Transcript Lecture1FoodChoiceStrachan

63-391: Basic Human Nutrition
Food Choices & Human Health
Lecture 1
Elisabeth Strachan
Nutrition in Your Life
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Nutrition
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Food
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The science of foods and the
substances they contain
Derived from plant or animal sources
Provide energy and nutrients
Diet
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The food one consumes
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Food Choices
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Personal preference
Habit
Ethnic heritage or tradition
Social interactions
Availability, convenience, economy
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Food Choices
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Positive and negative associations
Emotional comfort
Values
Body weight and image
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Nutrients in Foods
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There are 6 classes of nutrients:
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Water, Carbohydrate, Protein, Fat (lipids),
Vitamins and Minerals
These nutrients are essential to health
Non-nutrients
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Energy-Yielding
Nutrients
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Kilocalories
and
kilojoules
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Energy-Yielding
Nutrients
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Energy in the body
 Energy for activity
 Stored energy
Other roles of energy-yielding
nutrients
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Vitamins
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Organic
Not energy-yielding
Essential
Water-soluble vs. fat-soluble
Vulnerable to destruction
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Minerals
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Inorganic
Not energy-yielding
Essential
Indestructible
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Water
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Inorganic
Not energy-yielding
Essential
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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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Dietary Reference Intakes
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A set of scientifically based nutrient reference
values for healthy populations.
Used by governments and non-government
organizations in:
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the assessment of nutrient intakes of individuals
and groups,
planning of diets, development of nutrition
education materials,
the fortification of foods, and the formulation of
supplements and special dietary foods.
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DRI’s consist of 4 values
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Estimated average
requirements
Recommended dietary
allowances
Adequate intakes
Tolerable upper limits
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Estimated Average
Requirement (EAR)
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The median usual intake value that is
estimated to meet the requirement of
half the healthy individuals in a lifestage or gender group.
Used to determine nutrient adequacy to
reduce risk of chronic disease or other
disorders.
Used to calculate the RDA’s.
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DRI
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Recommended Dietary
Allowance (RDA’s)
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The average daily dietary intake level
that is sufficient to meet the nutrient
requirement of nearly all (> 97-98%)
healthy individuals in a life-stage and
gender group.
RDA = EAR + 2 SDREQ
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Adequate Intakes (A.I.)
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A recommended nutrient intake level
based on observed or experimentally
determined approximations or
estimates of a group (or groups) of
healthy people that are assumed to be
adequate.
Used only when and RDA cannot be
determined.
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DRI
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Tolerable Upper Intake Level
(UL)
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The highest level of daily nutrient
intake that is likely to pose no risk of
adverse health effects for almost all
individuals in the general population.
As intake increases above the UL, the
potential risk of adverse effects
increases.
No UL means no data, not no risk.
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DRI
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Energy
Recommendations
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Estimated Energy Requirement
Acceptable Macronutrient
Distribution Ranges
 Carbohydrate: 45% - 65%
 Fat: 20% - 35%
 Protein: 10% - 35%
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Energy
Recommendations
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Using Nutrient
Recommendations
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Estimates of energy & nutrient
intakes apply to healthy people
Recommendations are NOT
minimum requirements
Recommendations are NOT optimal
for all people
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Using Nutrient
Recommendations
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Recommendations should be met
by consuming a varied diet
Recommendations apply to
average daily intakes
Each DRI category serves a unique
purpose
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Health is affected by:
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Genetic inheritance
Diet choices
Lifestyle choices
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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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How do we determine what
we should eat?
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Government agencies provide us with
nutrition recommendations and guidelines.
Recommendations based on scientific
research.
These recommendations are translated into
food groups & serving sizes of foods, e.g.,
Canada’s Food Guide To Healthy Eating
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A World Tour
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A World Tour
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Canada’s Guidelines To
Healthy Eating
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Enjoy a variety of food
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 physical activity and
healthy eating
Limit salt, alcohol and caffeine.
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Canada’s Food Guide To
Healthy Eating
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“Other” foods
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Includes food and beverages that are not part
of any food group but are often used in
making meals or consumed as snacks.
E.g., foods that are mostly fats and oils
(butter and margarine), sugar ( honey, jam,
candies), high-fat and/or high salt snack
foods (chips, chocolate bars, cakes, cookies),
beverages (tea, coffee, water, soft drinks),
and condiments (pickles, ketchup).
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Limitations of Food
Guide
How to interpret:
 Miscellaneous foods
 Mixtures of foods
 Ethnic foods that do not appear
in the Food Guide
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Other limitations
Understanding:
 Nutrient density
 Recommended
servings
 Serving sizes
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Nutrition Recommendations
for Canadians
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The Canadian diet should provide energy
consistent with the maintenance of body
weight within the recommended range.
The Canadian diet should include essential
nutrients in amounts recommended.
The Canadian diet should include no more
than 30% of energy as fat (33g/1000
calories) and no more than 10% as saturated
fat (11 g/1000 calories).
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Nutrition Recommendations
Continued
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The Canadian diet should provide 55% of
energy as carbohydrate (138 g/1000 calories)
from a variety of sources.
The sodium content of the Canadian diet
should be reduced.
The Canadian diet should include no more
than 5% of total energy as alcohol, or two
drinks daily whichever is less.
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Nutrition Recommendations
continued
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The Canadian diet should contain no
more caffeine than the equivalent of
four regular cups of coffee per day.
Community water supplies containing
less than 1 milligram per liter should be
fluoridated to that level.
These recommendations were
established in 1990.
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Food Labels
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Ingredient list
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Serving sizes
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Nutrition facts
 Daily Values
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New Nutrition Label
Easy to
find, easy
to read and
on more
foods
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Nutrition claims
• 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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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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% 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
The actual numbers can be confusing, for example:
• 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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Key Messages
.
 Nutrition Facts: easy to find, easy to read, and
on more foods
 Use Nutrition Facts, the list of ingredients and
nutrition claims to make informed food choices.
 Nutrition Facts are based on a specific amount
of food - compare this to the amount you eat.
 Use % Daily Value to see if a food has a lot or a
little of a nutrient.
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Who speaks on Nutrition?
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Main sources of nutrition information:
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Product labels (ranked 1st)
Radio/TV (ranked 2nd)
Friends/Relatives/Colleagues (ranked 3rd)
Magazines (ranked 4th)
Physicians (ranked 8th)
Dietitian/Nutritionist (ranked 14th)
Internet (ranked last (6%)
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Nutrition Information
and Misinformation
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Dietitians of Canada (DC)
Registered dietitian (RD)
Dietetic technician,
registered (DTR)
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Nutrition Information
and Misinformation
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Identifying misinformation
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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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Who Falls Victim to Quackery?
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People who are:
Unsuspecting. If it appears in the media, it’s
true
Believe in magic, i.e., believe there is an easy
solution
Desperate; i.e., those with serious health
problems.
Alienated, i.e., have a deep distrust of
governments, medical profession, food
companies, etc.
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Misleading Claims
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Our food supply is inadequate
Vitamin and mineral deficiencies are common.
Most health problems can be cured by
nutritional methods.
Canadians are being poisoned by food
additives and pesticide residues.
Personal experience is the best way to tell
whether a health related action is effective.
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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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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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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
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http://www.navigator.tufts.edu/
http://www.quackwatch.org/
http://www.supplementwatch.com/supatoz/
http://www.lesliebeck.com/index.php
http://www.dietitians.ca/
http://www.eatright.org/Public/
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