Protein

Question 1

What did tarnopolsky et al (2004) find regarding N balance??

Answer 1

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

Question 2

Building from tarnopolsky 2004, what did Houtham and Rowlands (2014) find??

Answer 2

Protein requirements for endurance trained women estimated at 1.6g/kg/day

Question 3

What did Tarnopolsky (2004) state were the nitrogen balance to protein guidelines in endurance exercisers???

Answer 3

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)

Question 4

Phillips (2004) reviewed n balance in resistance exercisers, what did he find??

Answer 4

Average was the 1.19g/kg/d with the safe intake being 1.33g/kg/d

Question 5

What did Cermak et al (2012) find looking at protein??

Answer 5

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.

Question 6

What did biolo et al (1997) find looking at net muscle protein balance??

Answer 6

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

Question 7

Explain the key paper by Biolo et al 1995/1997 looking at MPS and MPB in response to exercise and nutrition

Answer 7

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.

Question 8

Briefly what did Phillips (2005) say about nutrient consumption post ex??

Answer 8

It stimulates MPS and inhibits the exercise induced rise in protein breakdown , resulting in gradual muscle mass increase.

Question 9

Discuss Biolo’s (1999) work??

Answer 9

Insulin does not further increase MPS, but does suppress breakdown in the post-exercise period, and therefore anabolic for breakdown reasons.

Question 10

What did Carraro et al (1990) find??

Answer 10

Showed that FSR (proxy of MPS) is significantly increased In recovery, whereas during exercise it is not.

Question 11

Discuss the work on protein metabolism by Hulston (2011)???

Answer 11

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.

Question 12

Howarth et al (2009) looked at mixed muscle FSR with nutrient ingestion after endurance exercise and found what???

Answer 12

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)

Question 13

Wilkinson et al (2008) discovered the response of different proteins is dependent on the type of exercise, how so??

Answer 13

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

Question 14

Discuss Moore et al (2009)?

Answer 14

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!

Question 15

Wittard et al (2014) looked at myofibrillar MPS, what did he find?

Answer 15

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

Question 16

What did MacNaughton et al (2016) find?

Answer 16

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.

Question 17

What did Tipton et al (1999) find?

Answer 17

That only EAA’s are required to increase MPS after resistance training

Question 18

What did Jackman et al (2017) find?

Answer 18

That BCAA’s can increase myofibrillar MPS after resistance exercise (a 22% increase in FSR from BCAA to placebo)

In Fed state

Question 19

What did Atherton et al (2010) find?

Answer 19

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

Question 20

Discuss the studies of Wilkinson et al (2007) and Hartman et al (2007)?

Answer 20

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.

Question 21

What did Breen and Phillips (2011) propose??

Answer 21

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.

Question 22

What did Tang et al (2009) find?

Answer 22

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

Question 23

What did Rasmussen et al (2000) find ??

Answer 23

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

Question 24

What did Res et al (2012) find when looking at casein?

Answer 24

Maybe a role for slow proteins in muscle remodelling, found overnight mixed MPS was sig higher than placebo when given 40g casein before sleep

Question 25

Discuss Burd et al (2011) ??

Answer 25

Suggests there is an enhanced amino acid sensitivity of myofibrillar protein synthesis which persists for upto 24h after resistance ex - the window is longer than first believed.

Question 26

What did Phillips et al (1997) state in his key paper?

Answer 26

Time window may be up to 48 h post exercise , with MPS still activated 48h after exercise above rest . However 3h is the most prominent rise, so ideally sooner rather than later similar to CHO.

Question 27

Discuss the Layman et al (2003) literature??

Answer 27

Gave obese women either CHO/PRO with a ratio of 3.5(68g pro) or 1.4(125g pro) a day.

Both groups lost weight, but the loss in the protein group was better partitioned, better fat/lean loss so more favourable body composition.

Question 28

What did Pasiakos et (2010) find ?

Answer 28

10 days of a 500kcal deficit significantly reduced resting mixed muscle FSR.

Question 29

What did Areta et al (2014) discover? - not 8x10 study.

Answer 29

showed that we can overcome the blunting of MPS during energy restriction by performing res ex and consuming protein (30g>15g) post exercise.

Just resistance exercise was superior to ED for myofib FSR
A 30g protein bolus, stimulated myo FSR ~34% above resting EB.

Question 30

What did Mettier et al (2010) find??

Answer 30

Showed a higher dietary protein can promote high quality weight loss during an energy deficit
- lost significantly less body mass and lean mass

Question 31

Discuss key findings from Areta from et al (2013)?

Answer 31

Showed that an intermediate dosage (4x20g bolus) and frequency (4 times over 12h) was most optimal for myofibrillar FSR compared to 2x40g or 8x10g!

Issues as only 80g a protein a day, well below recommended protein intakes

Question 32

What did Longland et al (2016) find??

Answer 32

Looked at 40 overweight recreationally active men.
A high protein diet (2.4g/kg/day) can lead to increases in LBM and sig decreases in body fat compared to a normal group (1.2g/kg/day).

Furthermore, Both groups Improved all strength / power measurements over the 4 weeks on a 40% caloric deficit. Following 6 day a week exercise.