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LectureLectureOutlineOutline
Chapter 7Chapter 7
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ProteinsProteins Chapter 7Chapter 7
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Chapter Learning OutcomesChapter Learning Outcomes1.1. List the primary functions of proteins in the List the primary functions of proteins in the
body.body.
2.2. Identify the basic structural unit of proteins.Identify the basic structural unit of proteins.
3.3. Distinguish between essential and Distinguish between essential and nonessential amino acids.nonessential amino acids.
4.4. Explain the basic steps of protein synthesis Explain the basic steps of protein synthesis and digestion.and digestion.
5.5. Discuss conditions that contribute to Discuss conditions that contribute to positive nitrogen balance, negative nitrogen positive nitrogen balance, negative nitrogen balance, and protein balance.balance, and protein balance.
Chapter Learning Outcomes Chapter Learning Outcomes (continued)(continued)
6.6. Identify food sources of protein and foods Identify food sources of protein and foods that provide high and low quality proteins.that provide high and low quality proteins.
7.7. Plan meals and snacks that reduce animal Plan meals and snacks that reduce animal protein intake.protein intake.
8.8. Discuss the pros and cons of vegetarian Discuss the pros and cons of vegetarian diets.diets.
9.9. Describe how protein-energy malnutrition Describe how protein-energy malnutrition (PEM) can affect the body.(PEM) can affect the body.
Quiz YourselfQuiz Yourself True or FalseTrue or False
1.1. Animal foods such as meat and eggs are almost 100% Animal foods such as meat and eggs are almost 100% protein. T Fprotein. T F
2.2. Foods made from processed soybeans can be sources Foods made from processed soybeans can be sources of high quality protein. T Fof high quality protein. T F
3.3. An adult body builder should consume about five times An adult body builder should consume about five times more protein than a healthy adult who is not a body more protein than a healthy adult who is not a body builder. T Fbuilder. T F
4.4. Registered dietitians generally recommend that Registered dietitians generally recommend that vegetarians take amino acids supplements to increase vegetarians take amino acids supplements to increase their protein intake. T Ftheir protein intake. T F
5.5. People can nourish their hair by using shampoo that People can nourish their hair by using shampoo that contains protein. T Fcontains protein. T F
How Did You Do?How Did You Do?
1.1. FalseFalse Animal foods such as meat and eggs Animal foods such as meat and eggs contain some protein, lipids, and lots of water.contain some protein, lipids, and lots of water.
2.2. TrueTrue Foods made from processed soybeans Foods made from processed soybeans can be sources of high quality protein.can be sources of high quality protein.
3.3. FalseFalse An adult body builder does An adult body builder does notnot need to need to consume about five times more protein than a consume about five times more protein than a healthy adult who is not a body builder.healthy adult who is not a body builder.
4.4. FalseFalse Registered dietitians do Registered dietitians do notnot generally generally recommend that vegetarians take amino acids recommend that vegetarians take amino acids supplements to increase their protein intake.supplements to increase their protein intake.
5.5. FalseFalse Hair is composed of protein, not living Hair is composed of protein, not living tissue. Therefore, it cannot be nourished.tissue. Therefore, it cannot be nourished.
What Are Proteins?What Are Proteins?
• Complex organic moleculesComplex organic molecules
– Chemically similar to lipids and Chemically similar to lipids and carbohydratescarbohydrates
• Composed of carbon, hydrogen, oxygen, andComposed of carbon, hydrogen, oxygen, and nitrogennitrogen
• The human body contains ~100,000 different The human body contains ~100,000 different proteins.proteins.
Variety of Protein FunctionsVariety of Protein Functions
AllAll cells in the body contain proteins.cells in the body contain proteins.
Specific types of proteins include:Specific types of proteins include:• StructuralStructural proteins in cartilage, ligaments, proteins in cartilage, ligaments,
bones, hair, skin, and nailsbones, hair, skin, and nails• ContractileContractile proteins that enable muscles to proteins that enable muscles to
movemove• PigmentPigment proteins such as proteins such as melaninmelanin
determine color of eyes, hair, and determine color of eyes, hair, and skin skin • ClottingClotting proteins that are needed for blood proteins that are needed for blood
clottingclotting
Functions of Proteins (continued)Functions of Proteins (continued)
• Certain hormones are proteinsCertain hormones are proteins– HormonesHormones are chemical are chemical
messengers that regulate body messengers that regulate body processes and responses.processes and responses.
• Examples include insulin and glucagon.Examples include insulin and glucagon.
• Enzymes are proteinsEnzymes are proteins– Compounds that speed up (Compounds that speed up (catalyzecatalyze) )
chemical reactions without becoming chemical reactions without becoming part of the products.part of the products.
Functions of Proteins (continued)Functions of Proteins (continued)
• TransportTransport proteins proteins– Oxygen and many nutrients are Oxygen and many nutrients are
transported by special proteins.transported by special proteins.
• Proteins aid in Proteins aid in fluid balance.fluid balance.
Fluid Balance Fluid Balance and Proteinsand Proteins
Proteins in blood, Proteins in blood, such as such as albuminalbumin, , help maintain the help maintain the
proper distribution of proper distribution of fluids within fluids within
bloodstream and bloodstream and body tissues.body tissues.
• Insert Figure 7.1Insert Figure 7.1
What is Edema?What is Edema?
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Acid-base Balance and ProteinsAcid-base Balance and Proteins
• Acid-base balanceAcid-base balance– Maintaining the proper pH of body Maintaining the proper pH of body
fluidsfluids
• Blood and tissue fluid must Blood and tissue fluid must maintain a maintain a pHpH of of 7.35 to 7.457.35 to 7.45
• Acidic Acidic - having an - having an excess of Hexcess of H++
• Too basic Too basic –– not enough H not enough H++
• Proteins act as Proteins act as buffersbuffers by by accepting or releasing Haccepting or releasing H+.+.
Amino AcidsAmino Acids
• Proteins are made of smaller units called Proteins are made of smaller units called amino amino acids.acids.
• 20 different amino acids in human proteins20 different amino acids in human proteins• Each amino acid is composed of:Each amino acid is composed of:
– An amino or a nitrogen-containing groupAn amino or a nitrogen-containing group • Amino groupAmino group has nitrogen bonded to 2 hydrogen atoms has nitrogen bonded to 2 hydrogen atoms
– R-groupR-group (side chain) (side chain) — varies with each amino acid— varies with each amino acid• Acid groupAcid group – acid portion – acid portion
Amino Acid: Basic Chemical StructureAmino Acid: Basic Chemical Structure
• Insert Figure 7.2Insert Figure 7.2
Classifying Amino Acids
Essential Amino AcidsEssential Amino Acids• Cannot be made by the body, so Cannot be made by the body, so
must be supplied in the dietmust be supplied in the diet• 9 of the 20 amino acids9 of the 20 amino acids
Nonessential Amino AcidsNonessential Amino Acids• Can be made by the bodyCan be made by the body• 11 of the 20 amino acids11 of the 20 amino acids
The Essential and Nonessential Amino AcidsThe Essential and Nonessential Amino Acids
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Proteins in FoodsProteins in Foods
• Nearly Nearly allall foods contain some protein, but foods contain some protein, but no natural food is 100% protein.no natural food is 100% protein.
• Animal foods typically have more protein Animal foods typically have more protein than plant foods.than plant foods.– Seeds, tree nuts, and legumes supply more Seeds, tree nuts, and legumes supply more
protein than fruit or the edible leaves, roots, protein than fruit or the edible leaves, roots, flowers, and stems of vegetables.flowers, and stems of vegetables.
Protein Contents of Some Commonly Eaten Protein Contents of Some Commonly Eaten FoodsFoods
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What Are Legumes?What Are Legumes?
• LegumesLegumes– Plants that Plants that
produce pods with produce pods with a single row of a single row of seedsseeds
Examples:Examples: Soybeans, peas, Soybeans, peas,
peanuts, lentils, peanuts, lentils, and beansand beans
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Protein QualityProtein Quality
• High-quality proteinHigh-quality protein– Protein that contains all 9 essential amino acids in Protein that contains all 9 essential amino acids in
amounts that support growthamounts that support growth– “ “Complete protein”Complete protein”– Most animal products and products made with Most animal products and products made with
processed soyprocessed soy
• Low-quality proteinLow-quality protein– Protein that lacks or has inadequate amounts of one Protein that lacks or has inadequate amounts of one
or more of the essential amino acidsor more of the essential amino acids– Most plant foods (except processed soy) Most plant foods (except processed soy) and gelatinand gelatin
What Happens to Protein in Your Body?What Happens to Protein in Your Body?
• How Your Body Synthesizes ProteinsHow Your Body Synthesizes Proteins– Cells assemble the 20 amino acids in Cells assemble the 20 amino acids in
specific sequences according to information specific sequences according to information provided by provided by DNA.DNA.
– Amino acids are connected by Amino acids are connected by peptide peptide bonds.bonds.
– PeptidesPeptides• Chains of fewer than 15 amino acidsChains of fewer than 15 amino acids
– PolypeptidesPolypeptides• Proteins made of > 50 amino acidsProteins made of > 50 amino acids
What Is a Protein?What Is a Protein?
• Each distinctive bead Each distinctive bead in the illustration in the illustration representsrepresentsa different aminoa different amino
acid. acid.
• The “hook” that The “hook” that connects the “beads” connects the “beads” represents a represents a peptide peptide bond.bond.
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Peptide BondPeptide Bond
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Protein SynthesisProtein Synthesis
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A ProteinA Protein Takes Shape Takes Shape
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Sickle Cell AnemiaSickle Cell Anemia• If the DNA code is faulty, the wrong amino acid may be inserted If the DNA code is faulty, the wrong amino acid may be inserted
into a protein. For example, into a protein. For example, sickle cell diseasesickle cell disease that affects red that affects red blood cells blood cells
Insert figure 7.4
Protein DenaturationProtein Denaturation
DenaturationDenaturation• Altering a protein’s natural shape and function by Altering a protein’s natural shape and function by
exposing it to conditions such as heat, alcohol, acid, exposing it to conditions such as heat, alcohol, acid, and physical agitationand physical agitation– Heat denatures the protein in raw eggs.Heat denatures the protein in raw eggs.– Acidic lemon juice “curdles” the protein in milk.Acidic lemon juice “curdles” the protein in milk.– Hydrochloric acid denatures food proteins in the Hydrochloric acid denatures food proteins in the
stomach, making them easy to digest.stomach, making them easy to digest.– Physical agitation includes whipping protein-rich Physical agitation includes whipping protein-rich
foods (e.g., beaten egg whites).foods (e.g., beaten egg whites).
DenaturationDenaturation
Insert Figure 7.9Insert Figure 7.9
Protein TurnoverProtein Turnover
• Protein turnoverProtein turnover– Breaking down old or unneeded proteins into Breaking down old or unneeded proteins into
amino acids and recycling the amino acidsamino acids and recycling the amino acids
• Amino acid “pool”Amino acid “pool”– Amino acids that have not been incorporated Amino acids that have not been incorporated
into proteinsinto proteins
• Endogenous amino acidsEndogenous amino acids– Those available from the amino acid poolThose available from the amino acid pool
• Exogenous proteinsExogenous proteins – Those from dietary sourcesThose from dietary sources
Transamination and DeaminationTransamination and Deamination
TransaminationTransamination– Transfer of nitrogen-containing group from an Transfer of nitrogen-containing group from an
unneeded amino acid to a unneeded amino acid to a carbon skeletoncarbon skeleton, , forming an amino acidforming an amino acid
DeaminationDeamination– Removal of nitrogen-containing group from an Removal of nitrogen-containing group from an
unneeded amino acidunneeded amino acid
Example of Transamination and Example of Transamination and DeaminationDeamination
Insert Figure 7.10Insert Figure 7.10
The Liver and The Liver and Deamination Deamination
AmmoniaAmmonia ( (NHNH33) )
is converted to is converted to ureaurea that the that the
kidneys excrete kidneys excrete in urine.in urine.
Insert Figure 7.11Insert Figure 7.11
Nitrogen BalanceNitrogen Balance
Nitrogen balanceNitrogen balance (or equilibrium) (or equilibrium)Balancing nitrogen intake with nitrogen lossesBalancing nitrogen intake with nitrogen losses
Positive nitrogen balancePositive nitrogen balanceBody retains more nitrogen than it losesBody retains more nitrogen than it loses
Negative nitrogen balanceNegative nitrogen balanceBody loses more nitrogen than it retainsBody loses more nitrogen than it retains
PPositive Nitrogen Balanceositive Nitrogen BalanceOccurs during growth, pregnancy, recovery from illness, and Occurs during growth, pregnancy, recovery from illness, and
as a result of certain hormones and resistance exerciseas a result of certain hormones and resistance exercise
insert Figure 7.12insert Figure 7.12
Nitrogen EquilibriumNitrogen EquilibriumOccurs when healthy adults meet protein and energy needsOccurs when healthy adults meet protein and energy needs
Insert Figure 7.12Insert Figure 7.12
NegativeNegative Nitrogen Balance Nitrogen BalanceOccurs with Occurs with protein intake, kidney disease, blood loss, bed protein intake, kidney disease, blood loss, bed
rest, fever, injuries, burns, or rest, fever, injuries, burns, or thyroid hormone or cortisol thyroid hormone or cortisol
Insert Figure 7.12Insert Figure 7.12
How Much Protein Do You Need?How Much Protein Do You Need?
• Daily protein needs of healthy adults:Daily protein needs of healthy adults:– RDARDA = = 0.80.8 g/kg body wt g/kg body wt
• Protein needs increase during periods of Protein needs increase during periods of growth, pregnancy, lactation, and growth, pregnancy, lactation, and recovery from illness or injury.recovery from illness or injury.
Determining Protein NeedsDetermining Protein Needs
• Using the RDA formula of 0.8 g of protein/kg of Using the RDA formula of 0.8 g of protein/kg of body wt, what is the RDA for protein for a person body wt, what is the RDA for protein for a person weighing 165 lbs?weighing 165 lbs?
1)1) Convert weight in lbs to weight in kg Convert weight in lbs to weight in kg
(165 (165 2.2 = 75 kg)2.2 = 75 kg)
2)2) Multiply kg of body wt by 0.8Multiply kg of body wt by 0.8
75 X 0.8 = 6075 X 0.8 = 60
Therefore, a person weighing 165 lbs will meet his/her Therefore, a person weighing 165 lbs will meet his/her RDA for protein by consuming 60 g of protein per dayRDA for protein by consuming 60 g of protein per day
Protein Digestion Protein Digestion
• Protein digestion begins in the Protein digestion begins in the stomach.stomach.– Hydrochloric acidHydrochloric acid denatures proteins denatures proteins– PepsinPepsin, an enzyme, digests proteins into smaller , an enzyme, digests proteins into smaller
polypeptides.polypeptides.
• Polypeptides enter the Polypeptides enter the small intestinesmall intestine – The enzymes The enzymes trypsintrypsin and and chymotrypsinchymotrypsin break down break down
polypeptides into shorter peptides and individual polypeptides into shorter peptides and individual amino acids.amino acids.
Protein AbsorptionProtein Absorption
• AbsorptionAbsorption occurs in the occurs in the small intestinesmall intestine– Absorptive cells release enzymes that digest Absorptive cells release enzymes that digest
most small peptides into individual amino most small peptides into individual amino acids.acids.
– Individual amino acids and some di- and Individual amino acids and some di- and tripeptides enter absorptive cells, where they tripeptides enter absorptive cells, where they are completely digested to amino acids.are completely digested to amino acids.
After Absorption…After Absorption…
• Amino acids enter Amino acids enter portal veinportal vein and travel to and travel to the the liverliver– Liver keeps some amino acids for its own use Liver keeps some amino acids for its own use
and releases others into general circulation.and releases others into general circulation.
• MostMost proteins are digested and amino proteins are digested and amino acids absorbedacids absorbed– Very littleVery little protein is eliminated in protein is eliminated in feces.feces.
What Is A Food Allergy?What Is A Food Allergy?
• AllergyAllergy– Inflammatory response resulting when body’s Inflammatory response resulting when body’s
immune system reacts inappropriately to a immune system reacts inappropriately to a substance that is typically harmlesssubstance that is typically harmless• Allergen Allergen — the offending substance — the offending substance
– Most food allergens are proteins that escape Most food allergens are proteins that escape digestion and are absorbed as digestion and are absorbed as whole proteins.whole proteins.
Common Signs of Food AllergiesCommon Signs of Food Allergies
Signs occur within a few minutes or Signs occur within a few minutes or couple of hours and typically couple of hours and typically include:include:– Hives (red raised bumps on skin) Hives (red raised bumps on skin) – Swollen or itchy lipsSwollen or itchy lips– Skin flushingSkin flushing– Scaly skin rash (Scaly skin rash (eczemaeczema))– Difficulty swallowingDifficulty swallowing– Wheezing and difficult breathingWheezing and difficult breathing– Abdominal pain, vomiting, and diarrheaAbdominal pain, vomiting, and diarrhea
Common Food AllergensCommon Food Allergens
Protein-rich foods- Cow’s milk- Eggs- Peanuts
- Wheat
- Soybeans
- Fish and shellfish
Nonproteins- Food dyes
- Sulfites added to:• Wine
• Fruits
• Vegetables
• Shellfish
Who Develops Food Allergies?Who Develops Food Allergies?
• People with People with family historyfamily history of food or of food or environmental allergiesenvironmental allergies
• ~ ~ 4%4% of children 5 to 17 yrs of children 5 to 17 yrs
• Most Most outgrowoutgrow by age 5 yrs by age 5 yrs– Allergies to nuts, seafood, and Allergies to nuts, seafood, and
wheat are typically not outgrownwheat are typically not outgrown
• ~ ~ 2%2% of adults of adults
Gluten and Celiac DiseaseGluten and Celiac Disease
• GliadinGliadin– Protein found in Protein found in glutengluten of wheat, buckwheat, of wheat, buckwheat,
barley, and rye barley, and rye – Triggers inflammatory response in small Triggers inflammatory response in small
intestineintestine– Condition called Condition called celiac diseaseceliac disease
• Symptoms includeSymptoms include– Chronic diarrhea, weight loss, poor growth in Chronic diarrhea, weight loss, poor growth in
childrenchildren
• TreatmentTreatment– Avoid glutenAvoid gluten-containing foods-containing foods
Treatment of Food AllergiesTreatment of Food Allergies
• AvoidAvoid offending foods offending foods• ReadRead food labels to check for food labels to check for
allergensallergens• Food Allergen Labeling and Consumer Food Allergen Labeling and Consumer
Protection Act requires manufacturers to Protection Act requires manufacturers to identify allergenic ingredients on product identify allergenic ingredients on product labels.labels.
• EducateEducate teachers and other adults teachers and other adults of allergic children’s need to avoid of allergic children’s need to avoid certain foodscertain foods
Treating Severe Allergic ReactionsTreating 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
What Is PKU?What Is PKU?
PhenylketonuriaPhenylketonuria (PKU) (PKU)
– GeneticGenetic disorder disorder– Affects ~ 1/15,000 infants Affects ~ 1/15,000 infants – Caused by Caused by lack of enzymelack of enzyme
that converts the amino that converts the amino acid acid phenylalaninephenylalanine to to another compoundanother compound
– If undiagnosed, infant will If undiagnosed, infant will develop develop mental retardationmental retardation
by first birthday.by first birthday.
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Low Phenylalanine DietLow Phenylalanine Diet
InfancyInfancy
Phenylalanine-freePhenylalanine-free formula and low-formula and low-phenylalanine foodsphenylalanine foods
Childhood and adult yearsChildhood and adult years
Allowed:Allowed: fruits, vegetables, and special low-fruits, vegetables, and special low-phenylalanine foodsphenylalanine foods
Avoided:Avoided: nuts, milk and milk products, eggs, nuts, milk and milk products, eggs, meats, and foods and beverages containing meats, and foods and beverages containing aspartameaspartame (e.g., Nutrasweet or Equal) (e.g., Nutrasweet or Equal)
Protein Consumption PatternsProtein Consumption Patterns
Insert Figure 7.14Insert Figure 7.14
MyPyramid Plan: MyPyramid Plan: Recommendations for Protein IntakeRecommendations for Protein Intake
• Choose Choose lean or low-fat meat and poultrylean or low-fat meat and poultry– Lean cuts of beef include:Lean cuts of beef include:
• Round steaks, top round, loin, top sirloin, chuck and arm Round steaks, top round, loin, top sirloin, chuck and arm roastsroasts
– Lean pork cuts include:Lean pork cuts include:• Loin, tenderloin, and center loinLoin, tenderloin, and center loin
• ChooseChoose “extra lean” ground beef “extra lean” ground beef– At least 90% leanAt least 90% lean
• TrimTrim visible fat from meats visible fat from meats
UnderstandingUnderstanding Nutritional Labeling Nutritional Labeling
• Nutrition FactsNutrition Facts panel only panel only provides grams of proteinprovides grams of protein
• Panel does Panel does notnot provide provide information concerning information concerning protein protein qualityquality
– Judge protein quality by Judge protein quality by reviewing items in the reviewing items in the ingredient listingredient list
Figure 7.15
Eating Well for LessEating Well for Less
- Substitute eggs, milk, cheese, and yogurt for - Substitute eggs, milk, cheese, and yogurt for meat, fish, or poultry.meat, fish, or poultry.
- Make meals that contain less animal proteins - Make meals that contain less animal proteins and more plant proteins.and more plant proteins.
- Extend cereal proteins with eggs and milk (e.g., - Extend cereal proteins with eggs and milk (e.g., pancakes, waffles, crepes, or cereal with milk).pancakes, waffles, crepes, or cereal with milk).
- Include more legumes in meals (e.g., chili, bean - Include more legumes in meals (e.g., chili, bean soups, and stews) while reducing meat content.soups, and stews) while reducing meat content.
Combining Complementary ProteinsCombining Complementary Proteins
Complementary combinationsComplementary combinations
- - Mixing certain plant foods to provide all essential Mixing certain plant foods to provide all essential amino acids without adding animal proteinsamino acids without adding animal proteins
Amino acids often low or limiting in plant Amino acids often low or limiting in plant proteins:proteins:
tryptophan, threonine, lysine,tryptophan, threonine, lysine, and and methioninemethionine
Complementary Dishes
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Peanut Butter (legume) on Bread (grain)
Couscous (grain) with Chickpeas (legume)
Complementary Protein DishesComplementary Protein Dishes
• Insert Table 7.3 Insert Table 7.3
VegetarianismVegetarianism
VegetariansVegetarians- - People who eat plant-based dietsPeople who eat plant-based diets
Types of VegetariansTypes of Vegetarians• Lactovegetarian Lactovegetarian
• Consumes milk and milk productsConsumes milk and milk products • OvovegetarianOvovegetarian
• Consumes eggsConsumes eggs
• LactoovovegetarianLactoovovegetarian• Consumes eggs and milk and milk productsConsumes eggs and milk and milk products
• VeganVegan
• Consumes Consumes onlyonly plant foods plant foods
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
Vegetarian Children and Teens
Children• 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
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
Meatless Menu Planning IdeasMeatless Menu Planning Ideas
• Insert Table 7.4Insert Table 7.4
Protein AdequacyProtein Adequacy
Excessive Protein IntakeExcessive Protein Intake– May May risk of heart disease and cancers of the risk of heart disease and cancers of the
colon/rectum, prostate, pancreas, and breastcolon/rectum, prostate, pancreas, and breast
What about High-Protein Weight-Loss Diets?What about High-Protein Weight-Loss Diets?– Diets decrease feelings of hunger and increase Diets decrease feelings of hunger and increase
sense of fullness.sense of fullness.– More info about safety of high-protein weight loss More info about safety of high-protein weight loss
diets in diets in Chapter 10Chapter 10
Protein DeficiencyProtein Deficiency
Uncommon in the U.S.Uncommon in the U.S.
– May occur in:May occur in:• elderly or low-income people elderly or low-income people • persons with alcoholism, anorexia nervosa, or persons with alcoholism, anorexia nervosa, or
intestinal tract disordersintestinal tract disorders
Kwashiorkor and MarasmusKwashiorkor and Marasmus
Protein-energy malnutrition (PEM)Protein-energy malnutrition (PEM)– Results from chronic lack of food or poor food choicesResults from chronic lack of food or poor food choices
Two types of PEM:Two types of PEM:– KwahsiorkorKwahsiorkor
• Adequate energy intake but intake of high-quality Adequate energy intake but intake of high-quality protein is lowprotein is low
» EdemaEdema
– MarasmusMarasmus• Starvation—extreme weight lossStarvation—extreme weight loss
Marasmic Marasmic KwashiorkorKwashiorkor
Characterized by Characterized by edema in the edema in the
abdomen, lower abdomen, lower legs, and feetlegs, and feet
Insert figure 7.17Insert figure 7.17
Severe Severe Protein-Protein-Energy Energy
MalnutritionMalnutritionInsert figure 7.18Insert figure 7.18
Chapter 7 HighlightBuilding a Bulkier Body
How to increase muscle mass?How to increase muscle mass?
• Resistance training is the only safe and Resistance training is the only safe and reliable way.reliable way.
• Dietitians generally do not recommend Dietitians generally do not recommend eating large amounts of protein-rich eating large amounts of protein-rich foods.foods.
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 positive nitrogen balancebalance).
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 notnot 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.