Transcript Chapter 1 What is Nutrition?

Chapter 1: What Drives
Our Food Choices?
© 2010 Pearson Education, Inc.
What Drives Our Food Choices?

What helps us determine our decisions about food?
• Taste and enjoyment
• Culture and environment
• Social reasons and trends
• Weight concerns, body image, and health benefits
• Advertising
• Time, convenience, and cost
• Habits and emotions
© 2010 Pearson Education, Inc.
Food Choices: Taste and Enjoyment

Taste
• Most important consideration in food choices
- More than 10,000 taste buds in the mouth
- Most people prefer salty or sweet
- Degree varies, partly because of genetics
- Taste for fat may be genetically linked
© 2010 Pearson Education, Inc.
Food Choices: Taste and Enjoyment

Texture
• Affects likelihood of enjoying foods
• 30% of adults dislike foods that are slippery
• Preference begins early in life and makes people resistant
to change
© 2010 Pearson Education, Inc.
Food Choices: Culture and Environment

Culture
• What we eat growing up affects our food preferences

Environment
• Availability and accessibility
• Size and shape of plates and glassware
• Packaging of foods
• Lighting
© 2010 Pearson Education, Inc.
Food Choices: Social Reasons and Trends

Eating is an important way to bond with others
• The more people who are present at a meal, the more
you’ll likely eat
- Meal size increases by over 40%
• Activities influence the food and amount eaten

Trends also affect food choices
• Frozen vegetables in the 1950s
• Prewashed, peeled, sliced, or diced fresh vegetables
today
• “Organic” foods
© 2010 Pearson Education, Inc.
Food Choices: Weight Concerns, Body
Image, and Health Benefits

Choices can be influenced by current state of health

People select foods based on perception
• Avoid foods associated with weight gain or loss

Awareness of food effects on health can increase effort to
improve eating habits
• Functional foods may provide additional health benefits
beyond the basic nutrient value
• Phytochemicals (anti-oxidants) may play a role in
fighting chronic diseases
© 2010 Pearson Education, Inc.
Food Choices: Advertising

Manufactures spend $10 to $15 billion annually on food
advertising
• It works, especially on young people
How many food ads have you seen today…
- While watching television?
- While serving the Internet?
- While driving to school?
© 2010 Pearson Education, Inc.
Food Choices: Time, Convenience, Cost

People want to
• Spend less than 15 minutes preparing a meal
• Purchase foods prepared and partially prepared

People eat out more

Cost affects the selection of fast food versus more
nutritious meals
• In the long run the health issues of excess fast-food
consumption increases health care cost
© 2010 Pearson Education, Inc.
Food Choices: Habits and Emotions

Daily routine and habits affect when and what you eat

Emotions can sometimes drive food choices
© 2010 Pearson Education, Inc.
What Is Nutrition?

The science that studies how nutrients and compounds in
foods nourish the body and affect body functions and
overall health

The study of the relationship between food and health

Exploration of how food is:
• Digested
• Absorbed
• Transported
• Metabolized
• Used or stored in the body
© 2010 Pearson Education, Inc.
What Is Nutrition?

Good nutrition
• Reduces the risk of the
leading causes of death
• Helps prevent harmful
diseases and conditions
• Reduces the risk of
developing obesity,
diabetes, and high blood
pressure
© 2010 Pearson Education, Inc.
What Are Nutrients?


Compounds in foods that sustain body processes
• Building blocks
• Energy
Six classes of nutrients that are found in foods
• Carbohydrates
• Fats (lipids)
• Proteins
• Vitamins
• Minerals
• Water
© 2010 Pearson Education, Inc.
We Are What We Eat

Water is the most abundant nutrient found in foods and in
the body

Carbohydrates, fats, proteins, vitamins, and minerals make
up the rest

Note that foods also contain nonnutritive compounds, such
as phytochemicals and fiber
© 2010 Pearson Education, Inc.
Nutrients in Foods and in the Body
Figure 1.1
Most Nutrients Are Organic

Organic compounds contain carbon or carbon–carbon
bonds.

Carbohydrates, proteins, lipids, and vitamins are organic
nutrients

Minerals and water do not contain carbon and are classified
as inorganic compounds
© 2010 Pearson Education, Inc.
The Chemical Composition of the Six
Classifications of Nutrients in Food
Figure 1.2
Essential Versus Nonessential Nutrients

Essential nutrients
• Must be consumed from food
• Cannot be made in the body in sufficient quantities to
meet its needs and to support health

Nonessential nutrients
• Can be made in sufficient quantities in the body to meet
the body’s requirements and to support health

Nonessential nutrients can become essential under some
circumstances
© 2010 Pearson Education, Inc.
Some Nutrients Provide Energy

Energy is the capacity to do work

The body derives energy from certain nutrients
• Energy-yielding nutrients
- Carbohydrates
- Lipids (fats)
- Proteins
• Non-nutrient source of energy
- Alcohol
© 2010 Pearson Education, Inc.
Energy Measurement

Kilocalorie (kcals)
• Amount of energy required to raise the temperature of 1
kilogram of water 1 degree Celsius
• Used to express the measurement of energy in foods
• 1 kilocalorie is equal to 1,000 calories (lowercase “c”)
• Calorie (uppercase “C”) is used on nutrition labels to
express the energy content of food
© 2010 Pearson Education, Inc.
Calculating the Energy in Foods

Each energy-yielding nutrient provides a set number of
kilocalories per gram
• 4 kilocalories per gram of carbohydrates
• 4 kilocalories per gram of protein
• 9 kilocalories per gram of fat (lipid)
• 7 kilocalories per gram of alcohol (non-nutrient)

Number of kilocalories in one serving of a given food can
be determined based on
• Grams of carbohydrates, protein, and fat in the food
© 2010 Pearson Education, Inc.
© 2010 Pearson Education, Inc.
© 2010 Pearson Education, Inc.
Energy in the Body

Energy is trapped within bonds that keep molecules
together
• Bonds break and energy is released

Energy is used in multiple bodily functions
• Needs vary according to age, gender, and activity level
• Unused energy is stored predominately as fat
• Using more energy than consumed results in fat
breakdown
© 2010 Pearson Education, Inc.
Primary Roles of the Individual Nutrients

Individual nutrients serve unique roles in the body
• Supply energy
• Regulate metabolism
• Provide structure
© 2010 Pearson Education, Inc.
Macronutrients and Micronutrients

Macronutrients
• Nutrients the body needs in large amounts
• Include the energy-containing carbohydrates, lipids,
proteins, and water

Micronutrients
• Essential nutrients the body needs in smaller amounts
• Vitamins and minerals
© 2010 Pearson Education, Inc.
Carbohydrates

Body’s main source of energy

Supply glucose
• Primary source of energy for several body cell types
- Red blood cells
- Brain cells
© 2010 Pearson Education, Inc.
Carbohydrates

Found in most foods
• Breads, cereals, legumes,
nuts, fruits, vegetables,
and dairy products

Animal products, other than
dairy, do not provide
significant amounts of
carbohydrates
• Eggs, meats, poultry, and
fish
© 2010 Pearson Education, Inc.
<insert Misc 1.2>
Lipids

Fats (triglycerides), oils, phospholipids, and sterols

Insoluble in water

Triglycerides
• Source of energy during rest and sleep
• Storage form for excess energy
- Adipose tissue beneath the skin and around several
organs
• The majority of lipids we eat
• Found in margarine, butter, oils, and animal products
© 2010 Pearson Education, Inc.
Proteins

Can be used as energy, but not usually the primary source

Contain nitrogen and some contain sulfur

Make amino acids, the basic building blocks
• Used to synthesize, grow, and maintain tissue

Primary source of tissues in muscle, bones, and skin

Participate as neurotransmitters
© 2010 Pearson Education, Inc.
Proteins

Play a role in the immune system

Act as enzymes
• Catalysts and control chemical reactions

Good food sources
include meats, dairy,
and legumes

Lesser food sources
include whole grains,
vegetables, some
fruits
© 2010 Pearson Education, Inc.
Vitamins and Minerals



Do not provide energy
Involved in numerous key functions in the body
• Metabolism regulation
• Function as coenzymes
- Substances that facilitate the activity of enzymes
• Essential to the structure and function of hard and soft
tissues
Deficiencies
• Fatigue
• Stunted growth
• Weak bones
• Organ damage
© 2010 Pearson Education, Inc.
Vitamins and Minerals

Vitamins
• Water-soluble
- Not stored in the body
- Consumed daily
- Eight B-complex
vitamins and vitamin C
• Fat-soluble
- Stored in body
- Vitamins A, D, E, and K
© 2010 Pearson Education, Inc.
Vitamins and Minerals

Minerals
• Major
- Need at least 100 mg/day
- At least 5 gm in the body
• Trace
- Need less than 100 mg/day
- Less than 5 gm in the body
© 2010 Pearson Education, Inc.
Water




Makes up the majority of all body fluid
Part of every cell in the body
Key body functions
• Essential during metabolism
• Digestion and absorption
- Transport medium that delivers nutrients and oxygen
to cells and excretes waste products through urine
• Maintenance of body temperature
• Lubricant for joints, eyes, mouth, and intestinal tract
• Cushions vital organs
Can not be stored, must replenish daily
© 2010 Pearson Education, Inc.
Quick Review
© 2010 Pearson Education, Inc.
What Is Credible Nutrition Research?

Diet trends change frequently

Scientific knowledge about nutrition is more consistent
• Based on a consensus of research information
© 2010 Pearson Education, Inc.
Evaluating Media Headlines with a
Critical Eye

Dramatic headlines are designed to grab attention

Dramatic headlines can be misleading

Ask the following questions
1. Was the research finding published in a
peer-reviewed journal?
2. Was the study done using animals or
humans?
3. Do the study participants resemble me?
4. Is this the first time I’ve heard about
this?
© 2010 Pearson Education, Inc.
Steps of the
Scientific
Method
A process used by
scientist to gather
and test information
for the sake of
generating sound
research findings
Controlled
Scientific
Experiments
Figure 1.6
Quick Review




Sound nutritional advice is based on years of research using
the scientific method
Methods used to conduct research
• Laboratory experiments – animals
• Experimental research – humans
• Observational research
Double-blind placebo-controlled studies
• Subject unaware of receiving treatment versus placebo
• Researcher unaware of who receives treatment versus
placebo
• Gold standard
Observational and epidemiological research valid with
adequate sample size
© 2010 Pearson Education, Inc.
What Is Nutrition Assessment?

Looking at a variety of information

To assess nutritional status (state of nutrition)
• Healthy
• Malnourished
• Undernourished
• Overnourished

Provide the basis for dietary recommendations
© 2010 Pearson Education, Inc.
Health History



Patient’s health history
• Acute or chronic illness
• Diagnostic procedures
• Therapies
• Treatments
Family history
• Diabetes
• Heart disease
Weight history
• Overweight in past
• Underweight in past
© 2010 Pearson Education, Inc.
Could any of these
increase nutritional
needs or induce
malabsorption?
Nutrition Expert or Quack?

Registered Dietitian is trained in medical nutrition therapy

Nutritionist is a generic term with no recognized legal or
professional meaning

Quack
• Introduces health fears
• Sells services or products to allay fears
• Makes unrealistic promises or guarantees
© 2010 Pearson Education, Inc.
Assessing Nutritional Status of a
Population

Large-scale collection of dietary intake information is
needed

Usually conducted through national surveys

Collect and publish reliable data used to develop current
dietary recommendations
• The National Health and Nutrition Examination Survey
(NHANES)
• The Behavioral Risk Factor Surveillance System
(BRFSS)
• The Framingham Heart Study
© 2010 Pearson Education, Inc.
Healthy People 2020

A nationwide health improvement program

Two broad goals
1. Help all Americans increase life expectancy and
improve quality of life
2. Eliminate health disparities among different segments
of the population

Includes 35 focus areas with disease prevention and health
promotion objectives within each area
© 2010 Pearson Education, Inc.
Quality of the American Diet

Americans
• Eat too much protein, sugar, sodium, and saturated fat
• Eat too little fiber and some vitamins (especially A and
E) and minerals (especially calcium)
© 2010 Pearson Education, Inc.
85% of Americans eat breakfast
Quality of the American Diet
• Approximately 40% eat the minimum of five fruits and
vegetables per day
• Sugar accounts for 30% of carbohydrate intake
• Fat intake is about 33% of our diet
• 40% take a vitamin or mineral supplement per day
• 90% of meals are eaten away from home
• 50% never eat meals as a family
© 2010 Pearson Education, Inc.
Obesity Trends Among U.S. Adults
Over the last two decades, rates of overweight and
obesity have risen significantly in the U.S.
Figure 1.7
Best Dietary Strategy for Health

Eat a well-balanced diet with a variety of whole foods

Individuals with dietary restrictions or higher nutrient needs
may benefit from a supplement in addition to consuming a
healthy diet
© 2010 Pearson Education, Inc.