and eEF2 (P = 0.999) did not change over time irrespective of condition. Cumulative (0-180 min) MPS increased in DILEU (0.075±0.032 %⋅hour-1), but not in LEU (0.047±0.029 %⋅hour-1; P=0.023). MPB did not differ between LEU (0.043±0.030 %⋅h-1) and DILEU conditions (0.051±0.027 %⋅hour-1; P = 0.659). Our results showed that dileucine ingestion elevated plasma dileucine concentrations and muscle protein turnover by stimulating MPS in young men.

scholarly journals Effects of Testosterone on Mixed Muscle Protein Synthesis and Proteome Dynamics During Energy Deficit

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 649-649 ◽  
Author(s):  
Stefan Pasiakos ◽  
Mahalakshmi Shankaran ◽  
Claire Berryman ◽  
Lee Margolis ◽  
Harris Lieberman ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Dynamics ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Controlled Trial ◽  
Weight Maintenance ◽  
Energy Deficit ◽  
Deuterated Water ◽  
Short Term ◽  
Double Blind

Abstract Objectives Short-term energy deficit reduces acute measures of mixed muscle protein synthesis (MPS) and suppresses the hypothalamic-pituitary axis and endogenous testosterone synthesis. We hypothesized that testosterone supplementation could mitigate the effects of energy deficit on MPS. We conducted a randomized, double-blind, placebo-controlled trial to determine the effects of 28 days of tightly-controlled severe energy deficit (deficit 55% of total energy requirements) on measures of mixed-MPS and proteome-wide protein dynamics in non-obese men either given 200 mg testosterone enanthate (Testosterone, n = 24) or placebo (Placebo, n = 26) injections per week. Methods Participants received daily aliquots of deuterated water (2H2O) for 42 consecutive days (14-d weight maintenance period followed by 28-d energy deficit). Muscle biopsies were collected at rest in a fasted state at the end of the weight maintenance phase (PRE) and at the middle (MID) and end (POST) of the 28-d energy deficit. Mixed-MPS and proteome-wide protein fractional synthesis rates (FSR) were quantified. Changes over time and differences between Testosterone and Placebo were determined for mixed-MPS, and cross-sectional comparisons between Testosterone and Placebo were performed at MID and POST for proteome dynamics. Results In both Testosterone and Placebo, mixed-MPS were 40% and 33% lower (P &lt; 0.0005) at MID and POST energy deficit, respectively, compared to PRE, with no differences between groups or between MID and POST. Proteome-wide FSR of individual muscle proteins did not differ between Testosterone and Placebo at any time point. However, at POST, the number of individual proteins with higher FSR in Testosterone than Placebo was significant by 2-tailed binomial test (P &lt; 0.05), with values ranging from 20–32% higher FSR for myofibrillar, mitochondrial and cytosolic proteins. Conclusions Findings confirm the pronounced effect of short-term severe energy deficit on mixed-MPS and suggest the anabolic suppression occurs largely independent of testosterone. However, proteome-wide protein dynamics may reveal a novel time sensitive signal by which supplemental testosterone triggers a delayed increase in MPS, providing a synthetic mechanism for muscle mass preservation or accrual. Funding Sources Supported by DHP JPC-5/MOMRP; authors’ views not official U.S. Army or DoD policy.

Effects of high‐protein diets on fat‐free mass and muscle protein synthesis following weight loss: a randomized controlled trial

2013 ◽  
Vol 27 (9) ◽  
pp. 3837-3847 ◽  
Author(s):  
Stefan M. Pasiakos ◽  
Jay J. Cao ◽  
Lee M. Margolis ◽  
Edward R. Sauter ◽  
Leah D. Whigham ◽  
...  
Keyword(s):  
Weight Loss ◽  
Randomized Controlled Trial ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Controlled Trial ◽  
Fat Free Mass ◽  
Randomized Controlled ◽  
High Protein Diets ◽  
Protein Diets

scholarly journals Effect of fast dietary proteins on muscle protein synthesis rate and muscle strength in ad libitum-fed and energy-restricted old rats

2011 ◽  
Vol 106 (11) ◽  
pp. 1683-1690 ◽  
Author(s):  
Stéphane Walrand ◽  
Aude Zangarelli ◽  
Christelle Guillet ◽  
Jérôme Salles ◽  
Karine Soulier ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Strength ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Old Rats ◽  
And Function ◽  
Muscle Protein Synthesis Rate

Sarcopenia is defined as age-related loss of muscle mass and strength. Energy restriction (ER) delays fibre loss by limiting the accumulated deleterious effects of reactive oxygen species on muscle. However, insufficient protein intake during ER might affect muscle mass and function. We hypothesised that ingestion of fast-digested proteins such as whey protein (WP) improves muscle protein synthesis and muscle strength in aged ER rats. The effect of WP or casein (CAS, slow protein) on muscle mass, protein synthesis and strength was evaluated in 21-month-old rats fed for 5 months either ad libitum (AL) or a 40 % protein and energy-restricted (PER) or 40 % AL-isonitrogenous ER diet. The nitrogen balance was reduced in PER-CAS rats only ( − 48 % v. AL-CAS). WP stimulated muscle protein synthesis rates compared with CAS in all groups (+21,+37 and +34 % in AL, PER and ER conditions, respectively). Muscle strength was higher in ER rats than in AL rats (+23 and +12 % for WP or CAS, respectively). Muscle performance tended to be greater in ER rats fed WP than in ER-CAS rats (P < 0·09). In conclusion, we observed that long-term ER combined with maintained protein intake had a beneficial impact on muscle protein synthesis rate and function during ageing.

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