Y khoa, dược - Chapter 1: Food choices: nutrients and nourishment

Chapter 1 Food Choices: Nutrients and NourishmentThe Science of NutritionIdentifies amount of food we needRecommends best food sourcesIdentifies components in food that are helpful or harmfulHelps us make better choices Improves our healthReduces our risk of diseaseIncreases our longevityWhy Do We Eat the Way We Do?Personal PreferencesEnjoymentNourishmentAgeWhy Do We Eat the Way We Do?Sensory Influences: Taste, Texture, and SmellFlavorClassic tastes: Sweet, sour, bitter, salty, and umamiWhy Do We Eat the Way We Do?Social, Emotional, and cognitive InfluencesHabitsComfort/Discomfort FoodsAdvertising and PromotionEating Away from HomeFood and Diet TrendsSocial FactorsNutrition and Health BeliefsWhy Do We Eat the Way We Do?Environmental InfluencesEconomicsLifestyleAvailabilityCultural InfluencesReligionThe Social Ecological ModelThe American DietHow healthful is the “American” diet?Too few nutrient-dense foodsFruits, vegetables, low-fat dairy, and whole-grain foodsToo much of the foods known to be harmfulSodium, solid fat, saturated fat, and sugarIntroducing the NutrientsNutrientsFunctions Normal growth and developmentMaintaining cells and tissuesFuel to do physical and metabolic workRegulating body processesIntroducing the NutrientsNutrientsSix classes of nutrientsCarbohydratesLipids (fats and oils)ProteinsVitaminsMineralsWaterIntroducing the NutrientsDefinition of nutrientsAbsence from the diet results in a specific change in healthPutting the chemical back in the diet will reverse the change in healthNot only chemicals in foodPhytochemicalsAntioxidantsIntroducing the NutrientsClassifications of nutrientsMacronutrientsCarbohydrates, lipids, and proteinsMicronutrientsVitamins and mineralsOrganic (contain carbon)Carbohydrates, lipids, proteins, and vitaminsInorganicMinerals and waterIntroducing the NutrientsCarbohydratesSugars and starchesFunctionsEnergy sourceFood sourcesGrainsVegetablesLegumesFruitsDairy productsIntroducing the NutrientsLipidsTriglycerides (fats and oils), cholesterol, and phospholipidsFunctionsEnergy source, structure, regulationFood sourcesFats and oilsMeatsDairy productsSome plant sourcesIntroducing the NutrientsProteinsMade of amino acidsFunctionsEnergy source, structure, regulationFood sourcesMeatsDairy productsGrains, legumes, vegetablesIntroducing the NutrientsVitaminsFunctionsRegulate body processesPlay a vital role in extracting energyFat-solubleA, D, E, KWater-solubleB vitamins, vitamin CFood sourcesAll food groupsIntroducing the NutrientsMineralsMacromineralsMicrominerals, or trace mineralsFunctionsStructure, regulationFood sourcesAll food groupsIntroducing the NutrientsWaterMost important nutrientFunctionsTemperature controlLubrication of jointsTransportation of nutrients and wastesFood sourcesBeveragesFoodsIntroducing the NutrientsNutrients and energyEnergyThe capacity to do workEnergy sourcesCarbohydrates, lipids, proteinMeasure of energyKilocalorie1,000 calories = 1 kilocalorieIntroducing the NutrientsEnergy in foodsWhen is a kilocalorie a calorie?CalorieKilocalorieSpecific measurement or unit of energy in foodGeneral term for energy in foodIntroducing the NutrientsHow can we calculate the energy available from foods?Example 30 g carb × 4 kcal/g = 156 kcalories10 g protein × 4 kcal/g = 40 kcalories 16 g fat × 9 kcal/g = 144 kcalories TOTAL = 340 kcaloriesIntroducing the NutrientsEnergy in FoodBe Food Smart: Calculate the Percentages of Calories in Food Diet and HealthWhat does it mean to be healthy?WHO defines health as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity”Diet and HealthDisease is “an impairment of the normal state of the living animal that interrupts or modifies the performance of the vital functions”Food choices are most likely to affect our risk for developing chronic diseasesDiet and HealthPhysical activitySedentary lifestyleRisk factor for chronic diseaseRole in long-term weight managementAt least 30 minutes per day of moderate activityReduce chronic disease riskAt least 60 minutes per dayWeight-managementApplying the Scientific Process to NutritionThe Scientific Process enables researchers to test the validity of hypothesesHypothesis: Proposed explanation made on the basis of limited evidence as a starting point for further investigationUsed to expand our nutrition knowledgeApplying the Scientific Process to NutritionCommon study designsEpidemiological studiesAnimal and cell culture studiesCase control studiesClinical trialsRandomizedDouble-blindPlacebo-controlledSteps of the Scientific ProcessFrom Research Study to HeadlinePublishing experimental resultsScientists publish results of experiments in scientific journals to communicate new informationPeer review process reduces chance that low-quality research is publishedFrom Research Study to HeadlineSorting facts and fallacies in the mediaPopular media may distort facts through omission of detailsIn-depth research article becomes 30-second sound biteEvaluating Information on the InternetThere are no rules for posting on the InternetConsider the sourceKeep in mind the scientific methodBe on the lookout for “junk science”