食品营养与安全1-8章要点 (2)

Chapter 1 Food Choices And Human HealthFood: medically, any substance that the body can take in and assimilate that will enable it to stay alive and to grow, the carrier of nourishment;socially, a more limited number of such substances defined as acceptable by each culture. Diet: the food (including beverages) a person usually eats and drinks.Nutrition: the study of the nutrients in foods and in the body; sometimes also the study of human behaviors related of food.Nutrients: components of food that are indispensable to the body’s functioning. They provide energy, serve as building material, help maintain or repair body parts, and support growth. Nutrition profoundly affects health: malnutrition营养失衡and chronic diseases. Malnutrition: any condition caused by excess or deficient food energy or nutrient intake or by an imbalance of nutrients.The nutrients include water, carbohydrate, fat, protein, vitamins and minerals.Food supplies energy and nutrients. The most vital nutrient is water. The energy-yielding nutrients are carbohydrates, fats (lipids), and protein. The helper nutrients are vitamins and minerals.Q:What exactly is a nutritious diet?Adequacy: the food provide enough of each essential nutrient, fiber, and energy.Calorie control: the foods provide the amount of energy you need to maintain appropriate weigh ——not more, not less.Moderation: the food do not provide excess fat, salt, sugar, or other unwanted constituents. Variety: the foods chosen differ from one day to the next.Balance: the choices do not overemphasize one nutrient or food type at the expense of another.Chapter2 Nutrition Tools——Standards and Guidelines Recommended Dietary Allowances (RDA) was used in U.S. and Recommended Nutrient Intakes (RNI) was used in Canada.Today, both of these standards are being replaced by the Dietary Reference Intakes (DRI)膳食参考摄入量包括以下四个方面：EAR: Estimated Average Requirement膳食推荐允许量RDA: Recommended Dietary Allowances 预计平均需要量AI: Adequate Intakes适宜摄入量UL: Tolerable Upper Intake Levels可耐受最高摄入量EAR, RDA, AI, UL；How do they differ?Recommended Dietary Allowances(RDA) ：Nutrient intake goals for individuals; the average daily nutrient intake level that meet the needs of nearly all (97 to 98 percent) healthy people in a particular life stage and gender group.Estimated Average Requirement（EAR）：The average daily nutrient intake estimated to meet the requirement of half of the healthy individuals in a particular life stage and gender group; Adequate Intakes （AI）：Nutrient intake goals for individuals; the recommended average daily nutrient intake level based on intakes of healthy people (observed or experimentally derived) in a particular life stage and gender group and assumed to be adequate.Tolerable Upper Intake Levels （UL）：The highest average daily nutrient intake level that is likely to pose no risk of toxicity to almost all healthy individuals of a particular life stage and gendergroup.Q1:Why can’t nutrient advice be kept simple?Setting intake recommendation for individualsPreventing chronic diseasesFacilitating nutrition research and policy (EAR)Establishing safety guidelines (UL)Making good tools betterQ2：How the committee establishes DRI values?(1)Find out how much of that nutrient various healthy individuals need: review studies of deficiency states, nutrient stores and their depletion, and the factor influencing them.(2)Different individuals have different requirement: average ——EAR(3)To decision we finally make is to set the value high enough so that the bulk of the population will be covered but not so high as to be excessive——RDA(4)The value set for energy intake is different from nutrient.Food LabelsList of ingredientsListed in descending order by weightChapter 3 The Remarkable Body1.The human body is made of trillions of cellsLiver cells: reproduce quickly and do so whenever repairs to the organ are neededBrain cells: do not reproduce at all; if damaged by injury or disease, lost forever2.The Body Fluids and the Cardiovascular SystemThe body’s main fluids are the blood and lymphBlood: arteries, veins 静脉and capillaries毛细血管Lymph: travels in separate vessels of its ownBody fluid supply the tissues continuously with energy, oxygen, and nutrients including water. Blood and lymph deliver nutrients and oxygen to all the body’s cells and carry waste materials away from them.3.The hormonal and nervous systems respond to the need for food, govern the act of eating, regulate digestion, and call for the stress response.4. The Immune SystemMaintain defenses against infection:Skin: physical barrierWhite blood cellsPhagocytes（吞噬细胞）Lymphocytes（淋巴细胞）:--B-cells: produce antibody--T-cells: attack antigenThe immune system enables the body to resist disease.5.The Digestive SystemBegins in the mouth:chewingsaliva moistens food for easier swallowingStomach and intestines liquefy foods by mashing and squeezingSmall intestine–site of most nutrient absorption - contracts to move contents to large intestine (colon)Colon’s main roles:Reabsorb waterAbsorb mineralsRectum（直肠）—stores feces until excretionfiber , undigested material, sloughed intestinal cells, bacteriaChapter4 Carbohydrates：Sugar, Starch, Glycogen, and FiberGlucose葡萄糖fructose 果糖Galactose半乳糖Lactose乳糖Maltose麦芽糖Sucrose蔗糖益生菌（probiotics）：对身体有好处的“好菌”，是一种可改善宿主肠內菌相平衡，有益宿主健康的活微生物体——双歧杆菌、乳酸菌。