Chapter 6: Proteins

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Chapter 6 Proteins
Contemporary Nutrition Issues and Insights

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Sources of Protein
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Protein in Foods
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Functions of Proteins

Protein has four primary functions
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1. Provides Structure

• Building block for body components
• Protein comprises 20 of muscle tissue which
  makes up about 50 of our body

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2. Helps With Regulatory Processes

• Functional proteins are synthesized
• Hormones messengers that turn on actions
• Enzymes cause a metabolic reaction
• Antibodies prevent infection
• Neurotransmitters generate and transmit nerve
  signals

• Fluid Balance
• Acid-Base Balance

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3. Transportation and Storage

• Bind with lipids to form Lipoproteins
• Carries fat in blood stream
• Hemoglobin
• Part of RBC that binds with O2 from lungs and
  helps to transport it to cells
• Iron
• Storage of certain minerals

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4. It CAN Provide Energy

• 4 kcal/gm
• Gluconeogenesis

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Essential and Nonessential Amino Acids (Table 6-1)
come from diet
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Amino Acid
NH2 O
R C C
OH H
R group
Acid group Amine group
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High-Quality Protein

• Complete protein
• Contains ample of all 9 essential amino acids
• animal protein

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Low-Quality Protein

• Incomplete protein
• Low or lacking in one or more essential amino
  acids
• Limiting amino acid
• Plant protein

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Limiting Amino Acid
C is the limiting amino acid in this example

• CCCCC
• AAAAAAAA CAR CAR CAR
• RRRRRR CAR CAR
• 
  R
• A A
  A

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Complementary Protein

• Two low-quality proteins combined
• Complete protein from the combination
• Legumes grains
• Legumes nuts/seeds
• Vegetables grains
• Vegetables nuts/seeds
• Corn legumes

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Complementary Protein
Food 1 Food 2
CC CCCC AAAA AA
CAR CAR CAR RRR RRR
CAR CAR

CAR
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Sickle Cell Anemia

• One amino acid is out of order
• Genetic disease
• Changes the hemoglobin structure

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RDA for Protein

• 10-15 of total kcals or for sedentary person,
• 0.8-.9 gm of protein / kg of healthy body weight
• 154 lb. 70 kg
• 2.2 kg/lb.
• 70 kg x 0.8 g protein 56 g protein
• kg healthy body wt

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How Much Food Do We need To Eat To Meet Our Needs?
60kg X 0.8gm Equates to 8 oz glass
milk.......................2 servs.............16
gms meat.......................................4
oz .................21 gms fruits/veg..........
......................7 serv...............16
gms Grains....................................6-
11 serv.....12-22 gms TOTAL intake
65-75 gms

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RDA for Protein

• Increased by 10-15 gm /day for pregnancy
• Endurance athletes may need 1.2 1.4 gm/kg
  healthy weight Lemon et al, 1994
• Strength Trainers may need 1.7-1.8 gm/kg Lemon et
  al, 1994
• Most of us eat more than the RDA for protein

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Protein Needed to Maintain CURRENT Muscle Tissue
for High LBM

• Muscle is 21 protein (structural), 68 water and
  11 connective tissue etc.
• Research shows that we only need 1.27 amt of
  structural protein over 6 months to replace
• 180 guy who has 11BF
• 180 X .11 20fat 180 - 20fat 160 FFM
• 160 X 21 (structural protein) 33.6 actual
  protein
• 33.6 X 1.27 42.67 protein needed over 6 mos to
  maintain/replace what you have
• 42.67 / 180 day 108 g/day or 1.3g/kg BW

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Protein Needs for EXERCISERS!
60kg X 1.8gm Equates to 8 oz glass
milk.....................4 servs...........32
gms meat.....................................8
oz ...............42 gms fruits/veg.............
.................7 serv.............16
gms Grains..................................6-11
serv.22 gms TOTAL intake 112
gms
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Protein Supplements
AA supplements BCAA Whey, Casein or Soy? Growth
Hormone
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Is A High-Protein Diet Harmful?

• Intake of animal protein increases risk for heart
  disease
• Excessive intake of red meat is linked with colon
  cancer
• Increase calcium loss
• Burden on the kidney
• Increase fluid needs
• National Academy of Sciences recommend no more
  than 2 x RDA (.8g/kg) for protein

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Protein Malnutrition

• Protein-Energy Deficiency
• Marasmus
• Kwashiorkor

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Kwashiorkor (Fig. 6-7)

• Low protein density diet
• Energy needs are marginally met
• Signs and symptoms
• Apathy, listlessness, failure to grow, poor
  weight gain, change in hair color, nutrient
  deficiency, flaky skin, fatty infiltration in the
  liver, massive edema in the abdomen and legs

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Marasmus (Fig. 6-8)

• Starving to death
• Insufficient protein, energy, nutrients
• skin and bones appearance
• Little or no subcutaneous fat
• Reduce brain growth

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Vegetarianism

• Why do it?
• Lacto
• Ovo
• Lacto-Ovo
• Fruitarian
• Vegan
• Deficiencies?

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Plant Protein

• Provide protein, minerals, and dietary fiber
• Contain no cholesterol
• Limited saturated fats
• Allow a few weeks for the GI tract to adjust to
  the higher fiber
• Availability of Beno

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Soy

• Soy protein is similar to animal protein (used in
  school lunches)
• High in linoleic acid and some ?-linolenic acid
• Calcium source and bone health
• Isoflavones
• Heart disease
• Cancer

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Vegetarian Food Guide Pyramid (Fig. 6-9)

• (Fig. 6-9)

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Concerns

• Vitamin B-12
• Iron
• Calcium
• Complete protein
• Weight/Health Guarantee?
• Children vegetarians
• kcal needs
• protein needs
• nutrient needs

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Low Carb Diets Hi Protein Consumption
LC Diets dont profess to be high protein Some
even say that they arent If you cant eat carbs,
then fat and protein are left SO? Diets are
either high fat/protein or low kcal Usually start
as high fat/protein and end as very low
kcal Result? weight loss (LBM, Water, SOME fat)
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Protein Power Plan

• CHO intake restricted
• 30 gms, 55 gms, or protein intake without
  exceeding gt30 of protein intake
• Protein prescription based on subjects fat-free
  mass and activity level
• Diet focuses on protein and carbohydrate intake
  rather than total calories or fat intake
• Subjects required to consume at least 25 gms
  fiber
• Subjects advised to engage in aerobic and
  resistance training
• Subjects required to consume at least 2 qts water
  per day (before meals) and keep food/exercise log

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Example of PPP Diet

• Breakfast 1 egg 1 egg
• white, scrambled .5 oz.
  Cheddar cheese .5 oz. Ham 1 slice ironkids
  bread 3 wheat thinsSnack 3/5 c. Broccoli
  flowerets 2 Tbl. Ranch dressing 1 oz American
  cheeseLunch 2 oz. tuna 1 TBl. Mayo 1 celery
  stalk 1 slice ironkids bread 1/2 cup
  strawberries

• Dinner Cabbage lasagna 1. 5 cup green
  beansEvening Snack 2 cups Sugar free Jello 4
  TBL. Lite cool whip

Total Kcal -1225. 91 Avg daily Protein
23 Avg daily CHO 22 Avg daily Fat
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Calculating Protein Needs

• How many grams of protein would a 70 kg male have
  to consume to meet the RDA? What if he were an
  endurance athlete?How many grams of protein would
  you have to consume according to RDAs on 1800
  kcal/day diet?
• 70 kg X 0.9gm/kg 63 gm protein
• 70 kg X 1.4 gm/kg 98 gm protein
• 1800 kcal/day X .12 216 protein kcals
• (RDA 12 total kcals in form of protein)
• 216 kcals/4 kcal/gm 54 gm protein per day