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SCIENCE OF NUTRITION Science Study of nutrients in food How body uses nutrients CAUSES OF DEATH FACTORS FOOD CHOICES 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 SIX 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 NUTRIENTS EVALUATION OF NUTRITION INFORMATION WHO SAID IT 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 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 CLAIMS 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! 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 GOVERNMENT Local Health Department Cooperative Extension Programs National Academy of Sciences FDA Role 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 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 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 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 RDAs 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 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 ADEQUATE INTAKE 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 Dietary 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 RECOMMENDATIONS Within each category recommendations for specific populations FOOD 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 PYRAMID Food 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 DENSITY DIET 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 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 - Continued 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 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? APPROVED 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 LABELS Mandatory vs voluntary statements on the label Definition of terms LABEL DEFINITIONS LABEL DEFINITIONS Food 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 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 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