UNIT 7: MACRONUTRIENTS--PROTEIN Flashcards by ROGER ALONSO

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

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Unit 7: Macronutrients - Protein

“__________” Amino Acids: cannot be synthesized by the body.

Essential

PVT TIM HLL

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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

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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

catabolized

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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

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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

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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

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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

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Unit 7: Macronutrients - Protein

Functions of Amino acids

• Biosynthesis of heme (therefore hemoproteins)
__________, essential for hemoglobin and others

Glycine

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Functions of Amino acids

Biosynthesis of GAGs (therefore ___________) Glutamate & Glutamine»>Glucosamine

• Biosynthesis of sphingolipids = ________

proteoglycans

Serine

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Functions of Amino acids

Biosynthesis of peptides and proteins

Biosynthesis of certain amino acids from other
amino acids

Antibody production for immune system

Know

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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

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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

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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

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Summary of the Alanine Cycle

The glucose-alanine cycle occurs in skeletal muscle to eliminate ________ while replenishing (renewing) the energy supply for muscle.

nitrogen

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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

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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

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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

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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

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Reactions in the LIVER

Within the liver, alanine is converted back to
pyruvate by ___________.

• ___________ is a source of carbon atoms for gluconeogenesis.

deamination

Pyruvate

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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. 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)

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 2. Net Protein Utilization (NPU), %= Measures retention of protein in the body. Assumes ALL proteins are __________ & absorbed

digested

Nutritional quality of a protein food 3. 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 4. 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