Protein

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Protein
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Protein

• Surprisingly little is known about protein and
  health but some recommendations
• Adults need 0.8 grams of protein/kg of body
  weight per day to keep from slowly breaking down
  their own tissues
• Just over 7 grams of protein are needed for every
  20 pounds of body weight

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Protein

• There's relatively little solid information
• on the ideal amount of protein in the diet
• a healthy target for calories contributed by
  protein
• the best kinds of protein.

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Too Little Protein?

• the conditions known as Kwashiorkor and Maramus.
• growth failure
• loss of muscle mass
• decreased immunity
• weakening of the heart and respiratory system
• You die

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Too Much Protein?

• Digesting it releases acids that the body usually
  neutralizes with calcium and other buffering
  agents in the blood.
• Eating lots of protein, such as the amounts
  recommended in the so-called low-carb or no-carb
  diets, removes lots of calcium from the body.
• Some of this may be pulled from bone.

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What is Protein?

• Take away the water and about 75 percent of body
  weight is protein
• Muscle, bone, skin, hair, and virtually every
  other body part or tissue. (25 of muscle)
• Enzymes that power many chemical reactions and
  the hemoglobin that carries oxygen
• At least 10,000 different proteins make the body
  what it is.

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What is Protein?

• Twenty or so basic building blocks, called amino
  acids, provide the raw material for all proteins.
  Following genetic instructions, the body strings
  together amino acids.
• Some genes call for short chains, others are
  blueprints for long chains that fold,
  origami-like, into intricate, three-dimensional
  structures.

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What is Protein?

• Because the body doesn't store amino acids, as it
  does fats or carbohydrates, it needs a daily
  supply of amino acids to make new protein.
• It does not need a supply of dietary amino acids
  to make ALL the protein the body synthesizes in a
  day
• Protein the body no longer requires is broken
  down to its component amino acids and they may be
  used to synthesis another body protein

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Amino Acids
Side group
Side group differences is how the twenty amino
acids are different .
O
H
N
C
C
H
OH
H
Amine Group
Acid Group
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The Chemists View of Proteins

• Amino Acids
• The unique side groups result in differences in
  the size, shape and electrical charge of an amino
  acid

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The Chemists View of Proteins

• Amino Acids
• Nonessential amino acids, also called dispensable
  amino acids, are ones the body can create.

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The Chemists View of Proteins

• Amino Acids
• Essential amino acids, also called indispensable
  amino acids, must be supplied by the foods people
  consume.
• Essential amino acids include histidine,
  isoleucine, leucine, lysine, methionine,
  phenyalanine, threonine, tryptophan, and valine.
• Conditionally essential amino acids refer to
  amino acids that are normally nonessential but
  essential under certain conditions.

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The Chemists View of Proteins

• Proteins
• Amino acid chains are linked by peptide bonds in
  condensation reactions.
• Dipeptides have two amino acids bonded together.
• Tripeptides have three amino acids bonded
  together.
• Polypeptides have more than two amino acids
  bonded together.

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Peptide Bonding
O
H
O
H
H
H
N
C
C
N
C
C
H
OH
H
OH
Side group 1
water
Side group 2
Amino Acid 1
Amino Acid 2
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Amino Acid Sequence

• Protein is made by bonding amino acids in a
  specific sequence
• .
• Each amino acid must be but in the order
  specified by the genetic code responsible for
  synthesizing the protein
• If an (essential) amino acid is unavailable,
  protein synthesis is limited

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Amino Acid Sequence
Amino acid 1
Amino acid 2
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Amino Acid Sequence
Amino acid3 3
Amino acid 1
Amino acid 2
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Amino Acid Sequence
Amino acid 3
Amino acid 1
Amino acid 4
Amino acid 2
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Amino Acid Sequence
Amino acid3 3
Amino acid 1
Amino acid 4
Amino acid 2
Amino acid 5
Amino acid 7
Amino acid 9
Amino acid 6
Amino acid 8
Amino acid 10
Amino acid 11
Amino acid 12
Amino acid 13
ETCgt
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Proteins in the Body

• Protein Synthesis
• Synthesis is unique for each human being and is
  determined by the amino acid sequence.
• Delivering the instructions through messenger RNA
  (genetic material)
• Carries a code to the nuclear membrane
• Presents a list to make a strand of protein
• Transfer RNA lines up the amino acids and brings
  them to the messenger

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Proteins in the Body

• Proteins are versatile and unique. The synthesis
  of protein is determined by genetic information.
• Protein is constantly being broken down and
  synthesized in the body.
• Researchers measure nitrogen balance to study
  synthesis, degradation and excretion of protein.

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Proteins in the Body

• Protein has many important functions in the body.
  
• Protein can be used for energy if needed
  (gluconeogenesis) and its excesses are stored as
  FAT.
• The study of proteins is called proteomics.

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Proteins in the Body

• Roles of Proteins
• Building Materials for Growth and Maintenance
  LIFE
• A matrix of collagen is filled with minerals to
  provide strength to bones and teeth.
• Replaces tissues including the skin, hair, nails,
  and GI tract lining

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Proteins in the Body

• Roles of Proteins
• Enzymes are proteins that facilitate anabolic
  (building up) and catabolic (breaking down)
  chemical reactions.

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Proteins in the Body

• Roles of Proteins
• Hormones regulate body processes and some
  hormones are proteins.
• An example is insulin.

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Proteins in the Body

• Roles of Proteins
• Regulators of Fluid Balance
• Plasma proteins attract water
• Maintain the volume of body fluids to prevent
  edema which is excessive fluid
• Maintain the composition of body fluids

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Proteins in the Body

• Roles of Proteins
• Acid-Base Regulators
• Act as buffers by keeping solutions acidic or
  alkaline
• Acids are compounds that release hydrogen ions in
  a solution.
• Bases are compounds that accept hydrogen ions in
  a solution.
• Acidosis is high levels of acid in the blood and
  body fluids.
• Alkalosis is high levels of alkalinity in the
  blood and body fluids.

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Proteins in the Body

• Roles of Proteins
• Transporters
• Carry lipids, vitamins, minerals and oxygen in
  the body
• Act as pumps in cell membranes, transferring
  compounds from one side of the cell membrane to
  the other

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Proteins in the Body

• Roles of Proteins
• Antibodies
• are large proteins that are found in blood or
  other bodily fluids of vertebrates
• Fight bacteria and viruses, also known as
  antigens, that invade the body
• Provide immunity to fight an antigen more quickly
  the second time exposure occurs

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Proteins in the Body

• Roles of Proteins
• Source of energy and glucose if needed
• Other Roles
• Blood clotting by producing fibrin which forms a
  solid clot
• Vision by creating light-sensitive pigments in
  the retina

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Proteins in the Body

• A Preview of Protein Metabolism
• Protein Turnover and the Amino Acid Pool
• Protein turnover is the continual making and
  breaking down of protein.
• Amino acid pool is the supply of amino acids that
  are available.
• Amino acids from food are called exogenous.
• Amino acids from within the body are called
  endogenous.

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Amino Acid Pool
Cellular Proteins
Dietary Proteins
Amino Acid Pool
Cellular Proteins
Amino Acids
ENERGY
NH3
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Proteins in the Body

• A Preview of Protein Metabolism
• Nitrogen Balance
• Zero nitrogen balance is nitrogen equilibrium,
  when input equals output.
• Positive nitrogen balance means nitrogen consumed
  is greater than nitrogen excreted.
• Negative nitrogen balance means nitrogen excreted
  is greater than nitrogen consumed.

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Proteins in the Body

• A Preview of Protein Metabolism
• Using Amino Acids to Make Proteins or
  Nonessential Amino Acids Cells can assemble
  amino acids into the protein needed.
• Using Amino Acids to Make Other Compounds
• Neurotransmitters are made from the amino acid
  tyrosine.
• Tyrosine can be made into the melanin pigment or
  thyroxine.
• Tryptophan makes niacin and serotonin.

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Proteins in the Body

• A Preview of Protein Metabolism
• Using Amino Acids for Energy and Glucose
• There is no readily available storage form of
  protein.
• Breaks down tissue protein for
• energy if needed

glucose
Body Protein
Dietary Protein
Amino Acids
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Proteins in the Body

• Proteins are versatile and unique. The synthesis
  of protein is determined by genetic information.
• Protein is constantly being broken down and
  synthesized in the body.
• Researchers measure nitrogen balance to study
  synthesis, degradation and excretion of protein.
• Protein has many important functions in the body.
  
• Protein can be used for energy if needed its
  excesses are stored as fat.
• The study of proteins is called proteomics.

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Proteins in the Body

• A Preview of Protein Metabolism
• Deaminating Amino Acids
• Nitrogen-containing amino groups are removed.
• Ammonia is released into the bloodstream.
• Ammonia is converted into urea by the liver.
• Kidneys filter urea out of the blood.
• Using Amino Acids to Make Fat
• Excess protein is deaminated and converted into
  fat.
• Nitrogen is excreted.

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Proteins in the Body
A Preview of Protein Metabolism
Deaminating Amino Acids
O
H
H

• Nitrogen-containing amino groups are removed.
• Ammonia is released into
• the bloodstream.
• Ammonia is converted into
• urea by the liver.
• Kidneys filter urea out of
• the blood.

N
C
C
H
OH
Side group
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Proteins in the Body

• A Preview of Protein Metabolism
• Using Amino Acids to Make Fat
• Excess protein is deaminated and converted into
  fat.
• Nitrogen is excreted.

FAT
Body Protein
Dietary Protein
Amino Acids
Ammonia
Ammonia
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Dietary Protein

• Complete protein contains all the essential amino
  acids needed to build new proteins.
• Animal sources of protein tend to be complete
• Incomplete proteins sources lack one or more
  essential amino acids that the body can't make
  from scratch or create by modifying another amino
  acid
• These usually come from fruits, vegetables,
  grains, and nuts.

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Protein in Foods

• Eating foods of high-quality protein is the best
  assurance to get all the essential amino acids.
• Complementary proteins can also supply all the
  essential amino acids.
• A diet inadequate in any of the essential amino
  acids limits protein synthesis.
• The quality of protein is measured by its amino
  acid content, digestibility, and ability to
  support growth.

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Protein in Foods

• Protein Quality
• Digestibility
• Depends on proteins food source
• Animal proteins are 90-99 absorbed.
• Plant proteins are 70-90 absorbed.
• Soy and legumes are 90 absorbed.
• Other foods consumed at the same time can change
  the digestibility

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Protein in Foods

• Protein Quality
• Amino Acid Composition
• The liver can produce nonessential amino acids.
• Cells must dismantle to produce essential amino
  acids if they are not provided in the diet.
• Limiting amino acids are those essential amino
  acids that are supplied in less than the amount
  needed to support protein synthesis.
• Reference Protein is the standard by which other
  proteins are measured. (Egg White)
• Based on their needs for growth and development,
  preschool children are used to establish this
  standard.

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Protein in Foods

• Protein Quality
• High-Quality Proteins
• Contains all the essential amino acids
• Animal foods contain all the essential amino
  acids.
• Plant foods are diverse in content and tend to be
  missing one or more essential amino acids.
• Complementary Proteins
• Combining plant foods that together contain all
  the essential amino acids
• Used by vegetarians

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Protein in Foods

• Protein Quality
• A Measure of Protein Quality - PDCAAS (protein
  digestibility-corrected amino acid score)
• Compares amino acid composition of a protein to
  human amino acid requirements
• Adjusts for digestibility

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Protein in Foods

• Protein Regulation for Food Labels
• List protein quantity in grams
• Daily Values is not required but reflects
  quantity and quality of protein using PDCAAS.

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Health Effects and Recommended Intakes of Protein

• Protein deficiency and excesses can be harmful to
  health.
• Protein deficiencies arise from protein-deficient
  diets and energy-deficient diets.
• This is a worldwide malnutrition problem,
  especially for young children.
• High-protein diets have been implicated in
  several chronic diseases.

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Health Effects and Recommended Intakes of Protein

• Protein-Energy Malnutrition (PEM) also called
  protein-kcalorie malnutrition (PCM)
• Classifying PEM
• Chronic PEM and acute PEM
• Maramus, kwashiorkor, or a combination of the two

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Health Effects and Recommended Intakes of Protein

• PEM
• Marasmus
• Infancy, 6 to 18 months of age
• Severe deprivation or impaired absorption of
  protein, energy,
• vitamins and minerals
• Develops slowly
• Severe weight loss and muscle wasting, including
  the heart
• lt 60 weight-for-age
• Anxiety and apathy
• Good appetite is possible
• Hair and skin problems

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Marasmus
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Health Effects and Recommended Intakes of Protein

• PEM
• Kwashiorkor
• Older infants and young children, 18 months to 2
  years of age
• Inadequate protein intake, infections
• Rapid onset
• Some muscle wasting, some fat retention
• Growth is 60-80 weight-for-age
• Edema and fatty liver
• Apathy, misery, irritability and sadness
• Loss of appetite
• Hair and skin problems

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Kwashiorkor
d
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Health Effects and Recommended Intakes of Protein

• PEM
• Marasmus-Kwashiorkor Mix
• Both malnutrition and infections
• Edema of kwashiorkor
• Wasting of marasmus

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Health Effects and Recommended Intakes of Protein

• PEM
• Infections
• Lack of antibodies to fight infections
• Fever
• Fluid imbalances and dysentery
• Anemia
• Heart failure and possible death
• Rehabilitation
• Nutrition intervention must be cautious, slowly
  increasing protein.
• Programs involving local people work better.

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Health Effects and Recommended Intakes of Protein

• Health Effects of Protein
• Heart Disease
• Foods high in animal protein also tend to be high
  in saturated fat.
• Homocysteine levels increase cardiac risks.
• Arginine may protect against cardiac risks.

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Health Effects and Recommended Intakes of Protein

• Health Effects of Protein
• Cancer
• A high intake of animal protein is associated
  with some cancers.
• Is the problem high protein intake or high fat
  intake?

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Health Effects and Recommended Intakes of Protein

• Health Effects of Protein
• Adult Bone Loss (Osteoporosis)
• High protein intake associated with increased
  calcium excretion.
• Inadequate protein intake affects bone health
  also.

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Health Effects and Recommended Intakes of Protein

• Health Effects of Protein
• Weight Control
• High-protein foods are often high-fat foods.
• Protein at each meal provides satiety.
• Adequate protein, moderate fat and sufficient
  carbohydrate better support weight loss.
• Kidney Disease
• High protein intake increases the work of the
  kidneys.
• Does not seem to cause kidney disease

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Health Effects and Recommended Intakes of Protein

• Recommended Intakes of Protein
• 10-35 energy intake
• Protein RDA
• 0.8 g/kg/day
• Assumptions
• People are healthy.
• Protein is mixed quality.
• The body will use protein efficiently.

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Health Effects and Recommended Intakes of Protein

• Recommended Intakes of Protein
• Adequate Energy
• Must consider energy intake
• Must consider total grams of protein
• Protein in abundance is common in the U.S. and
  Canada.

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Health Effects and Recommended Intakes of Protein

• Protein and Amino Acid Supplements
• Protein Powders have not been found to improve
  athletic performance.
• Whey protein is a waste product of cheese
  manufacturing. (Chicken Wings of the supplement
  industry)
• Purified protein preparations increase the work
  of the kidneys.

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Health Effects and Recommended Intakes of Protein

• Protein and Amino Acid Supplements
• Amino Acid Supplements are not beneficial and can
  be harmful.
• Branched-chain amino acids provide little fuel
  and can be toxic to the brain.
• Lysine appears safe in certain doses.
• Tryptophan has been used experimentally for sleep
  and pain, but may result in a rare blood disorder.

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Protein Chronic Disease

• Cardiovascular disease it is possible that
  eating more protein, especially vegetable
  protein, while cutting back on easily digested
  carbohydrates may benefit heart disease
• Diabetes the amount of protein in the diet
  doesn't seem to adversely affect the development
  of type 2 (adult-onset) diabetes, although
  research in this area is ongoing
• Cancer there's no good evidence that eating a
  little protein or a lot of it influences cancer
  risk

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Protein Weight Control

• High-protein, low-carbohydrate diets may work
  more quickly than low-fat diets, at least in the
  first six months.
• After a year or so, weight loss is about equal

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Protein Weight Control

• Slower stomach emptying means you feel full for
  longer and get hungrier later.
• Protein's gentle, steady effect on blood sugar
  avoids the quick, steep rise in blood sugar that
  occurs after eating a rapidly digested
  carbohydrate, like white bread or baked potato
• The body uses more energy to digest protein than
  it does to digest fat or carbohydrate.

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Recommendations for Protein Intake

• Get a good mix of proteins. Almost any reasonable
  diet will give enough protein. Eating a variety
  of foods will ensure that all of the amino acids
  need are available.
• Pay attention to the protein package Some comes
  packaged with lots of unhealthy fat, Some without
  much saturated fat and with plenty of healthful
  fiber and micronutrients.

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Recommendations for Protein Intake

• Balance carbohydrates and protein.
• Cutting back on highly processed carbohydrates
  and increasing protein improves levels of blood
  triglycerides and HDL, and may reduce the chances
  of having a heart attack, stroke, or other form
  of cardiovascular disease.
• It may also make you feel full longer, and stave
  off hunger pangs.
• Too much protein, though, could weaken bones.

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Recommendations for Protein Intake

• AGE grams/pound amount
• 0-6 months 1 gram/ 13 grams
• 6-12 mo .7 gms/ 14 grams
• 1-3 years .6 gms/ 16 grams
• 4-6 .55 gms/ 24 grams
• 7-14 .45 gms/ 28-45 gms
• 15-18 .4 gms/ 44-59 gms
• Adults .35 gms/ 50-65 gms

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Protein Intake Summary

• Important for growth (height) and development
• Needed in smaller amount than most people think
  (.8 grams/kilogram BW) RDA
• Can be gotten from a variety of plant foods as
  well as the animal foods (meat, dairy)?
• Use as a part of the meal, not as the meal (eat
  lean, less and last)?