chapter 5 protein: the cellular foundation copyright © 2015, 2010, 2005, 1998 by saunders, an...

CHAPTER 5CHAPTER 5

PROTEIN: THE CELLULAR PROTEIN: THE CELLULAR FOUNDATIONFOUNDATION

Copyright © 2015, 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc

Copyright © 2015, 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.

ProteinsProteinsChicken and fish are chosen Chicken and fish are chosen

more often, but beef is still more often, but beef is still the major source of animal the major source of animal proteinprotein

Proteins are large molecular Proteins are large molecular structuresstructuresAmino acids are building Amino acids are building

blocks of proteinsblocks of proteinsAll proteins are made from All proteins are made from

combinations of 10 amino combinations of 10 amino acidsacids

In Buzby J, Farah H: Chicken consumption continues In Buzby J, Farah H: Chicken consumption continues long run rise. Amber Waves, April 2006, USDA.long run rise. Amber Waves, April 2006, USDA.

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Classification of Amino AcidsClassification of Amino AcidsNonessential AAs (NEAAs) may be made in Nonessential AAs (NEAAs) may be made in

adequate amounts to meet physiological needsadequate amounts to meet physiological needsConditionally essentialConditionally essential

Essential in certain disease states or in certain stages of Essential in certain disease states or in certain stages of development: tyrosine, cysteine, arginine, glycine, proline, development: tyrosine, cysteine, arginine, glycine, proline, glutamineglutamine

Essential AAs (EAAs) Essential AAs (EAAs) cancan’’t be manufactured t be manufactured by the body in adequate amounts or are not by the body in adequate amounts or are not made by the bodymade by the bodyHistidine, isoleucine, leucine, lysine, methionine, Histidine, isoleucine, leucine, lysine, methionine,

phenylalanine, threonine, tryptophan, valinephenylalanine, threonine, tryptophan, valine

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Protein QualityProtein QualityProtein digestibility corrected amino acid score Protein digestibility corrected amino acid score

(PDCAAs): official method of evaluating protein (PDCAAs): official method of evaluating protein quality for people quality for people

Complete protein (high-quality protein)Complete protein (high-quality protein)All EAAs present in adequate amounts to sustain All EAAs present in adequate amounts to sustain

optimal growth (generally from animal sourcesoptimal growth (generally from animal sources——meat, meat, fish, milk, eggs)fish, milk, eggs)

Incomplete protein (low-quality protein)Incomplete protein (low-quality protein)Missing one or more EAAs required forMissing one or more EAAs required for

growth (e.g., legumes, grains, vegetables)growth (e.g., legumes, grains, vegetables)

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Nitrogen BalanceNitrogen BalanceNitrogen balance: equilibrium in breakdown and Nitrogen balance: equilibrium in breakdown and

consumption of proteinconsumption of proteinNitrogen balance: healthy individuals excrete (in feces, Nitrogen balance: healthy individuals excrete (in feces,

urine, and from skin) same amount of protein as urine, and from skin) same amount of protein as consumed consumed

Negative nitrogen balance: person with a burn or Negative nitrogen balance: person with a burn or illness excretes more nitrogen than is ingestedillness excretes more nitrogen than is ingested

Positive nitrogen balance: in periods of growth (a child Positive nitrogen balance: in periods of growth (a child or pregnant woman), more protein retained than lost or pregnant woman), more protein retained than lost

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Physiological RolesPhysiological RolesGeneration of new body tissuesGeneration of new body tissues——collagen collagen

matrix for skin, bones, and teethmatrix for skin, bones, and teethRepair of body tissuesRepair of body tissuesProduction of essential compoundsProduction of essential compounds

Hormones (e.g., insulin, thryoxine) Hormones (e.g., insulin, thryoxine) EnzymesEnzymes——amylase, lipase, pepsinamylase, lipase, pepsin

Regulation of fluid balanceRegulation of fluid balance

From Patton KT, Thibodeau GA: Anatomy & Physiology, ed From Patton KT, Thibodeau GA: Anatomy & Physiology, ed 8. St. Louis: Mosby, 2013.8. St. Louis: Mosby, 2013.

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Physiological RolesPhysiological Roles

Resistance to diseaseResistance to disease Antibodies, Antibodies,

immunoglobulins (IgA)immunoglobulins (IgA)

Transport proteins Transport proteins (e.g., lipoproteins)(e.g., lipoproteins)

EnergyEnergypH balancepH balance——sialin sialin

(buffering protein in (buffering protein in saliva)saliva)

From Patton KT, Thibodeau GA: Anatomy & Physiology, ed 8. From Patton KT, Thibodeau GA: Anatomy & Physiology, ed 8. St. Louis: Mosby, 2013.St. Louis: Mosby, 2013.

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Protein RecommendationsProtein RecommendationsRDA = 0.8 g/kg or AMDR = 10% to 35% of calories, RDA = 0.8 g/kg or AMDR = 10% to 35% of calories,

whichever is higher to ensure adequate intakewhichever is higher to ensure adequate intakeApprox 56 g of protein for patient weighing 150 lbApprox 56 g of protein for patient weighing 150 lbHigher intakes may lower risk for type 2 diabetes, coronary Higher intakes may lower risk for type 2 diabetes, coronary

heart disease, osteoporosis, and sarcopeniaheart disease, osteoporosis, and sarcopeniaRDAs established for EAAsRDAs established for EAAs

Lysine (51 mg)Lysine (51 mg) Low in grains and cereals; vegans need to addLow in grains and cereals; vegans need to add

legumeslegumesThreonine (27 mg) and tryptophan (7 mg)Threonine (27 mg) and tryptophan (7 mg)

Low in grains and some legumesLow in grains and some legumesSulfur (25 mg)Sulfur (25 mg)

Typically the Typically the ““limitinglimiting”” AA in the US diet AA in the US diet Highest in eggs and Highest in eggs and relatively high in beef, wheat,relatively high in beef, wheat,

brown ricebrown rice8


Protein Sources & Protein Sources & RecommendationsRecommendations

Meat and beans group (beef, poultry, eggs, Meat and beans group (beef, poultry, eggs, legumes, nuts and seeds, fish)legumes, nuts and seeds, fish)Children (2–8 yr) = 2–4 ounce equivalentsChildren (2–8 yr) = 2–4 ounce equivalentsGirls (9–18 yr) = 5 ounce equivalentsGirls (9–18 yr) = 5 ounce equivalentsBoys (9–18 yr) = 5–6 ounce equivalentsBoys (9–18 yr) = 5–6 ounce equivalentsWomen (19–51+ yr) = 5–5½ ounce equivalentsWomen (19–51+ yr) = 5–5½ ounce equivalentsMen (19–51+ yr) = 5½–6½ ounce equivalentsMen (19–51+ yr) = 5½–6½ ounce equivalents

Dairy group (milk, yogurt, cheese)Dairy group (milk, yogurt, cheese)Children (2–8 yr) = 2 cupsChildren (2–8 yr) = 2 cupsBoys and girls (9–18 yr) + men and womenBoys and girls (9–18 yr) + men and women

(19–51+ yr) = 3 cups(19–51+ yr) = 3 cups

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Underconsumption: Underconsumption: Protein Energy MalnutritionProtein Energy Malnutrition

Affects every fourth child or 150 million children Affects every fourth child or 150 million children worldwideworldwideMalnutrition magnifies the effect of infectionsMalnutrition magnifies the effect of infectionsContributes to 160 days of illness and 10.9 million child Contributes to 160 days of illness and 10.9 million child

deaths each yeardeaths each yearThose at risk for protein deficiency in the USThose at risk for protein deficiency in the US

Older adultsOlder adultsMedically compromised (AIDS, cancer)Medically compromised (AIDS, cancer)Low-income groupsLow-income groupsStrict vegetariansStrict vegetariansLack of educationLack of education

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Underconsumption: Underconsumption: Oral ImplicationsOral Implications

During development and growthDuring development and growthDelayed eruption Delayed eruption Retardation during mandibleRetardation during mandible

development development Smaller salivary glands result inSmaller salivary glands result in

diminished salivary flowdiminished salivary flowChanges in salivary protein composition and amylase and Changes in salivary protein composition and amylase and

aminopeptidase activity compromising the immune function aminopeptidase activity compromising the immune function of the salivaof the saliva

Marginal or deficient protein intake results in altered Marginal or deficient protein intake results in altered wound healing and suppressed immune responsewound healing and suppressed immune response

From Perry DA, Beemsterboer P: From Perry DA, Beemsterboer P: Periodontology for the Dental Hygienist, ed Periodontology for the Dental Hygienist, ed

4. St. Louis: Saunders, 2014.4. St. Louis: Saunders, 2014.

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Types of Types of Protein Energy MalnutritionProtein Energy Malnutrition

KwashiorkorKwashiorkorAcute form of PEM occurring from lack of high-quality Acute form of PEM occurring from lack of high-quality

protein despite adequate caloriesprotein despite adequate caloriesSymptomsSymptoms

Edema of the extremities, torso, faceEdema of the extremities, torso, face Fatty liverFatty liver Hair color change and sparse hairHair color change and sparse hair AnemiaAnemia LethargyLethargy Cracked, peeling, infection-prone skinCracked, peeling, infection-prone skin Opportunistic infectionsOpportunistic infections

At risk: children 18 to 24 monthsAt risk: children 18 to 24 months From Zitelli BJ, Davis HW: Atlas of From Zitelli BJ, Davis HW: Atlas of Pediatric Physical Diagnosis, ed 6. Pediatric Physical Diagnosis, ed 6.

Philadelphia: Mosby, 2012.Philadelphia: Mosby, 2012.

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Types of Types of Protein Energy Malnutrition (PEM)Protein Energy Malnutrition (PEM)

MarasmusMarasmusCause: long-term protein and energy deficitsCause: long-term protein and energy deficitsSymptomsSymptoms

Muscle weakeningMuscle weakening Fat and muscle tissue depletion; skin hangs in fold Fat and muscle tissue depletion; skin hangs in fold

w/clearly visible bones beneathw/clearly visible bones beneath Impairment of brain and nervous system Impairment of brain and nervous system Decrease in cognitive ability Decrease in cognitive ability Delayed tooth eruptionDelayed tooth eruption Changes in saliva quality and quantityChanges in saliva quality and quantity

At risk: children, homeless, older adults, At risk: children, homeless, older adults, substance abuserssubstance abusers

Courtesy Dr. Jonathan Spector, Courtesy Dr. Jonathan Spector, Boston. In Zitelli BJ, Davis HW Boston. In Zitelli BJ, Davis HW

(eds): Atlas of Pediatric Physical (eds): Atlas of Pediatric Physical Diagnosis, ed 6. Philadelphia: Diagnosis, ed 6. Philadelphia:

Mosby, 2012.Mosby, 2012.

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Overconsumption and Overconsumption and Health-Related EffectsHealth-Related Effects

Excess protein converted to fat; contributes to obesityExcess protein converted to fat; contributes to obesityExcess intake may result in fluid imbalancesExcess intake may result in fluid imbalancesNitrogen must be excreted—a concern for anyone Nitrogen must be excreted—a concern for anyone

with even mild kidney impairmentwith even mild kidney impairmentMany high-protein foods are high in fat/saturated Many high-protein foods are high in fat/saturated

fat/cholesterol; increases risk of CVD and some fat/cholesterol; increases risk of CVD and some cancerscancers

Higher protein diets are beneficial for weight control Higher protein diets are beneficial for weight control by enhancing loss of body fat with less muscle loss by enhancing loss of body fat with less muscle loss and improved control of blood glucose levels and improved control of blood glucose levels

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Nutrition ConsiderationsNutrition ConsiderationsSuggest Meals-on-Wheels, WIC, food stamps, Suggest Meals-on-Wheels, WIC, food stamps,

and food pantries for low-income patients at risk and food pantries for low-income patients at risk for poor nutritionfor poor nutrition

Animal sources of protein are most expensive; Animal sources of protein are most expensive; encourage use of plant proteinsencourage use of plant proteins

Suggest addition of cheese or milk powders to Suggest addition of cheese or milk powders to soups, mashed potatoes, etc.soups, mashed potatoes, etc.

Refer medically complex patients to a Refer medically complex patients to a registered dietitian and medical providerregistered dietitian and medical provider

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HEALTH APPLICATIONSHEALTH APPLICATIONSAs a healthcare provider, how would you As a healthcare provider, how would you

discuss dietary supplementation with the discuss dietary supplementation with the following groups for assuring adequate protein following groups for assuring adequate protein consumption?consumption?

LactovegetariansLactovegetariansOvolactovegetariansOvolactovegetariansVegansVegansSecular (religious) groupsSecular (religious) groups

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