Protein Flashcards
What are the 3 important parameters with protein?
- Protein amount
- Protein type
- Protein timing
What is the most important determinant of muscle protein synthesis?
Protein amount
What is the optimal intake of protein recommended for athletes?
- Endurance 1.2 - 1.4 g/kg/d
- Early strength/power programme 1.6 - 1.8 g/kg/d
- Established strength/power programme 1.2 - 1.4 g/kg/d
- ISSN: 1.4 - 2.0 g/kg/d
What is the rationale for increased protein requirements in athletes?
▪ Repair and replace damaged proteins
▪ Remodel proteins within muscle, bone, tendon, ligaments
▪ Maintain optimal function of cell metabolic pathways that use AA
▪ Support increments in lean mass
▪ Support immune system
▪ Support rate of production of plasma proteins
▪ The requirement is for an intake that is optimal to support athlete’s overall
metabolism – not to prevent deficiency
What is MTORC1?
- A strong stimulator of muscle protein synthesis
What stimulates master protein regulator MTORC1?
- Resistance exercise
- Amino acids (leucine)
True or False
Endurance exercise inhibits myofibrillar proteins synthesis
True
What regulate exercise recovery and performance through the modulation of mTOR, AMPK, FGF21 and immunity?
Protein intake and amino acid supplementation
I which state, rates of MPB exceed those of MPS and thus skeletal muscle is in a state of negative net protein balance?
In the rested, fasted state
What determine muscle protein balance and changes in muscle mass?
MPS and MPB rates
Do endurance athletes require more protein?
- Protein is not a major contributor
- Prolonged ET damages protein structure in muscle
- Increased oxidative capacity
What is the protein recommendation for endurance athletes?
0.3g/kg or 20-40g when taken every 3-5 hrs (1-3 g of leucine) including a dose immediately before or 0-2 h post-exercise
What is the ISSN protein (per hour) recommendation for endurance exercise?
0.25g/kg protein per hour with carbohydrates
How does muscle glycogen synthesis can increase by 40-100%?
by combining protein and carbohydrate in post-exercise
10g of protein can be found in:
- 40-50 g lean meat
- 2 eggs
- 300 ml low-fat milk/yogurt
- 1/2 - 3/4 cup dried beans, lentils
How many amino acids are?
- 9 EAAs
- 11 NEAAs
Name 4 protein type high in leucine content %
- Bovine milk 7%
- Whey isolate 10%
- Casein 5.8%
- Soy isolate 6.9%
Amount of leucine require to maximise the MPS response
2.5g “leucine threshold”
(1 scoop whey protein)
Which EAA have a greater stimulator effect on MPS?
Leucine
Percentage of ATP used during a training session (resistance training)
80% derived from glycolysis
Recommendation of CHO around training sessions to help train longer and impact net protein synthesis following a work-out
4-7 g/kg
How does protein intake can optimise the anabolic response?
intake needs to be spread throughout the day
Explain protein distribution
- feeding similar sized protein doses at each meal may result in improved anabolic response
20g every 3-4 hrs (breakfast, lunch, afternoon snack and dinner)
Recommendation for protein before exercise
- 6g amino acids (equivalent 15g high quality milk proteins) + 35g sucrose increases muscle anabolism 160% greater when ingested immediately pre-resistance exercise
- 20g whey pre-ex to up to 3 hours post-ex increases muscular uptake
Recommendation for protein post-exercise
- ∼10 g EAAs (20 – 30 g total protein) in the early recovery phase (0–2 h after exercise). Translates to a recommended protein intake of 0.25–0.3 g/kg bw or 15–25 g protein across the typical range of athlete body size
- 0.3 g/kg bw after key exercise sessions and every 3–5 hours over multiple meals
At what time does MPS spikes after ingesting protein?
~ 90-120 minutes
What are the potential side-effects of excessive protein intake?
- Excessive reliance on free-form AAs may lead to nutritional imbalance and dietary deficiency
- Impaired renal function
- Increased risk of osteoporosis
What are the 4 routes for excess dietary protein?
- Synthesised to new AAs
- Converted to CHO via gluconeogenesis
- Oxidised as an energy source
- Potential to be converted to CHO or fats
How much protein is required to hit the leucine threshold?
0.4 g/kg bw (high quality protein source)
What is the optimal protein feeding pattern for athletes?
Achieving sufficient protein at each meal and post-exercise
After exercise what type of proteins are synthesised in a) endurance trained muscle?
b) strength trained muscle?
a) mitochondrial proteins
b) muscle contractile (myofibrillar) proteins
Which type of dietary proteins are considered superior for muscle protein synthesis?
Whey protein and casein protein (milk)
Name two reasons why carbohydrates are important for strength/power athletes
- Prolonged training sessions
- Protein synthesis
Why is feeding equal sized protein portions throughout the day considered better than feeding the majority of protein at the main meal?
To optimise the anabolic response
what is the muscle full effect?
The anabolic response of skeletal muscle to essential amino acids (EAAs) is dose dependent, maximal at modest doses, and short lived, even with continued EAA availability
What is the optimal intake of protein recommended for hypo-caloric diet?
> 2.0 g/kg/d to preserve muscle mass
is it better to feed before, during or after exercise to promote muscle protein
synthesis, and why?
- Pre- and post-exercise meals should not be separated by more than
approximately 3–4 hours, given a typical resistance training bout lasting
45–90 minutes - Consume protein as soon as possible after ex to take advantage of the
anabolic response prompted by the exercise itself - Good for muscle protein synthesis, reduce muscle damage.
