Transcript Chapter 1

Introduction to Human
Nutrition
Course Web Page
Real Hope for Haiti –
Clinic for Malnourished
Children
Chapter Outline
 Nutrition
defined
 Classifying the nutrients
 Nutritional research – now in CH 2
 Nutrition and health

Healthy People 2020 goals
 Factors

impacting food choices
Small group exercise
Nutritional Goals
 Quality
intake that allows you to
function at your best and promotes
health.

Intake that provides adequate levels of each
nutrient
 Quantity
of intake that promotes a healthy
body weight.
Nutrition Defined
– the science of foods and
the nutrients they contain
 Nutrition
 Study


the:
action of foods and the nutrients in the body
relationship between diet and health
Nutrition Defined
 Actions

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
in the body include:
Ingestion
Digestion
Absorption
Transport
Metabolism
Excretion
What’s Considered Food?
 Foods
contain nutrients and are
derived from plant or animal sources
 Nutrients
are used by the body to
provide energy and to support
growth, maintenance and repair of
body tissues

~ 40 nutrients identified at this time
Classifying Nutrients (1.3)
There are 6 Classes of Nutrients
1.
2.
3.
4.
5.
6.
Carbohydrates
Lipids (fats)
Proteins
Vitamins
Minerals
Water
Body Composition
Describing the Nutrients
 There
are several ways to classify the
classes of nutrients.
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Essential or nonessential
Organic or inorganic
Macronutrient or micronutrient
Energy yielding or not
Classifying Nutrients
nutrients – nutrients the body
either cannot make or cannot make
enough of to meet its needs.
 Essential


These nutrients must be obtained from foods
(ingested in some manner)
Examples:
• Vitamins
• Calcium, iron, and other minerals
• Some of the amino acids
Essential Nutrients
 To



be classified as an essential nutrient:
The biological function of nutrient is known
Omission from the diet leads to a decline in a
biological function
Return of the nutrient restores the biological
function
Classifying Nutrients
nutrients – body can make
from other nutrients ingested
 Nonessential
 Examples:
• Cholesterol
• Some amino acids
Classifying Nutrients by
Composition
 Organic
nutrients - contain carbon
• Carbohydrates
• Lipids
• Proteins
• Vitamins
 Inorganic
nutrients - do not contain
carbon
• Minerals
• Water
Quantity Needed
 Macronutrients:
need in relatively large
amounts

Carbohydrates, lipids, proteins
 Micronutrients:
need in relatively small
amounts

All other nutrients
Classifying Nutrients
 Energy-yielding
nutrients (3):
Carbohydrates
 Fats (lipids)
 Proteins
 Where does the energy come from?

A little more on energy
 Measure


energy in kilocalories in U.S.
What most think of as a “calorie” is really a
kilocalorie
Kcal = amount of energy needed to raise the
temperature of 1 kg of water by 10C
 Measure
energy in kilojoules (kJ) in most
other countries
Energy in the Body
 The
body uses the energy yielding
nutrients to fuel all activities

 If
All energy yielding nutrients are “caloric”.
more energy is ingested than is needed
to fuel body activities the extra energy is
stored as _________ and ________
occurs.
Energy-Yielding
Nutrients
Energy-Yielding Nutrients
 Carbohydrates:
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C, H, O
4 kcal/gram
Body’s primary source of energy
• Use as glucose
• Glucose is the brain’s only source of energy

Carbohydrate stores are limited ~12-24 hours
(in liver and muscle)
Classes of Carbohydrates
 Simple
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sugars
Monosaccharides and disaccharides
 Complex


carbohydrates
Starch
Fibers
 Carbohydrate
rich foods……..
Lipids
 Lipids


– fats and oils: C, H, O
9 kcal/gram
Body’s alternate source of energy
• Use fat along with glucose as an energy source
most of the time

Stores are unlimited
Types of Lipids
– solids
 Oils – liquids
 Saturated (solids/fats)
 Fats

No carbon to carbon double bonds
 Unsaturated

(liquids/oils)
Carbon to carbon double bond(s) present
 Lipid
rich foods?
Proteins
 Proteins:
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C, H, O, N, S
4 kcal/gram (same as _______)
Body’s least desirable source of energy
• WHY? …….
Protein is used for energy only when
carbohydrate is NOT available as an energy
source.
Protein rich foods?
Energy-Yielding Non-nutrient
 Alcohol
– 7 kcal/gram
 Non-nutrient
because it interferes with
growth, maintenance and repair of the
body
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Alcohol’s metabolites are harmful
No required functions in the body
Energy Density
 Measure
of the kcal per gram of food
 _______ has the highest energy density of
the 3 energy-yielding nutrients.
 Foods
with a high energy density provide
more kcal per gram than low density
foods.
Energy Density
Evaluating a Food Label
 _____
grams carbohydrate
 _____
grams fat
 _____
grams protein
 TOTAL
KCAL:
____________
6 Classes of Nutrients
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•
•
•
Carbohydrates
Lipids (fats and oils)
Proteins
Vitamins
Minerals
Water
Vitamins
 Essential
 Organic,
micronutrient
 Not energy-yielding
 Can be water-soluble or fat-soluble
Examples:
Minerals
 Essential
 Inorganic,
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
micronutrient
Major minerals: Ca, P, Na
Trace minerals: Fe, Zn
 Not
energy-yielding
 Indestructible
Water
 Water
(H2O)

Essential
Organic or inorganic?
Noncaloric

We are ~60% water

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Not everyone has access to clean water
The Science of Nutrition
 One

of the newest sciences
New branch is nutritional genomics
• Study of the interaction of nutrients with
DNA/genes and how those genes impact health
 Like
all sciences, nutrition is based on
scientific research
 Skip
to slide 53 – Nutrition and health
Scientific Method
1.
2.
3.
4.
5.
Observations  Questions
Hypotheses  Predictions
Test hypotheses/predictions
Analyze data and draw conclusions
Share results
Observations and Questions
 Make
observations about diet and health.
These observations lead to questions
For example:


The incidence of breast cancer is much lower
in Japan than in the U.S.
Diet in Japan is rich in…..while in U.S. diet is
rich in ……
 Question?:
Develop Hypotheses and Make
Predictions
– tentative explanation of the
observations or answer to the question
 Hypothesis
prediction – If the hypothesis is
true what else is true?
 Make
Experiments
 Conduct
experiments to test the
predictions
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Easier said than done when people are
involved!
We’ll consider research designs later/soon.
One Experimental Design
 When
possible, randomly assign subjects
to either a control of experimental group
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Goal is for two groups to be as similar to each
other as possible
Control Group – either no change to diet or
given a placebo
Experimental group – diet changed or given
a supplement
Experimental Design
 Compare
the health/lab values of the two
groups before and after the diet change.

Example – DASH diet study
Analyze results…
 Analyze
results
 Draw conclusions about the validity of the
hypothesis
 Test alternate hypotheses
 Share findings


Publish in nutritional journals
Present findings at conferences
Common Research Designs
Epidemiological study (observe)
1.
Cross-sectional
Longitudinal
Case-control study
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Experimental (intervene)
2.
Animal studies
Human clinical trials
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•
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Double blind study
Lab studies
The Science of Nutrition
1. Epidemiological studies
• Study of populations
• Look for correlations between dietary
practices and health
• Nurses Health Study
Epidemiological Studies
Cross-sectional - look for correlations
between diet and health at a point in time
Longitudinal Studies - Follow a group of
people (a cohort) over a period of time
• Look for differences in diet that might
account for the differences in health
Epidemiological Studies
study – compare the diet of
individuals with a condition to that of
healthy individuals
 Case-control

Again, do not change their diet…..just
observe it.
Human Experimental Studies
Often called a Clinical Study
• Randomly assign like people to either the
experimental or control group
• Alter the diet of experimental group as
compared to a control group
• Compare incidence of disease/lab values/
performance …. of two groups
Types of Clinical Trials
 Blind
experiments
• Subjects do not know which group they are
in
 Double
blind experiments
• Neither subjects nor the researchers know
which group the subjects are in until after
the experiment is over
• Goal is to avoid bias in the reporting/recording of
the data.
Experimental Studies
Animal Studies
• Controlled studies in lab setting using
animals
• Alter diet of experimental group
• Compare health/lab values of control and
experimental groups
• Benefits? ….
• Drawbacks? ……
Experimental Studies
Lab-Based Studies
•
•
Also called in vitro studies
Examine impact of a substance on living tissue in
a “test tube”
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The Science of Nutrition
Size matters
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Good studies have relatively large sample
sizes
Preliminary studies have smaller sample
sizes
Peer review matters


Information in peer- reviewed research
journals is much more credible than that in
popular magazines, TV, Internet
Diet and Health
 Diet
- the foods one consumes
•The quality of your daily diet
affects the risk of chronic
diseases

Meaning…..The food choices you
make daily have a cumulative
impact on your health
Nutrition and Health
 Chronic
health issues associated with diet
include:
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Heart disease
Hypertension
Obesity
Type II Diabetes
Osteoporosis
Improving your Health
 Goal
is to reduce the number of risk
factors that are in your control

Risk factor = something that statistically
increases the incidence of a disease
• Risk factors may not be the cause of the disease
Leading Causes Death - US
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Heart disease: 616,067
Cancer: 562,875
Stroke: 135,952
Chronic respiratory diseases: 127,924
Accidents (unintentional injuries): 123,706
Alzheimer's disease: 74,632
Diabetes: 71,382
Influenza and Pneumonia: 52,717
Kidney disease: 46,448
Septicemia: 34,828
CDC, 2009
Leading Causes Death - US
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Heart disease: 596,577
Cancer: 576,691
Chronic lower respiratory diseases: 142,943
Stroke (cerebrovascular diseases): 128,932
Accidents (unintentional injuries): 126,438
Alzheimer's disease: 84,974
Diabetes: 73,831
Influenza and Pneumonia: 53,826
Kidney disease: 45,591
Intentional self-harm (suicide): 39,518
CDC, 2010 data
Improving Health
 Risk
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factors in your control:
Smoking
Alcohol intake
Over-consumption of calories
Physical inactivity
Poor quality diet
Improving Health
 Risk
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factors you cannot control:
Age
Gender
Genetics (family history)
Ethnicity
Maine Data
 27%

report NO physical activity
1 in 5 engage in moderate physical activity ~5
days/week
 74%
do NOT eat 5 servings of fruits and
vegetables daily
 28.9%
of Maine adults are obese (2013)
Healthy People 2020
 Americans

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with a healthful diet:
Consume a variety of nutrient-dense foods
within and across the food groups, especially:
• whole grains, fruits, vegetables, low-fat or
fat-free milk or milk products, and lean
meats and other protein sources.
Limit the intake of saturated and trans fats,
cholesterol, added sugars, sodium (salt), and
alcohol.
Healthy People 2020
 Limit

caloric intake to meet caloric needs.
All Americans should avoid unhealthy weight
gain, and those whose weight is too high may
also need to lose weight
Food Choices
 Small



group exercise
What influences your food choices each day?
Why do you eat what you eat?
Get into groups of ~4 and make a list of what
impacts your food choices most days.
• Turn this list in next time we meet.
Food Choices – Text Answers
1.
2.
3.
4.
5.
6.
7.
Personal
preferences
Habit
Ethnic heritage
Tradition
Social interactions or
pressure
Availability
Convenience
Economy $
9. Positive or negative
associations
10. Emotional Comfort
11. Values -Religious,
8.
political, environmental
Health concerns
13. Nutritional value
12.