NUTRITION – PROTEIN – MUSCLE PROTEIN SYNTHESIS – AGING


8 RESEARCH ARTICLES + 1 GRAPHIC – CLICK ON GRAPHIC TO ENLARGE



FAST DIGESTIVE PROTEINS AND SARCOPENIA OF AGING – 2017


Boirie, Yvesa; Guillet, Christelle
PURPOSE OF REVIEW
– The speed of dietary protein digestion influences post-meal amino acid availability which is crucial for improving altered anabolic response of skeletal muscle
– This is one feature of Sarcopenia during aging
RECENT FINDINGS
– Proteins can be classified as ‘fast’ or ‘slow’ proteins which can influence amino acids availability and their subsequent metabolic actions
– ‘Fast’ digestive proteins stimulate muscle protein synthesis and improve muscle function in several recent studies involving older patients
SUMMARY
– Using fast digestive proteins is of major interest to overcome ‘anabolic resistance’ of aging for limiting sarcopenia
– Fast proteins’ action on muscle anabolism may be stimulated by other nutrients like vitamin D or omega 3 fatty acids or by combination with exercise


HIGHER PROTEIN ASSOCIATED WITH LOWER FRAILTY IN OLDER ADULTS – 2016


Rahi B1, Feart C3. et al
METHODS
– Participants were community-dwelling older adults aged 65 and over
– Frailty was defined as a score of 3/5 among weight loss, exhaustion, muscle weakness, slowness, and physical activity
– Protein daily intake: ≥1 g/kg body weight
– Optimal energy intake defined as a daily intake ≥30 kcal/kg
CONCLUSIONS
– A 1 g/kg protein intake was associated with a lower prevalence of frailty in French community-dwelling older subjects


AGING IS ACCOMPANIED BY A BLUNTED MUSCLE PROTEIN SYNTHETIC RESPONSE TO PROTEIN – 2015


Benjamin Wall, Luc J. C. van Loon et al
PURPOSE
(1) Is impaired capacity to increase muscle PRO synthesis in response to protein intake a key contributor to sarcopenia?
(2) Do differences in post-absorptive and/or post-prandial muscle protein synthesis rates exist b/n healthy young and older men
PROCEDURES
(a) Comparing in post-absorptive muscle protein synthesis rates b/n 34 healthy young (22±1 y) and 72 older (75±1 y) men
(b) Comparing post-meal muscle protein synthesis rates between 35 healthy young (22±1 y) and 40 older (74±1 y) men
FINDINGS
(3) Muscle protein synthesis rates were >3 fold more responsive to dietary protein ingestion in the young
CONCLUSIONS
– Aging is associated with muscle anabolic inflexibility which represents a key physiological mechanism underpinning sarcopenia


EFFECT OF AGE ON MUSCLE PROTEIN SYNTHESIS – 2015


Markofski MM1, Volpi E8. et al
AIM
– Determine if age and sex differentially impact basal muscle protein synthesis and mTORC1 signaling
DESIGN
(1) 215 healthy, non-obese young (18-40y; 74 men, 52 women) and older (60-87y; 57 men, 32 women) adults
CONCLUSIONS
(1) Age and sex do not influence basal muscle protein synthesis
(2) However, basal mTORC1 in the elderly may contribute to insulin resistance and age-related anabolic resistance of skeletal muscle protein metabolism to nutrition and exercise


KEEPING OLDER MUSCLE YOUNG THROUGH PROTEIN & PHYSICAL ACTIVITY – 2014


Daniel R. Moore – Faculty of Kinesiology and Physical Education, University of Toronto
DIETARY PROTEIN
(1) Blunted muscle protein synthetic response to dietary protein, commonly referred to as “anabolic resistance,” is a major underlying cause of the loss of muscle with age
(2) Dietary strategies to overcome this decreased dietary amino acid sensitivity include:
– the ingestion of leucine enriched, rapidly digested proteins
– and/or greater protein ingestion in each main meal to maximally stimulate muscle anabolism
(3) Anabolic resistance is also a hallmark of a sedentary lifestyle at any age
EXERCISE
– Acute bouts of activity can restore the sensitivity of older muscle to dietary protein
– Provided physical activity is incorporated into the daily routine, muscle in older adults should retain its capacity for a robust anabolic response to protein comparable to younger peers
– Through its ability to “make nutrition better,” physical activity should be viewed as a vital component to maintaining muscle mass and function with age


BRANCHED AMINO ACIDS ARE ASSOCIATED WITH MUSCLE MASS IN OLDER ADULTS – 2014


Lustgarten MS1, Price LL2, Chale A1, Phillips EM1, Fielding RA3
BACKGROUND:
– Metabolic profiling may provide insight into biologic mechanisms related to muscle and fat-free mass in functionally limited older adults
CONCLUSIONS:
– Multiple BCAAs are markers of muscle CSA Cross-Sectional Area or the FFMI Fat-Free Mass Index in functionally limited older adults


INTERVENTIONS FOR SARCOPENIA IN AGING ADULTS – 2014


Cruz-Jentoft AJ1, Cederholm T
METHODS
– Studies investigating muscle mass plus strength or function outcome measures in populations of adults aged ≥50 years were selected
RESULTS
– Moderate quality evidence suggests that exercise interventions improve muscle strength and physical performance
– Essential amino acid (EAA) supplements, including ∼2.5 g of leucine, and HMB, show some effects in improving muscle mass and function parameters
CONCLUSION
– Supervised resistance exercise is recommended for individuals with sarcopenia


INTERACTIONS BETWEEN EXERCISE & NUTRITION TO PREVENT MUSCLE WASTING – 2012


Leigh Breen, Stuart M Phillips
MUSCLE ATROPHY
– Prolonged periods of net -ve muscle PRO balance, brought about by imbalance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB)
RESISTANCE TRAINING AND PROTEIN INTAKE
– Resistance exercise-induced rates of MPS and hypertrophy appear to be dependent on exercise volume (to achieve maximal muscle fibre recruitment), as opposed to the absolute load that is lifted


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