2.6.2. Creatinine and Protein Supplements

Question 1

Recommended intake of protein

Answer 1

0.8 g/kg body (ideal body) weight/day

Question 2

What are high quality proteins?

Where do we get them?

Answer 2

contain many essential amino acids (9)
His, Iso, Leu, Lys, Met, Phe, Thr, Trp, Val

usually from: dry beans and meat, chicken, or fish products

Question 3

What are low quality proteins?

Where do we get them?

Answer 3

lacks some essential amino acids required for human diet

from: many vegetables

Question 4

What happens in cases of high-protein diets, when very low in calories/protein of low quality or biologic value get a NEGATIVE NITROGEN BALANCE?

Answer 4

Body protein is degraded as AAs are converted to glucose. Even with high quality protein, ammonia and urea levels rise, putting stress on the kidneys.

Question 5

What is the major end product of nitrogen metabolism? Follow the track of ammonia out of the body

Answer 5

Urea.

ammonia created by oxidative deamination reactions (involving amino acids), which can only be excreted as urea

this conversion is the urea cycle (ornithine cycle), which occurs in the liver

urea is excreted at the kidneys

Question 6

Where did dietary standards come from?

Answer 6

Food and Nutrition Board (FNB) in 1940 came up with standards for war fighters

Question 7

Dietary Reference Intakes (DRI)

Answer 7

a system of nutrition recommendations from the institute of medicine

Question 8

Recommended Dietary Allowance (RDA)

Answer 8

daily dietary intake level considered sufficient by the FNB to meet the requirements of nearly 97-98%. This does NOT take into account the physically active

Question 9

RDA for men and women is what for protein?

Answer 9

.8 g of protein per kg body weight (.36g/lb)

Question 10

RDA changes based on activity.

What is the protein RDA for people who have:

• Low to moderate activity
• Endurance training
• strength and weight training
• High energy with insufficient calories

Answer 10

low to moderate activity = 0.8-1.0 g/kg

endurance training = 1.2-1.4 g/kg

strength and weight training = 1.2-1.7 g/kg

high energy w/ insufficient calories = 1.5-2.0 g/kg

Question 11

Effective limits on protein in a meal

Answer 11

anything above .25 +/- .05 g/kg/meal of protein will not given any significant benefit

this typically lands around 20-25 g per serving

Question 12

Estimated Average Requirement (EAR)

Answer 12

amount of nutrition needed to meet about 50% of population’s needs

Question 13

Acceptable Macronutrient Distribution Range (AMDR)

Answer 13

reflects an intake range with a reduced risk of chronic disease

Question 14

What percent energy of your total intake is protein?

Answer 14

protein = 10-35% total energy intake

Question 15

Tolerable Upper Intake Levels (UL)

Answer 15

highest level of daily consumption that data so far have shown no side effects in humans without medical supervision when used indefinitely

insufficient data to define an upper limit for protein intake at this point in time

Question 16

PDCAAS

Answer 16

Every protein source has a score associated with it called the Protein digestibility-corrected amino acid score (PDCAAS)

Question 17

The amount of protein that is oxidized is increased by consuming protein in amounts higher than the RDA, and protein turnover increases with increased protein consumption as well

What does this mean about the excess protein consumed?

Answer 17

This means that the excess consumed protein is NOT being used for building muscle, but instead for energy (when using protein for energy, it is not an energy efficient process)

Question 18

How much of muscle is protein? Water?

Answer 18

Muscle is only 20% protein

Most of it (75%) is water!

Question 19

Concerns with high protein diets:

Answer 19

1. generates an excess acid load
   - fish and meat are highest
   - plants are lower (leafy greens super low)
2. increase loss of calcium in the urine
3. decreased intake of carbohydrates in exchange for proteins
4. higher fluids needed with higher protein diets

Question 20

2 primary stimulants to muscle protein synthesis

Answer 20

1. Muscle contraction increases muscle protein synthesis
2. Food intake
   meal = increase in muscle protein synthesis

Question 21

Compare Fast vs. slow protein

Answer 21

Fast

• increase blood AA rapidly
• might be better in the case of aging and preventing muscle wasting
• example: Whey (in milk!)

Slow

• slower increase in blood AA, but blood AA lasts longer
• help inhibit muscle breakdown by keeping blood AA level higher longer, so no need to break down muscles
• example: Casein (in milk!)

Question 22

Muscle Mass Accretion

Answer 22

Muscle building

Question 23

What is gain of lean muscle based on?

Answer 23

Gain in lean muscle mass based ONLY on the dietary source of protein

Question 24

Whey vs. Casein on muscle building

Answer 24

Whey protein promotes a much greater insulin response than Casein

This does help prevent muscle wasting, HOWEVER, this does not dictate where the protein will be going or how it will be used

Question 25

What are Essential amino acids?

Answer 25

cannot be synthesized by the body, so must be consumed in the diet

Question 26

What are Conditionally Essential AAs?

Answer 26

the body CAN produce them, but this production can become the rate-limiting step in a series of reactions, so these AAs can become conditionally essential

the above means that they may not be synthesized in adequate amounts during highly demanding conditions

Question 27

Leucine appears to be a specific signal for protein synthesis. What does it become in the body and what does this molecule do?

Answer 27

becomes Beta-hydroxy-beta-methylbutyrate (HMB)

common supplement and potential signaling molecule for protein synthesis

Question 28

what 3 amino acids are needed to make creatine?

Answer 28

arginine
glycine
methionine

Question 29

What does creatine phosphate do for us?

Answer 29

Creatine phosphate transports high-energy phosphate from the mitochondria to actinomyosin fibers and provides ATP for muscle contraction

Creatinine is produced non-enzymatically from creatinine phosphate, and a constant amount (dependent on body mass) is released into the blood each day and excreted by the kidneys

Question 30

How should you use creatine in a muscle building diet?

Answer 30

3 g/day loads muscles maximally

may cycle on and off for periods of 28 days

NOT a booster of muscle performance (causes weight increase)

Question 31

What muscle fibers may store more muscle creatine?

Answer 31

type II muscle fibers may store more muscle creatine

Question 32

Muscle damage results in the release of creatine kinase (CK) into the blood; CK catalyzes reversible reaction:

Answer 32

creatine + ATP ←> creatine phosphate;

Question 33

What molecule in the blood reveals that you have had a heart attack?

Answer 33

release of heart isozyme confirms heart attack has occurred

Question 34

What is GFR and how is it related to Creatine Kinase?

Answer 34

creatinine kinase is cleared by the kidneys; used to approximate glomerular filtration rate (GFR); normally 100 mL/min; can use inulin because freely filtered (neither resorbed nor secreted)

Question 35

Formula for GFR?

Answer 35

GFR = U(insulin) * V/P(insulin) = C(insulin)