Chapter 7

Protein qulaity complementary proteins

Proteins lacking two or more essentail amino acids combined with protein that supplies the missing amino acids

Vegetarianism has evolved over centuries from a necessity into an option for many people. What are some of the reasons people choose a vegetarian diet?

Religious reasons • E.g. Hindus, Seventh-Day Adventists, and Trappist monks • Philosophical reasons • Ecological and/or economic reasons • E.g. Meat is not an efficient way of obtaining protein because it requires the use of ~40% of the world's grain production to raise meat-producing animals. • Health-related reasons • Diets rich in fruits, vegetables, legumes, and grains frequently result in increased intakes of antioxidant nutrients (e.g. vitamins C and E and carotenoids), dietary fiber, and healthful phytochemicals and a decreased intake of saturated fat and cholesterol

WHat if the body does not need new protein or if the body needs energy

amino acids can be taken furtehr apart into carbon, hydrogen, oxygen and nitrogen Deamination

Importance of protein

amino acids must be continually availalble to build new protein Needed each day Protein turnover

Legume

beans and peas Black beans Red beans Lima beans navy beans Chili beans Split peas

Thinking about food or chewing food stimulates

gastrin producing cells ofthe stomach to release hormone Produce acid, aides in digestion and activation of pepsin

Many legumes are deficient in the essential amino acid __________, whereas cereals are limited in ________.

methionine lysine

Essential amino acids

msut be supplied by the diet

• The ___________ ________ of a protein is a measure of how efficiently the absorbed food protein is converted into body tissue protein.

biologicbal value

Vegetable sources of protein

breads, crackers, rice Legumes( beans, peas and lentils Peanut butter Nuts-- cashewes, pecans, macadamia, filberts Seeds, sunflower

Proteins composed of central carbon bonded to 4 groups of elements such as

nitrogen: amino Acid: carboxyl group Hydrogen A side chain : R

Hemoglobin is an example of protein with what strcutrue

quarternary

• The most widely used measure of protein quality is called the _________ ________ _________ _______ _______ ________. • This score is derived by multiplying a food's chemical score by its digestibility.

protein digestibility corrected amino acid score

• ________ _________ _________ is another method for assessing a food's protein quality by comparing the amount of weight gain by growing a laboratory animal consuming a standardized amount of the protein being studied with the weight gain by an animal consuming a standardized amount of a reference protein (such as casein - milk protein).

protein efficiency ratio

• Most vital body proteins are in a constant state of breakdown, rebuilding, and repair. This process is called _______ ________, and it allows cells to adapt to changing circumstances.

protein turnover`

acquired or specific immunity

provides an immune response that is initiated by the recognition of a specific antigen. • Acquired immunity develops over a person's lifetime. • It may also be referred to as adaptive immunity because after exposure to an antigen the immune system can recognize the antigen and adapt its response to it

Proteins act as _______ - compounds that help maintain acid-base balance within a narrow range.

buffer

Amino acids

building blocks of protein

When gluconeogenesis occurs chronically, as in starvation, the conversion of amino acids into glucose results in the development of widespread muscle wasting in the body, called ____________

cachexia

Non essentail amino acid

can be made in the body

Marsmus

Common in children muscle wasting Impairments Disease conditions Preventing death

Protein deficiency is the worl leading form of

malnutrition

Sources of animal protein in a diet

Meat Poultry Fish Milk Cheese Eggs Yogurt Shellfish

RDA amt of protein

.8 gm/kg 10-35% of kcal Take weight'/ 2.2 Wt in kg x .8 grams

Protein in fruits and oils or fats

0 grams

RDA for protein

0.8 g/kg of body weight

Adult Protein requirements

0.8 gram/kg

Vegetarian protein requirements

0.9 gram/kg

Endurance athlete protein requirements

1.2-1.4 grams/kg

Athlete protein requirements

1.7-1.8 grams/kg

How to calculate nitrogen balance

16% of protein molecule N x 6.26 = g protein

Protien foods contain how many different amino aicd

20

Protein in grams amount of food

3 ounces of meat= 21 grams protein 1 cup milk= 8 grams protein 1 slice of bread = 3 grams protein 1/2 cup of veggies = 2 grams protein

• Growth • Pregnancy • Recovery state after illness/injury • Athletic training resulting in increased lean body mass • Increased secretion of certain hormones, such as insulin, growth hormone, and testosterone

56 46

• In typical North American diets, about __% of dietary protein is supplied by meat, poultry, fish, milk, cheese, legumes, and nuts. Worldwide, only __% of protein comes from animal sources.

70 35

Negative Nitrogen balance

Amount of nitrogen in urine is greater than amount in diet Body is losing nitrogen BOdy breaking down muscle for energy Seen in starvation, cancer, anorexiaq

Digestion and absorption of protein

Begins in stomach with pepsin Continues in the small intetine with trypsin from pancreas and protease form small intestine Breaks down into individual amino acids Amino acids absorbed into blood stream First stops at liver Amino acids stored temporarily

Amino acid supplements

Body desinged ot work with whole proteins No safe level of amino acid supplementation

Deamination

Break down of amino acid Takes place in liver used to generate energy Urea is a waste produce from theis process Urea is eliminated from the body in the urine

Non essential amino acids

Can be made in the body if protein is adequate Made in liver used to make body proteins

Several non essentail amino acids may be classified as ____ amino acids during infancy, disease or trauma

Conditionally essentail

Protein Excess

Consuming too mch protein Weight loss: not the propotion of eerngy nutrietns heart disease: animal derived protein rich foods Adult bone loss Cancer Low gluten diet

Protein suplments

Do not improve performance Not effective for weight loss

What happens in the liver

Growth and repair Amino acids can be organized into chains using the recipe provided by the DNA to make new proteins This is the primary use of protein the diet

• Vegans follow the most restrictive diet, as they only eat plant foods. Because they do not eat any animal foods, their diets may be low in:

High biological value protein • Riboflavin • Vitamin D • Vitamin B12 • Calcium • Zinc • Vegan diets are healthful when they are carefully planned. • Lacto-vegetarians include dairy in their diet but not meat, fish, poultry and eggs. • Lacto-ovo vegetarians diet includes milk and eggs but not meat, fish, and poultry

immunity is present at birth and provides the first barrier of protection against invading antigens.

INNATE OR nonspecific

what occurs when negative nitrogen balance occurs

Inadequate intake of protein • Inadequate energy intake • Conditions such as fevers, burns, and infections • Bed rest (for several days) • Deficiency of essential amino acids (e.g. poor quality protein consumed) • Increased protein loss (as in some forms of disease) • Increased secretion of certain hormones, such as thyroid hormone and cortisol

Positive Nitrogen Balance

Intake of nitrogen in food greater than amount in urine Means the body is retaining nitrogen Seen in growth and repair Kids are in positive balance Woemen during pregngnacy Recovery from injury

Incomlete protein

Lacking or more essential amino acids Usually vegetable protein Single food cannot promote

Examples of protein qulaity complementary proteins

Legumes lack methionin and tryptophan Grains lack isoleucine and lysine Mix grains with legumes to complete

Why is protein restricted in kidney disease

Liver continues ot make urea from excess nitrogen from excess amino acids Kideny cannot eliminate the urea Urea is increased in blood and can cause uremic poisoning

Tryptophan uses

Make B vitamin niacin Makes serotonin neurotransmitter

Examples of nonessentail amino acids

Phenyalanine can be changed into the non essentail amino acid tyrosine Factor in PKU disease

Essential amino acids building blocks of proteins

Phyenyalanine Valine Threonine Tryptophan Isoleucine Methionine Histidine Leucine Lysine

Examples of Incomplete protein

Plant origin Nuts, grains, peanut butter, beans

Most people most likely harmed by amino acid supplememtns

Pregnant women Infants/children Elderly people SMokers Low protein diets Chornic or acute mental or physical illness

Nitrogen Blanace

Protein 16% nitrotgen Amount can be calculated from food Lost in the body through urea: can measrue amt in urine Compare amount in nitrogen coming in to the amount excreted nitrogen balance

Transamination

The process by which an amino group from one amino acid is transferred to a carbon compound to form a new amino acid.

• True or False • Except during infancy, it is uncommon for intact proteins to be absorbed from the digestive tract.

True or False • Except during infancy, it is uncommon for intact proteins to be absorbed from the digestive tract. • In early infancy (up to 4-5 months of age), the GI tract is somewhat permeable to small proteins, so some small proteins can be absorbed. • Because proteins from foods such as cow's milk and egg white may predispose an infant to food allergies, pediatricians and registered dietitians recommend waiting until an infant is 12 months of age or older before introducing common allergenic foods.

Kwashirokor

Waning of babies off formula Fluid balance diminished Changes in body Risk of infection PEM at home

What could cause denaturation

acid/alakline Enzymes Heat Agitation

The release of pepsin is controlled by the hormone

gastrin

Examples of complete protein

anaial foods except gelatin Plant source is soy Single source can sustain growth and repair

Protein digestibility

animal proteins legumes

The protein quality of a food also can be evaluated by its _________ ________, which is the amount of each essential amino acid in a gram of the reference protein being tested, divided by the "ideal" amount for that amino acid in a gram of reference protein (usually egg protein)

chemical score

Unline animal proteins, plant proteins contain no ___ and little ____ fat

cholesterol Saturated fatq

These key structural proteins constitute more than a third of the body protein and provide a matrix for muscle, connective tissue, and bone:

collagen actin myosin

Structure of protein

consists of oxygen, carbon, hydrogren and nitrogen

• Protein quality is determined by the food's ___________ (amount of amino acids absorbed) and _____ _____ ____________ compared with a reference protein (e.g. egg white protein) that provides the essential amino acids in amounts needed to support growth.

digestibilty Amino acid composition

high quality proteins

enoug h of all essential amino acids

The concept of protein quality applies only under conditions in which protein intakes are:

equal to or less than the amount of protein needed to meet the requirement for essential amino acids.

Anaimal proteins contain all

essentail amino acids Complete protein

The nine amino acids that must be obtained from the diet are termed

essentail or indispenssable amino acids

Complete protein

food that contains all essentail amino acids

• If carbohydrate intake is inadequate to maintain blood glucose levels, the liver (and kidneys to a lesser extent) is forced to make glucose from the amino acids present in body tissues in a process called _____________.

gluconeogenesis

Amino acids are required for the synthesis of most _________, which act as messengers in the body and aid in regulatory functions, such as controlling the metabolic rate and the amount of glucose taken up from the blood stream.

hormones

• The enzymatic digestion of protein begins in the stomach with the secretion of _________ _____.

hydrochloric acid

Lacgto ovo

includes milk, eggs, vegetables, grains, legumes, fruits nuts Excludes meat, poultry, fish, and seafood

The essentail amino acid in the samllest supply in a food or diet in relation ot body needs is called the

limiting amino acid limits amount of protein body can synthesize

Protein energy malnutrioitn

locations of prevalence Effects of PEM: childrena dn adults 2 forms

Tryrosine used to

make skin pigment melanine and epinephrine

11 of the amino acids do not need to be obtained htorugh the diet they are termed ____ or ____ amino acids

nonessential or dispensible

• Once proteins are denatured by the stomach acid, _______, a major enzyme produced by the stomach, begins to break the long polypeptide chains into shorter chains of amino acids through hydrolysis reactions.

pepsin

• Pepsin is stored as an inactive enzyme called __________. This prevents it from digesting the stomach lining.

pepsinogen

Vegan

plant based foods: vegetables, grains,legumes, fruits, seeds, and nuts STRICT VEGETARIAN

• In the small intestine, chime triggers the release of the hormones ___________ and ___________ from the walls of the small intestine.

secretin Cholecystokinin

Elementas of protein are arranged into

strucutres called amino acids

Nonessentail amino acids synthesized thorugh

transamintation

Kwashiorkor characteristics

• Condition occurring primarily in young children who have an existing disease and consume a marginal amount of energy and severely insufficient protein. • It results in edema, poor growth, weakness, and an increased susceptibility to further infection and disease. • Bloated bellies • Occurs more rapidly

Marasmus characteristics

• Condition that results from a severe deficit of energy and protein, which causes extreme loss of fat stores, muscle mass, and body weight. • Develops slowly • Skin and bones appearance

The Food and Nutrition Board suggests that protein intake not exceed 35% of energy intake. Why would this be?

• Diets containing an excessive or disproportionate amount of protein do not provide additional health benefits. • High protein intakes may increase health and disease risks. • High protein diets may overburden the kidneys' capacity to excrete nitrogenous wastes. • Remember, the kidneys are responsible for excreting excess nitrogen as urea. • Because excess water is needed to dilute and excrete urea, inadequate fluid intake can increase the risk or dehydration as the kidneys use body water to dispose of the urea. • When excess protein is primarily from a high intake of animal proteins, the overall diet is likely to be low in plant-based foods and consequently low in fiber, some vitamins (vitamin C, vitamin E, and folate), minerals (magnesium and potassium), and beneficial phytochemicals. • Animal proteins are often rich in saturated fat and cholesterol and may be cured. As a result, these diets can increase the risk of cardiovascular disease and cancer. • High protein diets also may increase urinary calcium loss and eventually lead to a loss of bone mass and an increased risk of osteoporosis. • There are also health risks associated with excess protein and amino acid supplementation, since our bodies are designed to obtain amino acids from dietary sources of whole proteins.

What occurs wehn there is a positive nitrogen balance

• Growth • Pregnancy • Recovery state after illness/injury • Athletic training resulting in increased lean body mass • Increased secretion of certain hormones, such as insulin, growth hormone, and testosterone

• What 8 foods are responsible for 90% of all food allergies?

• Peanuts • Tree nuts • E.g. walnuts, cashews • Milk • Eggs • Fish • Shellfish • Soy • Wheatc