Chapter 6 Flashcards
The human body is about ____ protein
15%
AMDR of protein
10-35% of kcals
Amino acids
The building blocks of protein. Each contains a central carbon atom bound to a hydrogen atom, an amino group (with nitrogen), an acid group, and a unique side chain.
20 amino acids occurring naturally
- 9 are essential
- 11 are nonessential
Essential or lndispensable amino acids
Amino acids that cannot be synthesized by the human body in sufficient amounts to meet needs and therefore must be included in the diet.
- histidine
- isoleucine
- leucine
- lysine
- methionine
- phenylalanine
- threonine
- tryptophan
- valine
Nonessential or dispensable amino acids
Amino acids that can be synthesized by the human body in sufficient amounts to meet needs.
- alanine
- arginine
- aspargine
- aspartic acid
- cysteine
- glutamic acid
- glutamine
- glycine
- proline
- serine
- tyrosine
Transamination
The process by which an amino group from one amino acid is transferred to a carbon compound to form a new amino acid.
-when a nonessential amino acid is not available from the diet
Conditionally essential amino acids
Amino acids that are essential in the diet only under certain conditions or at certain times of life.
Ex: body uses phenylalanine (essential) to make tyrosine (non essential)
-but if body fails to provide phenylalanine then tyrosine becomes conditionally essential!
*cysteine, glutamine, proline, tyrosine, glycine, arginine
Dipeptide
Tripeptide
Polypeptide
Two amino acids linked by a peptide bond
3 amino acids linked by peptide bonds
More than 3 amino acids linked by peptide bonds
Denaturation
The alteration of a proteins 3-dimensional structure due to change in physical protostomes of the protein. (Unfolds protein bonds)
- PH
- Temperature
- mechanical forces
Could be good or bad
Protein digestion steps
- in the mouth, chewing breaks down proteins
- in the stomach, HCL and pepsin begin chemical digestion of proteins
- in small intestine, protein digesting enzymes secreted by pancreas break down polypeptides into amino acids, dipeptides and tripeptides
- variety of transport proteins move the products of protein digestion into the mucosal cell.
- dipeptides and tripeptides can enter mucosal cell and are broken into amino acids
- amino acids pass from mucosal cell into the blood and travel to the liver which distributes to rest of body.
- very little lost in feces
Food allergies are triggered when a protein from the diet is …..
Absorbed without being completely digested
Anaphylaxis
An immediate and severe allergic reaction to a substance. Symptoms include breathing difficulty, loss of consciousness, and a drop in blood pressure and can be fetal.
Food allergies triggered when a protein from the diet is absorbed without being completely digested. Immune system see this as a pathogen and create antibodies to it.
People with GI disease->prone to allergies because their damaged intestines allow for the absorption of whole proteins!
Amino acid pool
All of the amino acids in body tissues and fluids that are available for use by the body
Protein turnover
The continuous synthesis and breakdown of body proteins
Genes
A length of DNA containing the information needed to synthesize RNA or a polypeptide chain.
-determines protein synthesis or stop
-chemicals can turn genes on or off. Ex: high irons turns on the ferritin gene to
Make more ferritin to store iron
Transcription
Translation
The process of copying the information in DNA to a molecule of mRNA
The process of translating the mRNA into the amino acid sequence of a polypeptide chain
Limiting amino acid
The essential amino acid that is available in the lowest concentration in relation to the body’s needs.
Gene expression
The events of protein synthesis in which the information coded a gene is used to synthesize a product, either a protein or a molecule of RNA
Neurotransmitters
Molecules that function to transfer signals between the cells of the nervous system and can stimulate or inhibit a signal
Deamination
The removal of the amino group from an amino acid is order for body proteins to be used for energy
-results in nitrogen being released and the formation of ammonia which in high levels can be fetal.
Urea
A nitrogen-containing waste product formed from the breakdown of amino acids that is excreted in the urine
-protects body from high levels of ammonia. Liver combines ammonia with carbon dioxide which creates urea
Antibodies
Protein produced by cells of the immune system that destroy or inactivate foreign substances in the body.
Peptide hormone
Hormones made from amino acids
- insulin
- glucagon
- act by binding to protein receptors on the surface of the cell membrane
pH
A measure of the level of acidity or alkalinity of a substance
Protein-energy malnutrition (PEM)
A condition characterized by wasting and an increased susceptibility to infection that results from the long-term consumption of insufficient amounts of energy and protein to meet needs
Kwashiorkor
Marasmus
A form of protein-energy malnutrition in which only protein is deficient
- bloated belly
- typically in children
- lowers growth in weight and height
- susceptible to infection
- changes in skin colour=low melanin
- fat stores maintains
A form of protein-energy malnutrition in which a deficiency of energy in the diet causes severe body wasting.
- children and adults
- low growth in weight and height
- susceptible to infection
- ketosis
- no fat stores
Phenylketonuria
An inherited disease in which the body cannot metabolize the amino acid phenylalanine. If the disease is untreated, toxic byproducts called phenylketones accumulate in the blood and interfere with brain development
-aspartame breaks down into substances including phenylalanine
Celiac disease
An autoimmune disorder that causes damage to the intestines when the protein gluten (found in rye, barley and wheat) is eaten
- gluten causes body to attack the villi of small intestine
- NOT AN ALLERGY
Nitrogen balance
The amount of nitrogen consumed in the diet compared with the amount excreted by the body over a given period
- we want synthesis balanced with degradation
- protein intake balances with nitrogen excreted in urine, feces and sweat
The RDA of protein for pregnant and lactating women is _____g more than normal
25
Protein quality
A measure of how efficiently a protein in the diet can be used to make body proteins
Complete dietary protein
Incompletely dietary protein
Protein that provides essential amino acids in the propositions needed to support protein synthesis (animal meat)
- easily digested
- high quality proteins
- contain all 9 essential amino acids
- found in animal and soy and quinoa
- quantity and correct proportions to maintain nitrogen balance
Protein that is deficient in one or more essential amino acids relative to body needs (plant)
- lower quality protein
- grains, beans, lentils, nuts, veggies and fruit
Digestible indispensable amino acid reference ration (DIAA)
The ratio of (mg of indispensable amino acid in 1 g of protein x ileal digestibility) to (mg of same indispensable amino acid in 1 g of reference protein)
Digestible indispensable amino acid score (DIAAS)
A measure of the quilts of a food protein; expressed as a percentage.
DIASS% is the lowest DIAA reference ratio of a food protein x 100
Protein efficiency ratio
A measure of protein quality determined by comparing the weight gain of a laboratory animal fed a test protein with the weight gain of an animal fed a reference protein
Net protein utilization
A measure of protein quality determined by comparing the amount of nitrogen retained in the body with the amount eaten in the diet
Biological value
A measure of protein quality determined by comparing the amount of nitrogen retainer in the body with the amount absorbed from the diet
Protein complementation
The process of combining proteins from different sources so that they collectively provide the proportions of amino acids quoted to meet needs
- ensures all essential amino acids
- legumes and grains
Ex: bread and peanut butter
Ex: Rice and Beans
Ex: Chickpeas and Rice
Ex: Hummus and bread
Do not need to be eaten at same meal, but need to be in same day! Need to eat a variety to make plant based work!
What is an alcoholic beverage
-primarily water, ethanol and sugar
Ethanol: type of alcohol, yeast fermentation of sugar
Absorption, transportation and excretion of alcohol
- Rapidly absorbed by simple diffusion along the entire GI tract
- About 20% absorbed in the stomach
- absorbed alcohol—>rapidly distributed throughout all body water compartments
- About 90% of the alcohol metabolized by the liver
- 5% excreted into the urine, and the remainder eliminated via the lungs
Factors affecting blood alcohol level
- weight (more weight=more body water so more dilute alcohol)
- gender (men have more body water and more stomach alcohol dehydrogenase activity
- food slows alcohol absorption
- body metabolizes alcohol slowly, as number of drinks increase per hour, blood alcohol levels steadily rise
- type of drink (carbonated mixers cause body to absorb alcohol quicker)
Health effects of chronic alcohol use
- birth defects for baby
- GI problems
- liver disease
- malnutrition
- neurological disorders (memory)
- cardiovascular disorders
- blood disorders
- immune function issue
- sexual dysfunction
- cancer (>upper digestive tract)
- mortality
Alcohol intoxication
The circulating alcohol affects the central nervous system, breathing and heart rate
Alcohol poisoning
Quantity of alcohol consumed>tolerance for alcohol to be metabolized
-impairs mental and physical abilities
Binge drinking
Black out drinking
5+ drinks at one time
Amnesia following a period of excess alcohol
Adverse effects of alcohol
- interfere with organ functions for several hours after ingestion
- affect and interfere with nutritional status and produces toxic compounds
- effects of alcohol vary with age and life stage
Malnutrition and alcohol
Long term excessive alcohol consumption causes malnutrition
- decreasing overall nutrient intake
- interfering with nutrient absorption, storage, metabolism, and excretion
- increasing kCalorie intake
- 1g of alcohol=7 kCalories
Chronic effects of alcohol use
-long term excessive alcohol consumption generates toxins and free radicals that cause: liver damage (fatty liver, hepatitis, cirrhosis), hypertension, heart disease and stroke, increased risk of cancers
Moderate drinking and it’s benefits
No more than 1 drink for women and 2 drinks for men per day
- lowest mortality
- reduced risk for heart disease and stroke-especially with a combination of alcohol and phytochemicals (phenols)-bright colours
Canadas guide likes for alcohol
- 10 drinks a week for women and no more than 2 drinks a day
- 15 drinks a week for men and no more than 3 drinks a day
- have no more than 2 drinks in 3 hours
- have one non-alcoholic drink for each alcoholic drink
- eat while drinking
Proteins
A class of nutrients that include molecules made up of amino acids
- contain carbon, hydrogen, oxygen and nitrogen
- play crucial roles in all biological processes
- large, complex molecules found in the cells of living things
- help facilitate many of the body’s functions
Sources of protein
Animal products:
- meats
- eggs
- dairy
Properties
- high in B vitamins, iron, zinc and calcium
- high in protein, low in fibre and can be high in fat
Plant sources:
- grains
- nuts
- legumes
Properties
- low amounts of iron, zinc, calcium and B vitamins
- high in fibre, phytochemicals and unsaturated fats
- less absorbable forms
Peptide bond
A chemical bond formed when the amino group of one amino acid bonds with acid group of another to create a peptide
- dipeptide
- tripeptide
- polypeptide
The shape of protein
The shape is essential to its function
- elongated shape of collagen gives strength to tendons and ligaments
- spherical shape of hemoglobin
- linear shape in muscles allows to change shape during contraction
Digestion and absorption of single amino acids, dipeptides and tripeptides
- absorbed into the mucosal cells of the small intestine
- different transport system->amino acids compete for absorption
- dipeptides and tripeptides broken down into single amino acids
- single amino acids pass into the blood and brought to the liver
Structural proteins
Collagen, keratin, connective tissues
-bones, teeth, tendons, ligaments, arteries
Contractile proteins
Actin and myosin
Protein functions
- structural
- enzymes
- immune function and protection (antibodies, blood clots, skin)
- acid-base balance
- hormones
- neurotransmitters
- contractile
- transport (cell membrane channels)
- RBC’s (hemoglobin)
- Fluid balance (protein attracts fluid to blood)
If protein in blood is low then…
Fluid leaks into tissues and causes swelling (edema)
Protein when energy intake is very low
- vital body proteins broken down into amino acids
- most dispensable proteins broken down first, but eventually vital ones will be used
When protein intake>needs
- if diet is adequate in energy and high in protein: amino acids—>ATP
- if diet is high in energy and protein: amino acids—>fatty acids and stored in adipose
Elevated protein intake over long periods of time can result in
- hydration and kidney function issues
- bone health issues
- kidney stones
- increased risk of heart disease and cancer
Food allergies
An adverse immune response to a specific food protein
- side effects:rash, respiratory distress, GO distress, death
- allergies to fruit and veggies often occur later in life
Food intolerance
An adverse reaction to food that does not provoke the immune system
Protein needs is determined using ______
Nitrogen balance studies
- intake=output: nitrogen balance
- intake>output: negative nitrogen balance
- positive nitrogen balance: intake>output (pregnant)
RDA for protein-adults
0.8g protein/Kg of body weight/ day
Ex: 75kg man: 75X0.8=60g protein per day
Some groups who have higher protein needs
- infants and children to grow
- pregnancy and lactation
- illness and injury
Nutrients at risk in vegan diets
Protein Vitamin B12!!!!!!! Calcium Vitamin D Iron Zinc (finger nail marks) Omega-3 fatty acids
