Chapter 1 NUTR

Chapter 1

An Overview of Nutrition

© 2009 Cengage - Wadsworth

Food Choices
• Personal preferences for flavors of food are
the main reason people make food choices
and choices can be influenced by genetics.
• Habits are comforting and food choices are
often just a habit.
• Ethnic heritage or traditions are strong
influences on eating.
• Social interactions such as special events,
customs, and holidays are shared by
groups of people. Food is often involved.


Food Choices
• Food availability, convenience, and the economy
are affecting many food choices in today’s world.
• There are many positive and negative associations
with food that affect what food is chosen to eat.
• Eating for emotional comfort can be the result of
changes in brain chemistry that occur when foods
are consumed. While this may be appropriate at
times, it can lead to overeating.
• Values such as religious beliefs, political views, or
environmental concerns may affect food choices.
• Body weight and image can affect food choices
both positively and negatively.
• The nutrition and health benefits of functional
foods, such as whole, modified, or fortified foods,
are becoming more popular.

The Nutrients
• Nutrients in Foods and in the Body
 Composition of foods includes the six nutrient
classes of water, carbohydrates, lipids, proteins,
vitamins and minerals. Foods can also contain
nonnutrients and other compounds, such as fibers,
phytochemicals, pigments, additives, alcohols and
others.
 Composition of the human body is made of
chemicals similar to food.
 Chemical composition of nutrients includes both
organic (those that contain carbon) and inorganic
(those that do not contain carbon) compounds.
 Essential nutrients are those the body cannot make
or cannot make in sufficient quantities to meet
needs. These are also called indispensable nutrients.


The Nutrients
• Energy-Yielding Nutrients: Carbohydrate,
Fat and Protein
 Macro- vs. micronutrients
• Carbohydrate, fat, and protein are macronutrients
because the body needs them in large quantities.
• Water, vitamins, and minerals do not provide
energy and are known as micronutrients because
the body needs them in smaller quantities.
 Energy is measured in Calories (calories,
kilocalories, kcalories, kcal).
• Internationally, food energy is measured in
joules.


The Nutrients
• Energy-Yielding Nutrients: Carbohydrate, Fat and
Protein
 Energy from food differs in energy density.
Carbohydrate yields 4 kcalories per gram, protein 4
kcalories per gram, and fat 9 kcalories per gram.
 Activity in the body is fueled by food as energy is
released from bonds within carbohydrate, fat, and
protein as they are broken down. The processes by
which food is broken down to yield energy are called
metabolism.
 Excess energy is stored in the body as compounds
such as body fat.
 Other roles of energy-yielding nutrients include
building body tissues and regulating body processes.


Lower energy density Higher energy density
This 450-gram breakfast This 144-gram breakfast
delivers 500 kcal, for an energy delivers 500 kcal, for an energy
density of 1.1 density of 3.5
(500 kcal/450 g = 1.1 kcal/g) (500 kcal/144 g = 3.5 kcal/g)


The Nutrients
• Vitamins are organic, essential
nutrients that allow the body to
obtain energy from carbohydrate,
fat, and protein.
• Minerals are inorganic, essential
nutrients that are found in the bones,
teeth, and body fluids.
• Water is an indispensable and
abundant essential nutrient that
participates in many life processes.


The Science of Nutrition
• Conducting Research
 Nutrition Research tests hypotheses and
develops theories.
 Information based on personal experience is
known as an anecdote.
 Types of studies
• Epidemiological studies include cross-sectional,
case-control, and cohort designs.
• Laboratory-based studies include animal studies
and laboratory-based in vitro studies.
• Human intervention or clinical trials


• Conducting Research
 Controls
• Subjects are divided into two groups. The experimental
group receives the treatment being studied and the
control group does not receive the treatment.
• Randomization is used to randomly assign subjects to
the experimental or control group.
 Sample sizes must be large to accurately detect
differences.
 Placebos are used to control the placebo effect with
subjects in experiments. Subjects in blind
experiments do not know if they are in the
experimental or control group.
 In double-blind experiments, the researchers and
the subjects do not know their groups to prevent
researcher bias.

• Analyzing Research Findings
 Correlations and causes in experiments
involve studying variables and correlations,
or relationships, between variables.
• A positive correlation is when the same thing
happens to two variables: as one increases the
other increases.
• A negative correlation if when the opposite things
happen to two variables: as one increases the
other decreases.
 Cautious conclusions must be drawn when
examining or generalizing the results of a
study.



• Publishing Research
A peer review process is used to
evaluate the procedures used and the
conclusions drawn from a study.
When a study has validity it means
that the conclusions were supported
by the findings.
Replication is used to confirm or
disprove findings.


The Dietary Reference
Intakes (DRI)
• Establishing Nutrient Recommendations
 Estimated Average Requirement (EAR) defines the
requirement of a nutrient that supports a specific function
in the body for half of the healthy population.
 Recommended Dietary Allowances (RDA) use the EAR as a
base and include sufficient daily amounts of nutrients to
meet the known nutrient needs of practically all healthy
populations. This recommendation considers deficiencies.
 Adequate Intakes (AI) reflect the average daily amount of
a nutrient without an established RDA that appears to be
sufficient.
 Tolerable Upper Intake Level (UL) is a maximum daily
amount of a nutrient that appears safe for most healthy
people and beyond which there is an increased risk of
adverse health effects.


Intakes (DRI)
• Establishing Energy Recommendations
 Estimated Energy Requirement (EER)
represents the average daily energy intake
to maintain energy balance and good health
for population groups.
 Acceptable Macronutrient Distribution Range
(AMDR) represents the range of intakes for
energy nutrients that provide adequate
energy and nutrients and reduce risk of
chronic disease.


Intakes (DRI)
• Using Nutrient Recommendations
Apply to healthy people
Recommendations are not minimum
requirements and can be adjusted for
individuals by registered dietitians.
Achieved by consuming a variety of
foods
Apply to average daily intakes
Each DRI category serves a unique
purpose.


Intakes (DRI)
• Comparing Nutrient
Recommendations
Food and Agricultural Organization
(FAO)
World Health Organization (WHO)


Nutrition Assessment
• Nutrition Assessment of Individuals -
evaluates the many factors that influence
or reflect nutritional health.
 Historical information regarding diet, health
status, drug use, and socioeconomic status
is gathered.
 Anthropometric data measure physical
characteristics including height and weight.
 Physical examinations require skill and
reveal possible nutrition imbalances.
 Laboratory tests detect early signs of
malnutrition.


• Nutrition Assessment of Individuals
 Stages in Nutrient Deficiency (example is
given for iron)
• Overt is easy to observe
• Primary deficiency is inadequate dietary intake
• Secondary deficiency is caused by disease or
drugs
• Subclinical deficiency is the early stages of
deficiency without outward signs
• Covert is hidden



• Nutritional Assessment of Populations
National Nutrition Surveys
• National Nutrition Monitoring Program
uses survey research to collect data on
foods people eat and people’s health
status.
• Data collected is used for nutrition policy,
food assistance programs and food
supply regulation.


• Nutrition Assessment of Populations
 National Health Goals
• Healthy People is a national public health
initiative under the U.S. Department of Health
and Human Services that is published every 10
years.
• Identifies the most significant threats to health
• Focuses efforts on eliminating these threats
 National Trends show an increased intake of
fast food, increased portion sizes, and an
increased consumption of energy-dense
foods and drinks. This intake is associated
with an increased risk for overweight and
obesity.

Diet and Health

• Chronic Diseases
Research indicates that behavior and
certain conditions are related to
disease.
Five of six leading causes of death
have a relationship with diet or
alcohol.
Many leading causes of death have a
relationship with obesity.


Diet and Health

• Risk Factors for Chronic Diseases
Risk factors persist over time.
Risk factors cluster and focusing on
one factor may improve another.
Risk factors in perspective: The most
prominent are tobacco use, diet and
activity patterns and alcohol use.


Nutrition Information and
Misinformation
On the Net and in the News


Nutrition Information &
Misinformation
• Nutrition on the Net (Internet, World Wide
Web, www, cyberspace, websites)
 Internet information can be published by
ANYONE.
 May be high-quality information: National
Library of Medicine’s PubMed
 May be misleading, incomplete, and
inaccurate
• Nutrition in the News
 Can be misleading and contradictory
 May report scientific findings prematurely


Misinformation
• Identifying Nutrition Experts
 Consumers listen to many people except
dietitians.
 Qualifications of the speaker must be
evaluated.
 Dietitians have been educated and trained
in nutrition.
 Physicians and Other Health Care
Professionals
• American Dietetic Association (ADA) recommends
nutrition education be a part of all health care
professionals’ curricula.
• A qualified nutrition expert is a registered
dietitian (RD).

Misinformation
• Identifying Nutrition Experts
 Registered Dietitians (RD)
• Maintain up-to-date registration
• May use the title nutritionist
• Many states require a license to practice. These
are licensed dietitians (LD).
• Certified nutritionists, certified nutritional
consultants, and certified nutritional therapists do
not have the same credentials as an RD.
• Public health dietitians work for government-
funded agencies.
 Other Dietary Employees
• Dietetic Technicians assist RDs
• Dietetic Technicians Registered (DTR) are dietetic
technicians that have passed a national exam.

Misinformation
• Identifying Fake Credentials
Look for a degree from an accredited
college or university.
Be careful of correspondence schools.
Fraudulent businesses may provide
false credentials.


Misinformation
• Red Flags of Nutritional Quackery
 Nutritional misinformation can be identified
by using the following eight red flags:
• Satisfaction guaranteed
• Quick and easy fixes
• Natural
• One product does all
• Time tested
• Paranoid accusations
• Personal testimonials
• Meaningless medical jargon


Chapter 1 NUTR

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