HNSC 1210 - Chapter 6

Kwashiorkor

- 1-3 years age - protein deficiency - rapid onset, acute - some wt - some muscle wasting - 60-80% wt for age - edema - fatty liver - apathy, irritability - loss of appetite - hair, skin problems

Marasmus

- <2 years age - total diet deficiency - slow, chronic - severe weight loss - muscle and fat loss - <60% wt for age - no edema - no fatty liver - anxiety, apathy - appetite varies - hair, skin problems

Amino Acids

- Contain nitrogen - 20 amino acids: 8 are essential, some may become conditionally essential (histidine) - Are joined together by peptide bonds to form proteins

Protein Synthesis

- DNA (genetic sequence) determines the amino acid sequence in proteins - Different sequences account for - genetic diseases, e.g. sickle cell disease

Protein in Food

- Found in all 4 food groups - Recommendations for intake: - DRI: 0.8g/kg body weight; women: 46g/day, men: 56g/day. - DRI minimum amount: 10% total energy - DRI maximum amount: 35% total energy

Functions of Proteins

- Growth and maintenance - structure, new tissue, repair - Enzyme action - e.g. growth factors, insulin - Immune function - antibodies - Protein Transport - e.g. protein malnutrition and edema - Acid-base balance - Blood clotting - Energy (secondary function) - No storage form of amino acids

Pros of the Omnivorous Diet

- Growth is optimal - complete, more digestible protein - protein from meat, eggs, milk products - May be easier to meet additional requirements for pregnancy, illness, etc. - Vit. B12, Vit. D, calcium, iron and zinc intakes are usually adequate

Protein Absorption

- Intestinal cells absorb amino acids and some di- and tri-peptides and release them into the bloodstream. -Absorbing larger peptides may contribute to food allergies (immune response) - Carried to liver - used or released back into blood to be taken up by body cells - Body can reconnect amino acids to make proteins - Body can use a.a. for energy if necessary

Protein Quality and Quantity

- Malnutrition, infections, state of health can increase need for protein - Two factors influence protein quality: - Digestibility (improved by moist heat) - animal protein: >90% absorbed - plant protein: 70-90% absorbed - Amino acid composition - high-quality proteins contain ample amounts of all essential amino acids - Complementary proteins - 2 or more proteins whose amino acid structures supply the essential amino acids missing from the other - need complementary proteins in same day - legumes limiting in methionine and tryptophan - grains limiting in isoleucine and lysine - together they supply all 4 amino acids

What has the DRI recommended intake for protein been set at for healthy adults? A) O.8 grams per kilogram of body weight B) 2.2 pounds per kilogram of body weight C) 12 to 15 percent of total calories D) 100 grams per day

A

Peptide Bond

A bond that connects one amino acid with another, forming a link in a protein chain

Transamination

A chemical reaction that transfers an amino group to a carbon skeleton to form an amino acid

Serotonin

A compound related in structure to (and made from) the amino acid tryptophan. It serves as one of the brain's principal neurotransmitters

Kwashiorkor

A disease related to protein malnutrition, with a set of recognizable symptoms, such as edema

Protein Digestibility-Corrected Amino Acid Score (PDCAAS)

A measuring tool used to determine protein quality. The PDCAAS reflects a protein's digestibility as well as the proportions of amino acids that it provides

Gluten

A mixture of small proteins found in wheat, rye, and barley that helps give dough its elastic texture. It must be avoided by those diagnosed with celiac disease

Collagen

A type of body protein from which connective tissues such as tendons, ligaments, scars, and the foundations of bones and teeth are made

What are the basic building blocks for protein? A) Glucose units B) Amino acids C) Side chains D) Saturated bonds

B

Hormones

Chemical messengers secreted by a number of body organs in response to conditions that require regulation. Each hormone affects a specific organ or tissue and elicits a specific response

Proteins

Compounds composed of carbon, hydrogen, oxygen, and nitrogen atoms, arranged into amino acids linked in a chain. Some amino acids also contain sulfur atoms.

Bases

Compounds that accept hydrogens from solutions

Buffers

Compounds that help keep a solution's acidity or alkalinity constant

Acids

Compounds that release hydrogens in a watery solution

To prevent wasting of dietary protein, which of the following conditions must be met? A) Dietary protein must be adequate in quantity B) Dietary protein must supply all essential amino acids in the proper amounts C) The diet must supply enough calories from carbohydrate and fat D) All of the above

D

Which of the following statements is correct regarding protein and amino acids supplements? A) They help athletes build muscle even when energy intake is inadequate B) They help dieters lose weight quicker C) They can assist in relieving depression D) None of the above

D

High-Quality Proteins

Dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require. They may also contain nonessential amino acids

Lacto-ovo-vegetarian

Eats dairy and eggs; no flesh or seafood

Lacto-vegetarian

Eats dairy; no eggs, flesh or seafood

Ovo-vegetarian

Eats eggs; no milk products, flesh or seafood

Fruitarian

Eats raw/dried fruit, seeds, nuts

Acid-Base Balance

Equilibrium between acid and base concentrations in the body fluids

What can poorly planned vegetarian diets lack?

Iron, zinc, calcium, Vit B12, Vit D

Antibodies

Large proteins of the blood, produced by the immune system in response to an invasion of the body by foreign substances (antigens). Antibodies combine with and inactivate the antigens

Partial Vegetarian

No red meat or limited quantities

Pesco-vegetarian

No red meat or poultry

Vegan

Only food from plant sources (vegetables, grains, legumes, fruits, seeds, nuts, etc.)

Vegetarian

Plant-based foods, some or all animal foods eliminated

Alkalosis

The condition of excess base in the blood, indicated by an above-normal blood pH

Protein Turnover

The continuous breakdown and synthesis of body proteins involving the recycling of 300-400 amino acids each day

Fluid and electrolyte Balance

The distribution of fluid and dissolved particles among body compartments

Hemoglobin

The globular protein of red blood cells, whose iron atoms carry oxygen around the body via the bloodstream

Amine Group

The nitrogen-containing portion of an amino acid

Hunger

The physical craving for food; the progressive discomfort, illness, and pain resulting from the lack of food

Urea

The principal nitrogen-excretion product of protein metabolism; generated mostly by removal of amine groups from unneeded amino acids or from amino acids being sacrificed to a need for energy

Deamination

The removal of an amine group from an amino acid

Mutual Supplementation

The strategy of combining two incomplete protein sources so that the amino acids in one food make up for those lacking in the other food

Side Chain

The unique chemical structure attached to the backbone of each amino acid that differentiates one amino acid from another

Protein-Energy Undernutrition (PEU)

The world's most widespread malnutrition problem, including both marasmus and kwashiorkor and states in which they overlap

T or F: An example of a person in positive nitrogen balance is a pregnant women

True

T or F: Partially completed proteins are not held for completion at a later time when the diet may improve

True

T or F: Under certain circumstances, protein can be converted to glucose to serve the energy need of the brain

True

T or F: Vegetarian diets are categorized by the foods they exclude

True

Complementary Proteins

Two or more proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other

What can poorly planned omnivorous diets lack?

Vit A, Vit C, folate and fibre

Nitrogen Balance

- Nitrogen intake compared to nitrogen excretion (through urine, feces, skin, sweat, body fluids) - Depends on size and stage of growth: - equilibrium: normal healthy adult - need 0.8 grams protein/kg body weight - positive: growing child, pregnant woman - negative: surgery patient, astronaut

Measuring Protein Quality

- Protein digestibility-corrected amino acid score (PDCAAS): - Reflects protein digestibility - Proportion of amino acids provided - Scale of 0-100 - Egg white, ground beef, chicken products, fat- free milk, tuna = 100 - Soybean protein = 94 - Wheat protein = 25 - Combining complementary proteins can increase score

Pros of Vegetarianism

- Reduced risk of disease (obesity, heart disease, diabetes, hypertension, cancer) - Diet is high in vegetables, fruit, fibre, phytochemicals, some vits/minerals - Lifestyle often excludes smoking and alcohol, and emphasizes physical activity - Lower fat diet and leaner body composition - Maintain healthier body weight - Better control of caloric intake due to fibre-rich bulky foods

Protein Digestion

- Stomach - gastric acid denatures protein, and pepsin (enzyme) cleaves some peptide bonds - Small intestine lumen - pancreatic enzymes cleave polypeptides to di- and tri-peptides - Brush border membrane - enzymes cleave di- and tri-peptides to single amino acids

Protein Utilization

- Used to build proteins - Converted to other small nitrogen-containing compounds, e.g. vitamins (tryptophan -> niacin) - Converted to other amino acids - After removal of amino group: - gluconeogenesis: carbon skeleton -> glucose -> blood - lipogenesis: carbon skeleton -> fat (for fuel or storage) - Amino acids are wasted when - Energy is lacking - Protein is overabundant - An aa is oversupplied (e.g. supplement) - Diet has too few essential aa (i.e. low protein quality) - For protein synthesis, need adequate dietary protein with essential aa in proper amounts and energy from carbohydrate and fat

Protein Excess

- What is excess? (>35% calories from PRO) - High intakes of animal protein - Associated with obesity - Increased intake of saturated fat - Kidney and liver problems in expt'l animals - More bone mineral loss with high intakes of purified protein - more calcium lost in urine - Evidence mixed for effect of meat protein on Ca - High intakes of protein - Worsen existing kidney disease in humans - Increase work of the kidney to excrete nitrogen wastes: amine group of amino acids is excreted as ammonia or urea - does this lead to long term problems? - Effective treatment for kidney problems = reduce protein intake - High protein diets for weight loss: - protein used for energy and making glucose: - must remove amino group and excrete it as urea via kidneys - Low CHO: if <130 g CHO/d, then no glycogen stores and "ketotic": - body fat -> ketone bodies for energy, and - blood glucose made from - dietary amino acids (after meals), & - muscle protein (when post-absorptive), and this results in muscle wasting

Amino Acid Pools

Amino acids dissolved in the body's fluids that provide cells with ready raw materials from which to build new proteins or other molecules

Indispensable/Essential Amino Acids

Amino acids that either cannot be synthesized at all by the body or cannot be synthesized in amounts sufficient to meet physiological need

Dispensable/Nonessential Amino Acids

Amino acids that the body can synthesize in sufficient amounts to meet its need

Conditionally Indispensable/Essential Amino Acids

An amino acid that is normally nonessential but must be supplied by the diet in special circumstances when the need for it exceeds the body's ability to produce it

Limiting Amino Acid

An essential amino acid that is present in dietary protein in an insufficient amount, thereby limiting the body's ability to build protein

Dysentery

An infection of the digestive tract that causes diarrhea

Protein digestion begins in which part of the body? A) Mouth B) Stomach C) Small intestine D) Large intestine

B

Acidosis

The condition of excess acid in the blood, indicated by a below-normal pH

T or F: Too little protein in the diet can have severe consequences, but excess protein has not been proven to have adverse effects

False

T or F: Although protein-energy undernutrition (PEU) is prevalent in underdeveloped nations, it is not seen in developed countries

False. Impoverished people living in inner cities and rural areas, as wells as some elderly, homeless, and ill people in hospitals, have been diagnosed with PEM

Legumes

Plants of the bean, pea, and lentil family that have roots with nodules containing special bacteria. These bacteria can trap nitrogen from the air in the soil and make it into compounds that become part of the plant's seeds. The seeds are rich in protein compared with those of most other plant foods

Immunity

Protection from or resistance to a disease or infection by development of antibodies and by the actions of cells and tissues to response a threat

Polypeptide

Protein fragments of many (more than 10) amino acids bonded together. A polypeptide is a strand of amino acids

Tripeptides

Protein fragments that are three amino acids long

Dipeptides

Protein fragments that are two amino acids long

Enzymes

Proteins catalysts. A catalyst is a compound that facilitates a chemical reaction without itself being altered in the process

Edema

Swelling of body tissue caused by leakage of fluid from the blood vessels; seen in protein deficiency (among other conditions)

Amino Acids

The building blocks of proteins. Each has as amine group at one end, an acid group at the other, and a distinctive side chain

Marasmus

The calorie-deficiency disease; starvation

Macrobiotic Diet

progressively eliminates foods -> brown rice, herbal tea, water -> malnutrition and death