Transcript Diapositiva 1

Protein: Amino Acids
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Amino Acids
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Amino Acids
• Nonessential amino acids
–a.k.a dispensable amino acids
• Essential amino acids
–a.k.a indispensable amino acids
• Conditionally essential amino acids
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An Essential Amino Acid
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Nonessential Amino Acids
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Proteins
• Peptide bond
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Proteins
• Dipeptide
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Proteins
• Tripeptide
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Proteins
• Polypeptide
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Proteins
• Amino acid sequences
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• Protein
shape and
function
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Proteins
• Protein denaturation
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Protein Digestion
• Stomach
–HCl
–Pepsinogen  pepsin
•Proenzyme
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Protein Digestion
• Small intestine
–Proteases
•Intestinal and pancreatic
–Peptidases
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Protein Absorption
• Carriers
• Capillaries
• Absorption misconceptions
– Enzyme/amino acid supplements
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Protein Synthesis
• Delivering the instructions
–DNA
•mRNA
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Protein Synthesis
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Protein Synthesis
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Protein Synthesis
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Protein Synthesis
• Sequencing errors
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Protein Synthesis
• Nutrients and gene expression
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Roles of Proteins
• Building material
–Growth
–Maintenance
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Roles of Proteins
• Enzymes
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Roles of
Proteins
• Hormones
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Roles of Proteins
• Regulation of fluid balance
–Edema
• Acid-base regulation
–Acidosis
–Alkalosis
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• Transport proteins
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Roles of Proteins
• Immunity
–Antibodies
–Antigens
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Roles of Proteins
• Source of energy
• Other roles
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Protein Metabolism
• Protein turnover
–Amino acid pool
• Nitrogen balance
–Positive nitrogen balance
–Negative nitrogen balance
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Protein Metabolism
• Using amino acids to make proteins
• Using amino acids to make
nonessential amino acids
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Protein Metabolism
• Using amino acids to make other
compounds
–Neurotransmitters
• Using amino acids for energy and
glucose
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Protein Metabolism
• Deamination
• Using amino acids to make fat
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Protein Quality
• High-quality proteins
• Digestibility
–Animal vs. plant
• Amino acid composition
–Limiting amino acid
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Protein Quality
• Reference protein
• Complementary proteins
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Protein
Quality
• PDCAAS
–Protein
digestibilitycorrected
amino acid
score
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Food Labels
• Quantity of protein
• Daily Value
–50 g protein
•10% of a 2000 kcal diet
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Protein-Energy
Malnutrition (PEM)
• Acute PEM
• Chronic PEM
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Protein-Energy
Malnutrition (PEM)
• Marasmus
• Kwashiorkor
• Marasmus-kwashiorkor mix
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Protein-Energy
Malnutrition (PEM)
• Infections
–Dysentery
• Rehabilitation
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Health Effects
• Heart disease
• Cancer
• Adult bone loss
–osteoporosis
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Health Effects
• Weight control
• Kidney disease
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Recommended Intakes
• RDA
–0.8 g/kg/day
–10% - 35% of energy intake
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Recommended Intakes
• Adequate intake
• Protein in abundance
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Supplements
• Protein supplements
• Amino acid supplements
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Vegetarian Diets
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Vegetarian Diets
• Health benefits
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Vegetarian Diets
• Diet planning
–Protein
•Lacto-ovo-vegetarians
•Meat replacements
–Texturized vegetable protein
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Vegetarian Diets
• Vitamins and minerals
–Lactovegetarians
–Vegans
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Vegetarian Diets
• Omega-3 fatty acids
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Vegetarian Diets
• Vegetarian diets through the life span
–Pregnancy and lactation
–Infancy
–Childhood and adolescence
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Vegetarian Diets
• Healthy food choices
–Macrobiotic diets
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