A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly.

@article{Katsanos2006AHP,
  title={A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly.},
  author={Christos S. Katsanos and Hisamine Kobayashi and Melinda Sheffield-Moore and Asle A Aarsland and Robert R. Wolfe},
  journal={American journal of physiology. Endocrinology and metabolism},
  year={2006},
  volume={291 2},
  pages={
          E381-7
        }
}
This study was designed to evaluate the effects of enriching an essential amino acid (EAA) mixture with leucine on muscle protein metabolism in elderly and young individuals. [] Key Method Four (2 elderly and 2 young) groups were studied before and after ingestion of 6.7 g of EAAs. EAAs were based on the composition of whey protein [26% leucine (26% Leu)] or were enriched in leucine [41% leucine (41% Leu)].
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Leucine supplementation improves muscle protein synthesis in elderly men independently of hyperaminoacidaemia
TLDR
It is concluded that leucine supplementation during feeding improves muscle protein synthesis in the elderly independently of an overall increase of other amino acids.
Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men.
TLDR
Co-ingestion of leucine with carbohydrate and protein following physical activity does not further elevate muscle protein fractional synthetic rate in elderly men when ample protein is ingested.
Differential effects of leucine and leucine-enriched whey protein on skeletal muscle protein synthesis in aged mice.
Effect of a leucine-enriched essential amino acids mixture on muscle recovery
TLDR
LEAA consumption suppressed exercise-induced elevation of muscle damage markers in blood, which suggests that LEAA could attenuate muscle damage and aid muscle recovery.
Absence of leucine in an essential amino acid supplement reduces activation of mTORC1 signalling following resistance exercise in young females.
TLDR
The presence of leucine in the supplement enhances the stimulatory effect on mTORC1 signalling and reduces the level of tyrosine and the sum of the EAA in muscle and plasma, suggesting a stimulation of protein synthesis and (or) inhibition of breakdown, leading to improvement in net protein balance.
Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men
TLDR
Co-ingestion of leucine with carbohydrate and protein following physical activity does not further elevate muscle protein fractional synthetic rate in elderly men when ample protein is ingested.
Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women
Muscle protein synthesis and balance responsiveness to essential amino acids ingestion in the presence of elevated plasma free fatty acid concentrations.
TLDR
Elevated plasma FFA concentrations do not interfere with the response of muscle protein synthesis and balance to a bolus ingestion of EAAs and are associated with impaired glucose disposal in skeletal muscle.
Safety and Tolerability of Leucine Supplementation in Elderly Men.
TLDR
2 current studies to determine the Tolerable Upper Intake Level (UL) for leucine in young and elderly men are described and the conceptual model of determining the maximum oxidative capacity of an amino acid to be an ideal marker for identifying the UL is tested.
Leucine, Not Total Protein, Content of a Supplement Is the Primary Determinant of Muscle Protein Anabolic Responses in Healthy Older Women.
TLDR
Lower-protein supplements with added leucine may represent an advantageous approach in older adults to maintain skeletal muscle anabolic sensitivity and attenuate muscle loss; however, further work is needed using longer-term interventions to substantiate these findings.
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References

SHOWING 1-10 OF 39 REFERENCES
Amino acid ingestion improves muscle protein synthesis in the young and elderly.
TLDR
Despite differences in the time course of plasma phenylalanine kinetics and a greater residual IC phenylAlanine concentration, amino acid supplementation acutely stimulated muscle protein synthesis in both young and elderly individuals.
Leucine as a regulator of whole body and skeletal muscle protein metabolism in humans.
TLDR
It is concluded that leucine decreases protein degradation in humans and that this decreased protein degradation duringLeucine infusion contributes to the decrease in plasma essential amino acids.
Postprandial stimulation of muscle protein synthesis in old rats can be restored by a leucine-supplemented meal.
TLDR
It is concluded that acute meal supplementation with leucine is sufficient to restore postprandial stimulation of muscle protein synthesis in old rats.
Nonessential amino acids are not necessary to stimulate net muscle protein synthesis in healthy volunteers.
Aging is associated with diminished accretion of muscle proteins after the ingestion of a small bolus of essential amino acids.
TLDR
Data indicate that aging results in a diminished accretion of muscle proteins after ingestion of a small dose of EAAs, which may have practical implications with respect to the amount of protein contained in supplements given to the elderly for enhancing the stimulation of muscle protein synthesis.
Stimulation of in vitro rat muscle protein synthesis by leucine decreases with age.
TLDR
It is demonstrated that amino acids and leucine stimulate muscle protein synthesis and that aging is associated with a decrease in this effect, and it is hypothesize that a nutritional manipulation increasing the availability of this amino acid to muscle could be beneficial in maintaining the postprandial stimulation of protein synthesis.
Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults.
TLDR
Essential amino acids are primarily responsible for the amino acid-induced stimulation of muscle protein anabolism in the elderly.
Leucine. A possible regulator of protein turnover in muscle.
TLDR
The concentration of leucine in muscle cells or a compartment thereof may play a role in regulating the turnover of muscle proteins and influence the transition to negative nitrogen balance during fasting, uncontrolled diabetes, and the posttraumatic state.
Regulation of muscle protein by amino acids.
  • R. Wolfe
  • Biology
    The Journal of nutrition
  • 2002
TLDR
There is an interactive effect with amino acid ingestion, meaning the response to amino acids plus glucose is more than the sum of their individual effects, and acute anabolic responses in net MPS correspond quantitatively to differences in 24-h net muscle balances.
Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine.
TLDR
The results suggest that the leucine-induced enhancement of protein synthesis and the phosphorylation states of 4E-BP1 and S6K1 are facilitated by the transient increase in serum insulin, and assembly of the mRNA cap-binding complex occurs independently of increases in insulin and, by itself, is insufficient to stimulate rates ofprotein synthesis in skeletal muscle after leucINE administration.
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