UNIT 7: MACRONUTRIENTS--PROTEIN Flashcards
Unit 7: Macronutrients - Protein
In nutrition, proteins are classified as either _________ proteins–Contain all amino acids that occur in the body, including essential amino acids, at adequate levels
__________ proteins—Proteins lacking, or low, in some essential amino acids
Complete
Incomplete
Unit 7: Macronutrients - Protein
“__________” Amino Acids: cannot be synthesized by the body.
Essential
PVT TIM HLL
Unit 7: Macronutrients - Protein
• Proteins in food are digested (__________) to amino acids and small peptides.
• ___________: Enzymes that hydrolyze proteins – Examples (to jog your memory!)
zymogen
• Pepsin (stomach)
• Trypsin and chymotrypsinogen (pancreas)
• Amino acids are absorbed by the small intestine through specific transporters (some Na+-dependent, some not)
• Small peptides to be absorbed are further digested to amino acids in the intestine wall by _____________
hydrolyzed
Proteases
peptidases
Unit 7: Macronutrients - Protein
Transport and Storage
• Amino acids are water soluble
– Transported in body fluids (via ______)
• Storage of amino acids is limited. ~ ___% of serum albumin and skeletal protein may be considered protein reserve
• Body proteins are ___________ for energy under starvation or prolonged exercise
– May also be catabolized for biosynthesis of other more important proteins
capillary
5
catabolized
Unit 7: Macronutrients - Protein
Why aren’t proteins readily catabolized for energy (like fat and carbs?)
Most proteins are _________ proteins and enzymes… We NEED them
structural
Unit 7: Macronutrients - Protein
Major Functions of Proteins • Enzymes--Are all enzymes proteins? • Hormones--Are all hormones proteins? GH, insulin, glucagon, ACTH, etc • Contractile proteins--Actin, myosin • Transporters--\_\_\_\_\_\_\_\_\_\_ (O2 and CO2), Lipoproteins (lipids) Retinol binding protein (Vit A) • Structural proteins--\_\_\_\_\_\_\_\_\_, keratin, elastin, etc
Hemoglobin
Collagen
Unit 7: Macronutrients - Protein
Functions of Amino acids
- Precursor for _________ and _______= Conversion to glucose to maintain blood glucose level or make fat… all a.a. are glucogenic EXCEPT Leu and Lys
- Energy: Glucose-Alanine cycle = Minor source of energy
gluconeogenesis
lipogenesis
Unit 7: Macronutrients - Protein
Functions of Amino acids
Biosynthesis of nucleic acids, DNA, RNA __________, glycine, aspartic acid (and others) are required
• Precursors of specialized products: carnosine, SAM, NTs, melanin…
______________ (Phe»>Tyr), serotonin (Trp), melanin (Tyr)
Glutamine
Catecholamines
Unit 7: Macronutrients - Protein
Functions of Amino acids
• Biosynthesis of heme (therefore hemoproteins)
__________, essential for hemoglobin and others
Glycine
Functions of Amino acids
Biosynthesis of GAGs (therefore ___________) Glutamate & Glutamine»>Glucosamine
• Biosynthesis of sphingolipids = ________
proteoglycans
Serine
Functions of Amino acids
Biosynthesis of peptides and proteins
Biosynthesis of certain amino acids from other
amino acids
Antibody production for immune system
Know
Glucose-Alanine Cycle: Use of amino acids for energy
• Overview:
When muscles produce lactate during times of
decreased oxygen, they also produce _______.
***__________ gets shuttled to liver to make glucose
-Recycles ________ ________ between muscle and liver
-Transports ammonium to the liver»>converted to _______
alanine
Alanine
carbon skeletons
urea
Glucose-Alanine Cycle: Use of amino acids for energy
- Protein is NOT a major source of ______
- Protein is primarily metabolized during __________ (when demands for energy are higher)
- Protein used comes from skeletal muscle protein
energy
exercise
Summary of the Alanine Cycle
During extended periods of _______, skeletal muscle is degraded as an alternative source of energy.
• _________ is the major amino acid present when muscle (protein) is degraded.
fasting
Alanine
Summary of the Alanine Cycle
The glucose-alanine cycle occurs in skeletal muscle to eliminate ________ while replenishing (renewing) the energy supply for muscle.
nitrogen
Summary of the Alanine Cycle
The amino group transported from the muscle to the liver in the form of alanine, is converted to urea in the urea cycle and ________.
excreted
Glucose-Alanine Cycle: Use of amino acids for energy
After a high protein meal, the branch-chain amino acids find their way to ____ _____ and incorporate into muscle proteins
Branch-chain amino acids: Val, Leu, Ile
skeletal muscle
Glucose-Alanine Cycle: Use of amino acids for energy
During exercise (or gluconeogenesis), their carbon skeletons are needed to make glucose ...so they are \_\_\_\_\_\_\_\_\_\_\_
deaminated
Reactions in SKELETAL muscle
• In muscle cells and other peripheral tissues,
glycolysis produces ________.
• Pyruvate can be __________ to alanine.
• The alanine then enters the blood stream and is transported to the liver.
• Alanine is returned to the liver for _________________.
pyruvate
transaminated
gluconeogenesis
Reactions in the LIVER
Within the liver, alanine is converted back to
pyruvate by ___________.
• ___________ is a source of carbon atoms for gluconeogenesis.
deamination
Pyruvate
Reactions in the LIVER
_______________ converts pyruvate to form
glucose.
• The newly formed glucose can then enter the
blood for delivery back to the muscle.
• This pathway is termed the __________________ cycle
Gluconeogenesis
glucose-alanine
Daily Requirement Either of the following criteria can be used:
1. FNB – By age and average body weight • Up to 7 months:\_\_\_\_\_\_g /kg body weight • > 7 months \_\_\_\_\_g / kg (WHO recommends 0.75g/kg) – By % of daily energy need • Children 1-3: 5-20% kcal • Children 4-18: 10-30% kcal • Adults: 10-35% kcal 2. Dietary Guidelines for Americans – Adult: 10% of total daily kcal need
- 0
0. 8
Protein Deficiency
• Causes: – \_\_\_\_\_\_\_\_\_\_ Causes: • Economic deprivation • Improper practice of vegetarianism – \_\_\_\_\_\_\_\_\_ Causes: • GI Disorders • Allergy to protein-containing foods
Primary
Secondary
Protein Deficiency–Consequence: Protein-Energy Malnutrition (PEM)
– ____________: “Disease of the first child when the second child comes”
• Due to chronic ________ deficiency
• Signs/Sx: Weakness, edema, loss of hair, skin lesions, diarrhea, fatty liver, recurrent infections (MCC death is ___________).
Kwashiorkor
protein
infection
Protein Deficiency–Consequence: Protein-Energy Malnutrition (PEM)
________________: Total deficiency of all ergogenic macronutrients (C, P, F)
• No edema. Leads to TOTAL loss of body mass
Marasmus
Protein Excess
Excess protein leads to loss of _______ and osteoporosis in old age.
In western Europe and US protein intake is ~1.5-2x WHO recommendation
Ca2+
Protein Excess
Test =__________________ to determine if protein intake is excessive.
Normal:___-____ mg/dL (Upper limit: ___ mg/dL)
Blood Urea Nitrogen (BUN)
10-14
21
Protein Excess
High protein meals do NOT enhance myofibril synthesis with resistance exercises in the elderly.
Protein foods from animal sources are rich in saturated fats and cholesterol (___________)
atherosclerosis
Protein Excess
Daily intake of 1.6-2.9 g/kg resulted in:
Increased insulin secretion, but DECREASED sensitivity to insulin (diabetes), renal excretion of acid, oxalate (kidney stones), calcium (hypercalciuria), bone resorption (_________), increased GFR, liver glucose output.
osteoporosis
Protein Excess
High protein intake (+) correlated with INCREASES in GFR, __________ loss (increased PO4 and SO4), middle and forearm fracture, albuminuria, DM, renal cell and prostate cancer
Calcium
Protein excess and weight lifting
Excess protein=excess calories
– adds weight as FAT, NOT muscle
(slows down performance)
• Intakes >___% of calories or 2 grams protein/ kg of body weight
– burned for energy
– converted to fat
– Used for primary and structural roles (not muscle mass)
15
Protein excess and weight lifting
Muscle mass: High protein diets have NEVER been shown to be uniquely beneficial to athletes; muscle size is NOT determined by protein intake
– Muscle size is determined by:
• Training techniques
• __________
Genetics
Nutritional Quality of a protein food
All ergogenic nutrients supply C, H, & O, but only protein supplies ________ (in the form of amino acids).
– On average, ____% protein is nitrogen
nitrogen
16%
Nutritional Quality of a protein food
A good “______ _________” is one that is well- digested, absorbed, & retained by the body
Methods for determination:
1. Biologic value (BV), %
2. Net Protein Utilization (NPU), %
3. Protein Efficiency Ratio (PER)
4. Protein Digestion-Corrected Amino Acid Score (PD-CAS)
quality protein
Nutritional quality of a protein food
1. Biologic value (BV), % = Measures __________ of protein in the body
NOT digestibility or __________
retention
absorbability
Nutritional quality of a protein food
- Net Protein Utilization (NPU), %= Measures retention of protein in the body. Assumes ALL proteins are __________ & absorbed
digested
Nutritional quality of a protein food
- Protein Efficiency Ratio (PER) =
Average daily wt. gain (g)/ Daily protein consumed (g)
***_______ _________ amount of testing protein (along with adequate amounts of other nutrients) to growing lab animals for a given period of time (e.g. 10 days)
Feed controlled
Nutritional quality of a protein food
- Protein Digestibility-Corrected Amino Acid Score (PDCAAS)
Analyze levels of amino acids in protein, then correct for _________ ________
To determine _____ the protein provides the daily requirements of the essential amino acids as recommended by the RDA.
By this method, _________ protein is a complete protein, even though its BV and NPU are not very high
digestibility factor.
how
soybean
Animal Protein: ADVANTAGES
• Complete protein source
• Higher BV, PER, & NPU; tied with soy for PDCAAS
• These numbers indicate that animal protein is better than plant –derived protein as it offers more
– nitrogen-retaining,
– anti-________, and
– muscle building activity
-catabolic
Animal Protein: DISADVANTAGES
A–Excessive protein
- –Loss of bone calcium = ___________;
- -Impairs —-kidney function/ kidney stones ——–_____________
B—Fats and Cholesterol
- -Increase risk for _____ _______, strokes, cognitive impairment, mental diseases (dementia, Alzheimer’s)
- -Increase risk for some cancers (breast, lung, colon, kidney, brain, prostate)
osteoporosis
Dehydration
heart attack
Plant Protein: Advantages
May reduce risks of certain cancers (No cholesterol or SAFA) • Lowers blood cholesterol levels • High in \_\_\_\_\_\_\_\_, vitamins and minerals, complex carbohydrates, and \_\_\_\_\_\_\_\_\_\_\_ (reduce oxidative stress from exercising) • Soy is a complete protein
fiber
antioxidants
Plant Protein: Advantages
___________: soy protein is identical to that of egg whites and
casein; higher than proteins in beef and plant sources
• ____________ (antioxidant function)
• ______________ function: prevents CVD and osteoporosis
PDCAAS
Isoflavonoids
Phytoestrogen
The elite athlete diet (during training/competition):
Between ___-______ g protein/kg body weight
• Most protein from lean meat, eggs, casein, and whey protein (______= most popular supplement)
• 6-7 small meals/day (solid meal= concentrated protein source + fibrous vegetable; liquid meal= shake w/whey protein. Every fourth day, add more complex carbs (yams, oatmeal, brown rice, beans)
• Many abstained from red meat; no alcohol; no additives other than spices (no salt, sugar, dressings, soy sauce, etc.)
1–4
whey
Practical Issues
• Is amino acid supplementation valid?
Evidence is lacking to support claims of taking basic amino acids to REDUCE body fat.
Use of _____ as supplements in sports may be valid because they are the major ______ amino acids of muscle proteins, and can be used as an ______________ in prolonged exercise in glucose-alanine cycle.
BCAA may increase testosterone, increasing protein
BCAA
structural
energy source
Practical Issues • Creatine monohydrate
- Supplement to increase muscle protein synthesis, however, no scientific evidence for it.
- May increase __________ power (high-intensity, short endurance), muscular strength and endurance, and may spare lean tissue
- Synthesized from Arg, Gly, S-AM
- Converted to ______________ for energy storage
- Side effects: weight gain (water), cramping, dehydration, diarrhea, dizziness
anaerobic
creatine phosphate
Practical Issues • Aspartame (Nutrasweet)
- An artifical ________ sweetener (4 kcal/g)
- Metabolized to Aspartate, _______ & Methanol
- People with PKU must NOT eat it
- Side effects: Headache in some people
di-peptide
Phenylalanine
Practical Issues
• ______________: a risk factor for atherosclerosis.
Homocysteinemia is an independent risk factor for _____________.
Can be lowered by dietary and supplemental _______, vitamins B6 and B12 for the prevention of CVD or stroke
Homocysteine
atherosclerosis
folate
Focal Points
- While animal protein is a complete protein that is easily absorbed by the body, it has been linked to numerous chronic diseases: osteoporosis, kidney problems, heart attack, stroke, cognitive impairment, and _______.
- Plant-protein can aid in the prevention of many diseases, lower cholesterol, fight against cancer, relieve ________ stress during exercise, and boost __________.
cancer
oxidative
metabolism
Focal Points
_____ is a complete source of protein that offers many advantages in health promotion.
- While body builders have achieved optimal performance with the use of animal proteins, many vegetarian and vegan body builders have achieved similar success.
- Plant protein provides all the essential amino acids to meet nutritional needs; the key to a healthy vegetarian diet is _________!
Soy
VARIETY
Focal Points
- Protein needs for endurance athletes: 1.2-1.4 g/ kg body weight; for body building athletes: ___-_____ g/kg body weight.
- The average athlete gets more than enough protein to adequately train (for both endurance and body building competitions).
- Excess protein adds excess ______ (since the primary fuel of our bodies during activity is glucose and then fat) which adds _____, hindering athletic performance
1.6- 1.7
calories
FAT
