HLTH 230 Midterm Flashcards
role of carbohydrates
-provide energy for the brain & NS
-help keep digestive system healthy
-within limits, keep body lean
Indigestible carbohydrates
yield little or no energy
carbohydrate rich foods
-whole grains
-plants
-legumes
-vegetables and fruits
-milk products are the only animal-derived foods that contain significant carbs (milk, yogurt, sour cream)
-concentrated sugars
categories of carbohydrates
simple and complex
simple carbohydrates
Monosaccharides - single sugar
Disaccharides -pairs of monosaccharides (one is usually glucose)
3 monosaccharides
glucose, fructose and galactose
*all have the same number & kind of atoms arranged in different ways
Glucose
-blood sugar
-monosaccharide
-mildly sweet
-essential energy source for body activities
-one of 2 sugars of every disaccharide
-polysaccharides are made almost exclusively of glucose
Complex carbohydrates
polysaccharides - chain of monosachharides
galactose
-component of milk sugar
-not sweet at all
-one of the two sugars in milk products
-found occasionally as a single sugar (fermented milk products)
Fructose
-very sweet
-naturally in fruit and honey
-often used in soft drinks, cereals and desserts
-
high fructose corn syrup
syrup made from cornstarch that has been treated with an enzyme tha converts some of the glucose to the sweeter fructose
3 disaccharides
lactose (glucose + galactose)
Maltose (glucose + glucose)
Sucrose (glucose + fructose)
**joined by cindensation rxns, split by hydrolysis rxns that release a water
Lactose
-milk sugar
-glucose and galactose
-principle carbohydrate in milk
-provides about 1/2 kcal in skim milk
maltose
-2 glucose
-prodcued duing starch breakdown
-occurs during process of alcohol fermentation
-only occurs in a few foods ex. barley
Sucrose
-glucose and fructose
-sweetest disaccharide
-naturally in fruit, vegetables and grains
-table sugar is sucrose refined from beets or sugarcane
Eating sugar
-monosaccharides are absorbed diretly into the blood
-disaccharides are digested before absorption (slit into monosaccharides)
-glucose is most used nutrient in the body
sugar on nutrition label
-cannot tell from % DV what sugar is natural or artificial
most energy in fruit and vegetables comes from
sugar
why are fruits different than purified sugars?
fruit contains fibre, phytochemicals, vitamins and minerals
polysaccharides
-starch
-glycogen
-fibre
**made up of many strands of glucose units
Starch
-storage form of glucose in plants
-long chains of glucose molecules linked together (branched-amylopectin and unbranched-amylose)
-starch is nutritive: we digest starch to glucose
rich food sources of starch
-grains
-tubers (yams and potatoes)
-legumes (peas and beans)
Glycogen
-storage form of carbs in animals
-highly branched glucose chains (this allows for rapid hydrolysis and surge of glucose)
-stored in muscle(2/3) and the liver (1/3)
**meat does not contain glycogen because it breaks down when animal is slaughtered
how long could you sustain energy on stored glycogen
about 1 hr
Fibre
-is a prebiotic
-retains water to protect seeds
-support plant structure
-most are polysaccharides
-humans cannot digest fibre therefore passes through without providing energy*
*digest to small degrees via fermentation
prebiotics
foods that are not digested but promote bacterial growth by acting as food for bacteria
Soluble fibre
-dissolve in water
-form gels (viscous)
-can be digested by bacteria in colon
-soften stool
-slow glucose absorption
-associtaed with low risk of chronic disease (decrease cholesterol)
-used as thickening agent
-gums, pectin, psyllium, some hemicelluloses
rich sources soluble fibers
barley, legumes, oats, apples, citrus fruit
Insoluble fibres
-do not dissolve in water
-speed passage of feces and allieve constipation
-outer layers of whole grains
-retain structure and texture
-easily fermented and do not form gels
examples insoluble fibres
cellulose, lignin, resisant starches, hemicelluloses, inulin
need for carbs
-provied energy
-cheaper than protein
-glucose is used as fuel by the brain and CNS
gluten is a
protein
Ketogenic diet
-used as therapy for epilepsy and seizure control
-low carb high fat diet
-use fat for fuel
why recommend fibre rich foods
-supply vitamins, minerals, & phytochemicals
-little or no fat (except nuts)
-soluble fibres have cholesterol effect
-maintain bodyweight
-maintain blood-glucose concentration
Low fibre diet and cholesterol
you absorb more cholesterol and therefore your cholesterol increases
high fibre diet and cholesterol
soluble fibre lowers blood cholesterol by binding with cholesterol containing bile and carrys it out in the feces
Blood Glucose control
-viscous fibres trap nutrients and delay their transit through the digestive tract
-glucose absorption slows and helps steady levels of blood glucose ans insulin and glycemic index
maintenence of digestive tract health
-fibre and fluid intake play a role in maintaining colon function and preventing constipation
-enlarge and soften stools
-speed passage
need for carbs: constipation
-fibre prevent constipation
-softens stools for preventing hemorrhoids
-prevent compaction (therefore appendicitis)
-stimulates gi tract muscles to retain strenght and resist bulging out (diverticula)
healthy weight management
-foods rich in complex carbs tend to be low in fat and added sugar: may promote weight loss by providing less energy
-fibre creates fullness and delays hunger
how do we get fibre
-pure fibre compounds usually not necessary
-most benefits come from food not compounds
-too much fibre without water can cause constipation
too much fibre?
-purified fibre can lead to a blocked intestine especially with too little water
-binders in some fibres act as chleating agents (carry minerals out of body)
-can contribute to dehydration because they remove water from the body
-too much can limit food intake and cause nutrient and energy deficencies
Bran
-outer part of a whole grain
-largely made of cellulose
-protects the grain
-removed in milling
3 parts os a whole grain
bran, endosperm, germ
Endosperm
-largely starch grains embedded ina protein matrix
-generally what is used in refined flour
germ
-part where new grain develops
-majority of fat in the grains are located here
-often left out of processing to avoid rancidity
Modern milling
-removed germ and bran (whiter, smoother texture increasing starch content and lowering fibre content)
-loss of nutrients
Modern milling laws in canada
1970: mandatory addition of riboflavin, thiamin, niacin and iron
1990: mandatory addition of folic acid (important for cell division)
digestion of carbs
-begins in mouth (salivary amylase)
-then becomes deactivated by stomach acid
-starch digestion resumes in small intestine
-pancreatic enzymes: split starch into smaller polysachharides and disaccharides
-intestinal ezymes split these into monosaccharides
starch found in refined grains
rapidly broken down into. glucose which is then absorbed
*sometimes digested slower and releases glucose later (cooked beans)
Resistant starch
-behaves like fibre
-found in raw potaties, unripe bananas, husks of seeds
-digested slowly
-most remain intact until bacteria of colon break it down
-sometimes classified as insoluble fibre
Sugars digestiona nd absorption
-digestible carbs are split into monisaccharides before absorption
-pancreatic amylase splits most starch to disaccharides
-small polysaccharides and disaccharides are split by enzymes atatched to cells lining the small intstine (lactase, sucrase and maltase)
Once in the bloodstream, sugars travel:
-to the liver
-fructose & galactose are converted to glucose or related products
-circulatory system transports the glucose and other products to the cells
-liver and muscle cells may store glucose as glycogen
-all cells may use glucose for energy
Digested fibre
-many fibres can be fermented by intestinal bacteria
-odourous gases are bi-product
-gas production can be minimized by small servings and gradually increasing
Lactose intolerance
-some people produce less lactase
-ability to produce lactase declines with age
-lactase deficency may be use to damage to villi
-intestinal bacteria ferment the undigested lactose producing gas and intestinal irritants
Milk allergy
-immune response
-allergic rxn to the protein in milk
-cannot tolerate any milk product
-calcium supplement
Using glucose
-glucose is basic carbohydrate unit that cells use for energy
-body keeps supply to use
what processes release energy from glucose
glycolysis and krebs
DRI carb reccomendation
-minimum intake to reduse ketosis is 130g/day (RDA=130g/day)
-45-65% kcalories/day of carbs
-more is reccomended to maintain health and glycogen stores
Glucose below healthy minimum
-body fat cannot be converted to glucose to feed the brain
-with carb defecit, body uses protein to make glucose via gluconeogenesis
-fat fragments usually combine with a compound derrived from glucose (or protein) before being used for energy
-
after10 days of eating less than RDA of carbs
-body would adjust to partly use keytones
adults with chronic ketosis may face:
-vitamin and mineral deficiencies
-loss of bone minerals
-altered blood lipids
-increase kidney stone risk
-constipation, nausea and vomitting
-glycogen stores that are too low to meet a metabolic emergency or support maximal high-intesity muscular work
blood glucose after eating
-BG increases
-insulin secreted from pancreas
insulin stimulates
-uptake of glucose into cells
-storage of glucose into glycogen
-excess glucose into fat
blood glucose after activity
-cells on body use glucose decreasing BG
-glucagon secreted from pancreas
glucagon stimulates
-breakdown of glycogen therefore glucose released into bloodstream
epinephrine
breaks down liver glycogen as part of the bodys defense mechanism in times of danger
to meet glucose needs
-foods rich in free sugars & sugary drinks are not good choices
-balanced meals, at the same times help the body maintain BG levels
Glycemic Index
-measure of the ability of a food to elevate BG & insulin levels
-scored against standard
-many influences
glycemic load
glycemic index multiplied by grams of carbohydrate
excess glucose
-stored as glycogen until muscle and liver are at full cap
-2/3 of te body total glycogen is stored in and used by muscle
-small store in liver and brain
if there is still excess:
-liver converts it into fats and stored in fat tissues
-fat cells may convert glucose to fat
-fat cells can store unlimited quantities of fat
diabetes
-impairs a persons ability to regulate BG
-type 1 and 2
T1D
-little or no pancreatic secretion of insulin
-diagnosed in childhood
-less common
-external source of insulin can be used
T2D
-develops insulin resistance (genetic component)
-as BG rises, so does blood insulin Drugs:
-stimulate secretion
-improve glucose uptake
-extenral insulin
T2D & obesity
-require more insulin
-consistent high BG can be considered prediabetic
-impaired glucose tolerance
reducing diabetes
-control lifestyle factors and diets
-regular PA hifhtens senstivity to insulin
-nutrition
-weightloss
-adequate:nutrients, fibre, protein
-moderate added sugar
-control total carbs
-low saturates fat
reccomended fibre intakes
AI: females 19-50= 25g/day
AI: females 51+=21g/day
AI: males 19-50: 38g/day
AI: males 51+ = 30g/day
fibre and colon cancer
-dilute and speed the removal of cancer causing agents from the colon
-promote bacterial reproduction binding nitrogen & carrying it out
2018 carb guidelines
-eating patterns; maintain regularity to optimize glycemic control
dietary appraches for those with T2D:
-medeterrainean style
-vegan/vegetarian
-DASH
-diet patterns
hypoglycemia
-low blood glucose
postprandial hypoglycemia
low blood glucose after a meal
(body releases too much insulin)
fasting hypoglycemia
too long between meals causes for low BG
causes of low blood suagr in people with diabetes
-more PA
-not eating on time
-eating less than you should have
-too much medication
-drinking alcohol
honey vs white sugar
from a chemical standpoint, they are the same (suagr contains fewer calories per serving)
carbs in proteins
-no carbs is fish or meat
Free sugars:
-added sugars as well as sugars naturally present in honey, syrups and fruit juices etc
-DO NOT include naturally occuring sources of sugars found in intact or cut fruit and vegetables
Added sugar:
all sugars added to food and beverage during processing or preparation. all added sugar are also free sugar.
Total Sugars
account for all sugars present in food and beverage regardless of the source. This includes added, free and naturally occurring sugars found in intact or cut fruit and veggies and unsweetened milk.
canadas food guide sugar reccomendations
-prepare meals and snakcs using ingridents that have little to no added sodium, sugar or saturated fat
replacing sugar:
-energy-yieling sugar alcohols (nutritive sweetners)
-no energy artificial sweetners (nonutritive sweetners)
Sugar alcohols
-do not contain ethanol or any other intoxicant
-are polyols
-naturally found in small amounts in fruit and veg
-manufactured from common sugar
-provide energy
-produce low glycemic response: body absorbs them slowly
-gas, abdominal discomfort & diarhea from large amounts
-do not contribute to tooth decay
artificial/alternative sweetner
-make food taste sweet
-do not promote tooth decay
-provide ver little food energy
-can be toxic in high doses
Aspartame
-4kcal/g (same as sugar)
-not heat stable
-made of phenylalanine and aspartic acid and a methyl group
-sweeter so we use less
-in powder form, mixed with lactose
-in GI tract, the fragments are split, absorbed & metabolized just as would be any protein fragment
-byproducts are not toxic at the levels generated (formaldehyde, methyl alcohol…)
***NOT SAFE FOR PPL WITH PKU
Stevia
-naturally sweet herb
-natural sweetner
-approved as non medical and medical ingrident
-300x sweeter than sucrose
strgeties for artificial sweetner
-moderation is key
-does not lower energy intake
-safer for teeth
what is nutrition?
the study of nutrients and other biologically active compounds in foods and in the body; sometimes also the study of human behaviours related to food
what does diet mean?
the foods (including beverages) that a person usually eats and drinks
Malnutrition
any condition caused by excess or deficient food energy or imbalance of nutrients
Includes: undernutrition OR overnutrition
Undernutrition
nutrient or energy deficiencies
Overnutrition
nutrient or energy excess
the only two lifestyle habits that have more influence on long-term health than diet:
-smoking/tobacco
-alcohol consumption
what are the 4 leading causes of death in Canada (2018) and which are influenced by nutrition?
- Cancer
- Heart Disease
- Cerebrovascular Disease
- Acciedents
1,2,3 are influenced by nutrition
what are the 4 leading causes of death in canada in 2022
- Cancer
- Heart Disease
- COVID
- Accidents
nutrition and chronic diseases
genetics and lifestyle together with diet can influence the risk of getting chronic diseases such as: heart disease, diabetes, dental, bone loss and some types of cancer
genetics, individuality and nutrition
-some diseases are purely hereditary (sickle cell) but some can be influenced by diet (diabetes)
-some diseases are purely diet (vitamin deficiency)
-some are influenced by both genetics and nutrition (hypertension)
what is nutritional genomics? aka molecular nutrition or nutrigenomics
-the science of how nutrients affect the activity of genes & how genes affect the activity of nutrients
purpose of nutritional genomics
-helping to determine an individuals specific nutrient needs for heath and fighting disease
lifestyle choices affecting health
-smoking
-alcohol
-PA
-sleep
-stress
-air & water quality
What is energy
-the capacity to do work
where does the energy the fuels the human body come from
indirectly from the sun via plants and animals that eat plants
food energy is measured in
Calories (kcalories)
What are calories?
-unit measuring energy
-1kilocalorie is the amount of heat necessary to raise the temperature of 1kg of water by 1 degree celcius
1000calories = 1kilocaorie =1 Calorie
6 classes of nutrients
- carbohydrate
- Lipid (fat)
- Protein
- Vitamins
- Minerals
- Water
Macronutrients
-required in relatively large amounts per day (g/day)
-carbohydrates, protein, fat, water
Water
does not provide energy, need this in larger amount than any other nutrient
Micronutrients
-required in small amounts per day (mg/day)
-vitamins and minerals
Essential Nutrients
nutrients a person must obtain from food because sufficent amounts cannot be made from the body
Vitamin D
not essential in other countries because they recieve sun year round, but essential in Canada because we have seasons
Inorganic Nutrients
-nutrients that contain no carbon
-ex. water, iron, calcium & other minerals
Organic Nutrients
-carbon containing
-ex. carbs, proteins, lipids and vitamins
Energy Yielding Nutrients
-nutrients that can be broken down to provide energy to the body
-carbohydrates, lipids, potein
List the 4 macronutrients
carbs, protein, water & lipids
list the 2 micronutrients
vitmains & minerals
list the 2 inorganic nutrients
minerals & water
list the 4 organic nutrients
carbs, protein, lipids & vitamins
list the 3 non-energy yielding nutirents
minerals, water, vitamins
list the 3 energy yielding nutrients
carbs, protein, lipids
Vitmains & minerals
regulators that asssit in all body processes, such as digesting food & healing wounds
alcohol
not a nutrient but is energy yielding
carbohydrate energy from food
4kcal/g
protein energy from food
4 kcal/g
fat energy from food
9 kcal/g
alcohol energy yielding
7 kcal/g
Elemental Diets
Diets composed of purified ingredients can supply all the nutrients to people who cannot eat food
Can we live on supplements only
yes - but not superior to real food
what happens to digestive organs if they are not being used
they atrophy
nonnutrients
compounds other than the 6 classes of nutrients present in food that have biological activity in the body
Phytochemical
-type of nonnutrient
-found in plant-derived foods and have biological activity in the body
-contrivute to colour, taste etc
enriched and fortified foods
-foods that have nutrients added
are enriched/fortified foods good or bad
-if the starting material is a whole food it may be a nutritious food
-if the starting material is high in fat/sugar, the result may be less nutritious
what are functional foods?
possess nutrients or nonnutrients that might lend protection against diseases ex organge juice with added calcium
“Natural Foods”
-can label anything as natural, no legal definition
“Super Foods”
no such thing
“Processed Foods”
-not always bad
-foods subject to any milling, alteration in texture, additives, cooking or others
Nutracutical
a product that has been isolated from food and often sold in pill form
“staple foods”
foods used frequently or daily
5 characteristics for planning a healthy diet
- Adequacy
- Balance
- Calorie-control
- Moderation
- Variety
Adequacy
providing all essential nutrients, fibre and energy in sufficent amounts to maintain health and body weight
Balance
providing foods of a number of different types in proportion to each other, such that foods rich in some nutrients do not replace foods that are rich in other nutrients
Calorie-control
-coltrol of energy intake
-nutrient dense NOT calorie dense
Nutrient density
-a measure of the nutrients provided per kcalorie of food
-the more nutrients and the fewer calories, the higher the nutrient density
Moderation
providing constituents within set limits, not to excess (sugar, fat, salt)
Variety
providing a wide selction of foods
-increases adequacy
-limit toxins by limiting exposure
-make diet interesting
Why people chose foods (cultural/social)
-symbolism of sharing ethnic foods
-omnivore
-traditional cuisine & foodways
-vegetarian/vegan/ pescitarian
foodways
the sum of a cultures habits, customs, beliefs, & preferences concerning food
factors that drive food choices.
-convienence
-advertising
-economy
-emotional comfort
-availability
-habit
-personal preference
-positive associations
-regions of country
-social pressure
-values/beliefs
-weight
-nutritional value
nutrition is a young science that inclues:
-clinical nutrition
-community nutrition
-public health
-food policy
-food science
reasons why not to trust media
-report ideas before fully tested
-misunderstanding of complex principles
-scientists report findings before subject to scruitny
what to look for when reading about nutrition
-published in a peer reviewed journal
-state purpose & describe methods
-note limitations
-define subjects
-describe previous research & put current research into proper context
-common sense?
thinking about if post/article is reliable
-who is responsible
-do names appear
-editorial board?
-updated?
-selling product?
-sponsored?
Regestered Dietitian vs Nurtitionist
dietitians must meet practice standards while anyone can claim to be a nutritionist (not a protected title in ontario)
Nutrition Assessment
-individual assessment is vital
-generally includes: health & diet history, anthropometric measures, lab test, socioecomomic/social info
“eating well” in theory
-supply appropriate amount of nutrients, fibre, phytochemicals & energy
-dont exceed reccomendations for sugar, salt and fat
Primary deficiency
caused by inadequate dietary intake of a nutrient
Secondary Deficiency
NOT caused by inadequate intake but by something else such as a disease condition or drug interaction that reduces absorption
Dietary Reference Intake (DRI)
-used for reccomendations in canada and US
-set of 6 lists of values of nutrient intake values for healthy people
Estimated Average Requirement (EAR)
- th average daily nutrient requirement intake estimated to meet the requirement of half of the healthy individuals in a particular life stage and sex group
-basis for an RDA
types of DRIs
-estimated average requirements
-reccomended dietary allowances
-adequate intakes
-tolerable upper intake levels
-chronic disease risk redution
-acceptable macronutrient density ranges
if you dont know EAR;
you cant come up with an RDA, therefore you have an AI
**cant have both an EAR and AI
Reccomended dietary allowance (RDA)
-average daily nutrient intake level that meets the needs of nearly all (97-98%) healthy people in a particular life stage and sex group
-derived from EAR
-nutrient intake goal
Adequate Intakes (AI)
-reccomended daily nutrient intake level based on intakes of healthy people (observed or experimentally derived) in a particular life stage and sex group and assumed to be adequate
-used when insufficent evidence for EAR, therefore RDA
which is better AI or RDA
RDA would be used if possible, if not then AI is fine
Tolerable Upper Intake Levels
-highest average daily nutrient intake level that is likely to pose no risk of toxicity to almost all healthy individuals in a particular life stage and sex group
-intake above level may pose nutrient toxicity
-imp for people taking supplemets
-some nutrients dont have UL values
Chronic Disease Risk Reduction (CDRR)
-a new RDI category based on chronic disease risk
-only nutrient with this is sodium
Acceptable Macronutrient Distribution Ranges (AMDR)
-values for carb, protein and fat expressed as % of total daily caloric intake; ranges of intakes set for the energy yielding nutrients that are sufficient to provide adequate total energy and nutrients while reducing risk of chronic diseases
AMDR protein, fat & carbs
Carbs: 45-65%
Protein: 10-35%
Fats: 20-35%
people that have separate DRI reccomendations
-pregnancy
-lactation
-infants
-children
-sex
-specific age ranges
who do RDAs apply to ?
healthy people
Purpose of DRIs
-shown to help prevent the development of chronic diseases and include generous safety margin
what are DRIs designed for
helping healthy people maintain health not to restore depletion
Estimated Energy Requirements (EER)
average dietary energy intake predicted to maintain energy balance in a healthy adult of a certain age, sex, weight, height & level of PA consistent with good health
why is the value for EER not generous
no UL for energy; small excess amounts of energy consumed day after day cause weight gain & associated disease
PA DRI recommendations
60m moderate activity each day for weight control & health benefit
what does canadas physical activity guide suggest for adults aged 18-64
-150m moderate-vigourous PA/ week in bouts of 10 mins or more
-muscle/bone strenthening activity 2 days per week
-more PA= greater health benefit
benefits of PA
-more restful sleep
-better nutrition
-improved bone density
-enhanced immunity
-lower risk of cancer
-lower risk of CVD
-strong circulation & lung function
-lower type II diabetes risk
-stronger self image
-reduce gallbladder disease (women)
-lower MH problems
what foods are most nutrient dense?
vegetables (non-starchy), also rich in phytochemicals
Canadas food guide
-provides daily healthy eating pattern including a variety of healthy foods from 3 food categories
-helps reduce development of chronic disease
Recent revisions of canadas food guide
-did not meet with representatives from food and beverage industry
-open consultations to all stakeholders
-
Canadas fod guide reccomendations
-be mindful of eating habits
-cook more often
-enjoy food
-eat with others
-eat plenty of fruits and vegetables, whole grain and protein foods
-chose protein foods that come from plants more often
-make water drink of choice
-use food labels
-beware of marketing
which canadian population has separate food guide
first nations, inuit and metis
Image and recommendations on Food Guide help ensure:
Adequate: micro and macronutrients
Balance: ensuring one type of food is not eaten in excess and others not eaten
Variety: many choices in each group
Discretionary Calorie Allowance
the difference between the calories needed to maintain weight & those needed to supply nutrients
2 types of daily values
- Intake goal to strive for, ex fibre, fat, protein, vitamins & most minerals
- healthy daily maximums such as cholesterol, total fat, sum of saturated fat, trans fat & sodium
Daily values
are based on recommended daily intakes for vitamins and minerals or reference standards for carbs, protein, fats, fibre, sodium
Nutrition facts table present information in 2 ways:
- Absolute quantities
- Percent of standards
% daily values
-calaculations to determine are based on 2000 calorie diet
-5% is a little 15% is a lot
2 types of nutrition claims
Nutrient content claims: may highlight a nutrition featureof a food such as “light, low, less, free”
Health claims: include 2 types: disease reduction and functional
health claims: nutrient function claims
subset of function claims
Nutrient content claims
-meet criteria for specific claims defined by Canadas Food and Drug Regulations
ex. “cholesterol-free” or “source of fibre”
Disease Reduction Claims
-highlight relationship between consumption of food or ingrident and a persons health
-quite restricted
Function Claims
-describe the roles of a food or food consitiuent has on the normal functions or biological actvities of the body
Nutrient function claims
type of function claims, are statements about the roles of energy or nutrients that are essential for good health or normal growth and development
changes made to food labels
-make serving size more consistent (realistic)
-revising % daily value
-adding new % daily value for sugar
-adding postassium
-removing vitamin A and C
-adding mg for calcium, potassium and iron
-adding a footnote at bottom about % daily value
-changes to way sugars listed
how were the way sugars listed changed on food labels
grouping sugar-based ingredients in brackets after name “sugars”
how are ingredient lists organized
most to least by weight
foods exempt from nutrition facts
-fruits and veg
-alcohol
-refill glass dairy
-one bite candy
-raw meat except ground meat
-herbs and spices
-food sold in grocerys stores that is prepared and packaged there
front of package nutrition labelling
front of package symbol required on foods high in sodium, sugars, saturated fat because these are tied to chronic disease
Caroies on menus
as of 2017, food service chains with 20 + locations in ontario require to post the number of calories in the standard food and drink items
where will you see calories on menus
-fast food
-restaurants
-coffee shops
-bakeries
-grocery stores
-movie theatres
calorie recommenations for adults and children
13+ = 2000 calories
4-12 = 1500 calories
effects of phytochemicals
-sensory properties
-antioxidants
-mimicking hormones
-altering blood constituents that may protect against disease
Phytochemical rich foods that benefit health
-whole foods
-wine
-tea
-chocolate
-garlic
-tomatoes
-flaxseed
-soybeans
Chocolate
-flavonoid antioxidant in dark chocolate may reduce blood-cloting tendencies
-chocolate is high in sugar and saturated fat
where are antioxidant phytochemicals best obtained from
nutrient-dense, low-calorie fruit and vegetables, claorie-free green or black tea
Tomatoes
-5 tomato-containing meals per week equals a lesser likelihood of cancers of the esophagus, prostate or stomach
- contain Lycopene
Lycopene
-may inhibit the reproduction of cancer cells and protect against damaging sun rays
-in tomatoes, papaya, watermelon, pink grapefruit
Garlic
-contains organosulfur compounda, reported to inhibit cancer development
-investigating potential roles for garlic against allergies, heart disease, and bacterial cause of ulcers
Basic chemical tastes include:
sweet
sour
Bitter
Salty
Umami
Flavour vs Taste
-flavour is total sensory impression
-taste is based on 5 tastes
Flavour Includes
-aroma
-texture
-temperature
-taste
why are sugars important
provide energy for the brain
why are fats important
provide energy & essential nutrients
enjoyment of salt
assures the consumption of sodium & chloride
aversion to bitterness
discourages consumption of foods containing bitter toxins
purpose of digestive system
digest food & absorb components and excrete
Digest
to break molecules of food into smaller molecules
2nd part of mechanical digestion
-stomach and intestines liquify foods
-peristalsis
Absorb
movement of nutrients into intestinal cells after digestion
how far does digestive tract extend
mouth to anus
absorption of the digestive system
-absorbs nutrients
-absorbs some nonnutrients
-some substances are not absorbed (fibre)
1st step Mechanical digestion
-begins in the mouth
-chewing to shred food
-saliva added
-mastification releases nutrients trapped inside indigestible skins
what does saliva do
softens rough/sharp food
-moistens & coats food making it slippery
Sphincter muscle
-at base of esophagus
-Lower esophageal sphincter
-prevents reflux of stomach into esophagus
stomach
holds food, mashes and liquifies it
Chyme
liquified food, as a result of mechanical and chemical breakdown
3rd part of mechanical digestion
-chyme is released into the small intestine little by little when the pyloric valve opens
-vast majority of absorption occurs in the small intestine with the help of segmentation
Segmentation
alternating forward and backward movement allows for greater contact between partially digested food and intestinal juices and enzymes
Small intestine sections in order
duodenum, jejunum, ileum
4th step of mechanical digestion
-large intestine (colon)
-digestion & absorption almost finished by here
-reabsorbs water but also absorbs some minerals
-fibre and undigested material makes up feces
-rectum stores fecal material
transit from mouth to rectum takes
1 to 3 days
beginning of chemical digestion
-in the mouth
Ligual Lipase: digestion of fat
Salivary Amylase: enzyme that breaks down starch
How does saliva help maintain teeth
neutralizes acids produced by oral bacteria and washes away food particles that would promote tooth decay
when does the salivary amylase stop working
when it hits the stomach acid
when does protein digestion begin
in the stomach
gastric juices
-released by stomach
-mix of water, enzymes, HCl
-needed to active a protein-digesting enzyme (pepsin)
-HCl begins denaturation of proteins
how is the digestive tract protected from acid
by mucus
stomach acid pH
2
where does most digestion and absorption occur
in the small intestine
how is bile resleased from gallbladder into the intestine
hormonal messengers like CCK
bile
an emulsifier produced in the liver and stored in the gallbladder
emulsifier
mixes fat and water
CCK
slows gastric emptying & is stimulated by fat or protein in the small intestine
how does the pancreas release pancreatic juices
hormmonal mesengers liek secretin
pancreatic juice
contains enzymes & bicarbonate & water
-digest carbs, protein and fat (amylase, proteases, lipase)
-bicarbonate neutralizes stomach acid
what breaks down carbs, proteins & fats
pancreatic & intestinal enzymes
what remains in the digestive tract after absorption in the small intestine
water, fibre and some minerals
Fibre
-cannot be digested by human enzymes
-some are digested by bacteria living in the digestive tract (results in short chain fatty acids that can be absorbed)
can the body handle combinations of foods
some foods are handled better in combination and vise versa
which organ is sensitive in adjusting its output in response to the composition of the diet
the pancreas
Overview of digestion in the mouth
-food is chewed, mixed & chemically broken down by teeth, tongue and saliva
-each swallow triggers peristalsis to move food from esophagus to stomach
overview of digestion in the stomach
-starch digestion is stopped by pH of stomach
-acid denatures proteins, enzymes then break them down
-End result is chyme that slowly enters small intestine
where does some absorption of alcohol and drugs occur
the stomach
overview of digestion in the small intestine
-some sugars absorbed after they enter the small intestine
-bile emulsifies fat
-pancreatic enzymesbreak down starch, fat & protein
-cells of small intestinealso produce enzymes that complete chemical breakdown
-smsll fragments are absorbed into blood & lymph via the cells of the SI walls
-vitamins & minerals absorbed
Overview of digestion in the large intestine (colon)
-fibre fragments, fluid, & some minerals are absorbed
-fibres are partly digested by bacteria in the colon
-most fibre is absorbed and is excreted as feces
Number of microbes in the digestive tract
-up to 100 trillion microbes of many species in a heathy digestive tract
Microbiota
refers to the mix of microbial species of a community for example those in the digestive tract
systems intestinal bacteria affects:
muscle, adipose tissue, brain, immune system etc
Probiotics
comsumable products containing live microorganisms in sufficent numbers to alter the bacterial colonies of the body in ways believed to benefit health
Prebiotics
substances that may not be digestible, such a fibre, but serves as food for probiotic bacteria and thus promotes their growth
what is the small intestine lined with that facilitate absorption
villi & microvilli
(microvilli extend from villi)
Absorption in the small intestine is
SELECTIVE; we absorb more when we need it and absorb less when we dont
Blood vessel role in absorption
transport most of the products of carbohydrate & protein digestion, most vitamins & minerals to the liver
what transports nutrients to boyd cells
blood & lymph
Lymphatic vessels role in absorption
transport most of the products of fat digestion (large components), these are later delivered to blood stream
what happens to the surface of small intestines with severe undernutrition
small intestine atrophies
what happens to digestive tract without adequate nutrition
muscles become weak due to lack of exercise
Hiccups
hiccups are spasms of the vocal cords & diaphragm, caused by irritation
Gas & Belching
caused by air swallowed during eating, some vegetables, beans and milk products
Heartburn (GERD)
-reflux of stomach acid contents into the esophagus
-acid burns unprotected surface of esophagus
-can be caused by laying down after a meal or excess abdominal fat
potential contributors to heartburn
-overeating
-fat
-coffee
-chocolate
-carbonation
-alcohol
-smoking
-hot
Things that may help heartburn
avoid problem foods, eat smaller meals, drinking liquids hour before eating
-loose clothing
-relax but sit up
what can provide temporary relief to heartburn
antacids by neutralizing stomach acid
how does the body respond to antacids
-produce more acid
-interfere with ability to absorb nutrients
-cause indigestion & diarrhea
-mask symptoms of GERD or ulcers
Untreated GERD
-increase risk of esophageal cancer
-treatment may require surgery
Ulcer
an erosion in the layers of cells that form a lining (treatment = antibiotics)
Hernia
a protrusion of an organ or a body part through the wall of the body chamber that normally contains the organ (can cause food back up into esophagus, may require surgery)
Choking
-food lodged in trachea and blocks passage of air
Constipation
-infrequent bowel movements
-often caused by diet, inactvitiy, dehydration, medication
-increases risk of colon cancer
Dysphagia
-difficulty swallowing
-sometimes seenw ALS, parkinsons, or follwoing stroke
Prevention/Treatment of constipation
-defecate when needed
-consume fibre
-drink fluids
-be PA
Diarrhea
-frequent watery bowel movements
-often caused by diet, stress or irritation of colon -causes dehydration & mineral imbalances
irritable bowel syndrome
-intermittent disturbance of bowel function
-associated with diet, lack of PA, or stress
Inflammatory bowel disease
chrons & colitis; inflamation anywhere in GI tract
Liver processes wastes & either:
-sends them to the digestive tract with bile, to leave the body with feces
-or preares them to be sent to kidneys for disposl in urine
Kidneys and excretion
-imp for BP & fluid regulation and some minerals
-filter blood
-waste becomes concentrated in the urine which travels to bladder & emptied
How is kideny function regulated
by hormones
what happens to extra nutrients?
energy containing nutrients stored in forms: glycogen & fat
excess fat is stored in cells of
adipose tissue
what do glucose & fat stores ensure
body cells will have source of energy
what nutrients are stored without limit, even if they reach toxic levels
vitamin D
what nutrients are only stored in small amounts & readily depleted if not replenished
Vitamin C
fat soluble vitamins
A,D,E,K
water soluble vitamins
B & C
Elements in fat
carbon, hydrogen & oxygen
Lipids
organic compounds not soluble in water
Lipids include
-triglycerides (fats & oils)
-Phospholipids (lecithin)
-Sterols (cholesterol)
Fats @ room temp
solid
Oils @ room temp
Liquid
Functions of fat
-storage form for excess food energy
-provides much of the energy needed for work
-shock absorber
-thermoregulation
-cell membranes
-aid in absorption of phytochemicals
when food is not plentiful
we rely on fat for survival
Adipose (fat) tissue
metabolically active tissue that secretes hormones and produces enzymes that influence food intake & affect the body’s use of nutrients
Adipose cells (fat cells)
specialized for fat storage, they expand & multiply
why is fat stored more than glycogen?
fats pack tightly together without water (more efficient storage)
why do people naturally like high-fat foods
fats carry many compounds that give pleasant aromas & flavours and make things tender
usefulness of fat
-contributes to satiety
-valuable in some situations like long distances or cold weather
satiety vs satiation
satiety is feeling of fullness after meals, satiation is feeling of fullness when youre eating (volume)
ex. broccoli contributes to satiation but nuts contribute to satiety
how does fat promote satiety
triggers series of psychiological events that slow the emptying of the stomach & promote satiety
3 classes of lipids
- Triglycerides
- Phospholipids
- Sterols
Triglyceride
3 fatty acids + glycerol
what are fatty acids
organic acids composed of carbon chains of various lengths
-differ on length & degree of saturation
Glycerol
backbone for triglycerides
monounsaturated fatty acid chain
1 double bond
polyunsaturated fatty acid chain
more than 1 double bond
saturated fatty acid chain
no double bonds
naming based on double bonds
named from 1st double bond from methyl end
examples of polyunsaturate fatty acids
omega 3 & 6
Degree of saturation
affects melting temperature
-more unsaturated = more liquid fat is at room temperature
-more saturated = firmer at room temperature
health reccomendations for fats
using monounsaturated or poly unsaturated over saturated or trans
** the harder the fat, the poorer the choice)
most vegetable oils & fish oils
rich in polyunsaturated fat
how do fats influence CVD
benefit when replacing saturated and trans fat with monounsaturated or polyunstaurated fats
CHain Length
decreasing chain length, decreases firmness
long chain fatty acids are more common in the diet (12-24) like meat, seafood, oils
Medium chain (6-10) and short chain (>6) are found mainly in dairy and coconut oil
what oil is rich in monounsaturated fat
olive oil
animal & tropical fat
generally most saturated (fatty meat, whole milk dairy, coconut & palm oil)
Olive Oil
-rich in monounsaturated fat
-offers protection against heart disease
-dark delivers more phytochemcials
Canola oil
rich in polyunsaturated and monounsaturated fats, lowest in saturated fat
what is hydrogenation
hydrogens are added to remove double bonds, making fats more saturated , tjis forms transfat
how are transfatty acids formed
poluunsaturated fats are rarely hydrogenayted completely, the double bonds that remain change formation
** some occur naturally in milk & meat
advantages of hydrogenation
longer shelf life, higher smoke point & creamier
Partially hydrogented oils
now banned (2018) to improve heart health
Phospholipids
2 fatty acids + glycerol + phosphorous molecule
*fatty acid soluble in fat & phos soluble in water
*are emulsifiers
what plays structure of cell membrane
lecithin & phospholipids
*phospholipids help fats travel back & forth acorss lipid-containing membranes of cells into watery fluid on both sides
Lecithin
-lead to GI problems in high amounts
-body can make all it needs
Sterols
-large molecules consisteing of interconnected rings of carbon atoms with side chains of C, H & O
-present in food derived from plants and animals
Cholesterol
-only food derived from animals contain significant amounts of cholesterol
-can be made by body
-component of cell membranes
-manufactured in liver
-body makes more cholesterol than it eats
-narrows arteries
Phytosterols
-found in seeds/nuts
-plant-derived compounds that have structural similarities to cholesterol
-lower blood cholesterol by competing with cholesterol for absorption
what sterol is a precursor for making bile
cholesterol
bile
-emulsifier made by the liver & storred in gallbladder
-does not digest fats
-emulsifies fat allowing contact with enzymes in watery fluids to split the fatty acids from glycerol backbone for absorption
unique sterols
vitamin D & sex hormones (estrogen and progesterone)
Digestion of fats in the mouth
-lingual lipase acts on triglycerides with short/medium chain fatty acids
-little importance
digestion of fats in the stomach
-mix fat with other stomach contents
-churning grinds solid into pieces and disperses to small droplets
-gastric lipase breaks down triglycerides (works best in acidic environment)
How does fat digestion work if someone has gallbladder removed
-liver still produces bile
-no longer store bile
Digestion of fats in small intestine
-bile is secreted in response to CCK
-bile produced by liver & stored in gallbladder
-emulsified fat particles acted on by fat-digesting enzymes secreted by pancreas
how are emulsified fat particles acted on by fat digesting enzymes in the SI
-tyiglycerides; split into monoglycerides, FFA & glycerol
-bile shuttles lipids across the mucus layer to the absorptive cells of the intestinal villi
what % of triglycerides are absorbed
98%
Transport of smaller products of lipid digestion
-glycerol, short and medium chain fatty acids pass directly through the cells of the intestinal lining into the bloodstream and onto the liver
Transport of larger products of lipid digestion
-intestinal cells, monoglycerides & long chain fatty acids are reformed into triglycerides & cluther with proteins & phospholipids
-form chylomicrons
Chylomicrons
-type of lipoprotein
-transport vehicle
-travel in the lymph to the bloodstream
-body tissues take triglycerides from the chylomicrons in bloodstream
Very low density lipoproteins (VLDL)
carry triglycerides & other lipids made in the liver ti the body cells for their use
Major lipoproteins
chylomicrons, VLDL, HDL, LDL
Low density Lipoproteins (LDL)
-bas cholesterol, want this to be low
-transport cholesterol & other lipids to body tissues
–made from VLDL adter they have donated many of their triglycerides to body cells
High density lipoproteins (HDL)
-healthy cholesterol, want this to be high
-carry cholesterol from body cells to the liver for usage or disposal
-pick up things causing plaque
LDL features
-lighter, larger & richer in cholesterol than HDL
-deliver triglycerides & cholesterol from liver to tissues
-elevated LDL cholesterol is associated with increase heart disease
HDL features
-smaller, denser & packaged more in protein than LDL
-scavenge excess cholesterol & phospholipids from tissues
-elevated HDL is associated with decrease heart disease risk
risk factors that can be controlled for heart disease
-high HDL; low LDL
-high BP
-diabetes
-obesity
-physical activity
-cigarette smoking
-diet high in trans fat and low fruit and veg
what dies food cholesterol have to do with blood cholesterol?
most saturated food fats & trans fats raise blood LDL cholesterol
risk factors that cannot be controlled for heart disease
-age
-being male
-family history of premature heart disease
heart disease risk
relayed to proportions of lipids the lipoproteins contain & the tasks they perform NOT the type of cholesterol they carry
what plays a key role in cholesterol levels
genetics
how to lower LDL
-reduce trans and saturated fats
-weight loss
-add soluble fibre
how can LDL be damaged
oxidation, can be slowed by dietary antioxidants (vitamins E, C, selenium & phytochemicals)
How to raise HDL cholesterol
-dietary measures are ineffective
-trans fat lowers HDL (bad)
-saturated fat may raise HDL but also LDL
-PA raises HDL
-quitting smoking raises HDL
Mediterranian Diet (to lower cholesterol)
-low saturated fat
-low trans fat
-rich unsaturated fat
-rich complex carbs & fibres
-rich nutrients & phytochemicals
Portfolio Diet (to lower cholesterol)
-include nuts
-incorporate plant protein
-viscous (soluble) fibre
-include plant sterols
DASH eating plan
used to stop hypertension & lower LDL and BP
How can body fat be used for energy
-decrease intake
-increase expenditure
Essential Fatty Acids
Linoleic acid & linolenic acid
-only FA that cannot be synthesized by the body
-essential nutrients
-polyunsaturated FA
-used to make eicosanoids
eicosanoids
-compounds that regulate body functions
-muscle relaxation & contraction
-blood vessel dilation & constriction
-response to injury & infection
Fatty acid deficency
-growth delay
-reproductive failure
-skin lesions
-kidney & liver disorders
-neurological & vision problems
Linoleic acid
-Omega 6 FA
-polyunsaturated
-used to produce other omega 6 FA
-consumed in moderation
Arachidonic acid
-made from omega 6
-starting material from which a number of eicosanoids are made
Linolenic Acid
-omega 3 FA
-polyunsaturated
-used to produce other omega 3 FA
-support immunity &inhibit development cancer
EPA & DHA
-made from omega 3
-body makes limited amounts
-abundant in fish oils & cold water fish
-reccomendedto include 2 meals fo fatty fish/week
Visible fat
-fat trimmed from steak
-butter added at the table
invisible Fat
-marbling of meat
-fat ground into things
-fat blended
-fats present in foods
what is the single most contributor of saturated fat in the diet
cheeses
strong flavoured fat examples
sesame oil, peanut butter, nut oils
butter vs margrine
same number of calories
-hardened margarines are saturated
-soft margarines are less liekly to elevate blood cholesterol than saturated fats of butter
-some margarines have added phytosterols that compete with cholesterol for absorption
Fat replacers
-some contain artifical fats
-replace some or all functions of fats
ex.
-add water ot whip air
-fat-free milk to creamy food
-lean meat
-bake instead of frying
Fat replacers include:
Carbogydrates: fruit puree or starches
Sugars: provide calories but fewer
FIbres: viscous may provide similar texture
proteins: microparticulated proein or fermented whey
most vulnerable to foodborne illness
women, infants, children under 5, 60+ and weak IS
2 ways of foodborne illness:
- Foodborne infection
- Food intoxications
Foodborne infection
caused by eating foods contaminated with infectious microbes
Foodborne intoxications
caused by eating foods containing natural toxins, or microbes that produce toxins
Hepatitis A
INFECTION (affecting liver)
organism: hepatitis A virus
sources: undercooked/raw shellfish, cotaminated produce, water and ice, food prepped by infected person
Symptoms:
-2-4 weeks or up to 7
-lasts weeks - months
-fever
-loss of appetite
-cramps
-jaundice
-preterm labour
Prevention: cook throughly, avoid untreated water, avoid raw unpeeled fruit and veg
Listeriosis
INFECTION
organism: Listeria bacterium
Sources: unpasteurized milk, soft cheese, deli meat, raw meat
Symptoms: 3-70 days, mimics flu, blood poisioning can spread to NS, pregnancy complications
Prevention: pasteurized milk, cook thuroughly, sanitation
Salmonellosis
INFECTION
organism: samonella bacteria
Sources: raw egg, raw meat, unpasteurized dairy, raw produce
Symptoms: 1-3 days, nausea, fever, chills, vomit, cramps, diarrhea
Prevention: sanitation, cook throughly
E. Coli
INFECTION
sources: undercooked beef, unpasteurized milk, contaimated fruit and veg, person-person contact
symptoms: 1-10 days, bloody diarrhea, cramps, kidney failure, fatal
prevention: cook thuroughly, sanitation, wash hands after contact with animals
Botulism
INTOXICATION
organism: clostridum botulinum
sources: anaerobic environement with lots of acidity
Symptoms: 12-72 hrs, NS systems: double vision, inability to swallow, speech difficulty, progressive paralysis of respiratory system, death
Prevention: proper canning, refrigerate homeade things
Staphylococcal food poisoning
INTOXICATION (common)
*concentrated in wounds
*grows rapidly at room temp
organism: staphylococcus bacteria
sources: moisture drops or touching blemishes then food
Symptoms: 1-8 hrs, diarrhea, nausea, vomitting, cramps, fatigue, 1-2 days, rarely fatal
Vibrosis
INFECTION
organism: vibro bacteria
sources: undercooked or raw seafood
symptoms:
vibro p.: 24 hrs, diarrhea, cramps, vomit, headache, ends in 1-7 days
vibro v.: 12-72hrs, fever, chills, skin lesions, hypotension
Preventing foodborne illness
clean, separate, cook, chill
CLEAN
handwashing, sanitize, wash
CHILL
-bacteria grow most rapidly between 4-60
-freezing can stop growth but will not kill bacteria
-never thaw at room temp
-refrigerate/freeze within 2 hrs
SEPARATE
-dont cross contaminate
COOK
-to safe internal temp
-keep food hot
Storing Leftovers
-refrigerate within 2 hrs
-refrigerate when steaming stops
-uncovered or loosely wrapped shallow contaniers
-debone meat
Reheat leftovers
-to 74 degrees
-discard uneaten heated leftovers
proteins that are working molecules
-enzymes
-antibodies
-hormones
-transport vehicles
-cellular pumps
-oxygen carriers
Proteins for structure
-tendons
-ligaments
-scars
-muscle fibres
-cores of bone
-filaments of hair
-nails
insulin is made of
2 strands of protein
Proteins
-made of C,H & O
-composed of aa
-contain nitrogen
-some aa contain sulfur
Amino acids
-amine group
-acid group
-distinctive side chain (gives identity)
Side chains
-make amino acids differ in size, chape, electrical charge
Essential amino acids
-indispensible
-cannot be synthesized by body
-only replenished from foods
Nonessential amino acids
-dispensible
-can be synthesized by body
Conditionally indispensable amino acids
-normally nonessential
-special circumstance where need exceeds bodys ability to produce and it must be supplied by diet
ex. body cant conver phenylalanine to tyrosine (PKU) then tyrosine becomes conditionally essential
Recycling aa
-breaks down proteins to use aa
-provides access to aa for energy when needed
using aa for energy
-tissues can break down their ow proteins in glucose deprevation until a certain point
-most dispensible proteins used first
how do aa form proteins
Peptide bonds
peptide bonds
-connects one aa to another
-formed between amine of one aa and the actid group of the next aa
Primary aa structure
-amino acid sequence
-one conected to next
secondary structure
-polypeptide shapes
-weak electrical attractions
-twist into helix or fold into pleated sheet giving strength and stability
Tertiary Structure
-polypeptide tangles
-long chains twist and fold
-side groups can attract or repel
-side groups may be hydrophobic or hydrophillic
-disulfide bridges determine tertiary structure
-shape gives characteristic
Quaternary Structure
-multiple polypeptide interactions (2+)
-some protein strands funciton alone while others are composed of several strands
proteins perform tasks dictated by
shape
globular peoteins
water soluble & found in blood
hallow ball proteins
carry & store materials
proteins that are longer than they are wide
proteins of tendons
Collagen
-protein which connective tisssue is made
-act like glue between cells
Insulin
-regulate blood sugar
Enzymes
-protein catalysts
Sickle Cell disease
occurs to error in amino acid, one replaces another, completely alters protein
Denaturation
-irreversable change of protein shape
-cause by heat, acid, base, alcohol
Protein digestion in mouth
-protein crushed by chewimg & moistened
protein digestion in stomach
-acid helps uncoil strands
-protein digesting enzyme pepsin works in acidic environ. and cleaves aa strands into polypeptides
protein digestion in small intestine
-most digestion & absorption occurs here
-recieves small denatured pieces of protein from stomach (polypeptides or single aa)
-alkaline juices from pancreas neutralize acid to 7
-proteases from pancrease and small intestine continue breaking down protien until it is dipeptides, tripeptides or single aa
-cells along SI absorb aa
Amino acids in bloodstream
-carried to liver
-used by the liver or taken up by other cells
aa for the liver
used in protein synethesis for energy, or used to synthesize nonessential aa and release into bloodstream
aa for other cells
make proteins for their own use, ot release into lymph or blood for other uses OR use for energy when necessary
roles of protein in the body
-building enzymes, hormones and other compounds
-maintaining fluid & electrolyte balance
-maintaining acid-base balance
-clotting of blood
-providing energy and glucose
-supporting growth and maintenence
how do proteins support growth and maintenance
-a build proteins of new tissue
-protein helps replace worn out cells and sturctures
How do proteins play a role in building enzymes, hormones and other compounds
enzymes: facilitate chemical reactions
Hormones: some are made from aa that elicit specific responses
AA: building block for protein
antibodies: proteins of the blood
How do proteins help maintain fluid and electrolyte balance
-protein attracts water
-by maintaining protein stores, cels retain fluid
-lack of protein causes edema
how do proteins help maintain acid-base balance
act as buffers to maintain blood pH, pick up and drop off hydrogens
Acidosis
below normal pH
alkalosis
above normal pH
An amino acid that arrives at a cell can be used in one of 3 ways
- build part of growing protein
- Altered to make another needed compound
- Dismantled to use its amine group to build another aa
*or for fuel or converted to glucose/fat
if the cell is starved for energy & lacking glucose and fatty acids:
-the amine group will be removed & remainder used for energy
-amine group excreted as urine
When are amino acids “wasted”
- body does not have enough energy from other sources so used for energy
- has more protein than it needs
- too much of any single aa such as from supplement
- diet supplies protein of low quality with few too essential aa
Protein sparing
when youre taking in enough energy from carbs/fat you allow protein to be used for better things
3 things bodys response to protein depends on
- state of health
- other nutrients & energy taken within protein
- proteins quality
how does state of health determine protein use
-fighting infection requires more protein
-undernutrition increases need of protein
how does protein quality affect the body
-must be digestible
high quality proteins
dietary proteins containing all of the essential aa in relatively the same amounts that human beings require
aa pool
aa dissolved in bodys fluid provide cells with ready raw materials from which to build new proteins or other molecules
how long of restricted amino acid intake do cells begin to conserve it
a day
Limiting amino acids
an essential aa present in dietary protein in an insufficent amount limits the bodys protein synthesis
what happens from limiting amino acids
limiting aa act as limiting reagents, this is the first thing to deminish but you have all other reagents
when you cant make a potein bc of limiting aa, your body gets rid of the protein making machinery and must start over
Complementary Proteins
2 or more protiens whose aa assortments complement each other in such a way that the essential aa missing form one are supplied by the other
malnutritinon supplementation
the stragety of combinging 2 incomplete protein sources so that the aa in one food make up for those lacking in the other food (does not have to be in same meal)
Nitrogen Balance
the amount of nitrogen consumed compared with the amount excreted in a given time period
RDA protein
0.8g/kg body weight per day
**larger people have higher protein need
Positive nitrogen balance
nitrogen in > nitrogen out
-more protein is synthesized than degraded
Negative Nitrogen balance
nitrogen in < nitrogen out
-body degrades more protein than it synthesizes
examples of positive nitrogen balance
healthy growing children, pregnant women, people recovering from protein deficiencey (building tissues)
examples of negative nitrogen balance
starving, severe stresses, burns, injuries, infections, fever
Protein-energy Undernutrition
-worlds most widespread malnutrition problem
-marasmus & kwashhiorkor
marasmus
PEU
-chronic inadequate food intake
-shrivled & lean all over
Kwashiorkor
PEU
-severe acute malnutrition
-sudden deprivation of food
-swollen belly & skin rash
-too little energy & protein to support body functions
reasons for PEU
-poverty
-elderly
-anorexia
-homelessness
-over-diluted formula
-addiction
-cancer
what percent of diet should protein be
35% of calories from protein
overconsumption of protein
-no benefit
-risk of heart, kidney and bone
Diets high in protein rich foods
-satiated
-highest thermic affect
-animal protein can be high in saturated fat
-increase LDL cholesterol
-can worsen kidney problems
characteristic array of protein rich foods
-include B12 & iron
-lack vitamin C & folate
pros and cons of legumes
advantages: many B vitamins, iron, calcium
cons: lack vitamin A,C,B12
what protein is comparable to meat protein
soybean
*but using sot products in replace of meats inhibits iron absorption
omnivore
includes foods of both plant and animal origin
Lacto-ovo vegetarian
includes dairy and eggs but excludes animal flesh and seafood
Lacto-vegetarian
includes dairy products but excludes eggs, animal flesh and seafood
Ovo-vegetarian
includes eggs but excludes milk products, animal flesh and seafood
Pesco-vegetarian (pescatarian, pescetarian, pescotarian)
excludes animal flesh but eats seafood
Vegan
includes only food from plant sources and excludes all food from animal sources (strict vegitarian)
Flexitarian
includes primary plant based-foods but animal products such as meat and fish are eaten occasionally
Reasons for vegetarianism
-preference
-habit
-advertising
-economy
-comfort
-adversity
-availability
-positive associations
-social pressure
outcomes of vegetarian diets
decrease in
-obesity rates
-heart disease
-high blood pressure
-cancer
increase in
-lifespan
other factors that could affect vegetarian outcomes
-hard to study
-higher intake of fruit and veg leading to more potassium, fibre and vitamins
-vegetarians generally smoke less, exercise more and use alcohol less
vegetarian diets and weight control
-higher body weight with mixed diet compared to vegetarian
-weight increases as frequency of meat consumption increases
-lower body weight is correlated with: high fibre, low fat
Vegetarian diet & heart disease
-die less often from heart disease
-lower in saturated fat and cholesterol
-plant based diets contain unsaturated fat associated with decrease heart disease
-high in fibre
-lower risk due to phytochemicals
-blood lipids
Heart benefits from plant proteins
when soy protein replaced animal protein: reduced blood cholesterol, LDL cholesterol, triglycerides and BP
BP with vegetarian diets
-lower BP and rates of hypertension
-diets high in fibre, fruit and veg lower BP
Vegetarian diets and cancer
-lower rates of cancer
-may be the abundance of veg and fruit rather than absense of animal product
Meat Eaters Diet
-abundant fruit, veg, whole grain & milk
-small serving of fish and meat
**extreme eliminate fruit, veg and grains and increase risk of chronic disease
poorly planned omnivorous diet insufficent in
-vitamin A
-vitamin C
-Folate
-Fibre
poorly planned vegetarian diets at risk of inadequate:
-protein
-iron
-zinc
-calcium
-B12
-D
-omega 3
why do some people suggest a higher RDA for vegetarians even thugh it is the same
lower digestibility of plant proteins
Iron
-can be a problem for meat eater as well
-iron in plant foods is poorly absorbed
-enhanced with vitamin C
DRI committee reccomendations for vegetarians for iron
1.8x the general RDA
Zinc
-meat is richest source
-not well absorbed from plants
-sot interferes with absorption
-problem for growing children
reccomendations for vegetarian to meet zinc needs
-eat nutrient dense foods
-maintain adequate energy intake
-include whole grains, nuts, legumes
Calcium
risk deficiency without milk products
-sources should be varied
Vitamin B12
-requirement is small, but significant amounts are found only in animal-derived foods
-vegans rely on B12 fortified foods or supplements
Vitamin D
-animal foods are fortified
-fatty fish have vitamin D
-supplemets may be needed
