Protein Flashcards
(32 cards)
What did tarnopolsky et al (2004) find regarding N balance??
Gave endurance trained men a normal diet and an altered diet (high protein).
Found protein balance to be 1.37g/kg/day, with the safe intake estimated at 1.6g/kg/day
Building from tarnopolsky 2004, what did Houtham and Rowlands (2014) find??
Protein requirements for endurance trained women estimated at 1.6g/kg/day
What did Tarnopolsky (2004) state were the nitrogen balance to protein guidelines in endurance exercisers???
Low to mod intensity - same as general population.
Modestly trained athletes - negative N balance at 1g/kg/d (hence 1.1)
Elite endurance athletes - n balance achieved at 1.4g/kg/d (up to 1.6)
Phillips (2004) reviewed n balance in resistance exercisers, what did he find??
Average was the 1.19g/kg/d with the safe intake being 1.33g/kg/d
What did Cermak et al (2012) find looking at protein??
Protein does enhance lean mass gains with resistance exercise.
Strength and lean bm both favour the adaptation of protein compared to placebo in both old and young.
What did biolo et al (1997) find looking at net muscle protein balance??
Found that exogenous amino acids stimulate MPS at rest. Significantly higher synthesis occurred with infusion compared to basal, and decreases in breakdown were non significant.
Data also showed a negative nmpb at rest but this turned positive when fed AA
Explain the key paper by Biolo et al 1995/1997 looking at MPS and MPB in response to exercise and nutrition
AA stimulate MPS, exercise stimulates MPS, and ex plus AA has an additive effect and cause a positive npb.
Exercise may improve npb but without AA it still favours breakdown.
Briefly what did Phillips (2005) say about nutrient consumption post ex??
It stimulates MPS and inhibits the exercise induced rise in protein breakdown , resulting in gradual muscle mass increase.
Discuss Biolo’s (1999) work??
Insulin does not further increase MPS, but does suppress breakdown in the post-exercise period, and therefore anabolic for breakdown reasons.
What did Carraro et al (1990) find??
Showed that FSR (proxy of MPS) is significantly increased In recovery, whereas during exercise it is not.
Discuss the work on protein metabolism by Hulston (2011)???
Looking at pro metabolism during and after endurance exercise, showed recovery to be significantly higher for mixed muscle protein FSR for CHO + P compared to just CHO
Issues because it takes into account the whole response of the leg (e.g. Adipose / bone etc) as opposed to just looking at myofibrillar for e.g.
Howarth et al (2009) looked at mixed muscle FSR with nutrient ingestion after endurance exercise and found what???
Found pro-cho (0.4g/kg/h + 1.2g/kg/h) to be significantly higher than LOW CHO (1.2g/kg/h) and high CHO (1.6g/kg/h)
Wilkinson et al (2008) discovered the response of different proteins is dependent on the type of exercise, how so??
Once you are resistance trained, a single bout of res exercise does not stimulate mitochondrial FSR, hence over time, res ex is more of a myofibrillar response.
For untrained, res ex stimulated myo FSR greatly, and both endurance and res ex stimulate mito FSR, but endurance to a greater extent.
Remember work from Damas (2015) who showed that MPS is blunted with training after every bout etc. See paper
Discuss Moore et al (2009)?
He found that maximal mixed MPS was achieved with 20g egg protein - which equated to ~8.6g EAA or 0.25g/kg/meal
Obviously caveat is that fasted, and it’s mixed MPS not myofibrillar!
Wittard et al (2014) looked at myofibrillar MPS, what did he find?
Maximal myo MPS was found with 20g of whey protein compared from rest to exercise
Phe oxidation was sig higher for 40g of whey
Fed state strength exercise
Both moore and wittard were split body ex so led to MacNaughton
What did MacNaughton et al (2016) find?
He separated 30 resistance trained males into high LBM >70kg
Or low LBM <65kg and made them perform whole body routine.
Showed 40g of whey better than 20g regardless of LBM
Myofibrillar FSR significantly higher for 40g than 20g also.
What did Tipton et al (1999) find?
That only EAA’s are required to increase MPS after resistance training
What did Jackman et al (2017) find?
That BCAA’s can increase myofibrillar MPS after resistance exercise (a 22% increase in FSR from BCAA to placebo)
In Fed state
What did Atherton et al (2010) find?
That leucine is a potent nutrient for signalling the anabolic machinery in the body e.g. MTOR, P70S6K, 4EBP1, rpS6 - the phosphorylation significantly higher in leucine
Discuss the studies of Wilkinson et al (2007) and Hartman et al (2007)?
Wilkinson showed that post exercise milk consumption promotes greater MPS than soy following a 3h recovery period.
Hartman looked over the the long chronic time period, and found milk to be more beneficial than soy in the long term.
What did Breen and Phillips (2011) propose??
Hypothesised the leucine trigger hypothesis , where a leucine trigger must be met in order to optimise MPS, this occurs roughly 30 mins post whey protein consumption.
What did Tang et al (2009) find?
MPS is greater in both rested and exercised muscle with whey compared to soy and casein.
Whey’s effectiveness is a function of both composition and speed of delivery through the GI tract
What did Rasmussen et al (2000) find ??
Looked at 6 adults and showed there was no difference in protein synthesis 1h or 3h post exercise when consuming a CHO and EAA drink at these time points.
1h spiked at 1h
3h spiked at 3h
What did Res et al (2012) find when looking at casein?
Maybe a role for slow proteins in muscle remodelling, found overnight mixed MPS was sig higher than placebo when given 40g casein before sleep
