Health and Nutrition – Unit 7, Protein

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Animal foods, such as meat and eggs, contain some protein, lipids, and water.

False

Foods made from processed soybeans can be sources of high quality protein.

True

The typical American eats more protein from animal sources.

True

Registered dietitians generally do not recommend that healthy people take amino acids supplements to increase their protein intake.

False

People cannot "feed" their hair by using shampoo that contains protein. Hair is not a living tissue.

False

What Are Proteins?

•Complex organic molecules – Composed of carbon, hydrogen, and oxygen – Proteins also contain nitrogen •The human body contains an estimated 200,000 different proteins. Proteins are complex organic molecules that are chemically similar to lipids and carbohydrates – they contain carbon, hydrogen, and oxygen atoms. Proteins, however, contain nitrogen, the element cells need to make a wide array of important biological compounds. Plants, animals, bacteria, and even viruses contain hundreds of proteins.

The body uses proteins to make or function as

New cells and many components of cells Structures such as hair and nails Enzymes Lubricants Clotting Compounds Antibodies Compounds that maintain fluid and Ph balance Certain hormones and neurotransmitters Energy source – minor, under unusual conditions Proteins are necessary for muscle development and maintenance, but the more than 200,000 different proteins in your body have a wide variety of functions. Skin, blood, nerve, bone—all cells in your body—contain proteins. Structural proteins such as collagen are in your cartilage, ligament, and bone tissue. Keratin is another structural protein; it is in your hair, nails, and skin. Contractile proteins in your muscles enable you to move, and transport proteins carry many substances in the bloodstream. Proteins are also necessary for your blood to clot properly.

Types and Functions of Proteins

All cells in the body contain proteins. Specific types of proteins include: •Structural proteins in cartilage, ligaments, bones, hair, skin, and nails •Contractile proteins that enable muscles to move •Pigment proteins such as melanin determine color of eyes, hair, and skin •Clotting proteins that are needed for blood clotting

Certain hormones are proteins

– Hormones are chemical messengers that regulate body processes and responses. •Examples: insulin and glucagon

Enzymes are proteins

– Compounds that speed up (catalyze) chemical reactions without becoming part of the products

Transport proteins

– Oxygen and many nutrients are transported in blood by special proteins. •Proteins aid in fluid balance.

Fluid Balance and Proteins

•Proteins in blood help maintain the proper distribution of fluids within bloodstream and body tissues.

Acid-base balance

– Maintaining the proper pH of body fluids

Blood and tissue fluid must maintain a pH of 7.35 to 7.45

•Acidic – having an excess of H+ •Too basic – not enough H+ Proteins act as buffers by accepting or releasing H+

Proteins are made of smaller units called amino acids.

-20 different amino acids in human proteins

Each amino acid is composed of

1) An amino or a nitrogen-containing group •Amino group has nitrogen bonded to 2 hydrogen atoms 2) R-group (side chain) — varies with each amino acid 3) Acid group – acid portion

Essential Amino Acids

•Cannot be made by the body •must be supplied by the diet •9 of the 20 amino acids

Nonessential Amino Acids

•Can be made by the body •11 of the 20 amino acids

Proteins in Foods

•Nearly all foods contain some protein, but no natural food is 100% protein. •Animal foods typically have more protein than plant foods. -Seeds, tree nuts, and legumes supply more protein than fruit or the edible leaves, roots, flowers, and stems of vegetables.

What Are Legumes?

•Legumes – Plants that produce pods with a single row of seeds Examples: Soybeans, peas, peanuts, lentils, and beans

High-quality protein (complete protein)

-Contains all 9 essential amino acids in amounts that support growth -Most animal products -High-quality plant foods: quinoa and processed soy

Low-quality protein (incomplete protein)

-Lacks or has inadequate amounts of 1 or more essential amino acid -Most plant foods and gelatin (animal tissue byproduct)

How Your Body Synthesizes Proteins

-Cells assemble the 20 amino acids in specific sequences according to information provided in DNA. -Amino acids are connected by peptide bonds. -Peptides •Chains of < 15 amino acids -Polypeptides •Proteins made of > 50 amino acids

Amino Acids form Proteins

•Each distinctive bead in the illustration represents a different amino acid. •The "hook" that connects the "beads" represents a peptide bond

Sickle Cell Anemia

•If the DNA code is faulty, the wrong amino acid may be inserted into a protein, causing detrimental effects, such as defective hemoglobin. -Sickle cell anemia is an inherited condition that affects red blood cells.

Protein Denaturation

Denaturation •Altering a protein’s natural shape and function by exposing its various conditions, including heat, alcohol, acid, and physical agitation -Heat denatures protein in raw eggs. -Acidic lemon juice "curdles" protein in milk. -Hydrochloric acid denatures food proteins in the stomach, making them easy to digest. -Physical agitation includes whipping foods, such as beating egg whites to incorporate air into them

Protein digestion begins in the stomach.

-Hydrochloric acid denatures proteins. -The enzyme pepsin digests proteins into smaller polypeptides.

Polypeptides enter the small intestine

-The enzymes trypsin and chymotrypsin break down polypeptides into shorter peptides and individual amino acids.

•Absorption occurs in the small intestine

– Absorptive cells release enzymes that digest most small peptides into individual amino acids. – Individual amino acids and some di- and tripeptides enter absorptive cells, where they are completely digested to amino acids.

Protein turnover

– Breaking down old or unneeded proteins into amino acids and recycling the amino acids

Amino acid "pool"

– Amino acids that have not been incorporated into proteins 1)Endogenous amino acids – Those available from the amino acid pool 2)Exogenous proteins – Those from dietary sources

Transamination

-Transfer of nitrogen-containing group from an unneeded amino acid to a carbon skeleton, forming an amino acid

Deamination

– Removal of nitrogen-containing group from an unneeded amino acid

Deamination and Urea Formation

Ammonia (NH3) is converted to urea that the kidneys excrete in urine

Nitrogen balance (or nitrogen equilibrium)

Balancing nitrogen intake with nitrogen losses

Positive nitrogen balance

Body retains more nitrogen than it loses Occurs during growth, pregnancy, recovery from illness, and as a result of certain hormones and resistance exercise Growth Pregnancy Recovery from illness increased levels of hormones insulin, testosterone, & growth hormone resistance exercises

Negative nitrogen balance

Body loses more nitrogen than it retains Occurs with (down) protein intake, kidney disease, blood loss, bed rest, fever, injuries, burns, or (up) thyroid hormone or cortisol (stress hormones)

Nitrogen Equilibrium

Occurs when healthy adults meet protein & energy needs

How Much Protein Do You Need?

Daily protein needs of healthy adults: RDA = 0.8 g/kg body wt Protein needs increase during periods of growth, pregnancy, lactation, and recovery from illness or injury.

Determining Protein Needs

Using the RDA formula of 0.8 g of protein/kg of body wt, what is the RDA for protein for a person weighing 165 lbs? •Convert weight in lbs to weight in kg • 165 divided by 2.2 = 75 kg •2) Multiply kg of body wt by 0.8 • 75 X 0.8 = 60 •Therefore, a person weighing 165 lbs will meet his/her RDA for protein by consuming 60 g of protein per day

Allergy

-Inflammatory response resulting when body’s immune system reacts inappropriately to a substance that is typically harmless •Allergen — the offending substance -Most food allergens are proteins that escape digestion and are absorbed as whole proteins. certain amino acids or proteins cause havoc in the body, resulting in serious health problems and even death. the most allergenic proteins are in cow’s milk, eggs, peanuts and other nuts, wheat, soybeans, fish, and shellfish. Allergic responses to nonprotein food dyes or other food additives such as sulfites can also occur. Sulfites are a group of sulfur-containing compounds that result from the metabolism of certain amino acids. Sulfites can be found naturally in foods, but the compounds are often added to wines, potatoes, and shrimp as a preservative

Common Signs of Food Allergies

Signs occur within a few minutes or couple of hours and typically include: -Hives (red raised bumps on skin) -Swollen or itchy lips -Skin flushing -Scaly skin rash (eczema) -Difficulty swallowing -Wheezing and difficulty breathing -Abdominal pain, vomiting, and diarrhea

Common Food Allergens

Protein-rich foods -Cow’s milk -Eggs -Peanuts – Wheat – Soybeans – Fish & shellfish Nonproteins – Food dyes – Sulfites added to: •Wine •Potatoes •Shrimp

Who Develops Food Allergies?

•People with family history of food or environmental allergies •~ 6% of children •Most children outgrow their allergies by age 5 yrs – Allergies to nuts, seafood, and wheat are typically not outgrown •~ 3-4% of adults

Treatment of Food Allergies

•Avoid offending foods •Read food labels to check for allergens •Food Allergen Labeling & Consumer Protection Act requires manufacturers to identify allergenic ingredients on product labels. •Educate teachers and other adults of allergic children’s need to avoid certain foods

Treating Severe Allergic Reactions

•Emergency treatment for anaphylaxis may involve injecting a special medication. In the United States, approximately 6% of young children suffer from food allergies.10 Since 1997, the prevalence of food allergies among children under 18 years of age has been increasing in the United States. Children with food allergies are more likely than other children to experience other allergies and asthma. Most youngsters outgrow their food allergies by the time they are 5 years old. Allergies to nuts, seafood, and wheat, however, usually are not outgrown. According to the American Academy of Allergy, Asthma, and Immunology, 3 to 4% of adults in the United States have one or more food allergies Accurate diagnosis of a food allergy should be undertaken by an immunologist, a physician who specializes in the diagnosis and treatment of allergies. Skin testing is a reliable way to identify allergens. Although hair analysis, cytotoxic or electrodermal testing, and kinesiology are promoted by alternative medical practitioners to diagnose allergies, these are unproven diagnostic methods

Gluten and Celiac Disease

•Gliadin -Protein found in gluten of wheat, buckwheat, barley, and rye -Triggers inflammatory response in small intestine -Condition called celiac disease •Symptoms include -Chronic diarrhea, weight loss, and poor growth in children •Treatment -Avoid gluten-containing foods

Phenylketonuria (PKU)

-Genetic disorder -Affects ~ 1/10,000 to 1/15,000 infants -Caused by lack of enzyme that converts the amino acid phenylalanine to another compound -If undiagnosed, infant will develop mental retardation by first birthday.

Low Phenylalanine Diet

Infancy Phenylalanine-free formula and low-phenylalanine foods Childhood and adult years Allowed: fruits, vegetables, and special low-phenylalanine foods Avoided: nuts, milk and milk products, eggs, meats, as well as foods and beverages containing aspartame (e.g., Nutrasweet or Equal)

MyPlate: Recommendations for Protein Intake

•Choose lean or low-fat meat and poultry -Lean cuts of beef include: •Round steaks, top round, loin, top sirloin, chuck and arm roasts -Lean pork cuts include: •Loin, tenderloin, and center loin •Choose "extra lean" ground beef -At least 90% lean •Trim visible fat from meats

Understanding Nutritional Labeling

•Nutrition Facts panel does not provide information concerning protein quality -Judge protein quality by reviewing items in the ingredient list

Eating Well for Less

– Substitute eggs, milk, cheese, and yogurt for meat, fish, or poultry. – Make meals that contain less animal proteins and more plant proteins. – Extend cereal proteins with eggs & milk (e.g., pancakes, waffles, crepes, or cereal with milk). – Include more legumes in meals (e.g., chili, bean soups, and stews) while reducing meat content.

Combining Complementary Proteins

Complementary combinations – Mixing certain plant foods to provide all essential amino acids without adding animal proteins Amino acids often low or limiting in plant proteins: tryptophan, threonine, lysine, and methionine

Complementary Dishes

peanut butter on bread Couscous (grain) with chickpeas (legumes)

Vegetarians- People who eat plant-based diets

Types of Vegetarians • Lactovegetarian •Consumes milk and milk products • Ovovegetarian •Consumes eggs • Lactoovovegetarian •Consumes eggs, milk, and milk products •Vegan •Consumes only plant foods

Is Vegetarianism a Healthy Lifestyle? Pros

Pros •Compared to nonvegetarians, vegetarians tend to: -Weigh less -Have less heart disease (eat less saturated fat and cholesterol) -Often exercise more, meditate for relaxation, and avoid tobacco & alcohol

Is Vegetarianism a Healthy Lifestyle? Cons

Cons •If diets are poorly planned, vegetarians may lack: -Calories -High-quality protein -Omega-3 fatty acids -Vitamins B-12 and D -Zinc, iron, and calcium

Vegetarian Children and Teens

Children •May be difficult to consume adequate protein and energy, because plant foods tend to be filling. -Growth rates of vegan children need close monitoring. Teens Pro: Can be healthy diet because more fruits and vegetables are consumed Con: May be at risk of anorexia nervosa Pregnancy •May need vitamin B-12 supplements -Infant could be deficient in B-12 Breastfeeding •Breastmilk may be deficient in vitamin B-12 -Infant may develop severe developmental delays if fed breast milk that lacks vitamin B-12

Protein Adequacy

Excessive Meat Intake -May increase risk of heart disease and cancers of the colon/rectum and possibly prostate What about High-Protein Weight-Loss Diets? -Such diets decrease feelings of hunger and increase sense of fullness.

Protein Deficiency

Uncommon in the U.S. – May occur in: •elderly or low-income people •persons with alcoholism, anorexia nervosa, or intestinal tract disorders

Kwashiorkor and Marasmus

Undernutrition -Results from chronic lack of food or poor food choices Two types of protein-energy undernutrition: -Kwashiorkor •Adequate energy intake but intake of high-quality protein is low »Edema -Marasmus •Starvation—extreme weight loss

Marasmic Kwashiorkor

Characterized by edema in the abdomen, lower legs, and feet

Proteins: General Advice for Athletes

How to increase muscle mass? •Resistance training is the only safe and reliable way. •Protein and amino acids supplements are not needed.

What About Protein Supplements?

•Healthy people adapt to protein intakes higher than the AMDR with no problems. •Best to avoid supplements with individual amino acids.

Stretching Your Food Dollars

Where and What You Buy Vending machines, convenience stores, fast-food outlets, etc. How to Shop Wisely in Supermarkets Plan meals Use a shopping list Compare products and prices

A. General characteristics of protein

1. Complex organic molecules containing carbon, hydrogen, oxygen, and nitrogen 2. Vast array of body functions a. Development and maintenance of all body tissues b. Structure (e.g., collagen, keratin) c. Muscle contraction d. Pigments e. Blood clotting f. Hormones: chemical messengers that regulate body processes and responses g. Enzymes: compounds that speed up chemical reactions h. Immune function (e.g., antibodies) i. Source of energy (to a limited extent) j. Transport of nutrients and oxygen k. Maintenance of fluid balance i. Concentration of proteins in blood retains fluid in the blood ii. Low blood protein concentrations allow fluid to leak from blood into surrounding tissues, resulting in edema l. Maintenance of acid-base balance: proteins act as buffers because they have both acidic and basic components

Amino acids

1. Nitrogen-containing chemical building blocks of proteins 2. 20 different amino acids are used to make proteins for the human body 3. Chemical structure consists of: a. Carbon skeleton i. Carbon ii. R group (a.k.a. side chain): determines the amino acid’s physical and chemical properties iii. Acid group b. Amino (a.k.a. nitrogen-containing) group

Classifying amino acids

a. Essential amino acids (a.k.a. indispensable): cannot be made in sufficient quantities by the human body to support human needs; must be consumed in the diet i. Histidine ii. Isoleucine iii. Leucine iv. Lysine v. Methionine vi. Phenylalanine vii. Threonine viii. Tryptophan ix. Valine

Nonessential amino acids (a.k.a. dispensable): can be made by the body from other amino ac

i. Alanine ii. Aspartic acid iii. Asparagine iv. Glutamic acid v. Serine vi. Arginine vii. Cysteine viii. Glutamine ix. Glycine x. Proline xi. Tyrosine

Proteins in Foods, Animal sources generally have higher protein than plant sources, but no food is 100% protein

1. Meat 2. Poultry 3. Fish and shellfish 4. Eggs 5. Milk and milk products

plant sources of protein

1. Seeds (also provide fat) 2. Legumes: plants that produce pods that have a single row of seeds (e.g., soybeans, peas, peanuts, lentils, beans) 3. Tree nuts (e.g., walnuts, cashews, almonds; also provide fat) 4. Grains 5. Vegetables

quality of protein

1. High quality (a.k.a. complete) protein a. Contains all essential amino acids in amounts that will support growth and development b. Well digested and absorbed by the body c. Dietary sources: animal sources of protein, with the exception of gelatin 2. Low quality (a.k.a. incomplete) protein a. Lacks or has inadequate amounts of one or more of the essential amino acids b. Inefficient digestion and absorption c. Limiting amino acids: those essential amino acids that are lacking or inadequate in a low-quality protein (usually tryptophan, threonine, lysine, methionine, or cysteine) d. Dietary sources: plant sources of protein, with the exception of soy protein and quinoa

A. How your body synthesizes proteins

1. Deoxyribonucleic acid (DNA): hereditary material that provides instructions for making proteins (i.e., genes); double helix structure 2. Each protein has a unique arrangement of the 20 different amino acids connected by peptide bonds a. Peptide bond: chemical attraction between the amino group of one amino acid and the acid group of another amino acid b. Peptide: small chain of amino acids c. Polypeptide : chain of 50+ amino acids 3. Basic steps of protein synthesis a. Within the cell’s nucleus, a section of DNA’s double helix unwinds to expose a gene (set of instructions for protein synthesis) b. Transcription: messenger ribonucleic acid (mRNA) takes the code from the gene out of the nucleus into the cytoplasm to the ribosome c. Translation: transfer RNA (tRNA) conveys amino acids to the ribosome, where they are assembled according to the gene code into polypeptides d. The polypeptide is released into the cytoplasm and undergoes further processing at other sites within the cell e. One or more polypeptide chains coil and fold into a unique 3-D shape that confers the protein’s biological function 4. Diets lacking high-quality protein do not support protein synthesis because one or more amino acids is not available to assemble polypeptides 5. Error in the genetic code can lead to a mistake (e.g., substitution of an incorrect amino acid) in protein synthesis a. Sickle cell anemia is an example of an error in the genetic code that leads to production of faulty hemoglobin, which is unable to efficiently carry oxygen through the blood and causes tissue damage or death

Protein denaturation occurs when exposure to certain environmental conditions alters a protein’s shape, leaving it permanently dysfunctional

1. Heat 2. Alcohol 3. Acid 4. Mechanical disturbance (e.g., whipping)

C. Protein Digestion and Absorption

1. Protein digestion begins in the stomach where HCl denatures proteins and pepsin breaks proteins into smaller polypeptides 2. In the small intestine pancreatic enzymes breakdown polypeptides into shorter peptides and amino acids 3. Absorptive cells of the small intestine release enzymes that further break down peptides to amino acids 4. Amino acids are absorbed across the absorptive cells of the small intestine into the portal vein

D. Protein turnover

1. Constant breakdown of old or unneeded proteins into their component amino acids to recycle them into new proteins 2. Endogenous amino acid pool: amino acids available in the body from protein turnover 3. Exogenous amino acids: those obtained from the diet 4. Liver is the main site of production of nonessential amino acids a. Deamination removes the nitrogen-containing group from an amino acid to leave a carbon skeleton b. Transamination transfers the nitrogen-containing group from one amino acid to another substance to make a new amino acid (reversible) c. Byproduct of deamination reactions is ammonia (NH3), which is highly toxic d. The liver converts ammonia to urea, which travels through the blood to the kidneys for excretion e. The carbon skeleton that remains after deamination of an amino acid can be used for energy or converted into other compounds 5. Most excess dietary amino acids are deaminated, converted into glucose or fat, and then metabolized for energy or stored

E. Nitrogen balance

1. Some loss of nitrogen normally occurs by urinary elimination of urea and creatinine, growth of fingernails and hair, and shedding of cells from skin and GI tract 2. Nitrogen balance (a.k.a. nitrogen equilibrium): nitrogen intake balances protein turnover and nitrogen losses 3. Positive nitrogen balance: the body retains more nitrogen than it loses as proteins are added to tissues a. Growth b. Pregnancy c. Recovery from illness/injury d. Increased levels of insulin, testosterone, and growth hormone e. Resistance exercise 4. Negative nitrogen balance: nitrogen losses exceed nitrogen retention a. Inadequate protein intake or inefficient protein absorption b. Kidney disease or blood loss c. Bed rest d. Fever, injuries, burns e. Increased levels of thyroid hormone or cortisol

F. How much protein do you need?

1. EAR: 0.66 g/kg body weight 2. EAR increases during pregnancy, breastfeeding, periods of rapid growth, and recovery from serious illnesses, blood losses, and burns. 3. RDA for healthy adult: 0.8 g/kg body weight a. 4. Food Allergies, Celiac Disease, and PKUA food allergy is an inflammatory response resulting from an inappropriate immune reaction to a harmless substance in a food b. Occurs when proteins are not digested, but are absorbed intact by the small intestine c. Immune cells recognize the intact protein as a foreign substance and mount an immune response, which can include hives, swollen lips, breathing difficulties, vomiting, diarrhea, etc. d. Allergic reactions usually occur within minutes to hours of eating the offending food e. Some food allergies can be deadly if they result in anaphylactic shock, a dangerous drop in blood pressure f. Usual suspects for food allergies i. Cow’s milk ii. Eggs iii. Peanuts and other nuts iv. Wheat v. Soybeans vi. Fish and shellfish vii. Nonprotein food dyes or additives (e.g., sulfites) g. Approximately 6% of American children suffer from food allergies; approximately 3 to 4% of adults h. Most childhood food allergies are outgrown by age 5 i. What is Celiac Disease? i. Allergic reaction to gluten, a group of related proteins in wheat, buckwheat, barley, and rye, may trigger an inflammatory response in the small intestine, causing diarrhea, abdominal bloating, and weight loss ii. Other health effects include anemia, osteoporosis, infertility, liver disease, and intestinal cancer from untreated celiac disease j. 1 in 133 people has celiac disease in the U.S. k. Disease is probably inherited but environmental factors may trigger the condition l. Diagnosis is made through blood testing and intestinal biopsies m. Treatment of food allergies involves strict avoidance of gluten containing foods

PKU

Phenylketonuria (PKU) a. Rare, genetic disorder in which cells are unable to produce an enzyme that converts phenylalanine to other compounds, resulting in an accumulation of phenylalanine in the blood b. Although phenylalanine is essential for growth and development, excessive accumulation of this amino acid in the blood leads to damage of nerve and brain cells, which may result in mental retardation or behavioral problems c. Simple blood test after birth is used to diagnose PKU d. Treatment ii. Low-phenylalanine diet for life, which limits nuts, many animal foods, and food products containing aspartame iii. Frequent monitoring of blood levels of phenylalanine, especially during pregnancy

IV. Protein Consumption Patterns

A. Protein supplies 15% of total kcal in typical American diet (within AMDR of 10 – 35% of total kcal) B. Compared to early 1900s, today’s Americans consume about the same amount of protein, but more of the protein comes from animal sources C. MyPlate: Recommendations for protein intake 1. Animal sources of protein are often rich sources of saturated fat and cholesterol 2. Lean sources of protein should be emphasized a. Poultry b. Beef: round steaks, top round, loin, top sirloin, chuck roast, arm roast, extra lean ground beef c. Pork: loin, tenderloin, center loin 3. Trim visible fats from meats before cooking 4. Limit processed meat products (e.g., ham, bacon, sausage, frankfurters, bologna, salami) to reduce fat and sodium 5. Vary protein choices by including fish and plant sources of protein several times per week

Understanding Nutritional Labeling: Protein

A. Protein content is required on Nutrition Facts panel B. Protein quality is not indicated, but can be ascertained from ingredients

VI. Eating Well for Less

A. Animal foods comprise ~67% of protein sources in the typical American diet, yet are also quite expensive B. Consume only one animal source of protein per meal and reduce portion size C. How to decrease your intake of animal foods 1. Replace meat, fish, or poultry with other high-quality protein sources a. Eggs b. Milk c. Cheese d. Yogurt e. Cottage cheese f. Prepare meals with less animal protein and more plant protein; complete proteins will supply limiting amino acids missing from plant proteins g. Combine meat, poultry, or seafood with rice or pasta h. Egg and milk protein in waffles, pancakes, breakfast cereal completes grain proteins i. Meat in chili completes plant proteins from beans and macaroni

D. Combining complementary proteins

1. Research indicates that it is not necessary to consume all essential amino acids during one meal for proper growth and development 2. Complementary combinations of foods mix plant foods to obtain all essential amino acids 3. Green peas and other legumes are poor sources of tryptophan and methionine, but good sources of lysine 4. Cereal grains are good sources of tryptophan and methionine, but poor sources of lysine 5. Fruits are nutritious foods, but are generally poor sources of protein 6. Table 7.5 lists ideas for complementary protein dishes

VII. Vegetarianism
A. Defining vegetarianism

1. Vegetarian: rely on plant foods; may or may not include some animal foods 2. Semivegetarian: avoids red meat, but consumes other animal foods 3. Lactovegetarian: consumes milk and milk products, but avoids all other animal foods 4. Lactoovovegetarian: consumes milk and eggs, but avoids other animal foods 5. Vegan: total vegetarian, consumes no animal products B. Rationale 1. Religious, ethical, or philosophical beliefs 2. Environmental 3. Economics 4. Health beliefs C. Is vegetarianism a healthy lifestyle?

1. Health benefits associated with vegetarianism (may be influenced by other lifestyles practices besides diet)

a. Lower risk of obesity b. Lower risk of type 2 diabetes c. Lower risk of hypertension d. Lower risk of certain cancers 2. Nutritional advantages of well-planned vegetarian diets a. More fiber b. More folate c. More vitamin C and E d. More magnesium and potassium e. More phytochemicals f. Less saturated fat g. Less cholesterol

3. Nutritional risks of inappropriately-planned vegetarian diets

a. May lack in total energy b. Lack of high-quality protein c. Low omega-3 fatty acids d. Low vitamin B-12 e. Low vitamin D f. Low riboflavin g. Low iron h. Low zinc i. Low calcium

how do vegetarians get adequate vitamins and minerals

4. Vegetarians can obtain adequate vitamins and minerals by consuming fortified foods and/or multivitamin and mineral supplements 5. High-risk groups for nutrient deficiencies with plant-based diets a. Vegan children may not obtain adequate energy and protein due to early satiety from a bulky diet b. Breast milk of vegan mothers may be deficient in vitamin B-12, which could affect the infant’s mental development; requires B-12 supplementation c. Vegetarian teens have higher rates of eating disorders D. Meatless menu planning 1. Many mixed dishes can be prepared without meat (e.g., pizza, pasta, stir-fried dishes) 2. Soy-based meat alternatives available in grocery stores and restaurants 3. With careful planning, vegetarians can overcome the nutritional limitations of a plant-based diet

Protein adequacy
A. Excessive protein intake

1. Intakes of high amounts of animal protein are associated with increased risk of chronic diseases (e.g., heart disease, colorectal cancer, and possibly prostate cancer) 2. High intake of processed meats is associated with increased risks of pancreatic and stomach cancers 3. Excess protein (particularly animal protein) increases urinary excretion of calcium 4. Excess protein intake can lead to dehydration because kidneys require more water to dilute and excrete the metabolic byproducts of protein metabolism 5. People with liver and kidney diseases may need to limit protein intake 6. What about high-protein weight-loss diets? a. Examples: Atkins, Protein Power, Sugar Busters b. Decreased feelings of hunger, increased satiety

B. Protein deficiency

1. High-risk groups a. Alcoholism b. Eating disorders c. Intestinal tract disorders d. Low-income, especially elderly 2. Undernutrition is widespread in countries with famine resulting from crop failures, political unrest, or civil wars 3. Failure to consume nourishing food is often accompanied by vitamin and mineral deficiencies 4. Children are especially affected by undernutrition because they have high needs to support growth, but small stomachs, which limit the volume of plant sources of protein they can eat a. Most common in impoverished countries of Africa and Asia b. Poor growth, permanently stunted c. Weakness d. Irritability e. Susceptible to infections f. Low intelligence

5. Kwashiorkor and marasmus are defined by the World Health Organization as forms of protein-energy undernutrition (PEU), but the distinction between these two is often blurred

a. Kwashiorkor i. Occurs when child is weaned from breastmilk to a protein-deficient diet of cereal grains; diet is marginally adequate in calories but deficient in high-quality protein ii. Stunted growth iii. Unnaturally blond, sparse, brittle hair iv. Discolored skin v. Some subcutaneous fat vi. Swollen cheeks, arms, legs, and bellies due to edema vii. May progress to marasmic kwashiorkor, which is characterized by edema and wasting b. Marasmus (starvation) i. Extreme weight loss due to lack of sufficient energy and protein ii. Weakness and wasting iii. Skin and bones appearance

6. Proteins: General Advice for Athletes

a. Consuming large amounts of protein-rich foods and supplements does not lead to increased muscle mass b. Fitness program with resistance training and a nutritionally adequate diet is the only safe, reliable way to increase muscle mass c. Muscles grow larger during the recovery period (24 – 48 hours) after resistance exercise when amino acids are available d. Proteins: General advice for athletes i. Combination of carbohydrate and protein before and after exercise – carbohydrate spares protein from being used as fuel ii. Protein supplements are not recommended iii. Creates imbalances in amino acid absorption by the small intestinal cells iv. Excessive intakes may be toxic

the end product of protein digestion is

amino acids

Certain hormones, such as insulin and glucagon, are proteins.

Hormones are chemical messengers that regulate body processes and responses, such as growth, metabolism, and hunger.

Enzymes speed up the rate of (catalyze) chemical reactions without becoming a part of the products

Additionally, infection-fighting antibodies are proteins. Although cells can use proteins for energy, normally they metabolize very little for energy, conserving the nutrient for other important functions that carbohydrates and lipids are unable to perform.

In the bloodstream, proteins transport nutrients and oxygen. Proteins in blood, such as albumin, also help maintain the proper distribution of fluids in blood and body tissues

The force of blood pressure moves watery fluid out of the bloodstream and into tissues. Blood proteins help counteract the effects of blood pressure by attracting the fluid, returning it to the bloodstream. During starvation, the level of protein in blood decreases, and as a result, some water leaks out of the bloodstream and enters spaces between cells.

edema

accumulation of fluid in tissues

Proteins also help maintain acid-base balance, the proper pH of body fluids

To function properly, blood and tissue fluids need to maintain a pH of 7.35 to 7.45, which is slightly basic

Metabolic processes can produce acidic or basic by-products

If a particular body fluid becomes too acidic or too basic, cells can have difficulty functioning and may die

A buffer can protect the pH of a solution

Proteins can act as buffers, because they have acidic and basic components. For example, if cells form an excess of hydrogen ions (H+), the pH of tissues decreases. To help restore the pH level to within the normal range, the basic portions of protein molecules bind to the excess H+, neutralizing the excess ions and raising the pH.

Each amino acid has a carbon atom that anchors a hydrogen atom and three different groups of atoms:

the amino or nitrogen-containing group, the R group (sometimes called the side chain), and the acid group.

The chemical structure of the amino acid alanine

the nitrogen atom is in the amino group. The R group identifies the molecule as a particular amino acid, such as serine or lysine. When the nitrogen-containing group is removed, the R group, acid group, and anchoring carbon atom form the "carbon skeleton" of an amino acid

The carbon skeleton is an important component of an amino acid, because

the body can convert the carbon skeletons of certain amino acids to glucose and use the simple sugar for energy.

Amino acid: Basic chemical structure.

Alanine has the typical chemical features of an amino acid—the nitrogen-containing or amino group, R group, and acid group. When the nitrogen-containing component is removed from an amino acid, the "carbon skeleton" remains.

Sometimes, nonessential and essential amino acids are referred to as "dispensable" and "indispensable" amino acids, respectively

Several nonessential amino acids are "conditionally essential," which means they become essential in certain situations. For example, cells can make cysteine from methionine and serine. If a person’s methionine and serine intake is inadequate, his or her body cannot make enough cysteine to meet its needs and dietary sources of the amino acid are necessary.

what is the chemical unit that makes up a protein

amino acid

list 4 functions of protein in the body

cell development and maintenance production of enzymes, antibodies, some hormones, blood clotting, transport nutrients and oxygen in the blood stream, maintain acid and fluid balance and can be used for energy

identify the 3 groups of atoms that make up a typical amino acid

amino or nitrogen group R Group acid group

what is the carbon skeleton of an amino acid

the part of an amino acid that remains after the amino group is removed

How many different kinds of amino acids are needed to make human proteins? How many of these amino acids are essential?

20 9 are essential 11 are non essential

what food contains protein?

animal foots, beans, nuts, seeds, grains, and certain vegetables are good sources of protein too

nearly all foods contain protein

no naturally occurring food is 100% protein. Protein comprises only about 20 to 30% of the weight of a piece of beef; 25% of the weight of drained, water-packed tuna fish; and only 12% of an egg’s weight. animal foods generally provide higher amounts of protein than similar quantities of plant foods

A 3-ounce serving of broiled lean ground beef supplies 23 g of protein; a 3-ounce serving of steamed broccoli or cooked carrots provides only about 1 g of protein.

In general, most plant foods provide less than 3 g of protein per ounce.

Certain parts of plants contain more protein than other parts.

Seeds, tree nuts, and legumes supply more protein per serving than servings of fruit or the edible leaves, roots, flowers, and stems of vegetables. Tree nuts include walnuts, cashews, and almonds; legumes are plants that produce pods that have a single row of seeds, such as soybeans, peas, peanuts, lentils, and beans

A 3-ounce serving of almonds, dry-roasted peanuts, or sunflower seed kernels supplies about 20 g of protein

Many seeds and nuts, pack a lot of calories from fat. Snack on just 3 ounces of almonds, dry-roasted peanuts, or sunflower seed kernels, and you will add almost 500 kcal to your diet

Peas, lentils, and most kinds of beans contain more protein and complex carbohydrate than fat.

Eating a 3-ounce serving of vegetarian baked beans, for example, adds about 4 g of protein, 14 g of carbohydrate, and less than 1 g of fat to your diet. Although soybeans contain more fat than carbohydrate, soy fat is high in unsaturated fatty acids.

A high-quality or complete protein contains all essential amino acids in amounts that support protein deposition in muscles and other tissues, as well as a young child’s growth

High-quality proteins are well digested and absorbed by the body. Meat, fish, poultry, eggs, and milk and milk products contain high-quality proteins. Egg protein generally rates very high for protein quality because it is easy to digest and has a pattern of essential amino acids that closely resembles that needed by humans.

A low-quality or incomplete protein lacks or contains inadequate amounts of one or more of the essential amino acids. Furthermore, the human digestive tract does not digest low-quality protein sources as efficiently as foods containing high-quality protein.

The essential amino acids that are in relatively low amounts are referred to as limiting amino acids, because they reduce the protein’s ability to support growth, repair, and maintenance of tissues. In most instances, tryptophan, threonine, lysine, and the sulfur-containing amino acids methionine and cysteine are the limiting amino acids in foods

Limiting Amino Acids

Most plant foods are not sources of high-quality proteins. Quinoa (keen’-wa) and soy protein are exceptions. Quinoa is botanically related to sugar beets and spinach, but the quality and amount of protein in quinoa seeds are superior to those of many cereal grains.4 Cooked quinoa is often used as a cereal. After being processed, the quality of soy protein is comparable to that of most animal proteins. Processed soybeans are used to make a variety of nutritious foods, including soy milk, infant formula, and meat substitutes. Eating foods made from soybeans may reduce the risk of osteoporosis, cardiovascular disease, and certain cancers. More research, however, is needed to determine the long-term health benefits of eating diets that contain soy products.

Regardless of how much protein is eaten, a child will fail to grow properly if

diet lacks essential amino acids

Explain the difference between a high-quality protein and a low-quality protein.

high quality/complete protein contains all the essential amino acids necessary to support protein deposition in muscle, other tissues and support growth Low quality lacks one or more amino acids

Identify at least three dietary sources of high-quality protein and three dietary sources of low-quality protein.

high quality: animal proteins, quinoa, eggs, soy low quality: fruits, vegetables, grains

List at least three essential amino acids that are most likely to be limiting amino acids.

tryptophan, threonine, lysine, methionine, cysteine

Your body makes proteins by following information coded in your DNA, or deoxyribonucleic (de-ox′-e-rye′-bow-new-klay′-ik) acid, the hereditary material in a cell’s nucleus.

To make proteins, cells assemble the 20 amino acids in specific sequences according to the information provided by DNA. To understand this process, imagine proteins as various chains made from 20 different amino acid "beads."

Amino acids form proteins.Each type of bead represents a specific amino acid in human proteins.

The "hook" that connects the beads represents a peptide bond, a chemical attraction between the acid group of one amino acid and the amino group of another amino acid.

In living things, the beaded chains are proteins that contain amino acids.

DNA supplies the directions for synthesizing each protein and the "hook" on each bead is a peptide bond, a chemical attraction between the acid group of one amino acid and the amino group of another amino acid

A dipeptide forms when two amino acids bond and a molecule of water is released in the process.

Peptides usually contain fewer than 15 amino acids. Most naturally occurring proteins are polypeptides (poly = many; peptides = amino acids) comprised of 50 or more amino acids.

Peptide bond

A peptide bond is a chemical attraction between the acid group of one amino acid and the amino group of another amino acid. A dipeptide forms when two amino acids bond and a molecule of water is released in the process.

Protein synthesis begins with DNA in the cell’s nucleus. DNA is a twisted, two-stranded molecule referred to as a double helix.

a section of the DNA double helix unwinds, exposing a gene. A gene is a portion of DNA that contains information concerning the order of amino acids that comprise a specific protein. Messenger ribonucleic acid (mRNA), a compound that is chemically similar to DNA, "reads" or transcribes the gene.

The actual production of a protein occurs in the cytoplasm, so mRNA leaves the nucleus and moves to ribosomes—protein-manufacturing sites in the cytoplasm.

Ribosomes translate the gene’s coded instructions for adding amino acids to the polypeptide chain. During this translation process, transfer ribonucleic acid (tRNA) conveys specific amino acids, one at a time, to the ribosomes. At the ribosomes, the amino acid from tRNA is added to the last amino acid, causing the peptide chain to grow longer. After the mRNA is read completely, the ribosome releases the polypeptide, and then the new protein generally undergoes further processing at other sites within the cytoplasm.

Diets that contain low-quality protein can result in poor growth, slowed recovery from illness, and even death.

These situations occur because protein synthesis in cells cannot proceed when the supply or "pool" of amino acids does not have one or more of the essential amino acids needed for constructing the polypeptide chain. When this happens, production of the protein stops. The partially made polypeptide chain is dismantled, and its amino acids are returned to the pool.

When assembly of the new protein has been completed, the polypeptide acid chain coils and folds into a three-dimensional shape that is characteristic of that particular protein.

In some instances, more than one polypeptide chain curl around each other to form large protein complexes. For example, hemoglobin, a protein in red blood cells, is comprised of four polypeptide chains coiled together

The shape of a protein is important because

it influences the compound’s activity in the body.

Shaping of a protein

.A polypeptide chain can fold and coil into characteristic three-dimensional shapes, such as the four polypeptide chains of a hemoglobin molecule. In a hemoglobin molecule, each chain is associated with an iron-containing unit.

Occasionally, the wrong amino acid is introduced into the amino acid chain during the protein synthesis process. Cells usually check for such errors and replace the amino acid with the correct one.

If the DNA code is faulty, however, the wrong amino acid will be inserted into the chain consistently, forming an abnormal polypeptide. Such errors often cause genetic defects that have devastating, even deadly, effects on the organism. Sickle cell anemia, for example, is an inherited condition characterized by abnormal hemoglobin.

Cells in red bone marrow synthesize hemoglobin by following DNA instructions concerning proper amino acid sequencing.

If the DNA codes for the insertion of the wrong amino acid in two of hemoglobin’s four polypeptide chains, the resulting protein is defective and does not function correctly.

defective hemoglobin associated with sickle cell anemia

Crescent-shaped red blood cells cannot transport oxygen efficiently. As a result, the abnormal cells can clog small blood vessels, causing pain, organ damage, and premature death. Sickle cell anemia is a common genetic disorder that generally affects people with African, Caribbean, or Mediterranean ancestry.

A protein undergoes denaturation when it is exposed to various conditions that alter the macronutrient’s natural folded and coiled shape

heat also causes the proteins in foods to unfold. The protein in raw egg white, for example, is almost clear and has a jellylike consistency. When you cook egg white, it becomes white and firm as its proteins become denatured. Other treatments often used during food preparation also denature proteins, including whipping or exposing them to alcohol or acid. Wine, for example, is often used in marinades, because the alcohol it contains denatures proteins in meat, helping tenderize it. Adding acidic lemon juice to milk denatures ("curdles") the proteins in milk. In your stomach, hydrochloric acid denatures food proteins, making them easier to digest. Denaturation does not "kill" a protein (because proteins are not living), but the process usually permanently alters the protein’s shape and functions. Once an egg white has been cooked or milk has curdled, the food cannot return to its original state.

you cannot "feed" your hair, nails, or skin by using shampoos, conditioners, or lotions containing proteins or other nutrients.

Hair, nails, and the outermost layer of skin are not living. By eating a nutritious diet, you will provide your body with the nutrients it needs to make healthy hair, nails, and skin.

When you eat oatmeal mixed with milk for breakfast, the large proteins in these foods must be digested before undergoing absorption. Protein digestion begins in the stomach, where hydrochloric acid denatures food proteins and pepsin, an enzyme, digests proteins into smaller polypeptides.

Soon after the polypeptides enter the small intestine, the pancreas secretes protein-splitting enzymes, including trypsin (trip′-sin) and chymotrypsin (ki′-mo-trip′-sin). Trypsin and chymotrypsin break down polypeptides into shorter peptides and amino acids. Enzymes released by the absorptive cells of the small intestine break down most of the shortened peptides into dipeptides, tripeptides, and individual amino acids. Dipeptides and tripeptides are compounds that consist of two and three amino acids, respectively. Within the absorptive cells, di- and tripeptides are broken down into amino acids. Thus, amino acids are the end products of protein digestion. After being absorbed, the amino acids enter the portal vein and travel to the liver, where they may enter the general circulation. Protein digestion and absorption is very efficient: very little dietary protein escapes digestion and is eliminated in feces.

The liver keeps some amino acids for its needs and releases the rest into the general circulation.

By the time cells obtain amino acids from blood, they cannot distinguish the ones that were originally in oat proteins from those that were in milk proteins. The cells, however, now have all the amino acids they need to make your body’s proteins.

Protein turnover, the process of breaking down old or unneeded proteins into their component amino acids and recycling them to make new proteins, occurs constantly within cells.

Amino acids that are not incorporated into proteins become part of a small amino acid pool, a readily available supply of amino acids that cells can use for future protein synthesis. The amino acid pool is an endogenous, or internal, source of nitrogen. Your body obtains about two-thirds of its amino acid supply from endogenous sources and the remainder from exogenous (dietary) sources.

A healthy human body can make 11 of the 20 amino acids.

The liver is the main site of nonessential amino acid production. Chemical reactions called deamination and transamination are involved in the synthesis of amino acids.

Deamination is the process of removing the nitrogen-containing group (usually NH2) from an unneeded amino acid. As a result of deamination, the amino acid that gives up its amino group becomes a carbon skeleton

Transamination occurs when the nitrogen-containing group is transferred to another substance to make an amino acid. To make the amino acid alanine, for example, liver cells remove the amino group (NH2) from glutamic acid and transfer it to pyruvic acid. Transamination reactions are reversible.

Deamination occurs primarily in the liver. Liver cells remove NH2 from glutamic acid, forming ammonia (NH3), a highly poisonous waste product

The liver can use the ammonia to make urea, a metabolic waste product that is released into your bloodstream. The kidneys filter urea, small amounts of ammonia, and creatinine (a nitrogen-containing waste produced by muscles) from blood and eliminate the compounds in urine. After an amino acid undergoes deamination, the carbon skeleton that remains can be used for energy or converted to other compounds, such as glucose. Muscle cells can deaminate certain amino acids and use their carbon skeletons for energy.

If you consume more protein than you need, what happens to the extra amino acids?

The body does not store excess amino acids in muscle or other tissues. The unnecessary amino acids undergo deamination, and cells convert the carbon skeletons into glucose or fat, or metabolize them for energy.

Although your body conserves nitrogen by recycling amino acids, each day you lose some protein and nitrogen from your body. Urinary elimination of urea and creatinine accounts for most of the lost nitrogen

Daily nitrogen losses also occur as your nails and hair grow, and when you shed the outermost layer of your skin and cells from your intestinal tract. Your body uses amino acids from foods to replace the lost nitrogen.

Normally, an adult’s body maintains its protein content by maintaining nitrogen balance or nitrogen equilibrium, that is, balancing nitrogen intake and protein turnover with losses. During certain stages of life or physical conditions, however, nitrogen intake and retention do not equal nitrogen losses.

When the body is in a state of positive nitrogen balance, it retains more nitrogen than it loses as proteins are added to various tissues. In this case, a person must eat more protein to satisfy the increased need for the nutrient. Positive balance occurs during periods of rapid growth such as pregnancy, infancy, and puberty, and when people are recovering from illness or injury. Hormones such as insulin, growth hormone, and testosterone stimulate positive nitrogen balance. Performing weight (resistance) training also leads to nitrogen retention

When the body is in a state of negative nitrogen balance, the body loses more nitrogen than it retains and protein intake is less than what the body needs.

Negative balance occurs during starvation, serious illnesses, and severe injuries. Recovery from the illness or injury and refeeding protein results in positive nitrogen balance until nitrogen equilibrium is restored

The Estimated Average Requirement (EAR) for protein is 0.66 g of protein/kg of body weight

The EAR for protein increases during pregnancy, breastfeeding, periods of rapid growth, and recovery from serious illnesses, blood losses, and burns. A healthy adult’s RDA for protein is 0.8 g/kg of body weight.

To determine your RDA for protein, multiply your weight in kilograms by 0.8 grams. If you are underweight or overweight, use a healthy weight for your height when making this calculation

For example, a healthy man who is 5’10" tall and weighs 75 kilograms (his weight in pounds divided by 2.2) should consume 60 grams of protein daily (75 kg × 0.8 g) to meet his RDA for the nutrient.

Explain the basic steps involved in protein synthesis.

Protein synthesis begins with DNA in the cell’s nucleus. DNA is a twisted, two-stranded molecule referred to as a double helix. To begin the process, a section of the DNA double helix unwinds, exposing a gene. A gene is a portion of DNA that contains information concerning the order of amino acids that comprise a specific protein. Messenger ribonucleic acid (mRNA), a compound that is chemically similar to DNA, "reads" or transcribes the gene. The actual production of a protein occurs in the cytoplasm, so mRNA leaves the nucleus and moves to ribosomes—protein-manufacturing sites in the cytoplasm. Ribosomes translate the gene’s coded instructions for adding amino acids to the polypeptide chain. During this translation process, transfer ribonucleic acid (tRNA) conveys specific amino acids, one at a time, to the ribosomes. At the ribosomes, the amino acid from tRNA is added to the last amino acid, causing the peptide chain to grow longer. After the mRNA is read completely, the ribosome releases the polypeptide, and then the new protein generally undergoes further processing at other sites within the cytoplasm.

A healthy young woman weighs 143 pounds. Calculate her RDA for protein.

convert weight to kilograms by dividing weight by 2.2 143 = 65 multiply weight in kilograms (65) by .8 65 * .8 = 52

Explain what happens to proteins in beans as they undergo digestion and absorption in the human digestive tract.

stomach small intestine small intestinal cells liver rectum

A protein
is comprised of glucose molecules.
has nitrogen in its chemical structure.
provides more energy per gram than carbohydrate.
is a complex inorganic molecule.

is comprised of glucose molecules.

Which of the following statements is false?
Certain hormones are proteins.
Nearly all enzymes are proteins.
Proteins are part of triglycerides.
The body uses amino acids to make antibodies.

Proteins are part of triglycerides.

Which of the following foods generally provides the least amount of protein per serving?
fruits
milk
nuts
seeds

fruits

Which of the following foods is not a source of complete protein?
peanut butter
cheese
fish
eggs

peanut butter (peanut = plant)

In cells, ______ controls the assembly of amino acids into proteins.
PEU
DNA
IOM
ATP

DNA

______ is the process of removing nitrogen from an amino acid.
Transamination
Denaturation
Hydrogenation
Deamination

deamination

Which of the following physical states is (are) characterized by positive nitrogen balance?
starvation
illness
puberty
All choices are correct.

puberty

What is the RDA for protein of a healthy adult woman who weighs 62 kg?
49.6 g
59.6 g
69.6 g
79.6 g

49.6 62 * .8 = 49.6

Which of the following foods is not a source of complementary protein?
red beans and rice
hummus on pita bread
soynut butter on a bagel
whole-wheat bread with fruit spread

whole wheat bread with fruit spread (fruit = low protein)

A person following a vegan diet would eat
eggs.
cheese.
nuts.
fish.

nuts = nothing animal based

By eating more protein than needed, a person can
build bigger muscles.
lose weight.
absorb more calcium.
become dehydrated.

become dehydrated

People with celiac disease should
take amino acid supplements.
limit their protein intake to 20 g per day.
avoid foods that contain gluten.
eliminate protein from plant sources

avoid foods that contain gluten

Which of the following tips is a recommended way to reduce food costs?
buying food in bulk, if it can be used before spoiling
purchasing preportioned, packaged foods
shopping at convenience stores, if the stores are within 5 miles of your home
eating at fast-food outlets at least three times a week

buying food in bulk, if it can be used before spoiling

Every amino acid has _____ in its chemical structure

nitrogen

the ______ is main site of deamination in the body

liver

the deanmination process forms

ammonia

______is the process that changes the normal shape of a protein and as a result the molecule loses its usual function

denaturation

During digestion which of the following substances denatures the proteins in food?

stomach acid

which of the following substances in an enzyme that participates in the digestion of proteins

trypsin

a person suffering from celiac disease must avoid

consuming foods with gluten

the typical american eats more protein from ________ than he or she did in the early 1900s

fish

Erika is a vegan. To avoid developing a serious nutritional deficiency she needs to include a source of ______ in her diet

b12

plant based diets may not supply enough _____ to meet a child’s needs

energy

Consuming too much protein or excess amino acids can lead to

dehydration

which of the following statements is true?
dietitians generally recommend that strength and endurance athletes take amino acid supplements
About 70% of human muscle tissue is comprised of protein
A fitness training program that includes resistance exercise is recommended to increase muscle mass safely
all of these are correct

A fitness training program that includes resistance exercise is recommended to increase muscle mass safely

which of the following statements are true?
edema is a major sign of protein energy malnutrition
In the US teenagers have the greatest risk of protein energy malnutrition
Compared to children in other parts of the world impoverished children in the united states have the highest risk of protein energy malnutrition
Kwashiorkor affects babies while they are breastfeeding

edema is a major sign of protein energy malnutrition

which of the following foods is a poor source of essential amino acids?
fat free milk
peach
peanuts
sesame seeds

peach

which of the following foods is naturally a good source of high quality protein?
tuna
corn oil margarine
leaf lettuce
red grapes

tuna

which of the following foods is a good source of high quality protein?
soy milk
orange juice
boiled cabbage
leaf lettuce

soy milk

bernice is a vegan. What does she eat?

legumes

bryce is an ovovegetarian. What does he eat?

egg salad

To tenderize meat, place it in

red wine

which of the following foods is the least expensive per ounce?
sliced peaches at 1.49 per 16 ounce can
sliced peaches at 1.29 per 12 ounce can
frozen peaches at 2.59 per 10 oz bag
frozen peaches t 2.99 per 16 oz bag

sliced peaches at 1.49 per 16 ounce can

which of the following forms of produce is the least expensive per ounce?
sliced yellow apples at 1.00 per 1 oz bag
fresh yellow apples at 5.49 per 2 lb bag
canned delicious apple slices at 2.25 per 15 oz jar
all of these

canned delicious apple slices at 2.25 per 15 oz jar

The substance has carbon, hydrogen, and oxygen in its chemical structure. what is it?

protein

Rodney is an alcoholic. His feet are swollen. Why?
chronic bladder infection
essential fatty acid deficiency
lack of blood albumin
esophageal varices

chronic bladder infection

true statement

in the United States, alcoholics have a high risk of protein energy malnutrition

a child with protein energy malnutrition has a high risk of dying from
hyperglycemia
celiac
measles
diabetes

measles

a team of scientists wants to develop a formula diet for newborns that is nutritionally complete food that replaces human milk. The formula must have
lactose
lysine
lipase
all of these

lipase

When DNA does not provide instruction for assembling a protein properly
an abnormal polypeptide forms
a genetic defect can occur
an inherited disease can result
all of thesw

all

2 month old deanna is not growing normally

defective dna

replace barley with rice for chicken soup for someone with celiac

true

high protein snack
8 ounce glass of soy milk
1 ounce baby carrots
1/2 cup watermelon
all

8 ounce glass of soy milk

Most plant foods are poor sources of one or more essential amino acids, particularly tryptophan, threonine, lysine, and methionine.

Green peas, for example, are good sources of lysine, but they contain low amounts of tryptophan and methionine. Cereal grains such as wheat, rice, and corn are good sources of tryptophan and methionine, but they tend to be low in lysine. Wheat germ, however, is a rich source of lysine. Legumes are low in methionine. Seeds such as sesame and sunflower seeds are generally low in lysine. Walnuts, cashews, almonds, and other tree nuts also contain low amounts of lysine. Although most fruits and some kinds of vegetables are poor sources of protein, they add appealing colors and textures as well as vitamins, minerals, and phytochemicals to plant-based meals.

High-protein diets are generally not recommended for healthy individuals. Such diets may lead to higher-than-normal urinary losses of the mineral nutrient calcium.29 Such losses may be more likely to occur when people, particularly women, consume diets that are low in calcium and contain more animal than vegetable proteins. Some nutrition experts suspect that diets that supply a lot of animal protein are associated with osteoporosis, a condition characterized by thin bones that fracture easily.

Dehydration is a potentially life-threatening condition in which the body’s water level is too low. People with liver or kidney diseases may need to avoid protein-rich diets and amino acid supplements because metabolizing the excess amino acids is a burden to their bodies.

People suffering from alcoholism, anorexia nervosa, or certain intestinal tract disorders are at risk of protein undernutrition. People with low incomes, especially those who are elderly, are also at risk of protein deficiency. Many elderly Americans have limited incomes and must make difficult choices concerning their expenses.

in children, underweight is often a sign of (PEM). According to the World Health Organization (WHO), 18% of children are underweight.31 Impoverished children in Asia and Africa are most likely to be underweight, and the effects of undernutrition are especially devastating for the very young. Children whose diets lack sufficient protein and energy do not grow and are very weak, irritable, and vulnerable to dehydration and infections, such as measles, that can kill them. If these children survive, their growth may be permanently stunted and their intelligence may be lower than normal because undernutrition during early childhood can cause permanent brain damage.

kwashiokor &amp; marasmus

At one time, nutrition experts thought there were only two types of PEM, kwashiorkor and marasmus. The distinctions between these conditions, however, are often blurred, because protein deficiency is unlikely when a person’s energy intake is adequate. Nevertheless, dietitians generally consider kwashiorkor, marasmic kwashiorkor, and marasmus as forms of PEM. Kwashiorkor (qwash′-e-or′-kor) primarily occurs in developing countries where mothers commonly breastfeed their infants until they give birth to another child. The older youngster, who is usually a toddler, is fairly healthy until abruptly weaned from its mother’s milk to make way for the younger sibling. Although the toddler may obtain adequate energy by consuming a traditional diet of cereal grains, the diet lacks enough complete protein to meet the youngster’s high needs, and he or she soon develops signs of protein deficiency. Children affected by kwashiorkor have stunted growth (see Fig. 1.13); unnaturally blond, sparse, and brittle hair; and patches of skin that have lost their normal coloration. Children with kwashiorkor have some subcutaneous (under the skin) fat and swollen cheeks, arms, legs, and bellies that make them look well fed, but their appearance is misleading. An important function of certain proteins in blood is to maintain proper fluid balance within cells and blood vessels, as well as between cells. During starvation, levels of these proteins decline, resulting in edema, which can make the protein-deficient child look plump and overfed instead of thin and undernourished. In many cases, the child suffering from kwashiorkor does not obtain enough energy and eventually develops marasmic kwashiorkor, a condition characterized by edema and wasting (Fig. 7.19). Wasting is the loss of organ and muscle proteins as the body tears down these tissues to obtain amino acids for energy metabolism.

Severe PEM causes extreme weight loss and a condition called marasmus (mah-raz′-mus), which is commonly referred to as starvation (Fig. 7.20). Obvious signs of marasmus are weakness and wasting.

The body of a starving person loses most of its subcutaneous fat and deeper fat stores. The marasmic person is so thin that his or her ribs, hips, and spine are visible through the skin. People suffering from marasmus avoid physical activity to conserve energy, and they are often irritable.

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