Protein. Surprisingly little is known about protein and health but some recommendations Adults need...

Protein

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

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.

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

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.

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.

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.

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

Amino Acids

N C CH

HH OH

O

Side groupSide groupSide group differencesis how the twenty amino acids are different .

AmineGroup

Acid Group

The Chemist’s View of Proteins

Amino Acids The unique side groups result in

differences in the size, shape and electrical charge of an amino acid

The Chemist’s View of Proteins Amino Acids

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

The Chemist’s 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.

The Chemist’s 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.

Peptide Bonding

N C CH

H

H

OH

O

Side group 1

N C C

Side group 2

HH

H OH

O

water

Amino Acid 1 Amino Acid 2

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

Amino Acid Sequence

Amino acid 1 Amino acid

2

Amino Acid Sequence


2

Amino acid3 3

Amino Acid Sequence


2

Amino acid 3Amino acid 4

Amino Acid Sequence


2

Amino acid3 3 Amino acid

4

Amino acid 5

Amino acid 6

Amino acid 7Amino acid

8

Amino acid 9


11

Amino acid 13

Amino acid 12

ETC>

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

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.

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.

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


Roles of Proteins Enzymes are proteins that

facilitate anabolic (building up) and catabolic (breaking down) chemical reactions.


Roles of Proteins Hormones regulate body

processes and some hormones are proteins.

An example is insulin.

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


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.


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


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


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


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.

Amino Acid Pool

DietaryProteins

Amino AcidsAmino Acid

Pool

CellularProteins

CellularProteins

ENERGY NH3


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.

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.


Using Amino Acids for Energy and Glucose

There is no readily available storage form of protein.

Breaks down tissue protein for energy if needed

Dietary Protein Amino Acids

Body Protein

glucose

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.


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.


N C CH

H

H

OH

O

Side groupSide group

•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.

A Preview of Protein Metabolism Deaminating Amino Acids

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.

Dietary Protein Amino Acids

Body Protein

FAT

AmmoniaAmmonia

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.

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.

Protein in Foods

Protein Quality Digestibility

Depends on protein’s 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

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.

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

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

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.

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.


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


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 < 60% weight-for-age Anxiety and apathy Good appetite is possible Hair and skin problems

Marasmus


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

Kwashiorkor

d


PEM Marasmus-Kwashiorkor Mix

Both malnutrition and infections Edema of kwashiorkor Wasting of marasmus


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.


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.


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?


Health Effects of Protein Adult Bone Loss (Osteoporosis)

High protein intake associated with increased calcium excretion.

Inadequate protein intake affects bone health also.


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


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.


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.


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.


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.

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

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

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.

Protein & Weight Control

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.

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.

Recommendations for Protein Intake

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

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)

Protein Intake Summary

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Protein. Surprisingly little is known about protein and health but some recommendations Adults need...

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