Chapter 1
Nutrition: Food for
Health
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Describe the typical American diet and explain how it could be
improved. Is there anything you would like to change about the way
you eat? Why or why not?
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Americans are consuming more food and calories than 30 years ago
because portion sizes have increased. About 32% of calories are
from meals away from home. Americans do not eat enough whole
grains, legumes, fruits, dairy foods, and dark green or yellow
vegetables. Salt and sugar intake are higher than recommended.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Macronutrients
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Energy-yielding nutrients are also called
macronutrients.
Energy-yielding nutrients include
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carbohydrates
proteins
fats.
Macronutrients are needed in the body in
large amounts each day.
Copyright 2010, John Wiley & Sons, Inc.
Carbohydrates,
Lipids and
Proteins
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Macronutrients
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Macronutrients provide energy to the body.
The amount of energy is measured in
kilocalories or kilojoules, depending on the
country you are in.
1 kilocalorie = 4.18 kilojoules
4.18 kilojoules = 1 kilocalorie
Kilocalorie is abbreviated kcalorie or kcal.
Kilojoule is abbreviated kjoule or kJ.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Macronutrients
Copyright 2010, John Wiley & Sons, Inc.
A serving of hot
chocolate provides 5
grams of fat, 2 grams of
protein and 28 grams of
carbohydrate. How many
kcalories are in the
serving of hot chocolate?
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Macronutrients
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Carbohydrates are one type of
macronutrient.
Carbohydrates include sugars and starches.
Fiber belongs to the category of
carbohydrates but does not provide energy.
Carbohydrates contain 4 kcalories/gram.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Macronutrients: Lipids
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Lipids are commonly called “fats” or “oils.”
Lipids are a concentrated form of energy.
Triglyceride is a type of fat that is found
abundantly in the body.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Macronutrients: Lipids
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Foods high in saturated fatty acids may
promote certain diseases.
Foods high in unsaturated fatty acids may
help to prevent certain diseases.
Lipids contain 9 kcalories/gram.
Copyright 2010, John Wiley & Sons, Inc.
Categories of Macronutrients: Proteins
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Proteins are required for growth,
maintenance and repair of the body.
Proteins can also supply energy.
Meat, fish, poultry, dairy products, legumes
and grains can provide protein.
Copyright 2010, John Wiley & Sons, Inc.
Categories of Macronutrients: Proteins
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Proteins are made up of different
combinations of amino acids.
Proteins provide 4 kcalories/gram.
Copyright 2010, John Wiley & Sons, Inc.
Describe the three general functions of
nutrients.
Provide energy: Carbohydrate, protein and
lipids undergo biochemical reactions that
provide energy for synthesis, basic body
functions and physical activity.
Forming structures: bones, muscles, cells are
formed from protein, fats, minerals.
Regulating Body Processes: metabolism helps
to maintain a stable environment in the body.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Micronutrients
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Micronutrients provide no energy for the
body but are necessary for proper
functioning of the body.
Micronutrients include vitamins and
minerals.
Micronutrients are very important for good
health but are required in small amounts.
Micronutrients can be found in most fresh
foods.
Copyright 2010, John Wiley & Sons, Inc.
Classes of Nutrients: Water
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Water is a macronutrient, meaning that it is
required in large amounts.
Water does not provide kcalories.
Water makes up approximately 60% of the
healthy human body.
Copyright 2010, John Wiley & Sons, Inc.
Nutrients are classified as
macronutrients and micronutrients.
Which of the following is NOT
considered a macronutrient?
a)
b)
c)
d)
Carbohydrate
Fat
Protein
Vitamins
Copyright 2010, John Wiley & Sons, Inc.
Functions of Nutrients:
Providing Energy
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Working together, macronutrients and
micronutrients help the body to stay healthy.
Biochemical reactions in the body help to
release the energy contained in carbohydrates,
fats and proteins.
Energy is used to maintain body functions and
fuel physical work.
If more energy is consumed than is needed,
over time body weight will increase.
Copyright 2010, John Wiley & Sons, Inc.
Regulating Body Processes
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All the reactions that occur in the body are
called metabolism.
The proper regulation of metabolism is called
homeostasis.
Each nutrient plays a role in helping to
maintain homeostasis.
Water helps to regulate temperature.
Protein, vitamins and minerals help to speed
up or slow down metabolic reactions.
Copyright 2010, John Wiley & Sons, Inc.
Nutrient Intake and Health
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Malnutrition can be eating too little or too
much of one or more nutrients.
Undernutrition is malnutrition caused by
eating insufficient amounts of energyproviding foods.
Overnutrition is malnutrition caused by
eating an excess of energy-providing foods.
Copyright 2010, John Wiley & Sons, Inc.
Vitamin A toxicity as a result of excessive
intake of vitamin supplements
Osteoporosis as a result of inadequate
intake of calcium and Vitamin D over an
extended period of time
Overweight status as a result of regular
ingestion of large portions of meat, grains,
dairy foods.
Copyright 2010, John Wiley & Sons, Inc.
Nutrient Density
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Nutrient density is a measure of the nutrient
a food provides compared to its energy
content.
A nutrient-dense diet is a healthy diet.
Broccoli is more nutrient-dense than French
fries.
Copyright 2010, John Wiley & Sons, Inc.
Consuming nutrient dense foods helps to
ensure a proper diet. One effective
strategy is
eating foods that have been minimally
processed
eating foods with a high nutrient
content compared to the kcalories
provided
limiting added fats and sugars since
they reduce nutrient density
all of these are effective strategies
Copyright 2010, John Wiley & Sons, Inc.
Understanding Science
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Nutrition is a science.
Developing an understanding of the
processes in nutritional science will help us
to understand the relationship between
nutrition and health.
Understanding nutritional processes will help
us to make wise nutrition decisions.
Copyright 2010, John Wiley & Sons, Inc.
The Scientific Method
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Advances in nutrition are made using the
scientific method.
The scientific method uses an unbiased
approach to examine the interaction of food,
nutrients and health.
The steps in the scientific method are:
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Observation
Hypothesis
Theory
Copyright 2010, John Wiley & Sons, Inc.
What Makes a Good Experiment?
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A well-conducted experiment requires:
Quantifiable Data
- Can we measure the information in a scientific
manner?
Appropriate Experimental Population
- Is the population large enough and pertinent to
the study?
Proper Controls
- Can we ensure that the population ate or drank
what we said they did?
Copyright 2010, John Wiley & Sons, Inc.
The best reason for using a placebo as part of
experimental design is:
a)
It will not be possible for researchers
to know who is receiving an
intervention and who is not
b)
The only way to know if the
treatment works is to compare it to a
placebo
c)
All subjects are receiving some sort
of treatment, which will minimize
bias
d)
It makes it possible to include a larger
number of subjects in the experiment
Copyright 2010, John Wiley & Sons, Inc.
The correct sequence of events in the scientific
method is:
a) conduct the experiment, develop a hypothesis,
form a theory, and make an observation
b) develop a hypothesis, conduct the experiment,
make an observation, and form a theory
c) form a theory, conduct the experiment, develop
a hypothesis, and make an observation
d) make an observation, develop a hypothesis,
conduct the experiment, and form a theory
Copyright 2010, John Wiley & Sons, Inc.
What Makes a Good Experiment?
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Control groups act as a standard of comparison.
Placebos are identical in appearance to the actual
treatment but of no therapeutic value.
Single-blind study: subjects do not know which
treatment they are receiving
Double-blind study: neither the subjects nor the
investigators know which treatment is being
received
The peer review system allows for scientific
interpretation of experimental results.
Copyright 2010, John Wiley & Sons, Inc.
Types of Nutrition Research Studies
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Observational studies can include
epidemiology, the study of diet, health and
disease patterns, and correlation.
Human intervention studies are also known
as clinical trials.
Laboratory studies are conducted in
research facilities such as hospitals or
universities.
Copyright 2010, John Wiley & Sons, Inc.
Identifying Reliable Nutrition
Information
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Does the information make sense?
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For example, can you really lose forty pounds in
one week?
Where did the information come from?
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Information from personal testimony or from one
health care professional is probably not reliable.
Copyright 2010, John Wiley & Sons, Inc.
Identifying Reliable Nutrition
Information
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Is the information based on well-designed,
accurately-interpreted research studies?
Who will benefit when you purchase this
product?
Has this product stood the test of time?
Copyright 2010, John Wiley & Sons, Inc.