ch5 Flashcards
Amino acids contain which chemical elements?
Carbon, hydrogen, oxygen, nitrogen
How do the structures of amino acids differ?
The side chain differs, some may have acid groups, basic groups, or rings
What are the essential amino acids
Leucine
Isoleucine
Valine
Histidine
Phenylalanine
Methionine
Lysine
Threonine
Tryptophan
how are EAA determined
- determined by feeding a diet minus 1 aa
- if N balance becomes negative, AA is indespensable
What is meant by protein quality?
based on the amounts and types of amino acids and the extent to which the amino acids are absorbed.
what is a high quality protein
all of the EAAs
extra AA available for nonessential AA synthesis
good digestibility
usually animal derived
what is a low quality protein
lacks one or more EAAs
usually plant derived
What is it meant by complementary proteins
pairing different incomplete proteins to each other and bring the total concentration of all indespensable aa to an adequate level
when might this concept (complementary protein) be an important consideration?
vegetarians to limit protein deficiencies
Briefly describe the digestion, absorption, and transport of protein found in food.
go read book, p. 155-157
What are potential fates of amino acids?
- many used by villus for protein synthesis
- apoproteins for lipoprotein formation
- new digestive enzymes
- hormones
- N-containing compounds
- glutamine used for energy
What is the amino acid pool?
refers to free AA that are circulating in the blood or in the fluid found within or between cells.
Describe amino acid sources, turnover, and excretion of this pool.
Most AA come from the GI tract but some come from breakdown of body tissue including skeletal muscle.
AA pool is always in flux bc of food intake, exci, and breakdown or building of tissues -> protein turnover
Describe anabolic and catabolic processes that involve amino acids.
anabolic: synthesis of new proteins, building of complex molecules from simple molecules
catabolic: breakdown of complex molecules into simple ones, breakdown of protein for energy
factors affecting anabolism
genetics
resistance training
nutrition
hormones
What is nitrogen balance and protein balance?
nitrogen balance is the difference between tootal nitrogen intake and total nitrogen loss, determined over several weeks
protein balance involves muscle protein synthesis and muscle protein breakdown
Describe how protein is metabolized during exercise.
p161 of book
- ATP production (3-5% EE)
- inc in leucine oxydation due to dec glycogen (++ if dec in CHO intake) - gluconeogenesis
- leuucine and lysine are the only ones that cant make glucose
- inc with metabolic stress
- glucose used for tissues (brain, kidneys, muscles)
What is the recommended daily intake of protein for adult nonathletes? Athletes in training? Athletes who are restricting calories?
0.8g/kg/d
2.0
1.5
Why is the timing, dose, and distribution of protein intake important?
to maximize protein synthesis
What is the recommended protein dose and distribution and in what context might the timing, dose and distribution be considered?
0.25 to 0.3 g/kg within 2h after exercise
= dose of about 15 to 25 g
large bodied athletes may need 30-40g
for athletes in training should eat 3 to 5 meals a day with protein containing foods
How are high- or low-protein diets detrimental to training, recovery, performance, or health?
excessive protein may have an adverse effect on kidney health, can result in dehydration, decrease muscle glycogen stores affecting recovery and performance
increase caloric intake and increase body fat
low protein can decrease energy, decrease muscle mass, cause fatigue and poor performance weaken immune system, slow down recovery and muscle growth
How might short term changes in protein intake affect training and recovery?
decrease can lead to small losses of lean body mass, health concerns, decreases ability to exercise, depleated glycogen stores.
increase can increase recovery and decrease glycogen stores as well
Compare and contrast animal and plant proteins and why this information is important to vegetarians and vegans.
important to know which foods contain which macronutrient and how much protein they contain
vegetarians who consume animal products are likely to meet the protein recommendations for athletes
vegans there is more a concern that the protein source is lower quality and quantity
important to know to meet the recommendations and perform/recover
Compare and contrast whey, casein, and soy proteins.
whey: processed from milk, found in liquid portion, AA absorbed faster, higher % of indespensable AA, fast acting prot
casein: processed from milk, found in semi-solid portion, slow acting prot
soy: comparable to animal prot
