NUTRITION – PROTEIN – TYPE OF PROTEIN – AGING


5 RESEARCH ARTICLES + 3 GRAPHICS – CLICK ON GRAPHIC TO ENLARGE


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FAST DIGESTIVE PROTEINS AND SARCOPENIA OF AGING – 2017


Boirie, Yvesa; Guillet, Christelle
SUMMARY

– 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
– 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
– 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


QUALITY OF MEAL PROTEIN DETERMINES ANABOLIC RESPONSE IN OLDER ADULTS – 2017


BACKGROUND & AIMS
– The relative content and profile of essential amino acids (EAA) play a determining role for stimulation of muscle protein synthesis (MPS)
METHODS
– 12 subjects (57-74 yrs)
– determine whole body protein kinetics and MPS in the fasted state and following consumption of egg-based (EGG) or cereal-based (CEREAL) breakfast

– A standardized lunch, primarily consisting of beef protein was also consumed by each group
– Whole body protein kinetics [protein synthesis (PS), breakdown (PB), and net balance (NB)] were expressed as changes from basal fasted period
RESULTS
– EGG breakfast resulted in a greater NB through a greater suppression of PB compared with the CEREAL breakfast
– The greater NB during the post-breakfast period with the EGG was normalized following the standard lunch despite the sustained elevations in plasma EAA concentrations
– However, the EGG breakfast stimulated both PS and PB compared with the CEREAL breakfast during the post-lunch period
– MPS was not different between meals despite larges differences in the plasma EAA responses


MILK PROTEIN OR WHEY PROTEIN – SIMILAR INCREASE IN MUSCLE PROTEIN SYNTHESIS IN MIDDLE AGED MEN – 2015


METHOD
– 16 healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8)
CONCLUSION
– Despite evidence of increased rate of digestion and leucine availability following whey protein, there was similar activation of MPS with either 20 g of milk protein or whey protein


STRENGTH GAINS DURING RESISTANCE EXERCISE IS REDUCED WITH SOY COMPARED TO DAIRY IN OLDER ADULTS – 2015


METHODS
– 179 healthy older adults (age 61.5 ± 7.4 yrs) performed resistance training 3x per wk for 12 wks

(1) high dairy protein (HP-D, >1.2 g protein/kg body weight/d; ∼27 g/d dairy protein)
(2) high soy protein (HP–S, >1.2 g protein/kg body weight/d; ∼27 g/d soy protein)
RESULTS
– Strength increased less in HP-S compared with HP-D and UP


PROTEIN SYNTHESIS WITH SOY ISOLATE AFTER RESISTANCE EXERCISE IN ELDERLY MEN – 2012


Yifan Yang1, Churchward-Venne1, Burd1, Breen1, Tarnopolsky2 Phillips
METHODS
– 30 elderly men (age 71 ± 5 y) completed a bout of unilateral knee-extensor resistance exercise prior to ingesting:

(a) no protein (0 g)
(b) 20 g soy protein isolate (S20)
(c) 40 g soy protein isolate (S40)
– We compared these responses to previous responses from similar aged men who had ingested:
(a) 20 g whey protein isolate (W20)
(b) 40 g whey protein isolate (W40)
CONCLUSIONS
(1) The relationship between protein intake and MPS is both dose and protein source-dependent

(2) Isolated soy shows a reduced ability, compared to isolated whey protein, to stimulate MPS under both rested and post-exercise conditions


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