science of nutrition science study of nutrients in food how body uses nutrients

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