Download Factors Influencing What You Eat

Chapter 1
Introduction to Nutrition
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Learning Objectives
Identify factors that influence food selection.
Define nutrition, kilocalorie, nutrient, and nutrient density
Identify the classes of nutrients and their characteristics
Describe four characteristics of a nutritious diet
Define Dietary Reference Intakes and explain their function
Compare the EAR, RDA, AI, and UL
Describe the processes of digestion, absorption, and
metabolism
8. Explain how the digestive system works
9. Distinguish between whole, processed, and organic foods
10. Compare how a meat-based or plant-based diet impact the
environment
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Factors Influencing What You Eat
1. Flavor includes:
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Taste
Smell
Appearance
 How it feels in the
mouth
 Texture
 Temperature
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The most important consideration when
choosing something to eat is flavor.
The most important
consideration when
choosing something to
eat is flavor. (Courtesy
of PhotoDisc/Getty
Images)
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Factors Influencing What You Eat
 Other Aspects of Food
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Cost
Convenience
Availability
Familiarity
Nutrition
Factors Influencing What You Eat
 Demographics
 Age
 Gender
 Educational level
 Income
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Factors Influencing What You Eat
 Culture and Religion
 Traditional foods
 Special
events/celebrations
 Religious
foods/practices
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Factors Influencing What You Eat
 Health
 Health status
 Desire to improve
health/appearance
 Nutrition knowledge
and attitudes
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Factors Influencing What You Eat
 Social and Emotional
Influences
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Social status
Peer pressure
Emotional status
Food associations
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Factors Influencing What You Eat
 Food Industry and the Media
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Food industry
Food advertising
Food portrayal in
media
Reporting of
nutrition/health studies
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Factors Influencing What You Eat
 Environmental Concerns
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Use of synthetic fertilizers and pesticides
Wastefulness of fattening up livestock/poultry
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What is Nutrition?
Nutrition is a science that:
 studies nutrients and other substances in
foods and in the body and how these
nutrients relate to health and disease, and
 explores why you choose particular foods and
the type of diet you eat
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Nutrients are:
Nourishing substances in
food that provide
energy and promote the
growth and
maintenance of your
body
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Kilocalories
 A measure of the energy in food
 1 kilocalorie raises the temperature of 1
kilogram of water 1 degree Celsius
 Also called a Calorie
 Abbreviated as kcalorie or kcal
 When you hear “calorie,” it is really a
kilocalorie
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The number of kilocalories you need is
based on:
 Basal metabolism (about 2/3 of total energy
needs for individuals who are not very active)
 Physical activity
 Thermic effect or specific dynamic action of
foods (5 to 10% of total energy needs)
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BMR depends on factors such as:
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Gender
Age
Growth
Height
Temperature
Fever and stress
Exercise
Smoking and caffeine
Sleep
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Classes of Nutrients - Overview
 Carbohydrates
 Vitamins
 Lipids (fats)
 Minerals
 Proteins
 Water
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Carbohydrates
 A large class of
nutrients, including:
 Sugars
 Starch
 Fibers
that function as the
body’s primary source of
energy.
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Lipids
 A group of fatty
substances, including
triglycerides and
cholesterol, that
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are not soluble in
water
provide a rich source
of energy and structure
to cells
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Protein
 Major structural parts of
the body’s cells that are
made of nitrogencontaining amino acids
assembled in chains
 Particularly rich in
animal foods
 Present in many plant
foods
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Vitamins and Minerals
 Vitamins: Noncaloric,
organic nutrients found
in a wide variety of
foods that are essential
to:
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regulate body
processes
maintain the body
allow growth and
reproduction
 Minerals: Noncaloric,
inorganic nutrients
found in a wide variety
of foods that are
essential to:
 regulate body
processes
 maintain the body
 allow growth and
reproduction
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Water
 Inorganic nutrient that
plays a vital role in all
bodily processes and
makes up just over half
of the body’s weight
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Functions of Nutrients
Nutrients
Provide Energy
Promote Growth and
Maintenance
Regulate Body
Processes
Carbohydrates
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Lipids
X
X
X
Proteins
X
X
X
Vitamins
X
X
Minerals
X
X
Water
X
X
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Food Facts
 Most foods provide a
mix of nutrients
 Food contains more
than just nutrients –
food may contain
colorings, flavorings,
caffeine,
phytochemicals, and
other substances
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Carbohydrates
4 kcal/gram
Lipids
9 kcal/gram
Protein
4 kcal/gram
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More Vocabulary
 Micronutrients
 Carbohydrates
 Macronutrients
 Lipids
 Proteins
 Vitamins
 Organic nutrients
 Minerals
 Inorganic nutrients
 Water
Connect the columns
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Essential Nutrients
Nutrients that either cannot be made in the
body or cannot be made in the quantities
needed by the body; therefore, we must obtain
them through food
EXAMPLES
Glucose, vitamins, minerals, water, some lipids,
and some parts of protein
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Nutrient Density
 Which food is more nutrient dense?
OR
What is nutrient density?
 Nutrient density is:
A measure of the nutrients provided in a food
per kcalorie of that food
 Empty-Kcalorie foods: provide few nutrients
for the number of kcalories they contain
Nutrient Density Comparison: % DRI
intakes for selected nutrients.
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Characteristics of A Nutritious Diet
 Adequate
 Balanced
 Moderate
 Varied
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Dietary Reference Intakes (DRI)
 Recommended Dietary
Allowance (RDA)
Intake value sufficient to
meet nutrient requirements
of 97-98% of all healthy
individuals in a group
 Estimated Average
Requirement (EAR)
Intake value estimated to
meet requirement of half the
healthy individuals in a group
 Adequate Intake (AI)
Intake value used when a
RDA cannot be based on an
EAR because there’s not
enough scientific data
 Tolerable Upper Intake Level
(UL)
Maximum intake level above
which toxicity would increase
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Dietary Reference Intakes
 Estimated Energy Requirement (EER)
The dietary energy intake measured in kcalories that
is needed to maintain energy balance in a healthy
adult
There is no RDA or Upper Intake Level for kcalories
because these concepts do not apply to energy and
would lead to weight gain
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Dietary Reference Intakes
 RDA and AI – useful in planning diets for
individuals
 EAR - useful in planning diets for groups
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Digestion, Absorption, & Metabolism
 Digestion: Process by which food is broken down
into its components in the gastrointestinal tract with
the help of digestive enzymes
 Absorption: The passage of digested nutrients
through the walls of the intestines or stomach into the
blood or lymph, where they are transported to the
cells
 Metabolism: All the chemical processes by which
nutrients are used to support life, includes anabolism
and catabolism
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Mouth – Oral Cavity
 Tongue and teeth help chew food
 Saliva contains digestive enzymes and
lubricates the food to move further along GI
tract
 Tongue rolls chewed
food into bolus
From Mouth to Esophagus
 When swallowing, the epiglottis covers the
tubes to the lungs so that food does not get
into the lungs
 The bolus moves from
the mouth through the
pharynx to the esophagus
 What is peristalsis?
Stomach
 Food passes from esophagus through the
LES into the stomach
 Mucous membranes
secrete hydrochloric acid
 Chyme
 Pyloric sphincter
Small Intestine
 15 – 20 feet long
 Duodenum – first foot
of s.i. – much digestion
& absorption goes on
 Bile – fat digestion
 Most nutrients pass
through villi into blood or
lymph vessels – transported to liver - body
Villi & Microvilli
Large Intestine
 Connects small intestine to the rectum
 About 5 feet long
 Receives waste products of digestion and
passes them on to rectum
 Absorbs water, some minerals, and a few
vitamins (such as vitamin K) made by
bacteria residing there
Food Facts
1. Whole foods
2. Organic foods
3. Processed foods
4. Enriched foods
5. Fortified foods
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Organic Foods
 Organic food is produced without using most:
 Conventional pesticides
 Petroleum-based fertilizers or sewage sludgebased fertilizers
 Bioengineering
 Ionizing radiation (irradiation)
 Organic farms must be inspected annually.
 All organically-raised animals may not be
given hormones or antibiotics, and must have
access to pasture.
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Labeling of Organic Foods
Courtesy of USDA
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Hot Topic: How the American Diet
Impacts the Environment
 Consider:
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Livestock use 30% of the earth’s surface –
increased deforestation has led to the
accumulation of greenhouse gases
Livestock farms are major air & water polluters
Enormous quantities of water, fuel, fertilizers,
and pesticides are required to grow feed for
livestock
Sustainable Agriculture
 Produces abundant food without depleting
the earth’s resources or polluting its
environment
How Restaurants Are Going Green
 Energy-efficient equipment and lighting
 Buying tableware and cups made of recycled
and renewable materials
 Buying nontoxic cleaning and sanitation
supplies
 Installing flow restrictors on faucets
 Recycling
 Using an energy management program
Copyright ©2010 John Wiley & Sons, Inc.
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