The Science of Nutrition1. What is the definition of nutrition?The study of the nutrients in foods and the body, also the human behaviors related to food2. Why is nutrition classified as a science?It uses the scientific method to uncover unknown nutrition factsNew findings must be repeated before they can be considered validNew findings must withstand the test of time3. What are the four types of study designs that we discussed? What are the strengths and limitations of each? What type of study is considered the “gold standard” in terms of proving cause and effect?Case StudyAbout an individual—a report on that individual’s “case”Good for clinical teaching and advertisements and “observations”Not good for statistics—too small numberNot good for scientific studiesEpidemiological StudyInvolve large population groupsEx. Nations, ethnicity, genderRelate various things but do not prove cause and effectGood for statistics because of large population numberCohort StudyA type of epidemiological studyInvolve groups with something in common (sub-population)Ex. Similar religion (7th Day Adventist; vegetarians), similar profession (doctor, nurse), similar age group (Baltimore Longitudinal Aging Study)Relate various things but do not prove cause and effectMay be good for statistics depending on size of sub-groupFollow over long time periodIntervention StudyExperimental design in which you change nutritional intake or lifestyle (has a control without change and experimental group with change)Ex. Smokers are given no beta carotene/Vitamin A or supplemental beta carotene/Vitamin A (smokers who took supplements developed more cancer than those who did not)Strong design to test cause and effect because of comparison of change/intervention to no change/interventionCan be clinical type of intervention (therapeutic)Limited in what you can test in humans (blood, urine, clinical tests, body composition)Laboratory StudyUse animals or humansMost common animal used is rat, pig, or primate because of similarities to humansStrong design to test mechanisms for exact cause and effectIn animal studies, results may be limited in the application to humansIntervention Study is known as the “gold standard”Food Choices and Human Health1. What is the difference between hunger and appetite?Hunger- “have to”, physiological responseAppetite- “want to”, psycho-social response2. What are some mechanisms that the body has to regulate hunger?HypothalamusSatiety center in the brainProcesses nerve signals from throughout the bodyHormones/Brain ChemicalsCortisol from adrenal glands (stress hormone)Leptin from adipose (fat) tissueNeuropeptide Y from hypothalamusComposition of MealsDietary fiber and water more fillingStomach expansion3. What factors affect our appetite?Stress, habit, special occasions, social norms4. Describe the four influences on food availability.Natural EnvironmentClimateTopography of landRainfallTechnologyFarming practicesFood storage (e.g. freezing, refrigeration, dehydration)AdvertisingFood processingEconomics“Cash crops” versus food for family consumptionIncomeDemandPopulationSizeStructure5. What are the six classes of nutrients?ProteinsCarbohydratesLipids (fats)VitaminsMineralsWater6. How many calories per gram are there in carbohydrates, fat and protein? Which is the most concentrated source of calories?Protein- 4kcal/gramCarbohydrates- 4kcal/gramLipids- 9kcal/gramLipids is the most concentrated source of calories7. If you consumed a meal containing 100 grams of carbohydrate, 25 grams of fat and 15 grams of protein, how many calories did you consume?Carbohydrates: 100g x 4g = 400 kcalFat: 25g x 9g = 225 kcalProtein: 15g x 4g = 60 kcal400 kcal + 225 kcal + 60 kcal = 685 kcal8. It is recommended that no more than 35% of your calories come from fat. If your calorie needs at 2200 kcal/day, how many grams of fat should you consume?2200 kcal x .35 = 770770/9 = 85.56 g9. What is the difference between micronutrients and macronutrients? Which nutrients are micronutrients and which are macronutrients?Micronutrients- need in larger amountsProtein, Carbohydrates, Lipids (grams)Macronutrients- need in smaller amountsVitamins, minerals (milligrams, micrograms)10. What are phytochemicals?Foods that contain beneficial, non-nutrients11. What are the characteristics of a nutritious diet?AdequacyBalanceModerationVarietyCalorie control12. What is meant by the term “nutrient density”?Nutrient Content/Kilocalorie Content“Choose your calories by the company they keep”Guidelines1. What are the three tools for diet evaluation produced by the US government? What is the purpose of each?Dietary Guidelines for AmericansFood Guide PyramidDRI’s2. What is the recommended macronutrient breakdown of the diet?Total Fat 20-35% of kcalLess than 10% saturated fatLess than 300 mg cholesterolCHO 45-65% of kcalProtein 10-35% of kcal3. How much sodium should one consume each day? How much cholesterol?Sodium- less than 2300 mg (approximately 1 tsp)Cholesterol- less than 300 mg4. How does the food guide pyramid represent the concepts of activity, adequacy, personalization, proportionality, variety and gradual improvement?All foods can fit into a healthy diet in certain amounts5. What are discretionary calories?“Energy allowance”Gain energy allowance by eating or inducing proper the food; the proper food is for the specific action you will be taking6. Give examples of serving sizes for three foods in each of the Food Guide Pyramid categories.Bread, cereal, rice and pasta3-8 ounce equivalents1 slice of bread1 ounce of ready-to-eat cereal½ cup of cooked cereal, rice, or pastaVegetables1-3 cups2 cup of raw leafy vegetablesFruit1-2 cups1 medium apple, banana, or orange½ cup of chopped, cooked, or canned fruit¾ cup of fruit juiceMeat, poultry, fish, dry beans, eggs, and nuts2-6 ½ ounces1 ounce of cooked lean meat, poultry, or fish1 egg1.2 ounce nuts or tablespoon of peanut butter7. What is the difference between a serving and a portion?Serving- a unit of measurePortion- amount of food actually served or consumed8. Define the following terms: DRI, RDA, EAL (EAR?), UL, AI.DRI- Dietary Reference IntakesAn umbrella term for RDA (97.5% population), EAR (middle of the curve, average mean of the population), AI, and ULRecommended intakes of specific nutrients to prevent deficiency and chronic diseaseRDA- Recommended Dietary AllowancesLevels of nutrient intake adequate to meet needs of nearly all healthy
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