1. Lecture Outline Chapter 7
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2. Proteins Chapter 7
Insert photo of BBQ chicken from 1st page of chapter

3. Chapter Learning Outcomes
List the primary functions of proteins in the body.
Identify the basic structural unit of proteins.
Distinguish between essential and nonessential amino acids.
Explain the basic steps of protein synthesis and digestion.
Discuss conditions that contribute to positive nitrogen balance, negative nitrogen balance, and protein balance.

4. Chapter Learning Outcomes (continued)
Identify food sources of protein and foods that provide high and low quality proteins.
Plan meals and snacks that reduce animal protein intake.
Discuss the pros and cons of vegetarian diets.
Describe how protein-energy malnutrition (PEM) can affect the body.

5. Quiz Yourself True or False
Quiz Yourself True or False
Animal foods such as meat and eggs are almost 100% protein. T F
Foods made from processed soybeans can be sources of high quality protein. T F
An adult body builder should consume about five times more protein than a healthy adult who is not a body builder. T F
Registered dietitians generally recommend that vegetarians take amino acids supplements to increase their protein intake. T F
People can nourish their hair by using shampoo that contains protein. T F

6. 
How Did You Do?
False Animal foods such as meat and eggs contain some protein, lipids, and lots of water.
True Foods made from processed soybeans can be sources of high quality protein.
False An adult body builder does not need to consume about five times more protein than a healthy adult who is not a body builder.
False Registered dietitians do not generally recommend that vegetarians take amino acids supplements to increase their protein intake.
False Hair is composed of protein, not living tissue. Therefore, it cannot be nourished.

7. What Are Proteins? Complex organic molecules
Chemically similar to lipids and carbohydrates
Composed of carbon, hydrogen, oxygen, and nitrogen
The human body contains ~100,000 different proteins.

8. Variety of Protein Functions
All cells in the body contain proteins.
Specific types of proteins include:
Structural proteins in cartilage, ligaments, bones, hair, skin, and nails
Contractile proteins that enable muscles to move
Pigment proteins such as melanin determine color of eyes, hair, and skin
Clotting proteins that are needed for blood clotting

9. Functions of Proteins (continued)
Certain hormones are proteins
Hormones are chemical messengers that regulate body processes and responses.
Examples include insulin and glucagon.
Enzymes are proteins
Compounds that speed up (catalyze) chemical reactions without becoming part of the products.

10. Functions of Proteins (continued)
Transport proteins
Oxygen and many nutrients are transported by special proteins.
Proteins aid in fluid balance.

11. Fluid Balance and Proteins Proteins in blood, such as albumin, help maintain the proper distribution of fluids within bloodstream and body tissues.
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12. What is Edema?
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13. Acid-base Balance and Proteins
Maintaining the proper pH of body fluids
Blood and tissue fluid must maintain a pH of 7.35 to 7.45
Acidic - having an excess of H+
Too basic – not enough H+
Proteins act as buffers by accepting or releasing H+.

14. Amino Acids Proteins are made of smaller units called amino acids.
20 different amino acids in human proteins
Each amino acid is composed of:
An amino or a nitrogen-containing group
Amino group has nitrogen bonded to 2 hydrogen atoms
R-group (side chain) — varies with each amino acid
Acid group – acid portion

15. Amino Acid: Basic Chemical Structure
Insert Figure 7.2

16. Classifying Amino Acids
Essential Amino Acids
Cannot be made by the body, so must be supplied in the diet
9 of the 20 amino acids
Nonessential Amino Acids
Can be made by the body
11 of the 20 amino acids

17. The Essential and Nonessential Amino Acids
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18. Proteins in Foods
Nearly all foods contain some protein, but no natural food is 100% protein.
Animal foods typically have more protein than plant foods.
Seeds, tree nuts, and legumes supply more protein than fruit or the edible leaves, roots, flowers, and stems of vegetables.

19. Protein Contents of Some Commonly Eaten Foods
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20. What Are Legumes? Legumes Examples:
Plants that produce pods with a single row of seeds
Examples:
Soybeans, peas, peanuts, lentils, and beans
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21. Protein Quality High-quality protein Low-quality protein
Protein that contains all 9 essential amino acids in amounts that support growth
“Complete protein”
Most animal products and products made with processed soy
Low-quality protein
Protein that lacks or has inadequate amounts of one or more of the essential amino acids
Most plant foods (except processed soy)
and gelatin

22. What Happens to Protein in Your Body?
How Your Body Synthesizes Proteins
Cells assemble the 20 amino acids in specific sequences according to information provided by DNA.
Amino acids are connected by peptide bonds.
Peptides
Chains of fewer than 15 amino acids
Polypeptides
Proteins made of > 50 amino acids

23. What Is a Protein?
Each distinctive bead in the illustration represents a different amino
acid.
The “hook” that connects the “beads” represents a peptide bond.
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24. Peptide Bond
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25. Protein Synthesis
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26. A Protein Takes Shape
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27. Sickle Cell Anemia
If the DNA code is faulty, the wrong amino acid may be inserted into a protein. For example, sickle cell disease that affects red blood cells
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28. Protein Denaturation Denaturation
Altering a protein’s natural shape and function by exposing it to conditions such as heat, alcohol, acid, and physical agitation
Heat denatures the protein in raw eggs.
Acidic lemon juice “curdles” the protein in milk.
Hydrochloric acid denatures food proteins in the stomach, making them easy to digest.
Physical agitation includes whipping protein-rich foods (e.g., beaten egg whites).

29. Denaturation
Insert Figure 7.9

30. Protein Turnover Protein turnover Amino acid “pool”
Breaking down old or unneeded proteins into amino acids and recycling the amino acids
Amino acid “pool”
Amino acids that have not been incorporated into proteins
Endogenous amino acids
Those available from the amino acid pool
Exogenous proteins
Those from dietary sources

31. Transamination and Deamination
Transfer of nitrogen-containing group from an unneeded amino acid to a carbon skeleton, forming an amino acid
Deamination
Removal of nitrogen-containing group from an unneeded amino acid

32. Example of Transamination and Deamination
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33. The Liver and Deamination Ammonia (NH3) is converted to urea that the kidneys excrete in urine.
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34. Nitrogen Balance Nitrogen balance (or equilibrium)
Balancing nitrogen intake with nitrogen losses
Positive nitrogen balance
Body retains more nitrogen than it loses
Negative nitrogen balance
Body loses more nitrogen than it retains

35. insert Figure 7.12
Positive Nitrogen Balance Occurs during growth, pregnancy, recovery from illness, and as a result of certain hormones and resistance exercise

36. Insert Figure 7.12
Nitrogen Equilibrium Occurs when healthy adults meet protein and energy needs

37. Insert Figure 7.12
Negative Nitrogen Balance Occurs with  protein intake, kidney disease, blood loss, bed rest, fever, injuries, burns, or  thyroid hormone or cortisol

38. How Much Protein Do You Need?
Daily protein needs of healthy adults:
RDA = 0.8 g/kg body wt
Protein needs increase during periods of growth, pregnancy, lactation, and recovery from illness or injury.

39. Determining Protein Needs
Using the RDA formula of 0.8 g of protein/kg of body wt, what is the RDA for protein for a person weighing 165 lbs?
Convert weight in lbs to weight in kg
(165  2.2 = 75 kg)
Multiply kg of body wt by 0.8
75 X 0.8 = 60
Therefore, a person weighing 165 lbs will meet his/her RDA for protein by consuming 60 g of protein per day

40. Protein Digestion Protein digestion begins in the stomach.
Hydrochloric acid denatures proteins
Pepsin, an enzyme, digests proteins into smaller polypeptides.
Polypeptides enter the small intestine
The enzymes trypsin and chymotrypsin break down polypeptides into shorter peptides and individual amino acids.

41. Protein Absorption Absorption occurs in the small intestine
Absorptive cells release enzymes that digest most small peptides into individual amino acids.
Individual amino acids and some di- and tripeptides enter absorptive cells, where they are completely digested to amino acids.

42. After Absorption…
Amino acids enter portal vein and travel to the liver
Liver keeps some amino acids for its own use and releases others into general circulation.
Most proteins are digested and amino acids absorbed
Very little protein is eliminated in feces.

43. What Is A Food Allergy? Allergy
Inflammatory response resulting when body’s immune system reacts inappropriately to a substance that is typically harmless
Allergen — the offending substance
Most food allergens are proteins that escape digestion and are absorbed as whole proteins.

44. Common Signs of Food Allergies
Signs occur within a few minutes or couple of hours and typically include:
Hives (red raised bumps on skin)
Swollen or itchy lips
Skin flushing
Scaly skin rash (eczema)
Difficulty swallowing
Wheezing and difficult breathing
Abdominal pain, vomiting, and diarrhea

45. Common Food Allergens Protein-rich foods Nonproteins Cow’s milk Eggs
Peanuts
- Wheat
- Soybeans
- Fish and shellfish
Nonproteins
- Food dyes
- Sulfites added to:
Wine
Fruits
Vegetables
Shellfish

46. Who Develops Food Allergies?
People with family history of food or environmental allergies
~ 4% of children 5 to 17 yrs
Most outgrow by age 5 yrs
Allergies to nuts, seafood, and wheat are typically not outgrown
~ 2% of adults

47. Gluten and Celiac Disease
Gliadin
Protein found in gluten of wheat, buckwheat, barley, and rye
Triggers inflammatory response in small intestine
Condition called celiac disease
Symptoms include
Chronic diarrhea, weight loss, poor growth in children
Treatment
Avoid gluten-containing foods

48. Treatment of Food Allergies
Avoid offending foods
Read food labels to check for allergens
Food Allergen Labeling and Consumer Protection Act requires manufacturers to identify allergenic ingredients on product labels.
Educate teachers and other adults of allergic children’s need to avoid certain foods

49. Treating Severe Allergic Reactions
Emergency
treatment for
anaphylaxis (a
severe allergic
reaction) may
involve injecting a special medication.
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girl using epi
Pen from page 200

50. What Is PKU? Phenylketonuria (PKU)
Genetic disorder
Affects ~ 1/15,000 infants
Caused by lack of enzyme that converts the amino acid phenylalanine to another compound
If undiagnosed, infant will develop mental retardation by first birthday.
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51. Low Phenylalanine Diet
Infancy
Phenylalanine-free formula and low-phenylalanine foods
Childhood and adult years
Allowed: fruits, vegetables, and special low-phenylalanine foods
Avoided: nuts, milk and milk products, eggs, meats, and foods and beverages containing aspartame (e.g., Nutrasweet or Equal)

52. Protein Consumption Patterns
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53. MyPyramid Plan: Recommendations for Protein Intake
Choose lean or low-fat meat and poultry
Lean cuts of beef include:
Round steaks, top round, loin, top sirloin, chuck and arm roasts
Lean pork cuts include:
Loin, tenderloin, and center loin
Choose “extra lean” ground beef
At least 90% lean
Trim visible fat from meats

54. Understanding Nutritional Labeling
Nutrition Facts panel only provides grams of protein
Panel does not provide information concerning protein quality
Judge protein quality by reviewing items in the ingredient list
Figure 7.15

55. Eating Well for Less
- Substitute eggs, milk, cheese, and yogurt for meat, fish, or poultry.
- Make meals that contain less animal proteins and more plant proteins.
- Extend cereal proteins with eggs and milk (e.g., pancakes, waffles, crepes, or cereal with milk).
- Include more legumes in meals (e.g., chili, bean soups, and stews) while reducing meat content.

56. Combining Complementary Proteins
Complementary combinations
- Mixing certain plant foods to provide all essential amino acids without adding animal proteins
Amino acids often low or limiting in plant proteins:
tryptophan, threonine, lysine, and methionine

57. Complementary Dishes Insert photo of girl making BPJ from page 207
Insert couscous photo from page 209
Couscous (grain) with
Chickpeas (legume)
Peanut Butter (legume) on
Bread (grain)

58. Complementary Protein Dishes
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59. Vegetarianism Vegetarians- People who eat plant-based diets
Types of Vegetarians
Lactovegetarian
Consumes milk and milk products
Ovovegetarian
Consumes eggs
Lactoovovegetarian
Consumes eggs and milk and milk products
Vegan
Consumes only plant foods

60. Is Vegetarianism a Healthy Lifestyle?
Pros
Compared to nonvegetarians, vegetarians tend to:
Weigh less
Have less heart disease (eat less saturated fat and cholesterol)
Often exercise more, meditate for relaxation, and avoid tobacco and alcohol
Cons
If diets are poorly planned, vegetarians may lack:
Kilocalories
High-quality protein
Omega-3 fatty acids
Vitamins B-12 and D
Zinc, iron, and calcium

61. Vegetarian Children and Teens
May be difficult to consume adequate protein and energy, because plant foods tend to be filling
Growth rates of vegan children need close monitoring.
Teens
Pro: Can be healthy diet because more fruits and vegetables are consumed
Con: May be at risk of anorexia nervosa, an eating disorder

62. Vegetarian Women Pregnancy May need vitamin B-12 supplements
Infant could be deficient in B-12
Breastfeeding
Breastmilk may be deficient in vitamin B-12
Infant may develop severe developmental delays if fed breast milk that lacks vitamin B-12

63. Meatless Menu Planning Ideas
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64. Protein Adequacy Excessive Protein Intake
May  risk of heart disease and cancers of the colon/rectum, prostate, pancreas, and breast
What about High-Protein Weight-Loss Diets?
Diets decrease feelings of hunger and increase sense of fullness.
More info about safety of high-protein weight loss diets in Chapter 10

65. Protein Deficiency Uncommon in the U.S. May occur in:
elderly or low-income people
persons with alcoholism, anorexia nervosa, or intestinal tract disorders

66. Kwashiorkor and Marasmus
Protein-energy malnutrition (PEM)
Results from chronic lack of food or poor food choices
Two types of PEM:
Kwahsiorkor
Adequate energy intake but intake of high-quality protein is low
Edema
Marasmus
Starvation—extreme weight loss

67. Marasmic Kwashiorkor Characterized by edema in the abdomen, lower legs, and feet
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68. Severe Protein- Energy Malnutrition
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69. Chapter 7 Highlight Building a Bulkier Body
How to increase muscle mass?
Resistance training is the only safe and reliable way.
Dietitians generally do not recommend eating large amounts of protein-rich foods.

70. How Resistance Training Builds Bigger Muscles
During training, muscle proteins break down.
Synthesis occurs during recovery and lasts ~ 24 to 48 hrs.
Muscles grow larger if adequate energy and protein are available (positive nitrogen balance).

71. Proteins: General Advice for Athletes
Since carbohydrates spare proteins, eat a snack before or after exercise that includes adequate carbohydrate and protein.
Protein supplements are not needed for healthy persons.
If supplements are used, avoid those that contain a single amino acid.
Avoid high-protein diets, especially ones high in red meats.