Download Proteins- Fall 13

PROTEINS
Chapter 5
Learning Objectives
• Describe the structure and functions of
protein
• Explain how the body uses protein
• Discuss the quality and quantity of protein
necessary in the diet
• Give examples of complementary
proteins
Learning Objectives
• Describe the unique nutritional benefits of
legumes
• Distinguish between animal and plant
proteins
• Plan diets with proteins coming from animal
and vegetable sources
• Identify appropriate portions of protein
foods per serving and for daily consumption
Food Protein Sources (grams)
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3 oz meat = 21-28
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1 oz meat = 7-8
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1 cup milk = 8
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1 cup yogurt = 8
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2 T. peanut butter = 7
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1 egg white = 7
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½ c nuts/seeds = 7
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½ legumes/beans = 7
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½ cup grain = 3
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1 slice bread = 3
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½ cup veg = 2
1 cup soy milk = 8
1 oz. tofu = 8
½ cup meat substitute = 7
Veggie Burger = 14
Scoop of protein powder = 14-25
Protein Bars- 7-14
MyPlate- 76 grams
Protein Sources are also
sources of…..
Iron
 B-vitamins (thiamin, niacin, riboflavin, B-6,
B-12)
 Zinc
 Magnesium and vitamin E (nuts/seeds)
 Fiber (legumes)
 Omega 3 fats (fish, eggs)

How the Body Uses Protein
• Muscles, organs, blood, bones, nails, hair
and skin are mostly protein
• Proteins in the blood help transport
nutrients and oxygen
• Antibodies, enzymes and hormones are
composed of proteins
How the Body Uses Protein
• Necessary for blood clotting
• Necessary to maintain acid-base balance
within cells
How the Body Uses Protein
• Energy

1 gram of protein = 4 calories
• Used as fuel after carbohydrate and fat
How the Body Uses Protein
• Body breaks down protein in muscle
tissue if:
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Calories very low
Prolonged physical activity
High fever
Severe burns
Some diseases
Protein Structure
• Amino acids (20) are the building blocks
of protein that contain nitrogen in the
chemical structure


Essential amino acids (8 or 9)
 Cannot be produced by the body
 Must be provided by food
Nonessential amino acids
 Can be made by the body from essential
amino acids
Amino Acids
Essential Amino Acids
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Nonessential Amino Acids
Alanine
Arginine
Aspargine
Aspartic Acid
Cysteine
Glutamic Acid
Glutamine
Glycine
Proline
Serine
Tyrosine
Protein
Made of amino acids
combined in a specific
sequence
• Large, complex chemical
structures

Protein Digestion
• Proteins from food
are broken down
into separate
amino acids and
then absorbed
into the body
Hemoglobin
Protein Digestion
• Digestive enzymes
break protein down


Proteases
Pepsin
• 50,000 different
proteins are created in
cells from amino acids
in the bloodstream
Hemoglobin
Complete Proteins
• Foods that provide all essential amino
acids in amounts to support growth and
maintenance of body tissues
• High biological value
• Primarily from animal sources
Complete Proteins
• Foods:
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Meat
Fish
Poultry
Cheese
Eggs (perfect amount and variety of amino
acids)
Milk
Isolated soy protein
Incomplete Proteins
• Foods that lack one or more of the
essential amino acids in sufficient quantity
to support growth and maintenance of
body tissues
• Have one or more limiting amino acids
• Lower biological value score
• From plant sources
Incomplete Proteins
• Foods:
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Grains
Legumes
Nuts
Seeds
Vegetables
Complementary Proteins
• Combining foods that complement limiting
amino acids
• The combination of plant protein foods
which when eaten together provide all
the essential amino acids.
Complementary Proteins
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Cereal grain and legumes
 Hummus and pita bread
Grain and beans
 Black beans and bulgur
 Tofu and rice
Nuts and grain
 Nut butter sandwich
A small amount of complete protein makes
an incomplete protein complete
 Cheese and pasta
 Pork and beans
Protein Recommendations

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Body weight
Grams per kg of body weight
 170 pounds ÷ 2.2 = 77.2 kg
 77.2 kg x .8 gram/kg = 62 grams protein a day

Adults- .8 grams/kg (RDA)

Infants- 2.2 grams/kg
Teens- 1.8 grams/kg
Older Adult- 1.3 grams/kg
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Malnourished, Health Issues- 1.5-3.0 grams/kg
Athletes- 1.2 - 2.0 grams/kg
Protein Needs
• World Health Organization: 40 grams
protein
• Dietary Guidelines for Americans:
• 10 -35 % of calories from protein
• 2000 calories
• 50-175 grams/day
Protein and Health: Too Much Protein

High protein foods are often high in fat
and cholesterol
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Few high protein foods are low-fat foods
No extra health benefit
VERY high protein may decrease calcium
absorption and increases work of kidney
and liver to process
Protein and Health: Too Much Protein
cont.
• Very high protein, very low carbohydrate
diets are difficult to maintain and are not
usually nutritionally adequate
• High-protein foods are usually more
expensive
Protein and Health: Too Little Protein
• Protein Energy Malnutrition (PEM)
• Marasmus

Severe protein-calorie malnutrition
• Kwashiorkor
• Seen in children in underdeveloped countries
 Severe protein malnutrition but with enough
calories from starchy foods
 Probably not a nutritional problem; due to
aflatoxins in the grains eaten
Protein and Satiety
• Protein is more
satiating than
carbohydrate diet
• Protein reduces
hunger
Protein Equivalents
• MyPlate: 1 ounce protein equivalent = 7
to 8 grams protein
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1 ounce meat, poultry, fish
¼ cup cooked beans
1 tablespoon peanut butter
½ ounce nuts or seeds
Protein Sources: Meat
• Generally, meats
compared in 100 gram or
3 ½ ounce servings
• Cuts from loin and round
are often leanest
• Check ground meats
•%
• 80 vs 90%
Protein Sources: Meat
• Most sausages,
spareribs, short
ribs are high in fat
• Game meats are
often low in fat
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Venison
Buffalo
Protein Sources: Poultry
• Lighter meat is lower in
fat
• Much fat under the skin
• Skin can be removed
before or after cooking
Protein Sources
• Goose and duck is higher in
fat that chicken or turkey
• Protein not very different in
free-range, organic, kosher,
without hormone or other
methods of raising
Protein Sources: Seafood
• Most seafood is high
in excellent quality
protein
• Most seafood is
either low in fat or
high in heart-healthy
fat
Protein Sources: Eggs
• Egg protein is of highest
biological value
• Egg white is low-fat
protein
Protein Sources: Eggs
• Omega-3 eggs are
produced by feeding
fishmeal to chickens,
usually cost more
• Shell color does not
influence nutrients
Protein Sources: Dairy
• 3 cups or equivalent
for most adults
• Low-fat, non-fat
• Yogurt, especially
Greek yogurt
Protein Sources: Milk Substitutes
• Soymilk is usually protein-rich
• Nut, hemp, oat and grain milk is usually low in
protein
• Some milk substitutes are fortified with calcium
and vitamin D
Protein Sources: Legumes
• Soy protein availability is limited in raw
product.
• tofu or well-cooked allow protein
digested
• Textured vegetable protein (TVP) and
isolated soy protein are good sources for
vegans
Protein Sources: Nuts and Seeds
• Nuts, nut butters,
seeds have protein
and fiber
• Most are high in
heart-healthy fats
and high in calories
• 1 ounce is only a
few nuts but a large
portion of seeds
Protein Sources: Grains
• The limiting essential amino
acid is generally lysine
• Eat with legumes for
complementary protein
• Kamut and teff are highest
in protein
Protein in Cooking
• Denaturation
 Change in chemical structure of protein
by heat, whipping or adding salt or
acid
• Coagulation
 Protein strands break and re-bond,
releasing water
Protein in Cooking
• Gluten

Protein in wheat. Gluten is the protein that
influences texture and structure of dough
• Amino acids are sometimes used as
ingredients
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To boost nutrients
As flavor enhancers
Made into sweeteners
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Vegetarians
Vegetarians – Types
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Strict vegetarian,
vegan
Excludes all animal products including meat, poultry, fish, eggs, milk,
cheese, other dairy products, ingredients from animal sources such as
gelatin.
Lacto-vegetarian
Excludes meat, poultry, fish and eggs but includes dairy products.
Lacto-ovo
vegetarian
Excludes meat, poultry and fish but includes eggs and dairy products.
Most vegetarians in the United States in this category.
Raw vegan
Includes raw vegetables and fruits, nuts and nut pastes, grain and
legume sprouts, seeds, plant oils, sea vegetables, herbs and fresh juices.
Excludes all food of animal origin, and all food cooked above 118° F.
Flexitarian
A mostly vegetarian diet with an occasional meat consumption – “semi”
or sometimes vegetarian.
Pescetarian
A mostly vegetarian diet that includes fish and shellfish but excludes
mammals and birds.
Meeting the Needs of Vegetarians
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Key nutrition points
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Include a variety of foods including whole
grains, legumes, nuts and seeds, fruits and
vegetables
Nutrients of concern that may be limited
include
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Protein
Vitamin B12
Calcium
Iron
THE END!
Chapter 5