Transcript Introduction / Nutritional Guidelines

Kinesiology 110
Human Nutrition :
Current Issues
Instructor : Ryan Dill
email [email protected]
778-782-7851 (Vancouver)
Office HC 2622 (ring doorbell at 2600)
Office hours : Mondays 3-4 pm
Also by appointment through email
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Course Tools
Course Web Site
www.sfu.ca/~ryand/kin110.htm
Course outline
Grading system
Download Assignments
Lecture Schedule
– Download Course notes
• Link to web site for Text book
– Multiple choice quizzes
– Nutrition Crossword puzzles
– Animation tools
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Nutrients and
Nourishment
Chapter 1
Chapter 2
p 31-72
Appendix D
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• Lecture Outline
– Why do we eat the way we do?
– Overview of the Study of Nutrition
– Nutrients and their roles in the body
– Scientific process in Nutrition
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Why do we eat the way we do?
• Sensory
– Flavour (taste and smell), texture, appearance
• Cognitive
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Learned food habits (early experiences with food)
Social factors - time crunch versus relaxing experience
emotional needs
Nutrition and health beliefs
advertising
• Environmental
– Economic, lifestyle, cultural factors, religious beliefs
• Health
– Physical restrictions due to disease
– Declining taste sensitivity
– Age and gender
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What drives us to eat?
• A complexity of factors influence eating
• Hunger - physiological drive to find and eat food
• Appetite - primarily psychological influences
encouraging us to find and eat food - often in
absence of hunger
• Satiety - state in which there is no longer a desire
to eat; a feeling of satisfaction
• Hypothalamus - portion of brain that regulates
satiety - influenced by
– blood glucose, bulk of meal, composition of meal,
hormones
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What is Nutrition ?
• Nutrition defined as:
– Science of foods
– and their components (nutrients and other
substances),
– including the relationships to health and disease
(actions, interactions and balances);
– processes within the body (ingestion, digestion,
absorption, transport, functions and disposal of
end products); and the social, economic, cultural
and psychological implications of eating.
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Nutrients and Nourishment
• Nutrients - any substance in food that
the body can use to obtain energy, build
tissues, or regulate functions
• Essential nutrients - substances that
must be obtained in the diet because
the body either cannot make them or
cannot make adequate amounts of
them
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Six Classes of Nutrients
• Organic
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Carbohydrates
Proteins
Lipids
Vitamins
• Inorganic
– Minerals
– Water
• Diet must supply about 45 Essential Nutrients
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General Functions of Nutrients
• Fig 1.9
• Regulate Body Process
• proteins, lipids, vitamins, minerals, water
• Contribute to cell and body structure
• Growth and development of bone, muscle and other cells
• proteins, lipids, vitamins, minerals, water
• Provide Energy
• carbohydrates, proteins, lipids
• calorie - heat energy needed to raise one gram of water
by one degree Celsius. (1 kcal = 1000 cal).
• Food labels use cal in place of kcal
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Carbohydrates
• Major source of fuel (4 kcal/gram)
• Carbon, Hydrogen and Oxygen
• Simple sugars - glucose
– Sucrose (glucose-fructose)
• Complex sugars
– storage forms - links between simple sugars
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Eg, glucose-glucose-glucose-glucose-glucose-glucose-glucose
– Starch (potatoes, rice)
• Dietary Fiber (un-digestible - bran, apple skin)
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Lipids
• Concentrated fuel (9 kcal / g)
• Fats (solid) and Oils (liquid)
at room temperature
• Do not dissolve in water
• Triglycerides are major form of lipid
• Fatty acids are the basic structural unit
– Saturated - generally solid, animal derived
– Unsaturated - generally liquid, plant derived
• Some Fatty acids are essential nutrients - vital
for cell synthesis and repair
– one table spoon of vegetable oil supplies our daily
requirements
– omega 3 and omega 6 - healthy fish oils
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Proteins
• Major component of Body Structure
• muscle, bone, enzymes, hormones
• Energy (4 kcal / g)
• Amino Acid is structural unit
• 20 types, 9 are essential
• Typical consumption is 1.5 to 2 times dietary
need
– excess is used for energy or stored as carbohydrate
or FAT
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Vitamins and Minerals
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Needed in small amounts
not a direct source of energy
high potential for toxicity
balanced diet can easily supply all
vitamins and minerals
• should not rely on supplements
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Vitamins
• Essential - carbon containing substances
(Organic)
• Enable many chemical reactions to occur in
body
• 13 kinds
• 4 fat soluble A, D, E and K
• potential for toxic build up
• 9 water soluble
• easily excreted, but can be destroyed by cooking
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Minerals
• Inorganic ions
• Not a source of energy
• Role in facilitating metabolism
• Iron in oxygen transport
• Sodium in nerve conduction
• Calcium in muscle contraction
• Make up structure of body and components
of blood stream
– eg. Calcium in bones
• Two groups - Major minerals and Trace
minerals - categorization based on dietary
needs
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Water
• Nourishes the body in
many vital ways
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dissolves substances (solvent)
lubricates joints
provides a means of transport for nutrients and waste
Medium for temperature regulation and chemical processes
• body is ~ 60% water, need almost 2 L per day
• not a source of energy
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Are you what you eat?
• The amount of nutrients your body needs
varies widely from one nutrient to another.
• .5 Kg of energy food
• 2.5 Kg of water
• mg of vitamins and minerals
• Your structure is determined by genetic
blueprint, you are not what you eat, but your
food is the raw materials.
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Energy for Body Function
• Energy - capacity to do work
– Chemical energy from food converted to
mechanical, electrical and heat energy
• Carbohydrates, Fats, and Protein
• Alcohol is also an energy source
– Not an essential nutrient
– Typically a contributor to excess energy intake in
the diet
• energy is in Carbon-Hydrogen bonds
• Harnessed by Plants from Suns energy
• Used to: - Build compounds
– Perform muscular movements
– promote nerve transmission
– maintain ion balance in cells
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• Energy in foods
– Measured in kilocalories (kcal)
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Energy Intake
• calorie - energy it takes to raise temperature
of 1 gram of water 1 degree Celsius
– Nutrition - use kilocalories (1000 calories) - same
as common Calorie
• Typical diet (% of total calories)
– Protein 16%, Carbohydrates 50% Fats 33%
• Recommend
– P(15%), C(50-60%), F(25-35%)
• Use Food labels - fig 2.11- Canadian p D12
• Common Dietary Problems
– reduced activity, increased caloric intake
• obesity, health risks
– low vegetable and fruit intake
• Missing major sources of vitamins and minerals
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Calculating Energy in Foods
• One bagel plus 1.5
ounces of cream
cheese contains
• 39 grams of
carbohydrate
• 10 grams of protein
• 16 grams of fat
• 39 g carbohydrate x
4 kcal/g = 156 kcal
• 10 g protein x 4
kcal/g = 40 kcal
• 16 g fat x 9 kcal/g =
144 kcal
• Total = 340 kcal
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Applying the Scientific
Process to Nutrition
• Scientific method
• Types of studies
– Epidemiological
– Animal
– Cell culture
– Human
• Case control
• Clinical trial
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Finding Scientific Information
Versus Misinformation
• As scientific information is made
accessible to more and more people,
less detail is provided and more opinion
and sensationalism are introduced.
• Sources include professional journals,
scientific magazines, generalist
magazines and newspapers, nightly
news bites, unattributed Internet sites.
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Evaluating Information on the Internet:
Red Flags of Junk Science
• Recommendations that offer a quick fix
• Dire warnings of danger from a single product
or regimen
• Claims that sound too good to be true
• Simplistic conclusions drawn from a single
study
• Dramatic statements that are refuted by
reputable scientific organizations
• Evidence vs hype
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Kin 110
Chapter 2
Nutritional Guidelines and
Assessment
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Overview of Lecture
• Chapter 2
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Tools for diet design
Food Guide and its uses
Dietary Guidelines
Recommended Nutrient Intakes
Food Labeling
Nutrient Density and the Exchange System
Nutritional Assessment
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Dietary Planning Principles
Six dietary planning principles form the
foundation of all health diets.
Adequacy
• provides sufficient energy and enough of all of
the nutrients to meet the needs of healthy
people
Balance
• provides an appropriate distribution of nutrients
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Dietary Planning Principles
- kiloCalorie Control
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management of food energy intake (avoids over
consumption of energy)
Nutrient Density - nutrients obtained in relation to overall
kilocalories - aim to maximize
Energy Density - energy obtained per gram of food - aim to
minimize
Example of nutrient density
1 cup skim milk
301 mg Calcium
1 cup whole milk
290 mg Calcium
85 kcal
150 kcal
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Dietary Planning Principles
cont.
Moderation
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avoiding extremes of energy or nutrient
consumption
Keeping serving sizes reasonable
Variety
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consuming a wide selection of different foods
why is variety important?
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Canada’s Guidelines for Healthy
Eating
• Enjoy a VARIETY of foods
• Emphasize cereals, breads, other grain
products, vegetables, and fruits
• Choose lower fat dairy products, leaner
meats, and foods prepared with little or no fat
• Achieve and maintain a healthy body weight
by enjoying regular exercise and healthy
eating
• Limit salt, alcohol, and caffeine
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Eating Well with Canada’s Food
Guide
• group foods according to the primary nutrients they
contain & similarity in origin
• used to assess the diet for adequacy & assist in diet
planning
• many foods can contribute to more than one food
group
• a balanced diet means choosing foods from each
group
• a varied diet means choosing different foods form
within each food group
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Eating Well with Canada’s Food
Guide
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How much from each food group
should I consume?
Female (Age 19-50)
Male (Age 19-50)
Create your own food guide
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What is a “serving” size?
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Estimating Serving Sizes
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3 oz meat ≈ a deck of cards
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1.5 oz of cheese ≈ 3 dominoes
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1 cup ≈ a baseball
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1 tsp ≈ tip of thumb
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1 medium fruit ≈ 1 tennis ball
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2 tablespoons ≈ golf ball or shot glass
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2 once bagel ~ 1 hockey puck
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1/2 cup cooked rice or pasta~ tennis ball
Eating Well with Canada’s Food
Guide
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Eating Well with Canada’s Food
Guide
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Eating Well with Canada’s Food
Guide
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Eating Well with Canada’s Food
Guide
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Recommendations for
Nutrient Intake
• Dietary Reference Intakes (DRIs)
– Recommendations for nutrient intake
– Developed by the Food and Nutrition
Board
– Apply to healthy people in the United
States and Canada
– Four basic elements
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Dietary Reference Intakes (DRIs)
• Estimated Average Requirement
(EAR)
– Amount that meets the nutrient
requirements of 50% of people in a life
stage/gender group
– Based on functional indicator of optimal
health
• Recommended Dietary Allowance
(RDA)
– Amount that meets the needs of most
people (97-98%) in a life stage/gender
group
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Dietary Reference Intakes
(DRIs)
• Adequate Intake (AI)
– Amount thought to be adequate for most
people
– AI used when EAR and RDA can’t be
determined
• Tolerable Upper Intake Level (UL)
– Intake above the UL can be harmful
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Dietary Reference Intakes
(DRIs)
• Using the DRIs
– Population groups
• Assess adequacy of intake
• Plan diets
• Set policy and guidelines
– Individuals
• Use RDA and AI as target levels for intake
• Avoid intake above the UL
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Food Labels
• Mandatory information on food labels
– Statement of identity
– Net contents of the package
– Name and address of manufacturer,
packer, distributor
– List of ingredients
• Listed in descending order by weight
– Nutrition information
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Canadian Nutrition Food
Labeling(p D12)
Nutrition Facts Box
Nutrient information
based on a specified
amount of food for
easy comparisons
allows calculation of
the percent energy
derived from each of
the energy yielding
nutrients
Daily values based on
recommendations for
healthy eating.
Provide context for the
amount of nutrient.
allow for quick
evaluation of
contribution to daily
needs, comparison
between products
and estimation of
nutrient density50
Food Labels: Claims
• Nutrient content claims
– Descriptive terms, e.g., low fat, high fiber
• Health claims
– Link one or more dietary components to reduced risk of
disease
– Must be supported by scientific evidence
• Structure/function claims
– Describe potential effects on body structure or function
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Nutritional Health States
•Desirable Nutrition
•Intake supports body functions
•Undernutrition
•Nutrient intake does not meet needs
•body stores can make up for short term, but
become depleted
•body does not function appropriately
•serious problems can arise with long term
under nutrition
•Symptoms develop, may take years for
clinical evidence ( Skin, hair, nails, tongue,
eyes
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Nutritional Health States
•Overnutrition
•Prolonged over consumption of more than the body
needs
•long term can lead to toxic build up and serious
disease Eg Iron
•most common is excess energy intake
•Eg. excess weight leads to serious disease
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Measuring Nutritional State
•Overall body health is determined by the sum of its
nutritional status for each nutrient
•Components Include
•Anthropometry - height, weight, skin folds, girths
•Biochemical measurement - blood, urine analysis
•Clinical Examination - signs of malnutrition
•Hair nails, skin, eyes, lips, mouth, bones…
•Dietary History - food intake over time
•Economic Status - only a minor influence in North
America (often worse diet with higher income),
beginning to have larger impact worldwide
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Limits of Nutritional Assessment
•Can be a very long time between the
onset of poor nutritional health and the
first clinical evidence
•Often too late
•Calcium deficiency - low bone density,
osteoporosis later in life (30 to 50 years).
•High Cholesterol - builds up in circulatory
system, heart disease later in life.
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