NUTRITION – PROTEIN – TYPE OF PROTEIN – AGING


6 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
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


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
CONCLUSIONS
– In the context of mixed meals, quality of protein affects NB through changes in protein breakdown and affects protein turnover following subsequent meal intake


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


STIMULATION OF MUSCLE PROTEIN SYNTHESIS BY WHEY AND CASEINATE (MILK) AFTER RESISTANCE EXERCISE IN THE ELDERLY – 2011


DESIGN:
– 24 elderly men and women (68 ± 1 years) were randomized to one of 4 groups:
(a) caseinate intake before exercise (CasPre),
(b) caseinate intake immediately after exercise (CasPost)
(c) whey intake immediately after exercise (Whey)
(d) or intake of a non-caloric control drink (Control)
RESULTS
(1) No differences were observed in muscle myofibrillar and collagen FSR with Whey compared with CasPost
(2) and it did not differ between CasPre and CasPost.
CONCLUSION
– MPS does not differ with whey and caseinate (Milk) feeding immediately after heavy resistance exercise in elderly individuals


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