science of nutrition science study of nutrients in food how body uses nutrients
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SCIENCE OF NUTRITIONSCIENCE OF NUTRITION
ScienceStudy of nutrients in foodHow body uses nutrients
CAUSES OF DEATHCAUSES OF DEATH
FACTORSFACTORS
FOOD CHOICESFOOD CHOICES Personal preference Habit Ethnic heritage or tradition Social interaction Availability, convenience Positive, negative associations Emotions Values Body weight and image Nutrition
NUTRIENTSNUTRIENTS
Obtained from foodUsed in the body for: > regulating growth > maintaining body tissues > repairing body tissues
SIX CLASSES OF NUTRIENTSSIX CLASSES OF NUTRIENTS
CARBOHYDRATES…….4 CAL/GRAM PROTEIN…………………4 CAL/GRAM FAT……………………….9 CAL/GRAM VITAMINS MINERALS WATER
ALCOHOL = 7 CAL/GRAM
ELEMENTS IN THE NUTRIENTSELEMENTS IN THE NUTRIENTS
EVALUATION OF NUTRITION EVALUATION OF NUTRITION INFORMATIONINFORMATION
WHO SAID ITWHO SAID IT Check credentials, background, education-
degree of reliability RD, LD BS focus on science 900 clinical hours National registration exam Licensure according to each state Continuing education
MOTIVE?MOTIVE?
Scientific truth Refereed journal Reputable Professional Journals Articles screened by panel of
experts/peers Sensationalism Profit
WHAT IS EXPERIENCE?WHAT IS EXPERIENCE?
Human Nutrition? Evidence Scientific studies Testimonials NOT acceptable Uncontrolled experiment NOT acceptable Look at: Placebo effect Population studied Blind, double blind, random,
BEWARE OF CLAIMSBEWARE OF CLAIMS
Poor diet claimed as cause of most disease Conspiracy of medical community Normal foods are “bad” Exaggerated promises
RESPONSIBILITYRESPONSIBILITY
Author?Publisher ?Editor?Bookstore owner? READER IS RESPONSIBLE!! THAT’S YOU!
OBTAIN RELIABLE OBTAIN RELIABLE INFORMATIONINFORMATION
American Medical AssociationAmerican Academy of PediatricsAmerican Dietetic AssociationAmerican Heart AssociationAmerican Cancer SocietyAmerican Diabetes AssociationDairy and Nutrition Council
GOVERNMENTGOVERNMENT
Local Health DepartmentCooperative Extension ProgramsNational Academy of SciencesFDA
Role of Health ProfessionalRole of Health Professional
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 IntakesDietary Reference Intakes
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
TERMSTERMS
DRI - TERMSDRI - TERMS
ESTIMATED AVERAGE ESTIMATED AVERAGE REQUIREMENTREQUIREMENT
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
RECOMMENDED DIETARY RECOMMENDED DIETARY ALLOWANCESALLOWANCES
Recommended intake – NOT required, NOT minimum
Standards for good nutritionAverage daily amount of nutrient
considered adequate to meet known nutrient needs of all HEALTHY PEOPLE
RDAsRDAs
Designed for groups Most nutrient levels higher than
average Divided into age groups, gender after
age 10
USES OF RDAsUSES OF RDAs
Assess adequacy of dietsPlan diets for groupsStandard to evaluate nutritional
statusMost appropriate for populations –
individuals over a period of time
SETTING RDAsSETTING RDAs
ENERGY RDAENERGY RDA
NAÏVE VS ACCURATE VIEWNAÏVE VS ACCURATE VIEW
RDAs - LIMITATIONSRDAs - LIMITATIONS
No RDA for every nutrientFood analyses differNot user friendly for publicNo data for fiber, cholesterol, fat
ADEQUATE INTAKEADEQUATE INTAKE
Average amount of a nutrient that appears sufficient to maintain a specific criterion
Insufficient scientific data to establish EAR
Tolerable Upper Intake LevelsTolerable Upper Intake Levels
Maximum daily amount of a nutrient that appears safe for most healthy people
Above this level may be toxic
Dietary Guidelines 2005Dietary Guidelines 2005
Adequate nutrients within calorie need Weight management Physical activity Food groups to encourage Fats Carbohydrates Sodium and potassium Alcoholic beverages Food safety
KEY RECOMMENDATIONSKEY RECOMMENDATIONS
Within each category recommendations for specific populations
FOOD GUIDE PYRAMIDFOOD GUIDE PYRAMID
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 PYRAMID2005 PYRAMID
Food Composition TablesFood Composition Tables
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 DENSITYNUTRIENT DENSITY
DIET BASICSDIET BASICS
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 LabelsFood Labels
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 - ContinuedFood Labels - Continued
Maximums : Total Fat Saturated Fat Cholesterol Sodium Minimums Total Carbohydrates Fiber
DAILY VALUESDAILY VALUES
To show how a food fits into daily pattern
Percent of nutrient or food component2000 calories for women, children up
to age 11, and older adults2500 calories for men, pregnant
women, children over 11 years of age
DAILY VALUESDAILY VALUES
Watch total fat intakeCalories from fat / total kcals = if
more than 30% or 1/3 “WARNING”Required nutrients: vitamins A & C,
Minerals: iron and calciumDo DRVs apply to everyone?
APPROVED CLAIMSAPPROVED CLAIMS
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 LABELSFOOD LABELS
Mandatory vs voluntary statements on the label
Definition of terms
LABEL DEFINITIONSLABEL DEFINITIONS
LABEL DEFINITIONSLABEL DEFINITIONS
Food PatternsFood Patterns 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 PatternsEating Patterns 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 PatternsEating Patterns
Fat: > Percent of calories: 32% in 190936% (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