What is Nutrition?
All foods, the physical and chemical process by which food is converted into body tissue. The scientific study of food and drink (especially in humans). Materials brought in from the external environment of an organism that can be used for growth and regenerational purposes.
Where do we get nutrients?
Food
Supplements
Meal replacements
What are the classes of nutrients?
Carbohydrates Fats Proteins
Vitamins
Minerals
Water Which nutrients provide energy?
Carbohydrates
CH2O 4 kcal/gram
Protein
Amino acids Essential, nonessential
4 kcal/gram
Lipids
Glycerol + fatty acids
9 kcal/gram
Why is energy balance important?
BMI equals a person's weight in kilograms divided by height in meters squared. (BMI=kg/m2).
Transformation of Energy
To build new compounds For muscular movements For nerve transmissions For ion balance
What units are used to measure energy content of nutrients?
Calorie kilocalorie
On nutrition labels Calories= kilocalories
Energy Yielding Nutrients
CHO: 4 kcal/gm Protein: 4 kcal/gm Fat: 9 kcal/gm (Alcohol: 7 kcal/gm) Adjusted for digestibility Accounts for substances (in food) not available for energy use
Sample Calculation of a Nutrition Label
Per serving
CHO: 15g x 4 kcal/g = 60 kcal PRO: 3g x 4 kcal/g = 12 kcal FAT: 1g x 9 kcal/g = 9 kcal TOTAL: 81 kcal, rounded down to 80
Calculation of Contribution to Total kcals
Assume one day’s intake is 1980 kcal 290 gm of CHO (x 4 kcal/gm) 60 gm of fat (x 9 kcal/gm) 70 gm of protein (x 4 kcal/gm) % of kcal as CHO= (290 x 4)/1980 = 0.59 or 59% % of kcal as Fat= (60 x 9)/1980 = 0.27 or 27% % of kcal as PRO= (70 x 4)/1980 = 0.14 or 14%
What are vitamins and minerals?
Classification of vitamins Functions of vitamins Sources of vitamins
What are essential nutrients?
Vitamins
Composed of various elements Vital to life Needed in tiny amounts Cooking loss Fat soluble Water soluble Yields no energy
Minerals
Inorganic substances Needed in tiny amounts Not destroyed in cooking Trace minerals Major minerals Yields no energy
Why is water important?
Solvent and lubricant Transport nutrients and waste
Temperature regulation
History of Nutrition
It is a combination of physiology, chemistry, and medicine Nutrient can treat conditions Nutritional deficiencies and diseases Identification of vitamins and 45 essential nutrients
Why is the history of nutrition important?
How is nutrition studied?
Review the scientific method Example questions in nutrition
How much calcium does a 45 year old woman need to maintain bone density? There is a higher rate of diabetes in obese people. Does obesity cause diabetes? Does a vegetarian diet provide all the essential amino acids?
What types of methods could we use?
Historical observation Epidemiology Animal models Human studies
What are controls? What is the placebo effect?
Data Collection
Surveys Continuing Survey or Food Intake by Individuals (CSFII) National Health and Nutrition Examination Survey (NHANES)
Who are the experts in nutrition?
American Dietetic Association
Registered Dietitian Food and Nutrition Board Appendix K
How would you rate these sources of information? Why? Food label Government web page/brochure University web page Personal web page Company web page Organization web page Review pages 26 & 27
Facts vs. Fiction
Inconsistencies Reliable references? Use of testimonials Lack of evidence List of good and bad foods Dramatic results; too good to be true Reputable journals?
Tools For Healthy Eating
Daily Reference Intake (DRI)
New nutrient recommendations Nutrient recommendations to prevent chronic diseases DRI set for all vitamins and minerals In the plans macronutrients, electrolytes, water and other components
Standards Under the DRI
Est. Ave. Requirements (EARs)
RDAs
Daily Ref. Intake
Adequate Intake (AIs)
Tolerable Upper Intake Levels (ULs)
Estimated Average Requirements
intake estimated to meet the needs of 50% of the individuals in a certain age and gender group Uses a measurable marker Used to evaluate the adequacy of diets of a group
Nutrient
The Recommended Dietary Allowances
“Recommended intakes of nutrients that meet the needs of almost all healthy people of similar age and gender”---- the Food and Nutrition
Board of the National Academy of Sciences
RDA
Based on EARS (RDA=EAR x 1.2) RDA for only 19 of the important nutrients Amount to prevent deficiency and chronic diseases RDA for healthy males and females of various age groups RDA for pregnant and lactating women RDAs, by definition, are generous allowances
RDA
Improvement in health is not expected if consume more than the RDA amounts Goal is to eat close to the RDA level Short term deficiencies appear harmless Eating less regularly, the greater your risk of a nutritional deficiency
Adequate Intakes
Not enough information available Based on observed or experimentally determined estimates Set for some vitamins, choline, some minerals, essential fatty acids, fiber Planned for children under the age of 1
Tolerable Upper Intake Levels
level of daily intake without causing adverse health effects Chronic daily use Not a goal, but a ceiling
Maximum
Uses for the DRIs
planning Aim for RDA or AI Do not exceed the UL For the healthy population
Diet
Content Review
is the Daily Reference Intake? What standards are used in the DRIs? Do these standards take age and gender into consideration?
What
RDA’s
Dietary Reference Intakes DRI AI’s Vitamins D,K Pantothenate Biotin Choline
Vitamins A,C E, B12 Thiamine Riboflavin Niacin Folate
Minerals Cu,I,Mg,Mo,P,Se,Z
Energy and Building blocks
Minerals Ca,Cr,F,Mn,
Energy and
Building blocks
Fiber, Fat, Linoleic acid
Carbohydrate,Proteins
How do you use intake recommendations?
Dietary planning
Variety
Moderation
Nutrient density
Soda versus Milk
Lettuce versus chocolate chip cookie
Energy Density
Topics to review on your own
What are the standards for nutrition? Who sets the standards for nutrition?
Bring answers to class on Thursday Work on Chemistry homework