Unit 1: Proteins

Question 1

What are proteins?

Answer 1

Proteins are the most diverse of all macromolecules serving numerous physical, chemical, and functional roles

Question 2

Amino Acids

Answer 2

building blocks of proteins used to maintain bodily homeostasis via numerous mechanisms and pathways

Question 3

Essential amino acids

Answer 3

must be consumed within the diet as the body cannot produce them internally at sufficient levels

Question 4

Non-essential amino acids

Answer 4

can be produced internally to meet homeostatic needs and therefore do not need to be consumed in the diet

Question 5

Conditional amino acids

Answer 5

need to be consumed during specific times during the lifespan (e.g., infancy) or in response to specific additional stresses (e.g., disease

Includes cysteine, glutamine, arginine, glycine, proline, serine and tyrosine

Question 6

Functional amino acids

Answer 6

mixture of essential and non-essential amino acids known to promote optimized health, performance, and function due to the roles they fulfill

Question 7

What are the functional amino acids?

Answer 7

1. Arginine
2. Glutamine
3. Leucine
4. Tryptophan
5. Cysteine
6. Glutamate
7. Proline

Question 8

What do function amino acids regulate?

Answer 8

protein synthesis, gene expression, cell signaling, nutrient transport/metabolism, immune responses, reproduction, antioxidant defense, hormone secretion, neurological functions, digestion, recovery from injury, blood flow, etc.

Question 9

Protein Turnover

Answer 9

Constant protein synthesis and degradation occurs within the body in a process referred to as protein turnover – serves to maintain the health and function of all tissues

Question 10

Protein synthesis

Answer 10

process of new protein creation or building of tissues in response to signaling stimuli such as nutrition or exercise

Question 11

Proteins and anabolism?

Answer 11

Exercise greatly stimulates protein synthesis in muscle cells with timely intake of protein/amino acids post-exercise (anabolism)

Question 12

Proteins and catabolism?

Answer 12

Without protein intake net balance will be negative (catabolism)

Question 13

Branched chain amino acids (BCAA)

Answer 13

includes leucine, isoleucine and valine; are critical for triggering protein synthesis and account for a large portion of the free amino acid pool in muscle

BCAAs, and especially leucine, are recommended post-exercise for optimized protein synthesis

Question 14

Protein degradation or proteolysis

Answer 14

breakdown of amino acids to create energy, produce a different type of amino acid based on need, limit unhealthy tissue decay or serve another homeostatic function

Question 15

Transamination

Answer 15

conversion of an amino acid into a new amino acid following breakdown

Question 16

Reverse Transamination

Answer 16

Reverse transamination occurs to create NEAAs in the body

Question 17

How is nitrogen created during protein turnover cleared from the body?

Answer 17

Amino acids are broken down into ammonia, which the liver converts into urea, and mobilized by the kidneys in urine; this cycle clears nitrogen created during protein turnover

Question 18

Complete protein

Answer 18

includes all of the essential amino acids and is therefore optimal for reducing the risk for deficiencies; includes meat, poultry, fish, soy, quinoa, and seafood

Question 19

Incomplete protein

Answer 19

missing one or more essential amino acids and should be combined with other proteins to minimize the risk for a deficiency; includes beans, legumes, grains, nuts, vegetables, and fruits

Question 20

Complementary proteins

Answer 20

sources that are incomplete when consumed in isolation but when appropriately combined provide all of the essential amino acids

Question 21

Examples of complete proteins

Answer 21

animal based: meat, poultry, dairy. eggs, fish

Question 22

Incomplete Proteins

Answer 22

plant based: vegetables, grains, legumes/beans, nuts/seeds

Question 23

Complementary Proteins

Answer 23

Grains and legumes/vegetables, nuts/seeds and vegetables/legumes

Question 24

Milk proteins

Answer 24

whey and casein possess a high leucine content, high bioavailability

Casein breaks down slower and is optimal before sleep to limit overnight catabolism, whey digests quicker and is useful pre/post-exercise

Question 25

Egg protein

Answer 25

albumen is rich in easily-digestible amino acids including leucine and valine High bioavailability makes a great source for anabolism among athletes – each egg white contains 4-6 g protein

Question 26

Meat protein

Answer 26

beef and pork are rich in EAA including leucine, iron, creatine and vitamins; useful for inducing anabolism and hypertrophy but fat content must be considered

Question 27

Soy protein

Answer 27

soybean is an attractive alternative to animal sources, contains less leucine than milk proteins Complete protein, rich in BCAAs, useful for vegan/vegetarians and lactose intolerance, provides phytochemicals and fiber

Question 28

Physiologic/metabolic responses to protein quality

Answer 28

- absorption-digesitbility - metabolic utilization - nitrogen balance - lean mass/muscle/bone - tissue turnover - secretory proteins - host defense/immunity - growth and maturation - tissue repair

Question 29

Short-term outcomes of protein quality

Answer 29

- growth and tissue repair (wasting and stunting) - immune function and host defense system (prevalence and severity of infection) - muscle and skeletal mass capacity for physical work and athletic performance) - mental performances, mood, sleep patterns - detoxication of chemical agents and antioxidant systems

Question 30

Long-term outcomes of protein quality

Answer 30

- life course events, linear growth, menarche, aging - age-related functional losses, muscle, bone strength, immunity, cognitive decline - nutrition-related chronic diseases. Cardiovasular disease, cancer, hypertension, oxidative damage, repair systems

Question 31

How should protein intake be calculated?

Answer 31

Protein intake should be calculated in grams per kilogram of body weight per day (g/kg/day) - percentage of calories does not account for actual need

Question 32

What is the best amount of protein intake for athletes? (for performance and recovery)

Answer 32

For athletes, protein intake above the recommended dietary allowance (RDA) 0.8 g/kg given to the general population will best support performance and recovery

Question 33

Is protein quality, dosage, and timing important for intake?

Answer 33

yes

Question 34

How much more protein intake than the RDA has been shown to be useful during periods of energy restriction for weight loss?

Answer 34

3x; Some research has shown protein intake 3x that of the RDA to be useful during periods of energy restriction for weight loss

Question 35

What does protein above the RDA of 0.8 g/kg/BW seem beneficial for?

Answer 35

1. maintaining muscle mass 2. attenuating hunger via improved satiety 3. improving body composition 4. improving recovery