食品营养与安全1-8章要点 - 图文

Chapter 1 Food Choices And Human Health

Food: 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 gender

group.

Q1:Why can’t nutrient advice be kept simple? Setting intake recommendation for individuals Preventing chronic diseases

Facilitating nutrition research and policy (EAR) Establishing safety guidelines (UL) Making good tools better

Q2：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 Labels

List of ingredients

Listed in descending order by weight

Chapter 3 The Remarkable Body 1.The human body is made of trillions of cells

Liver cells: reproduce quickly and do so whenever repairs to the organ are needed Brain cells: do not reproduce at all; if damaged by injury or disease, lost forever 2.The Body Fluids and the Cardiovascular System The body’s main fluids are the blood and lymph Blood: arteries, veins 静脉and capillaries毛细血管 Lymph: travels in separate vessels of its own

Body 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 System

Maintain defenses against infection: Skin: physical barrier White blood cells

Phagocytes（吞噬细胞 ） Lymphocytes（淋巴细胞 ）: --B-cells: produce antibody --T-cells: attack antigen

The immune system enables the body to resist disease. 5. The Digestive System Begins in the mouth: chewing

saliva moistens food for easier swallowing

Stomach and intestines liquefy foods by mashing and squeezing

Small intestine – site of most nutrient absorption - contracts to move contents to large intestine (colon)

Colon’s main roles:

Reabsorb water Absorb minerals

Rectum（直肠）—stores feces until excretion

fiber , undigested material, sloughed intestinal cells, bacteria

Chapter4 Carbohydrates：Sugar, Starch, Glycogen, and Fiber Glucose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。 益生源（prebiotics）：是指可以刺激腸道里的好菌生长的“食物”，这类物质能够被有益菌利用而产生有机酸，刺激肠蠕动，并且能促进有益菌生长，抑制坏菌数量，使肠道更健康——寡糖

Starch is a plant’s storage form of glucose. Plant store energy as starch for use during growth and reproduction.

Rich sources of starch:

-Grains: wheat, rice, corn, oats? -Legumes: peas, bean, lentils? -Tubers: potatoes, yams, cassava?

Nutritive for humans: it is an important carbohydrates source of our diets. Glycogen

Storage form of glucose in animals and human beings.

Undetectable in meats because glycogen breaks down rapidly when the animal is slaughtered.

Since plant foods do not contain glycogen, it isn’t a carbohydrate source in our diets. But glycogen play an important role in our body as a readily mobilizable store of glucose. Lactose intolerance

As people age, upward of 75 percent of the world’s people lose the ability to produce the enzyme lactase which digests lactose

Milk allergy is due to the immune system’s reaction to milk protein. Harm to the body

Chronically elevated blood glucose alters metabolism in every cell in the body -Blindness

-Kidney disease -Heart disease -Nerve damage

-Increased infections

Q1:Fiber benefits the body in all these ways

-Improve the body’s handing of glucose and the hormone insulin ,perhaps by slowing the digestion or carbohydrate.

-Possibly reduce the risk of colon cancer. -Reduce energy consumption.

-Reduce the risk of heart and artery disease.

-Help feelings of fullness because they absorb water and swell.

-Help prevent constipation,hemorrhoids and other intestinal problems by keeping the contents of the intestine moist and easy to eliminate.

-Help prevent bacterial infection of the appendix .

-Stimulate the muscles of the digestive tract so that they retain their health and tone. What are the consequence of eating too much ？

Too much fiber and too little liquids can overwhelm the digestive system.

Too much purified fiber may displace nutrients from the diet or cause them to be lost by binding the nutrients and speeding up transit.

The daily value for fiber is 25 - 30 g per day.

Q2：How can fiber help maintain a healthy weight?

-Whole foods rich in carbohydrate tend to be low in facts and added sugars and therefore promote weight loss by delivering less energy per bite. -Fiber provides a feelings of fullness.

-Fiber delays hunger because fibers swell as they absorb water.