chapter1 Flashcards
ear
estimated average requirement – Amount that meets the nutrient requirements of 50% of people in a life stage/gender group – Based on functional indicator of optimal health
rda
recommended dietary allowance Amount that meets the needs
of most people in a life
state/gender group
ai
adequate intake,Nutrient intake of healthy people assumed to be adequate • Used when an RDA cannot be established • Insufficient data to determine an EAR • Based on observed intakes, experimental data, etc
ul
tolerable upper intake level- Highest daily nutrient intake likely to
pose no risk of adverse health effects to
almost all the general population
• Applies to daily use
• Not a recommended level of intake
– No established benefits of higher level
– Increased risks at higher intakes
what nmol./l of vitamen D will protect against rickets
25
wht is theappropriete range of vitamin that will prtect against osteporosis without promosting cancer
75
a bmi of 24 compared to 45 will extand your life by how much
20 y
what is a healthy diet
– Focuses on vegetables and fruit
– Includes a good source of protein (usually meat)
– Low in:
• Salt
• refined carbohydrate (sugar, white flour)
• fat (may include different types of fat)
– Concept of quality
• freshness, unprocessed, homemade
– Concepts of balance, variety, moderation.
what is the goal of a healthy diet
Avoid nutritional deficiencies and
excesses along with their consequences
• Decrease risk of infectious and chronic
diseases
• Promote optimal health across the lifespan
and to subsequent generations
who ha s a lower risk of obesity- urban or rural
it depends where you live- in developed country its urban, in undeveloped countries its rual- e have equipement and have to drive everywhrere
what are the problematic trend in obesity epidemic
Eating • Soft drink and juice consumption • More food available • Convenience food • More eating out … more fast food • Advertising of food • Larger portions of food
how many cans of pop do teen boys drink a day. girls?
3/4 drink 3 cans
girls: 2/3-2cans
who is exposed to more fast food outlets
People living in low income neighbourhoods are exposed to 2.7 times more fast food outlets than those living in middle or upper income neighborhoods • Grocery stores (61) moved to periphery • Fast-food outlets (761)
what are problematic trends in physical activity
Habitual use of cars (even for short trips)
• Inadequate public transportation
• Urban designs, e.g., no sidewalks or bike
racks, poorly lit trails, etc.
• TVs → multiple channels, round-theclock,
remote control, big-screen
• Labour saving devices
Decline in school physical education
• Elite sport vs. sport for all
• Over-organization of physical
activities/sport
• Children driven to school
• Lack of adequate outdoor recreational
facilities
• Lack of non-traditional physical activities
why is the problem with food labels
difficult to interpret, limited math skills
what does diet mean
“food and drink regularly
provided or consumed”.
It is derived from the Greek “diaita” which
means “manner of living, from diaitasthai to
lead one’s life” (Merriam-Webster Dictiona
what is the basis for DRIs
– assessing & planning diets of healthy
people
– federal nutrition & food programs
originaly what was the goal of “DRIs”
To protect against nutrient deficiencies -
not provide for optimal health (changes thru lifespan)
Provide goals for good nutrition
For maintenance, not restoration of health
what are RNIs
Recommended Nutrient Intakes
RNIs) in Canada (1990
what were the uses of the old RNIS and RDAs
• Good for planning diets for population groups (e.g., schoolchildren, military personnel, etc...) • Do not give minimum or optimal intakes safe and adequate intakes with a generous margin of safety • Assume nutrients come from foods, NOT supplements
what is the purpose of DRIs
To maintain nutritional adequacy • To promote health • To reduce risk of chronic disease • To provide a measure for evaluating inadequacy and/or excess • To assess intakes as distributions – Across population groups – For individuals • To plan diets
What are characteristics of
the DRIs?
Apply to healthy individuals • Refer to average daily nutrient intakes • Values set for several life stage and gender groups • May vary substantially from day to day without ill effect in most case
who established DRIs
Food and Nutrition Board, Institute of Medicine, National Academy of Sciences • Panels of experts; chosen by the National Academy; independently selected • Funded by DHHS, USDA, Health Canada, private industry • Serially published: 1997 – 2006 (Summary Book), and ongoing (revisions)
what is the AMDR
Acceptable Macronutrient Distribution Range:
what is a requirement
the lowest
continuing intake that will
maintain a defined level of
nutriture (indicator of adequacy)
what is the EAR
Nutrient intake to meet the requirement of
half the healthy people of an age & gender
• The MEDIAN (Think bell curve)
WHAT IS THE rda
Nutrient intake to meet the requirement for nearly
all (97-98%) healthy people of an age & gender
• Derived from an EAR
• EAR + 2 standard deviations
what is 2 standard deviation
98%,
what types of studies were considered in setting the DRIs
Intervention Studies (e.g., doubly labeled water,
dose-response feeding trials)
• Epidemiological Data (e.g., associations
between intake and risk of chronic disease)
• National Survey Data (e.g., median intakes for
setting AIs and AMDRs)
• Special Analysis of existing data (e.g.,
regression analysis of doubly labeled water
data, re-analysis of national survey data)
how are ai determned for babies
look at nutrients in breast milk- experiment but not invasive
where are there no ULs
amino acids, vit B12
which tool is not used for group assessment
RDA, RDA: intake levels that exceed requirements of 97–98 % of all individuals when requirements in the group have a normal distribution • Thus, RDA is not a cut-point for assessing nutrient intakes of groups - serious overestimation of the proportion of the group at risk of inadequacy would result RDAs can be used in planning for groups or individuals – but not in assessing adequacy of intake.
What is the different btw macro and micro nutrients
“Unlike vitamins and minerals, which perform
functions to meet the body’s needs, most of
(these) macronutrients supply energy for daily
activity”
“Fats, carbohydrates, and protein can substitute
for one another to some extent to meet the
body’s energy needs”
“…eating excessive amounts of some the
macronutrients can lead to health problems,
including obesity, heart disease, and diabetes
what is AMDR
Acceptable Macronutrient Distribution Range • Range of intakes for an energy-yielding macronutrient that is associated with reduced chronic disease while providing adequate intakes of essential nutrients – 45-65% kcal from CHO – 20-35% kcal from fat – 10-35% kcal from protein
the minimum number example -% what do the numbers mean
- RDA-10%
35%- The amont if you ate the lower levels of the other one- CHO, Fat
-
EER
• EER = Estimated Energy Requirement
– Dietary energy that is predicted to maintain
energy balance in a healthy adult of a defined
age, gender, weight, height and level of
physical activity (sedentary, low activity, active,
very active) consistent with good health
(therefore, no EER for overweight/obese)
what is the appropriate mesurememnt for energy
AIs, RDAs or ULs not appropriate (weight
gain)
EER IS GOOD
what amonut of physical activity is associated with preventing CHD
– 1 hour of moderately intense activity per day
• defined as “brisk walking”
• more intense exercise, such as running or cycling,
requires shorter duration and less frequency
– Recommendation is double the half-hour goal set
by the Surgeon General in 1996
what is energy
the capacity to do work
wht is gross energy
Gross Nrg: total available nrg (chem nrg) in food
what is net energy
nrg available to the animal after metabolic
processes of digestion, absorption, excretion
how much energy is lost as heat
50-60%the nrg available to the animal after metabolic
processes of digestion, absorption, excretion
what is a calorie
(small calorie):
• amt of nrg (heat) req to raise the temp of 1 g or L
of H2O by 1 °C (14.5-15.5 °C)
• 1000 calories = 1 Calorie (1 Kilocalorie, 1 Kcal)
what is a joule
amount of nrg expended when 1 kg is moved a
dist of 1 m by a force of 1 newton (SI)
• 1 Kilocalorie (Kcal) = 4.184 Kilojoules (KJ)!!!!
what is GE
Gross Energy (GE)
• heat of combustion
• amount of heat released when a substance is [O] completely (as in a
bomb calorimeter [BC])
– depends on: 1. proportion of CHO, ptn, fat in food
2. composition of individual CHO, ptn, fat
(varies directly with C and H content, varies indirectly with O2 content)
• From Proximate Analysis (BC) GE values are:
Kcal/g KJ/g
• Ether Extract (fat) 9.40 39.3
• Crude Protein 5.65 23.6
• NF Extract (CHO) 4.15 17.4
WHY ARE THE GE NUMBERS 9(fat), 4(pro), 4((CHO)
we cant digest all the food we eat - some is lost as feces
why is protein so well absorbed
because the nitrogen is lost in the urine as urea
WHAT IS • Digestible Energy (DE)
– DE in monogastrics = GE - fecal energy (BC)
what is Metabolizable Energy (ME)
– nrg that is useful to the animal
– ME = GE - fecal E - urinary E
– healthy animal, urinary losses mainly urea
– fat & CHO do not contribute sign. to urinary
compounds
– when AAs are [O] for nrg, amino groups removed
– urea is formed (NH2
-CO-NH2
)
– 1 g ptn used for nrg → 1.25 Kcal urea excreted
what is Basal metabolism
nrg expended to sustain life (cost of living) – ie,heart beat, breathing, brain, nervous fn, involuntary muscle activity, organ fn, cell turnover, body temp
how can we mesure BMR
- Direct Calorimetry (Figure 15.6)
Principle: - measures directly the heat loss from an animal to its environment
Application: - measures a summation of heat load of an animal on its environment
Technique: - animal is placed in insulated chamber - H2O flows through coils in room wall - heat loss measured from temp diff & rate H2O flow - heat loss by vapourization (lung, skin) by measuring change in moisture content in air - quite complex and requires very elaborate and expensive equipment - limited use , - Indirect Calorimetry (two kinds, closed and open) (Respiratory Calorimetry)
Principle: – gives an indirect measurement of the heat production of an animal by measuring directly O2 consumption and CO2 expelled 1 L of O2 consumed (STP) 6 4.8 Kcal expended
Application: - measures the biological response of an animal with respect to fuel being [O] under certain conditions eg, during basal metabolic “conditions” during change in dietary sources of nrg (CHO, fat, ptn) during various conditions of “stress” (intensive exercise, burns etc)
Technique: relatively simple
what is closed circuit
Closed Circuit
- subject breathes into and out of a spirometer which is filled initially with 100% oxygen - the CO2 in the expired air is chemically removed by passing the expired air through soda lime prior to entering the spirometer - as the subject continues to breathe from the spirometer, the gas volume of the spirometer decreases. - this decrease in volume represents the volume of oxygen consumed during the breathing period, and can be interpreted directly - in essence, the subject continues to rebreathe the same air (a closed circuit), and the volume of oxygen in the spirometer decreases continuously in proportion to the subject’s oxygen consumption. - allows quick determination of oxygen consumption but does not provide for an estimate of CO2 production
what is open circuit
Open Circuit
- subject breathes from the normal room air and his/her expired air is either collected in some form of closed container (i.e., Douglas bag, gasometer, meteorological balloon, etc.) from which the volume is later obtained, or is passed directly through (i.e., mask or hood fixed over nose & mouth) a gasometer - in either case, it is necessary to obtain the volume of expired air and an analysis of the percentage oxygen and carbon dioxide production simply by taking the differences between their inspired and expired volumes (i.e., vol O2 inspired - vol CO2 consumed) - more complicated then closed circuit method and involves considerably more calculations but it is generally regarded as being more precise and less prone to serious error, especially during moderate to severe exercise - due to its greater accuracy and general acceptance, the open circuit method is used most extensively in present day research
what could affect the ventilated hood system
CO2 concentration in the room, the personis nervous and breathing faster- look for numbers of steady state(not beginning or end)
what is indirect calorimetry
Theoretical Basis: - during biological [O] in the body of nrg-yielding nutrients, the ratio of nrg produced / L O2 consumed (thermal equivalent) is more or less constant ie, = 4.8 Kcal or 20 KJ/L - however, in order to express the oxygen consumed in heat equivalents (i.e., Kcal or KJ, it is necessary to know what type of food is being metabolized - the reasons for this deals with the energy equivalents of the particular food being metabolized (place food in bomb calorimeter and measure heat energy equivalents per 1 litre of oxygen, CHO=5.05kcal, protein=4.46kcal, fat=4.74kcal) - it would be rare if a person would be using fat, protein or CHO exclusively (fasting subject more fat; during exercise subject would be likely on a mixed diet); therefore, through measuring not only the oxygen consumed but also the CO2 produced permits us to know the mixture of foods being metabolized and hence to properly assign the correct caloric value to each litre of oxygen consumed
what are the condition for measuring BMR
a. completely relaxed b. reclining in a comfortable position c. awake d. in a thermal neutral environment (20-27°C) e. in a postabsorptive state f. no heavy physical activity within 12h
factors that affect basal metabolic rate
body size and composition (FAT ppl decrease) 2. age ( 3. environmental temperature (colder and hotter you will burn more to stay normal) 4. hormonal status (eg, thyroid (increases)hormone) 5. stress (eg, epinephrine) 6. illness or injury 7. sleep versus awake 8. previous nutritional history
what is the RQ
The Respiratory Quotient (RQ)
- ratio of CO2 produced : O2 consumed - can be calculated using either the volumes or mols of O2 and CO2 - tell us what your body is using as a fuel source
resting metabolic rate is higher or lower than basal metabolic rate
resting
the higher your BMR is
the more calories you’ll burn
hypometabolic
reduced metabolic rate
can you lower your metabolic rate
yes with yoyo dieting
close to 1 RQ
carbs- fed state- uses less o2 to break all the bonds
close to 0.7 RQ
faty acid- fasting state- no more glucose to use and using fat stores- uses more o2 to comsume
ehat is the use of biological oxidation data
Determine, from O2 consumption, EE of an animal (ie,Metabolizable Energy Expenditure) 2. If RQ is close to 0.7, can predict FAs are main fuel being [O] - never be quite as low as 0.7; “obligate glu users” 3. If RQ is close to 1.0, can predict glu (hence CHO) is the main physiological fuel being [O] 4. If RQ is between 0.7 - 1.0, you cannot predict, with this data alone, the “mix” of fuel being [O]
what has the most relationship to BMR
body weight
what are the ways of calculation BMR
ONE WAY: BMR (Kcal/24h) = 70 (body wt)0.75 BMR (KJ/24h) = 300 (body wt)0.75
- is a fn of metabolic body size = body weight (kg) - is related to surface area (avg 1000Kcal / 24h / m2) - is a fn of the lean body mass (fat-free) - includes assumptns: body comp, age, body shape etc - applies to all species (from mouse to elephant)
ANOTHER WAY: Harris-Benedict predictive equations (e.g., indirect calorimetry) based on sex, weight, height and age (Examples found on in Chapter 15)
how can physical activity be mesured
can be measured by direct and indirect calorimetry
- nrg expended for physical activity depends on: 1. intensity of the activity 2. duration of the activity 3. body weight of subject (the more the more you spend)
- the most variable component of EE among individuals (eg, humans)
eg, 70 kg young adult male
Type of Activity kcal/min kJ/min Resting metabolism 1.2 5.0 Light activity 3.2 13.4 Moderate activity 5.6 23.4
what are the heat increment of feeding
averages 6-10% of ME intake
- depends on food: - ptn 20% - fat 2% - CHO 7%
what are the three approaches of energy neeeds
3 approaches:
1. FACTUAL: find intake that maintains bwt at desirable level 2. FACTORIAL: add up needs (part of which could be measured) 3. MEASURED: Doubly Labeled Water (DLW) – Used for DRI
what is the factorial approach
Factorial approach (examples)
EE: RDA,WHO
Sedentary: BMR + 25% BMR + TEF 1.3 BMR Light Activ: BMR + 50% BMR + TEF 1.5 BMR Moderate Act: BMR + 75% BMR + TEF (thermal effect of feeding) 1.7 BMR Heavy Act: BMR + 100% BMR + TEF 2.1 BMR
- BMR could be measured or calculated from predictive equations
for men bmr is calculated how
weight times 24
for women how to alculate BMR
BMR = 0.9 x 60 x 24 = 1300 kcal Activity cost = 50% x 1300 = 650 kcal TEF = 10% x (1300 + 650) = 195 kcal TOTAL = 2150 kcal/60 kg = 36 kcal/kg- a way to calculate energy expenditure
- Direct Calorimetry (Figure 15.6)
Principle:
- measures directly the heat loss from an animal to its environment
Application:
- measures a summation of heat load of an animal on its environment
Technique:
- animal is placed in insulated chamber
- H2O flows through coils in room wall
- heat loss measured from temp diff & rate H2O flow
- heat loss by vapourization (lung, skin) by measuring change in moisture content in air
- quite complex and requires very elaborate and expensive equipment
- limited use
co2 is not recordered
closed circuit allows quick determination of oxygen consumption but does not
provide for an estimate of CO2 production
ventilated hood sysstem
open circuit (indirect calorimetry)
due to its greater accuracy and general acceptance, the open circuit method
is used most extensively in present day research
indirect calorimetry
therefore, through measuring not only the
oxygen consumed but also the CO2 produced permits us to know
the mixture of foods being metabolized and hence to properly assign
the correct caloric value to each litre of oxygen consumed
