Chapter 1 An Overview of Nutrition

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An Overview of
Nutrition
Chapter 1

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Introduction
• Daily food choices
• Benefit health
• Harm health
• Chronic disease
• Diet
• Foods and
beverages

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Food Choices Are Highly
Personal
• Personal preference
• Taste: sweet and salty, genetics
• Habit
• Ethnic heritage or tradition
• Social interactions
• Availability, convenience, and economy
• Benefits of home-cooked meals
• Positive and negative associations

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Food Choices – Other Factors
• Emotions
• Boredom, depression, anxiety
• Stress
• Values
• Religious beliefs, political views, environmental
concerns
• Body weight and image
• Nutrition and health benefits
• Functional and fortified foods

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The Nutrients
• Water
• Hydrogen & oxygen
• Inorganic (no carbon)
• Minerals
• Simplest nutrient
• Inorganic
• Vitamins
• Organic (contains
carbon)
• Carbohydrates
• Organic
• Proteins
• Organic
• Contains nitrogen
• Lipids (fats)
• Organic

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Body Composition of Healthy-
Weight Men and Women

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The Six Classes of Nutrients
Nutrient Organic Inorganic Energy-yielding Macronutrient Micronutrient
Carbohydrates ✓ ✓ ✓
Lipids (fats) ✓ ✓ ✓
Proteins ✓ ✓ ✓
Vitamins ✓ ✓
Minerals ✓ ✓
Water ✓

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Macronutrients and
Micronutrients
• Macronutrients yield energy
• Carbohydrate
• Fat
• Protein
• Water and minerals do not yield energy
• Micronutrients
• Vitamins and minerals
• Human body needs small amounts

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Energy-Yielding Nutrients
• Macronutrients: source of kcalories
• Carbohydrate = 4 kcal/g
• Protein = 4 kcal/g
• Fat = 9 kcal/g
• Higher energy density
• Alcohol
• Not a nutrient
• Yields energy – 7 kcal/g
• Lower energy density foods
• Contribute to weight loss

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Energy in the Body
• Body uses macronutrients
• Bonds between the nutrients’ atoms break
• Energy is released
• Can then be used or stored
• Macronutrients
• Provide raw material for building tissue and
regulating body activities
• Proteins regulate digestion and energy
metabolism

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The Vitamins
• Thirteen organic vitamins
• Each has a special role to play
• Facilitate energy release
• Almost every bodily action requires assistance
from vitamins
• Vulnerable to destruction
• Heat (as from cooking), light, and chemicals

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The Minerals and Water
• Minerals
• Do not yield energy
• Sixteen essential minerals
• Other minerals are environmental contaminants
• Example: lead
• Indestructible
• But can be lost into cooking water, for example
• Water
• Environment for nearly all body processes

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The Science of Nutrition
• Foundation in several other sciences
• Biology, biochemistry, physiology
• Tremendous growth
• Knowledge gained from sequencing the human
genome
• Nutritional genomics

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Conducting Research
• Use of scientific method
• Systematic process for conducting research
• Research studies
• Controls
• Randomization
• Sample size
• Placebos
• Double-blind experiments

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The Scientific Method

16. Stepped Art
NEW OBSERVATIONS
& QUESTIONS
THEORY
Develop a theory that
integrates conclusions
with those from
numerous other studies
HYPOTHESISSUPPORTED HYPOTHESISNOTSUPPORTED
HYPOTHESIS & PREDICTION
Formulate a hypothesis—a
tentative solution to the problem
or answer to the question—and
make a prediction that can
be tested
Identify a problem to be
solved or ask a specific
question to be answered
OBSERVATION & QUESTION
RESULTS & INTERPRETATIONS
Summarize, analyze, and
interpret the data; draw
conclusions.
EXPERIMENT
Design a study and
conduct the research to
collect relevant data

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Types of Research
• Epidemiological studies
• Cross-sectional studies
• Case-control studies
• Cohort studies
• Experimental studies
• Laboratory-based animal studies
• Laboratory-based in vitro studies
• Human intervention (clinical) trials

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Examples of Epidemiological
Studies

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Examples of Experimental
Studies

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Analyzing Research Findings
• Correlations – only show association
• Positive correlation
• Not necessarily a desired outcome
• Negative correlation
• No correlation
• Cautious interpretations and conclusions
• Accumulation of evidence

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Publishing Research
• Peer review
• Research has validity
• Findings are preliminary when published
• Not meaningful by themselves
• Findings need to be replicated

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Parts of a Research Article
• Abstract. The abstract provides a brief overview of the article.
• Introduction. The introduction clearly states the purpose of the current study and
provides a comprehensive review of the relevant literature.
• Review of literature. A comprehensive review of the literature reveals all that
science has uncovered on the subject to date.
• Methodology. The methodology section defines key terms and describes the study
design, subjects, and procedures used in conducting the study.
• Results. The results report the findings and may include tables and figures that
summarize the information.
• Discussion: The discussion draws tentative conclusions that are supported by the
data and reflect the original purpose as stated in the introduction. Usually, it answers
a few questions and raises several more.
• References. The references reflect the investigator's knowledge of the subject and
should include an extensive list of relevant studies (including key studies several
years old as well as current ones).

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Dietary Reference Intakes
• Standards defined for:
• Energy
• Nutrients
• Other dietary components
• Physical activity
• Collaborative effort between United States
and Canada
• Recommendations apply to healthy people
• May be different for specific groups

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EAR and RDA
• Estimated Average Requirements (EAR)
• Average amount sufficient for half of population
• Recommended Dietary Allowances (RDA)
• Recommendations to meet needs of most healthy
people
• Set near the top end of the range of EAR

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EAR and RDA Compared

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Adequate Intakes and Upper
Intake Levels
• Adequate Intakes (AI)
• Insufficient scientific evidence to establish EAR
• AI value set instead of RDA
• Expected to exceed average requirements
• Tolerable Upper Intake Levels (UL)
• Point where nutrient is likely to be toxic
• Helps protect against overconsumption

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Inaccurate versus Accurate
View of Nutrient Intakes
1. If a person’s usual intake
falls above the RDA, the
intake is probably adequate
because the RDA meets
the needs of almost all
people.
2. A usual intake that falls
between the RDA and the
EAR is more difficult to
assess; the intake may be
adequate, but the chances
are greater or equal that it
is inadequate.
3. If the usual intake falls
below the EAR, it is
probably inadequate.

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Establishing Energy
Recommendations
• Estimated Energy Requirement (EER)
• Average dietary energy intake to maintain energy
balance
• Healthy body weight
• Physical activity
• No upper level

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Acceptable Macronutrient
Distribution Ranges (AMDR)
• Adequate energy and nutrients
• Reduce risk of chronic diseases
• Ranges
• 45-65% kcalories from carbohydrate
• 20-35% kcalories from fat
• 10-35% kcalories from protein

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Using Nutrient
Recommendations
• Estimates apply to healthy people
• Needs adjusting for medical problems,
malnourishment, or other condition
• Recommendations – not minimum levels nor
optimal levels
• Goals intended to be met through diet
• Apply to average daily intakes
• Each DRI category serves a unique purpose

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Nutrition Assessment
• Deficiency or excess over
time leads to malnutrition
• Undernutrition and
overnutrition
• Symptoms of malnutrition
• Diarrhea
• Skin rashes
• Fatigue
• Others

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Creating a “Total Picture” of
the Individual
• Historical information
• Health status, SES, drug use
• Diet history – intake over several days; portion
sizes; computer analysis
• Anthropometric measurements
• Height and weight – track to identify trends
• Physical examinations
• Laboratory tests

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Stages in the Development of a
Nutrient Deficiency

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Nutrition Assessment of
Populations
• National nutrition surveys
• Conducted by various agencies
• One survey collects data on food
types and amounts
• Another collects data about people
themselves
• Oversample high-risk groups
• National health goals
• Healthy People program
• National trends

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Healthy People 2020 Nutrition
and Weight Status Objectives
• Increase the proportion of adults who are at a healthy weight
• Reduce the proportion of adults who are obese
• Reduce iron deficiency among young children and females of childbearing age
• Reduce iron deficiency among pregnant females
• Reduce the proportion of children and adolescents who are overweight or obese
• Increase the contribution of fruits to the diets of the population aged 2 years and older
• Increase the variety and contribution of vegetables to the diets of the population aged
2 years and older
• Increase the contribution of whole grains to the diets of the population aged 2 years
and older
• Reduce consumption of saturated fat in the population aged 2 years and older
• Reduce consumption of sodium in the population aged 2 years and older
• Increase consumption of calcium in the population aged 2 years and older
• Increase the proportion of worksites that offer nutrition or weight management classes
or counseling

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Healthy Weight Objectives
(Cont’d.)
• Increase the proportion of physician office visits that include counseling or education related
to nutrition or weight
• Eliminate very low food security among children in US households
• Prevent inappropriate weight gain in youth and adults
• Increase the proportion of primary care physicians who regularly measure the body mass
index of their patients
• Reduce consumption of kcalories from solid fats and added sugars in the population aged 2
years and older
• Increase the number of states that have state-level policies that incentivize food retail outlets
to provide foods that are encouraged by the Dietary Guidelines
• Increase the number of states with nutrition standards for foods and beverages provided to
preschool-aged children in childcare
• Increase the percentage of schools that offer nutritious foods and beverages outside of
school meals
NOTE: Nutrition and Weight Status is one of 38 topic areas, each with numerous objectives. Several of the
other topic areas have nutrition-related objectives, and these are presented in Appendix J.
SOURCE: www.healthypeople.gov

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Diet and Health
• Food plays vital role
in supporting health
• Chronic disease –
epidemic levels
• Multiple factors over
multiple years
Percentage of
Total Deaths
1. Heart disease 23.7
2. Cancers 22.9
3. Chronic lung diseases 5.7
4. Strokes 5.1
5. Accidents 4.9
6. Alzheimer's disease 3.4
7. Diabetes mellitus 2.9
8. Pneumonia and influenza 2.1
9. Kidney disease 1.8
10. Suicide 1.5
NOTE: The diseases highlighted in bold have relationships with
diet
SOURCE: Deaths: Preliminary data for 2011, National Vital
Statistics Reports. October 10, 2012. Centers for Disease Control
and Prevention, www.cdc.gov/nchs.

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Chronic Disease Risk Factors
• Risk factors
• Persist over time
• Cluster
• Prominence of risk
factors
• Tobacco
• Diet and activity
patterns
• Others
Factors Percentage of
Deaths
Tobacco 18
Poor diet/inactivity 15
Alcohol 4
Microbial agents 3
Toxic agents 2
Motor vehicles 2
Firearms 1
Sexual behavior <1
Illicit drugs <1
SOURCE: A. H. Mokdad and coauthors, Actual causes of death
in the United States. 2000. Journal of the American Medical
Association 291 (2004): 1238-1245, with corrections from
Journal of the American Medical Association 293 (2005): 298.

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Nutrition
Information and
Misinformation
Highlight 1

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Nutrition on the Internet
• Validity of information
• Who is providing information?
• Qualifications
• Internet
• Anyone can publish anything
• No guarantees of accuracy
• Evaluate websites
• Who, when, where, why, and what?

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Nutrition in the News
• News often tells lopsided story
• Testimonials
• Tight deadlines
• Limited understanding
• Current and controversial

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Identifying Nutrition Experts
• Physicians and other health-care
professionals
• Training in nutrition is limited
• Registered dietitian (RD)
• Degree and clinical internship
• National exam
• Maintain up-to-date knowledge
• Dietetic technician registered (DTR)

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Credentials
• Identifying fake credentials
• College accreditation
• Diploma mills
• Fraudulent businesses
• Red flags of nutrition
quackery
• Misinformation
• Consider the source
• Buyer beware

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Red Flags of Nutrition
Quackery