Transcript Basic Human Nutrition Lecture 1

63-391: Basic Human Nutrition
Food Choices & Human Health
Lecture 1
Elizabeth Strachan
What Is Nutrition?
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Nutrition: the study of food, including
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How food nourishes our bodies
How food influences our health
Nutrition is a relatively new discipline of
science.
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Why Is Nutrition Important?
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Nutrition contributes to wellness.
Wellness: the absence of disease
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Physical, emotional, and spiritual health
Critical components of wellness:
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Nutrition
Physical activity
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Why Is Nutrition Important?
Nutrition can prevent disease.
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Diseases caused by nutrient deficiency:
scurvy, goiter, rickets
Diseases influenced by nutrition:
chronic diseases such as heart disease
Diseases in which nutrition plays a role:
osteoarthritis, osteoporosis
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What Are Nutrients?
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Nutrients: the chemicals in foods that are
critical to human growth and function.
There are six classes of nutrients:
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Carbohydrates
Fats and oils
Proteins
Vitamins
Minerals
Water
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What Are Nutrients?
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Macronutrients: nutrients required in
relatively large amounts.
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Provide energy to our bodies
Carbohydrates, fats and oils, proteins
Micronutrients: nutrients required in
smaller amounts.
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Vitamins and minerals
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Energy From Nutrients
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We measure energy in kilocalories (kcal).
Kilocalorie: amount of energy required to
raise the temperature of 1g of water by
1oC.
On food labels, “Calorie” actually refers to
kilocalories.
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Carbohydrates
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Primary source of fuel for the body
especially for the brain.
Provide 4 kcal per gram.
 Found in grains (wheat, rice),
vegetables, fruits, milk, and legumes.
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Fats and Oils
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Fats and oils are composed of lipids,
molecules that are insoluble in water.
Provide 9 kcal per gram.
 An important energy source during rest
or low intensity exercise.
 Found in butter, margarine, vegetable
oils.
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Proteins
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Proteins are chains of amino acids.
Proteins can supply 4 kcal of energy per
gram, but are not a primary energy
source.
 Proteins are an important source of
nitrogen.
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Vitamins
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Vitamins: organic molecules that assist
in regulating body processes.
Vitamins are micronutrients that do
not supply energy to our bodies.
1. Fat-soluble vitamins
2. Water-soluble vitamins
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Minerals
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Minerals: inorganic substances
required for body processes.
Include sodium, calcium, iron,
potassium, and magnesium.
 Many different functions such as fluid
regulation, bone structure, muscle
movement, and nerve functioning.
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Water
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Water is a critical nutrient for health and
survival.
Water is involved in many body processes:
fluid balance
nerve impulses
muscle contractions
nutrient transport
chemical reactions
removal of wastes
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Non-nutrients in Foods
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Phytochemicals e.g, Beta Carotene,
Lycopene, etc., are non-nutrients in
foods.
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Appears to give food its taste, aroma,
colour and other characteristics
May play a role in disease prevention.
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Health is affected by:
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Genetic inheritance
Diet choices
Lifestyle choices
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What influences Food
Choices
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Personal preference
Habit
Ethnic heritage or tradition
Social interactions
Availability, convenience, economy
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Food Choices continued
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Positive and negative associations
Emotional comfort
Values
Body weight and image
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Healthy Eating
A nutritious diet has 5
characteristics
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Adequacy: foods provide enough of
each nutrient, fibre, & energy
Balance: not choosing one
food/nutrient over another
Calorie control: eating enough to
maintain a healthy weight
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Nutritious diet continued
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Moderation: Foods
high in fat, salt, or
sugar can be eaten
as part of a healthy
diet if not eaten to
excess.
Variety: necessary
in order to get all
the nutrients one
requires.
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Eating the right amount of
nutrients for our needs
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Nutrient density
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Measure of nutrients provided per calorie of food
Nutrient density is a tool to help make good
nutrition easier
Nutrient density can help you distinguish
between more and less nutritious foods
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The concept of nutrient density can help people
identify bulk without a lot of calories
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Nutrient Density
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Foods that offer the most nutrients per
calorie are vegetables
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Especially nonstarchy vegetables
These foods are rich in phytochemicals
These foods are inexpensive but take time
to prepare
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Using nutrient density
effectively
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Today most households do not have time for
food preparation
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Busy people should look for convenience foods
that are nutrient dense
Bags of ready-to-serve salads
Refrigerated prepared meats
Frozen vegetables
Fat-free milk
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Using nutrient density effectively
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Achieving nutritional health does not
just depend on the individual foods you
choose
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It is the way you combine them into meals
The way you arrange meals to follow one
after another over days and weeks
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Designing a Healthy Diet
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The tools for designing a healthy diet
include:
Food Labels
 Dietary Guidelines
 Food Guides
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Food Labels
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In Canada, food labels are required on
most products. These labels can
include:
1.
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4.
Ingredient list [required]
Nutrition Facts table [required]
Nutrient Content claims
Health claims
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Nutrition Facts Panel
The Nutrition Facts Panel
in standard format contains
required nutrition
information.
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This information can be
used in planning a healthy
diet.
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Nutrition Facts Panel
Serving size and servings per
container
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Serving sizes can be used to plan
appropriate amounts of food.
Standardized serving sizes allow for
comparisons among similar products.
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Serving size
• the specific amount of food
listed under the “Nutrition Facts”
title
• all nutrient information is based
on this amount of food
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Nutrition Facts Panel
2. List of nutrients
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Calories
Fat (total; saturated and trans)
Cholesterol
Sodium
Carbohydrate (total; fibre, sugars)
Protein
Vitamin A, vitamin C, calcium, iron
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% Daily Value
can make it easier to
compare foods
 helps you see if a food has
a lot or a little of a nutrient
 provides a context to the
actual amount of a nutrient
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% Daily Value continued
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The actual numbers can be confusing, for
example:
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2 mg of iron seems small but it is
15 % of the Daily Value for iron
110 mg of sodium seems large but
it is only 5 % of the Daily Value for
sodium
% Daily Value makes it easy to see if
there is a lot or a little of a nutrient
without having to do any math.
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Nutrition claims
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Regulated statements made when a
food meets certain criteria
Optional, so may be found only on
some food products
Often on the front of food packages
A quick and easy way to get
information about a food
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Nutrition Claims -examples
“A healthy diet low in saturated and
trans fats may reduce the risk of heart
disease.”
“A healthy diet rich in a variety of
vegetables and fruit may help reduce
the risk of some type of cancer.”
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Dietary Guidelines
Canada’s Guidelines for Healthy Eating
(1990)
Nutrition Recommendations (1990)
 Canada’s Food Guide to Healthy
Eating (2007)
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Food Guide
Canada’s Food Guide to Healthy Eating
(2007)
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Originated as Canada's Official Food Rules
in 1942.
Helps Canadians plans meals while
reducing risk of chronic diseases.
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Background - Purpose
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Promotes healthy eating for Canadians
Provides a healthy eating pattern to
meet nutrient needs and reduce risk
of disease
Provides guidance on the prevention
of obesity
Emphasizes importance of combining
healthy eating and physical activity
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Background - Development
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Based on the DRIs
Two step process
1.
2.
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Composite diet
Specific diets (500)
Current literature on foods and chronic
disease
Based on a sedentary person
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What’s New?
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Clear guidance on number of
servings – age and gender
specific
Addition of younger children: 23 years of age
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Specific Recommendations
Vegetables and Fruit:
 Eat at least one dark green and one
orange vegetable each day
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Rich in beta-carotene and folate
Have vegetables and fruit more often
than juice
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Increased fibre in the whole food
Increases satiety
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Specific Recommendations
Grain Products:
 Make at least half of your grain
products whole grain each day
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Reduce risk of cardiovascular disease
Increased consumption of vitamins
Increased consumption of fibre
Increased satiety
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Specific Recommendations
Milk and Alternates:
 Drink skim, 1% or 2% milk each day
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Source of vitamin D
Provides all of the nutrients of whole milk
(protein, calcium, vitamin A, B6, B12, D,
magnesium, zinc) without the saturated fat
and calories
Select lower fat milk alternatives
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Specific Recommendations
Meat and Alternates:
 Have meat and alternatives such as
beans, lentils and tofu often
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Lower in saturated fat
Higher in fibre and folate (legumes) which
increase satiety
Higher in unsaturated fats (nuts, seeds)
which promote cardiovascular health
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Specific Recommendations
Fish:
 Eat at least two Food Guide Servings of
fish each week.
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Reduces the risk of cardiovascular disease
Good sources of omega-3 unsaturated fats
Char, herring, salmon, rainbow trout,
mackerel and sardines
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Mercury and Fish
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Higher risk groups:
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Children
Pregnant and breastfeeding women
Women of childbearing age
Do not eat high mercury fish
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Shark, king mackerel, swordfish, fresh/frozen tuna, escolar, orange
roughy, marlin
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Pregnant/breastfeeding women – max. 150 g/month
Children: 1-4 yrs – max. 75 g/month
5-11 yrs – max. 125 g/month
Consume 2 servings of lower mercury fish
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Salmon, herring, sardines, shrimp,
mackerel, trout, pollock, catfish,
scallops, tilapia, canned light tuna
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Mercury and Fish
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Canned Albacore (White) Tuna
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Women of childbearing years
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Max. 300 g (four Food Guide servings)/wk (~
two 170g cans of albacore tuna)
Children:
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1-4 yrs: max. 75 g (1 serving or about ½ of a
170-g can/wk).
5-11 yrs: max. 150 g (2 servings or about one
170-g can/wk)
**Note that there are approximately 120 grams of tuna meat in a 170-g
can of tuna after the liquid is drained.
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Specific Recommendations
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Select foods prepared with little or
no added fat, sugar or salt
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Fewer calories
Less saturated fat
Less salt/sodium
Reduces the risk of overweight/obesity,
cardiovascular disease and
hypertension
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Specific Recommendations
Oils and Fats
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2-3 Tbsp of unsaturated fats each day
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Contain essential fatty acids (omega-6 and
omega-3)
A diet low in saturated fats reduces the risk for
cardiovascular disease
Polyunsaturated fats decrease cholesterol
(corn, soybean, safflower)
Monounsaturated fats maintain HDL, lower LDL
(olive, canola, peanut)
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Portion Sizes
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Food Guide Servings are the same
size for all ages
Don’t need to eat an entire Food Guide
Serving at once
Serve small meals/snacks throughout
the day
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Advice for different ages and
stages…
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Children
Women of childbearing age
Pregnant
Breastfeeding
Men and women over 50
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Advice for different ages and
stages… Children
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Follow CFG to grow and thrive
Small appetites & need calories for growth
and development
Serve small nutritious meals and snacks
Do not restrict nutritious foods because of fat
content
Offer variety of foods from 4 food groups
Be a good role model
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Women of childbearing age
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Multivitamin with folic acid
every day
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Pregnant & Breastfeeding
Need more calories
 Include an extra 2-3 Food Guide
Servings each day
 Take multivitamin with iron
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Men & Women over 50
Increased need for Vitamin D
 Need to take daily Vitamin D
supplement of 400 IU
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Water
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Canada’s Food Guide recommends
drinking water when thirsty
Individual fluid needs vary
Water from foods, plain water and other
beverages all count to fluid needs
Additional fluids may be needed if
active or in very hot weather
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Resources for You
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Health Canada
(http://www.healthcanada.gc.ca/foodguide)
 My Food Guide
 A Resource for Educators
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Dietitians of Canada (www.dietitians.ca)
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EATracker
Virtual Grocery Store
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Cultural Adaptations
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French is currently available
First Nations, Inuit, Metis tailored
version this spring
My Food Guide in a “number of
languages” this spring
No date on translations of the actual
guide
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Eat Well
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Limit foods and beverages high in calories,
fat, sugar or salt (sodium), such as cakes,
pastries, chocolate, candies, cookies, granola
bars, doughnuts, muffins, ice creams, frozen
desserts, french fries, potato chips, nachos
and other salty snacks, alcohol, fruit
flavoured drinks, soft drinks, sports and
energy drinks, and sweetened hot or cold
drinks.
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Determining Nutrient Needs
Dietary Reference Intakes (DRIs) are
updated nutritional standards for Canada
and USA.
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Expand on the traditional recommended
values of each country
Set standards for nutrients that did not
previously have recommended values
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Determining Nutrient Needs
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Determining Nutrient Needs
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DRIs consist of 4 values:
1.
2.
3.
4.
Estimated Average Requirement (EAR)
Recommended Dietary Allowances (RDA)
Adequate Intake (AI)
Tolerable Upper Intake Level (UL)
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Determining Nutrient Needs
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Estimated Average Requirement (EAR)
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The average daily intake level of a nutrient
that will meet the needs of half of the
people in a particular category (life stage
and gender).
Used to determine the Recommended
Dietary Allowance (RDA) of a nutrient.
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Determining Nutrient Needs: EAR
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Determining Nutrient Needs
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Recommended Dietary Allowances (RDA)
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The average daily intake level required to
meet the needs of 97 – 98% of healthy
people in a particular life stage and gender
group.
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Determining Nutrient Needs:
RDA
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Determining Nutrient Needs
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Adequate Intake (AI)
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Recommended average daily intake level
for a nutrient.
Based on observations and estimates from
experiments.
Used when the RDA is not yet established:
e.g., calcium, vitamin D, vitamin K,
fluoride.
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Determining Nutrient Needs
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Tolerable Upper Intake Level (UL)
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Highest average daily intake level that is
not likely to have adverse effects on the
health of most people
Consumption of a nutrient at levels above
the UL is not considered safe
No UL does not mean safe; means no data
available to set UL.
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Determining Nutrient Needs
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Estimated Energy Requirement (EER)
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Average dietary energy intake (kcal) to
maintain energy balance.
Based on age, gender, weight, height, level
of physical activity.
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Determining Nutrient Needs
Acceptable Macronutrient Distribution
Ranges (AMDR)
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Describes the portion of the energy intake
that should come from each macronutrient.
Expressed as ranges (percentage of total
energy) with upper and lower boundary.
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Determining Nutrient Needs:
AMDR
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Nutrition Advice
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Who can you trust?
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Trustworthy experts are educated and
credentialed
Government sources of information are
trustworthy
Professional organizations provide reliable
nutrition information.
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Can I Trust the Media to
Deliver Nutrition News?
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News media often report ideas before they
have been fully tested
Reporters, who may lack a science
background, may misunderstand complex
scientific principles
Sometimes scientists report their findings
before they are subject to serious scrutiny
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Can I Trust the Media to
Deliver Nutrition News?
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Do not take actions based on the findings of
single study
Science works by the accumulation of
evidence and by consensus
Sometimes the media sensationalizes even
confirmed findings
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Reading Nutrition News with
an Educated Eye
An educated consumer of nutrition
information keeps the following in mind
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The study being described should be
published in a peer-reviewed journal
The news report should state the purpose
of the study and describe the research
methods
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Should note the limitations of the study
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Consumer Corner:
Reading Nutrition News with
an Educated Eye
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The report should clearly define the
subjects of the study
Valid reports describe previous research
and put the current research into
proper context
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Credible sources of Nutrition
Information
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Professional health associations like the
Dietitians of Canada, American Dietetic
Association
Government organizations like Health Canada
Volunteer agencies like Canadian Cancer
Society, Heart & Stroke Foundation, Canadian
Diabetes Association
Reputable consumer groups like National
Council Against Health Fraud
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Fads, Frauds and Quackery
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Food Faddism is defined as the adoption
of an unusual pattern of food behaviour.
Quackery is defined as the promotion
for profit of a medical scheme or
remedy that is unproven or known to be
false.
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Dubious Credentials
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Many promoters of nutrition quackery
claim degrees and titles of Dr., PhD.,
consultant or medical nutritionist, etc.,
which are false and do not exist.
Title of Registered Dietitian is protected
in both Canada and the USA.
Title, Nutritionist is not.
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Cost of Nutrition Quackery
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Economic loss from a few dollars to
thousands of dollars for seriously ill
people, e.g., Laetrile for cancer.
Death or disability from unproven and
harmful remedies, e.g., Ma Huang
(ephedra) for weight loss, potassium for
treating colic in babies.
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Internet Site Reliable?
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Who is responsible for the site?
Do the names and credentials of information
providers appear?
Are links with other reliable information sites
provided?
Is the site regularly updated?
Is the site selling a product or service?
Does the site charge a fee to gain access to
it?
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Reliable websites for nutrition
information
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http://www.dietitians.ca/
http://www.eatright.org/Public/
http://www.healthcanada.gc.ca
http://www.navigator.tufts.edu/
http://www.quackwatch.org/
http://www.supplementwatch.com/supatoz/
http://www.lesliebeck.com/index.php
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