Exam 3: Protein: influences of training on dietary requirements and roles of dietary protein and amino acid supplements Flashcards
Protein requirement for strength athletes:
recommended range?
about 1.2g/kg - 1.8g/kg
T/F: Strength athletes protein requirements are highly used for energy.
False
Strength athletes protein requirements are at increased need mainly due to
a. energy
b. tissue synthesis
c. hormone balance
d. energy and synthesis demands
b. tissue synthesis
Protein requirement for endurance athletes:
recommended range?
1.0 g/kg - 1.6 g/kg
T/F: endurance athletes protein requirements needs increased for energy only
False
energy and synthesis demands
Strength athletes protein requirements are at increased need mainly due to
a. energy
b. tissue synthesis
c. hormone balance
d. energy and synthesis demands
Tissue synthesis
Protein requirement for endurance athletes:
ultraendurance athletes?
1.5 g/kg - 1.7 g/kg
endurance athletes and strength athletes both require ________ of calories
a. 12% - 15%
b. 16% - 19%
c. 20% - 23%
d. 24% - 27%
12% - 15%
T/F: endurance athletes and strength athletes both should select a high quality protein
True
List Key Protein Function
- enzyme
- peptide hormones
- structural proteins
- transport proteins
- immunoproteins
which stomach enzymes digest protein
HCL and pepsin
where does most of protein digestion occur?
small intestine
In what form are proteins absorbed
amino acids, dipeptides, and tripeptides
after digestion and absoprtion, amino acids can be ________ or ______________
AA used or transported to liver
what are the metabolic fate?
- resynthesized to proteins or nonprotein with nitrogen compound
- AA degradation forming urea
- carbon skeleton used for fat or CHO
AA degradation: ______
N forms urea and other waste-eliminated mainly by kidney
carbon skeleton used for ________
fat or carbohydrate production
Are proteins a key contributor energy source?
a. yes
b. no
c. usually not
d. usually are
usually not a key contributor
protein during exercise are typically not a key contributor as an energy source but can
increases with duration and intensity
BCAA directly used by ______
muscle
other AA converted to ______, _________, or___________
fat, ketones, or carbohydrate
how does aerobic training effects the use of protein?
increased synthesis of mitochondria and oxidative enzymes
how does anaerobic training effects the use of protein?
increased synthesis of contractile proteins
T/F: protein supplements have a clear advantage over regular food proteins
False
T/F: protein supplements have a clear advantage over regular food proteins, except for sometimes convenience
True
T/F protein supplements can help if athlete can’t eat enough food
True
does the kind of protein supplement matter?
relatively little research available
fast vs slow protein
Fast Proteins (e.g., whey protein): These proteins are digested and absorbed quickly by the body. They are typically used post-exercise because they rapidly stimulate muscle protein synthesis (MPS), supporting muscle recovery and growth.
Slow Proteins (e.g., casein protein): These proteins are digested more slowly, providing a steady release of amino acids into the bloodstream over time. They are often recommended before periods of fasting, such as before sleep, to prevent muscle breakdown (catabolism) during the night.
Key Point: Fast proteins are great for immediate muscle repair, while slow proteins help provide a longer-lasting supply of amino acids for muscle preservation, especially during periods of fasting.
plant vs animal protein
Animal Protein: Animal-based proteins (e.g., meat, dairy, eggs) are considered complete proteins because they contain all nine essential amino acids in the proper ratios necessary for the body. They are also typically rich in other important nutrients like iron, zinc, and B vitamins.
Animal proteins generally offer higher biological value (BV) and digestibility.
Plant Protein: Plant-based proteins (e.g., beans, lentils, soy, quinoa) may be considered incomplete proteins because they lack one or more of the essential amino acids (though soy and quinoa are exceptions). However, when consumed in a varied and balanced diet, plant proteins can provide all the essential amino acids over the course of the day.
Plant proteins tend to be lower in saturated fat and are a good source of fiber and antioxidants, which may contribute to better overall health.
Key Point: Animal proteins are often better for muscle building due to their complete amino acid profile, while plant proteins offer additional health benefits and can be combined to form a complete protein profile.
mix of proteins
Key Point: Mixing different protein sources (both plant and animal) can provide a wider array of nutrients and ensure a balanced intake of all essential amino acids.
what does the overall research say about protein supplements?
overall data arent clear and real food often tastes better and is cheaper
does time matter when taking protein supplements?
maybe but not clear when is best
one bout of exercise can increase protein synthesis up to
2 days
highest amino acids and anabolic hormones occur within ______ after intake
1- 3 hours
T/F: higher muscle protein synthesis with post-workout protein intake than no protein
True
T/F: post-workout protein intake is best 2 hours after
False
Immediately may be better than 2 hours after
T/F protein just before exercise may be even better
True
what is staggering?
CHO minimally stimulates protein synthesis
before bed
Slow-digesting proteins like casein (found in dairy products such as milk, cottage cheese, or casein protein powder) are ideal for consumption before bed. Casein provides a steady release of amino acids into the bloodstream over several hours, which helps prevent muscle breakdown (catabolism) while you sleep.
For individuals looking to build or maintain muscle mass, consuming protein before bed can help support muscle protein synthesis (MPS) during sleep, a critical time when the body is recovering from the stress of the day’s activities and workouts.
Oversaturation of carriers may lead to deficiency due to an imbalance
triue
Essential amino acid mixtures: as little as _______ after exercise can increase muscle protein synthesis
6g
resistance exercise and protein
when resistance exercise is performed before protein ingestion,
the combination _____ protein synthesis rates above protein
breakdown, allowing for muscle ______
increases, hypertrophy
aerobic endurance exercise
rate of ATP
production is much slower than carbohydrate and fat, the preferred
fuels.
rate of ATP
production is much slower than carbohydrate and fat, the preferred
fuels
amino acids (BCAAs), asparagine, aspartate, and glutamate—are metabolized in the _____
muscle
Ammonia Production: Ammonia, a by-product of amino acid breakdown, is produced in the ____ during exercise. Elevated ammonia levels indicate increased protein _____ and can contribute to _____, similar to lactic acid buildup. High ammonia may impair both muscle oxidative processes (reducing energy production) and brain functions, which may cause ______
msucle,
breakdown
fatigue
central fatigue theory
describe glucose alanine cycle
where muscles break down leucine (and other amino acids) during exercise, forming alanine by combining the amino group with pyruvate. Alanine is then transported to the liver, where it’s converted back into glucose through gluconeogenesis. This glucose is released into the bloodstream to fuel muscles and other tissues, while the liver processes the leftover nitrogen as urea for excretion. This cycle supports energy supply and nitrogen transport during prolonged exercise, though its contribution is relatively small compared to other energy sources.
