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SCIENCE OF NUTRITION
Science
 Study of nutrients in food
 How body uses nutrients
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CAUSES OF DEATH
FACTORS
FOOD CHOICES
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Personal preference
Habit
Ethnic heritage or tradition
Social interaction
Availability, convenience
Positive, negative associations
Emotions
Values
Body weight and image
Nutrition
NUTRIENTS
Obtained from food
 Used in the body for:
> regulating growth
> maintaining body tissues
> repairing body tissues
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SIX CLASSES OF
NUTRIENTS
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CARBOHYDRATES…….4 CAL/GRAM
PROTEIN…………………4 CAL/GRAM
FAT……………………….9 CAL/GRAM
VITAMINS
MINERALS
WATER
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ALCOHOL = 7 CAL/GRAM
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ELEMENTS IN THE NUTRIENTS
EVALUATION OF NUTRITION
INFORMATION
WHO SAID IT
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Check credentials, background, educationdegree of reliability
RD, LD
BS focus on science
900 clinical hours
National registration exam
Licensure according to each state
Continuing education
MOTIVE?
Scientific truth
 Refereed journal
 Reputable Professional Journals
 Articles screened by panel of
experts/peers
 Sensationalism
 Profit
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WHAT IS EXPERIENCE?
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Human Nutrition?
Evidence Scientific studies
Testimonials NOT acceptable
Uncontrolled experiment NOT acceptable
Look at:
Placebo effect
Population studied
Blind, double blind, random,
BEWARE OF CLAIMS
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Poor diet claimed as cause of most
disease
Conspiracy of medical community
Normal foods are “bad”
Exaggerated promises
RESPONSIBILITY
Author?
 Publisher ?
 Editor?
 Bookstore owner?
READER IS RESPONSIBLE!!
THAT’S YOU!
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OBTAIN RELIABLE
INFORMATION
American Medical Association
 American Academy of Pediatrics
 American Dietetic Association
 American Heart Association
 American Cancer Society
 American Diabetes Association
 Dairy and Nutrition Council
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GOVERNMENT
Local Health Department
 Cooperative Extension Programs
 National Academy of Sciences
 FDA
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Role of Health Professional
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Examine evidence – risk vs benefits
Give best advice based on scientific
evidence
Don’t make promises
Food alone cannot make a person healthy
Keep open mind – update
Translate guidelines into food – what to
eat, what to limit
Dietary Reference Intakes
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DRI committee
Develops framework for recommendations
Set of nutrient intake values for HEALTHY
people in the US and Canada
Values are used for planning and assessing
diets
TERMS
DRI - TERMS
ESTIMATED AVERAGE
REQUIREMENT
Amount of nutrient that will maintain
specific biochemical or physiological
function in half the people of given
age and sex group
 Criteria for each nutrient based on
the role it performs – used to set RDA
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RECOMMENDED DIETARY
ALLOWANCES
Recommended intake – NOT
required, NOT minimum
 Standards for good nutrition
 Average daily amount of nutrient
considered adequate to meet
known nutrient needs of all
HEALTHY PEOPLE
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RDAs
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Designed for groups
Most nutrient levels higher than
average
Divided into age groups, gender after
age 10
USES OF RDAs
Assess adequacy of diets
 Plan diets for groups
 Standard to evaluate nutritional
status
 Most appropriate for populations –
individuals over a period of time
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SETTING RDAs
ENERGY RDA
NAÏVE VS ACCURATE VIEW
RDAs - LIMITATIONS
No RDA for every nutrient
 Food analyses differ
 Not user friendly for public
 No data for fiber, cholesterol, fat
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ADEQUATE INTAKE
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Average amount of a nutrient that
appears sufficient to maintain a specific
criterion
Insufficient scientific data to establish
EAR
Tolerable Upper Intake Levels
Maximum daily amount of a nutrient
that appears safe for most healthy
people
 Above this level may be toxic
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Dietary Guidelines 2005
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Adequate nutrients within calorie
need
Weight management
Physical activity
Food groups to encourage
Fats
Carbohydrates
Sodium and potassium
Alcoholic beverages
Food safety
KEY RECOMMENDATIONS
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Within each category
recommendations for specific
populations
FOOD GUIDE PYRAMID
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Visual representation of USDAs
Dietary Guidelines
Number of servings that are right for
you depends on how many calories
you need  age, gender, size, activity
2005 PYRAMID
Food Composition Tables
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Average nutrient values based on lab
analysis of food samples
Advantages; convenient, cheap, available
NUTRIENT DENSITY
Disadvantage:
Limited data
Uncommon or ethnic foods not included
BIOAVAILABILITY – in a form body can
use or available for use
NUTRIENT DENSITY
DIET BASICS
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Variety
Moderation
Balance of intake and output
Guidelines for fat and carbohydrate
Below 1200 calories – can’t supply
adequate micronutrients
Below 45 grams of protein – can’t supply
essential amino acids
Food Labels
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Daily values- based on 2000 calories and
current nutrition recommendations
Fat = <30% of total calories
Saturated Fat = <10% of total calories
CHO = 55-60% of total calories
Pro = 10 – 15% of total calories
Fiber = 12 grams/ 1000 calories
Food Labels - Continued
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Maximums :
Total Fat
Saturated Fat
Cholesterol
Sodium
Minimums
Total Carbohydrates
Fiber
DAILY VALUES
To show how a food fits into daily
pattern
 Percent of nutrient or food component
 2000 calories for women, children up
to age 11, and older adults
 2500 calories for men, pregnant
women, children over 11 years of age
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DAILY VALUES
Watch total fat intake
 Calories from fat / total kcals = if
more than 30% or 1/3 “WARNING”
 Required nutrients: vitamins A & C,
Minerals: iron and calcium
 Do DRVs apply to everyone?
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APPROVED CLAIMS
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Calcium and osteoporosis
Fats and cancer
Saturated fats, cholesterol and heart disease
Fiber containing fruits, vegetables, and grains and
cancer
Sodium and hypertension
Fruits and vegetables and cancer
Folate or folic acid and neural tube defects
Oat bran or oatmeal and reduced risk of heart
disease
FOOD LABELS
Mandatory vs voluntary statements
on the label
 Definition of terms
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LABEL DEFINITIONS
LABEL DEFINITIONS
Food Patterns
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Food energy: 3500 cals (1909) 3800
cals (1994) /capita/day
Carbohydrates:
> Percent of cals 57% (1909)52%
(1994)
> Drop in use of grains and white
potatoes
> Per capita consumption of sweeteners
steadily increasing (aspartame ^ in
1981)
Eating Patterns
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Protein:
> Sources changed – animal and plant
equal in 1909, animal sources in 1994
> Red meat down, poultry up, fish up
slightly
> Shell egg consumption down used in
pastas, etc
> Use of dairy products down
Eating Patterns
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Fat:
> Percent of calories:
32% in 190936% (1989)38%(1994)
> Shift from animal to vegetable fat sources
> Marked increase in low-fat and nonfat
milk (54% decline in whole milk)
Vitamins – per capita consumption above
RDA for A, C, E, thiamin, riboflavin, niacin,
B6, B12, folate
Calcium-Levels peaked in 1946, still below
RDA