Transcript protein - Nutrition Educators of Health Professionals

PROTEIN
Proteins and Amino Acids
Made of carbon, hydrogen,
oxygen, and nitrogen
 Amino group (NH2) &
Carboxylic group (COOH)
make backbone
 Side groups make the difference

Side Chain
Peptide
Bond
Backbone
Leucine
COOH
Tyrosine
NH2
Amino Acids
Linked in certain sequence
 dipeptides = 2 A2
 tripeptides= 3 A2
 polypeptides= 4 or more
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most contain hundreds of A2
A2 = Amino Acids
Structures
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Primary
–
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Secondary
–
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Shape along one dimension
Tertiary
–
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Unique sequence
3-dimensional shape
Quaternary
–
Joining of 2 or more 3-dimensional
polypeptides into larger protein molecules
Essential Amino Acids
Cannot be synthesized
 Nine A2 are essential
 Some nonessential are essential
during stress

–
glutamine, alanine, carnitine
Peptide bonds join A2
 Body protein makes you different

Protein
Part of every cell
 Do cell’s work
 Determine nutritional status
 Part of antibodies
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enzymes
hormones
structural materials
Protein Function

Repair and building
–
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collagen mending material
Energy if not enough CHO
–
supplies 4 kcal/g
Enzymes
All are proteins
 Function as catalysts
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join and dismantle
Unchanged during enzymatic action
Fluid Balance
Maintain body’s fluid balance
 Fluids are in 3 major compartments
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inside blood vessels
within cells
surrounding cells
flow is back and forth
Fluid Balance
Proteins and minerals in fluids help
to maintain distribution among
spaces
 Albumin is big regulator
 Maintains osmotic pressure
 Prevents fluids from leaking out of
cells into intercellular spaces

Fluid between cells
Intercellular or Interstitial
Fluid within the Cell
Intracellular
Fluid within blood vessels
Intravascular
Acid-Base Balance
Albumin and friends prevent
imbalances
 Acids and bases created by normal
body functions
 Removed by kidneys (bicarb)
or lungs (carbonic acid)

Acid-Base Balance
If kidneys and lungs fall behind,
proteins gather or release
extra H2 ions
 Called buffering
 Why?

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Too much acid or alkaline can denature
protein
Cooking is also a way of denaturing
Acid-Base Balance
pH tightly regulated
 Imbalances are acidosis or alkalosis
 Can be respiratory or metabolic

pH of selected substances
Battery
Acid
Gastric
Juice
pH <1
Death
pH <2
Alkalosis 6.8-
Water
pH ~7
Blood
pH ~8
Lye
pH~14
<6.8
7.34
Normal 7.457.35
Alkalosis 7.468.00
Death
>8.00
Protein Function
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Antibodies
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Messenger
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against viruses and bacteria
thyroid and insulin
Transport proteins
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move nutrients in and out of cells
hemoglobin and lipoproteins
carry vitamins and minerals
DNA
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Deoxyribonucleic acid-in every cell
Genetic codes in DNA
Metabolic pool
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A2 not stored
Limited amount available in Metabolic pool for
“daily use”
Protein Turnover
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Constant breakdown/synthesis of endogenous
proteins
Exogenous=from food
Endogenous=from protein tissues
Nitrogen Balance
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Positive N2 balance or equilibrium
means eating what you need
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growth, pregnancy, healing
+2-4 g/day
Negative N2 balance means not
enough protein or CHO
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stress and trauma
auto digestion of muscles and organs
Energy
Energy of last resort
 No specialized storage form
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Only muscles and organs
Energy deprivation or starvation
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Wasting of lean body tissue
Fat loss
Protein Energy Malnutrition
PEM or Protein Calorie Malnutrition
 Most widespread form of
malnutrition in world
 Cause of 50% of infant deaths in
developing countries
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Marasmus
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Chronic condition
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Low Kcal intake
Little subcutaneous fat
Lethargic and weak
Protein tissues preserved secondary to
adaptation
Marasmus
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Initial treatment IV or oral glucose
followed by liquids
Vitamin and mineral supplements
Solids as part of a soft diet
Limit kcal to 25 kcal/kg for 1st week
Increase to 30-35 kcal/kg
Kwashiorkor
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Complex syndrome
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Deficient protein in most cases
Catabolic, oxidative, or toxic stressors also to
blame
More correct as syndrome of protein
dysmetabolism
Edema thought to be from alteration in
capacity to manage salt
Kwashiorkor
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Correct protein deficiency
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2 methods in literature
Adequate protein with adequate nonprotein kcal for protein sparing
High protein diet – 2.5 to 3.0 grams/kg
Excess
Increase risk of colon Cancer
 High protein, Low CHO
=poor bone health
 Amino Acid supplements are
unnecessary
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eat more high protein, low fat foods
To build muscles-exercise, adequate
kcal, and adequate protein
To BUILD muscles

Extra Exercise
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Average Protein
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Extra kcal from carbohydrates
Protein Needs
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Needs Increase with
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growth
start of an exercise program
Kcal restriction (dieting, anorexia)
Depleted glycogen stores
Requirements
Minimum 0.6 g/kg
 Normal 0.8-1.2 g/kg
 10-20% of total Caloric intake

Protein
Found in milk, vegetables, meats,
and starches
 Trace amount in fruit
 None in pure fat
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Amino Acids
Food proteins start as polypeptides
 Broken down to A2 by digestion
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casein = milk and cheese
albumin = eggs
gluten = wheat
Cause of food allergies
Protein and Foods
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Body Builder, 200 lbs.
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Marathon runner, 150 lbs.
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~140-180 g protein day
90-135 g protein day
Young gymnast, 80 lbs.
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72 - 80 g protein day
Protein Sources
1 cup low fat milk or yogurt = 8 g
 1 oz. Cheese = 8 g
 2 T. Peanut Butter = 8 g
 2 large eggs = 12 g
 4 oz chicken or beef = 30 g
 1 can tuna = 40 g
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Protein
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Complete proteins
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Incomplete proteins (limiting AA)
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contain all essential
animal sources
missing some essential
plant sources
Complementary proteins
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matched to provide all essential
Complementary Proteins
Black beans and rice
 Peanut butter and wheat bread
 Tofu and stir fried vegetables
 Vegetarians usually eat enough
complementary proteins over
course of one day

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want lots of variety
Vegetarian Diets
Vegans-only eat plant foods
 Lacto-vegetarians-includes dairy
 Lacto-ovovegetarians-includes dairy
and eggs
 Nutrients of concern
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Iron and zinc
Calcium and Vitamin D
Linolenic Acid and Vitamin B12
Supplements
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Hydroxicitric Acid (Ultra Burn)
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Modified form of citric acid
Effectiveness not proven
Chitosan (Fat Trapper)
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plant fiber plus chitosan
potential to impair absorption of fat
soluble drugs
Supplements
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Conjugated Linoleic Acid
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Ephedrine (Metabolife, Diet fuel)
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Not effective
Increase BMR, can cause stroke/chest
pain/seizures
Pyruvate (Exercise in a Bottle)
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Effective dose $300 per day
Study used kcal control diet/ experimental
group lost 3.5 pounds more
At the Olympics
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Aranesp or Epoetin
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Indicated for treatment of anemia
associated with chronic renal failure
Helps build red blood cells
Similar to getting a transfusion prior to
an event
Not illegal yet
Caffeine

Limit: 12 mcg caffeine/ml urine
8 Coffees
 16 Colas
 24 Anacin
 4 Vivarin

Safe and effective
dose: 2.5 mg
caffeine/lb/bw
2-3 cups coffee
as tolerated
Caffeine and Exercise
Pro: May make exercise seem easier
and enhance performance
 Con: May cause upset stomach,
nervousness
 Each person responds differently
 Know YOUR BODY!
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Creatine
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Loading (5-7 days) = 20-25g/d
–
0.3g/kg
Dose 5 g q 3-4 hours, take with food
 Maintenance = one 5 g dose/ d
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0.3 g/kg
Unknown long term side effects
 Caution if renal disease, cramping,
GI distress
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L-carnitine
Promoted to increase fatty acid
oxidation
 Studies have failed
 Supplementation probably not
necessary
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Chromium
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Enhances transport of glucose into the
muscles; enhances insulin’s effect if
chromium deficient.
No benefits seen in professional research
with football players or novice body
builders.
RDI: 200 mcg (cheese, mushrooms,
chicken, corn, beef)
Excess can create mineral imbalances
Supplements
Recommended to the President’s
Council that no NCAA member
institution should supply “dietary
supplements” to athletes
 The dose makes the poison.
 Natural is not always safe.
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