HE204 Chapter 1 Introduction to Nutrition PDF

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Nutrition Chapter 1...

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Chapter 1 Introduction to Nutrition 1.1 The Importance of Nutrition: Why Study Nutrition? Food is a basic human need for survival Nutrients‐ the life‐ sustaining substances found in food ● Necessary for growth, maintenance, and repair of the body’s cells Nutrition‐ the scientific study of nutrients and how the body uses them Diet ‐ a person’s usual pattern of food choices To eat well we should learn about: ● The nutritional value of foods ● The effects of diet on health ● Changing our ingrained food‐ related behaviors What People Eat in America: Most Americans do not purchase recommended amounts of fruits, vegetables, whole grains, fish, and low‐ fat dairy products Americans tend to purchase more than recommended amounts of red meats, candies, cheese, sugary beverages, and refined grain products Health experts are concerned with Americans’ eating habits ● Poor dietary practices are associated with: ○ Obesity ○ Type 2 diabetes To live longer, we must improve the nutritional quality of our diets 1.2 The Nutrients: The Six Classes of Nutrients: Carbohydrates, Lipids, Proteins, Vitamins, Minerals, Water Comparing Body Composition: Men and women have similar amounts of vitamins, minerals, and carbohydrates Women have less water and protein and more fat 50 to 70% of total weight is water

Role of Nutrients: Each nutrient has more than one physiological role in the body The body uses nutrients for: ● Energy ● Growth and development ● Regulation of processes Cells use nutrients to carry out metabolic activities Metabolism ‐ the total of all chemical processes that occur in living cells Nutrients and their Major Functions: Carbohydrates: ● Major source of energy (most forms) ● Maintenance of normal blood glucose levels ● Elimination of solid waste from gastrointestinal tract (fiber) Lipids: ● Major source of energy (fat) ● Cellular development, physical growth and development ● Regulation of body processes (certain hormones, for example) ● Growth and development of the brain ● Absorption of fat‐ soluble vitamins Proteins: ● Production of structural components, such as cell membranes, and functional components, such as enzymes ● Cellular development, growth, and maintenance ● Regulation of body processes (certain hormones, for example)

● Transportation of substances within the blood ● Energy (normally a minor source) Vitamins: ● Regulation of body processes ● Immune function ● Production and maintenance of cells ● Protection against agents that can damage cellular components Minerals: ● Regulation of body processes, including fluid balance and energy metabolism ● Formation of certain chemical messengers ● Formation of structural and functional components of various substances and tissues ● Cellular development, growth, and maintenance Water: ● Maintenance of fluid balance ● Regulation of body temperature ● Elimination of wastes ● Transportation of substances ● Participation in many chemical reactions Nutrients: Elements Nutrients are sources of elements needed by the body to carry out its activities Elements‐ substances that cannot be separated into simpler substances by ordinary or physical means Elements in Nutrients: Carbohydrates: ● Carbon, hydrogen, oxygen Lipids: ● Carbon, hydrogen, oxygen; phosphorus (phospholipids); nitrogen (certain phospholipids) Proteins: ● Carbon, hydrogen, oxygen, nitrogen ● Sulfur (methionine and cysteine) Vitamins: ● Carbon, hydrogen, oxygen ● Nitrogen, sulfur, phosphorus, cobalt Minerals: ● Sodium, magnesium, potassium, calcium, chromium, manganese, iron, cobalt, copper, zinc, molybdenum, phosphorus, sulfur, chlorine, selenium, iodine, fluorine Water: ● Hydrogen, oxygen Nutrient-RelatedElements in the Human Body: 98% of the body is composed of five elements:

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Oxygen Carbon Hydrogen Nitrogen Calcium

Chemistry: Organic refers to compounds that contain carbon ● Carbohydrates ● Lipids ● Proteins ● Vitamins Inorganic nutrients do not contain carbon ● Minerals ● Water Essential Nutrients: The body can use raw materials from food to synthesize many nutrients ● Cholesterol ● Fats Essential nutrient‐ must be supplied by food because the body does not synthesize it or make enough to meet needs ● Water is the most essential nutrient Is a Nutrient Essential? To be considered an essential nutrient: ● A deficiency disease results if the nutrient is missing ● When added back to the diet, abnormal physiological changes are corrected ● There is an explanation about why the abnormalities occurred when the substance was missing Deficiency Disease: Deficiency disease‐ a state of health characterized by certain abnormal physiological changes that occur when the body lacks a nutrient Signs‐ the physical changes associated with a disease state that are observable or measurable Symptoms‐ subjective complaints of ill health that are difficult to observe and measure Vitamin C Example: To test a subject’s need for vitamin C: ● Subject avoids foods with vitamin C ● Develops scurvy ○ Gums bleed when brushing teeth ○ Wounds heal slowly

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Foods with vitamin C are again incorporated Signs and symptoms of scurvy disappear

Conditionally Essential Nutrients: Conditionally essential nutrients are normally not essential but become essential under certain conditions: ● Metabolic disorders ● Serious illness ● Prenatal development Classification Based on Body’s Need: Macronutrients‐ nutrients that the body needs in large amounts ● Carbohydrates ● Fats ● Proteins Micronutrients‐ nutrients that the body needs in very small amounts ● Vitamins ● Minerals Phytochemicals: Phytochemicals‐ substances in plants that are not nutrients but may have healthful benefits Examples include caffeine and beta‐ carotene Not all phytochemicals have beneficial effects: ● Nicotine ● Ricin ● Oxalic acid 1.3 Food as Fuel: Food is a Source of Energy: Most foods are sources of biological fuels Every cell in the body needs energy to carry out its activities People need to consume energy in foods and beverages to survive Calories vs Kilocalorie: A calorie is the amount of heat needed to raise the temperature of 1 g (1 mL) of water 1°C ● Small unit of measurement ● Food energy is reported in 1000‐ calorie units A kilocalorie (or Calorie) is the heat energy needed to raise the temperature of 1000 g (1 L) of water 1°C Direct Calorimetry: A bomb calorimeter is a device used to measure the calorie content of foods and beverages

Calculating Food Energy: To calculate the number of kcal in a diet, know the amounts of macronutrients and alcohol in the food and beverages ● 1 g of carbohydrates has 4 kcal ● 1 g of protein has 4 kcal ● 1 g of fat has 9 kcal ● 1 g of alcohol has 7 kcal Example: Calorie Content of a Pumpkin Pie Step 1: Determine how many kcal are provided by each type of macronutrient ● 54 g carbohydrate x 4 kcal/g = 216 kcal ● 15 g fat x 9 kcal/g = 135 kcal ● 6 g protein x 4 kcal/g = 24 kcal Step 2: Add the individual kcal from macronutrients to determine the total ● Total kcal = 216 kcal + 135 kcal + 24 kcal = 375 kcal 1.4 Does Diet Matter? Leading Causes of Death in the United States: Several of the leading causes of death in the United States are diet‐ related ● Heart disease and cancer make up about 50% of all deaths

Chronic Diseases: Chronic diseases are long‐ term conditions that usually take many years to develop and have complex causes ● Heart disease ● Diabetes ● Cancer Risk Factors: Risk factors‐ personal characteristics that increase a person’s chances of developing a chronic disease ● Genetic background ● Family history ● Unsafe environmental conditions ● Psychological factors ● Lack of access to health care ● Advanced age ● Unhealthy lifestyle Lifestyle: Lifestyle ‐ a routine way of living ● Dietary practices ● Exercise habits A person’s lifestyle may increase or reduce their chances of developing a chronic disease or delay their occurrence Healthy People 2020: The U.S. Department of Health and Human Services issued Healthy People 2020 in 2011 ● It includes national health promotion and disease prevention goals to be met by 2020 ● Several nutrition‐ related objectives are included ● Its major focus is to prevent obesity and chronic health problems

Healthy People 2020 Selected Objectives for Topic Area: Nutrition and Weight Status (NWS) NWS‐9: ● Reduce the proportion of adults who are obese. NWS‐ 14: ● Increase the contribution of fruits to the diets of the population aged 2 years and older. NWS‐ 16: ● Increase the contribution of whole grains to the diets of the population aged 2 years and older. NWS‐ 17.3: ● Reduce consumption of calories from solid fats and added sugars. 1.5 Factors That InfluenceEating Habits: Influences on Food Selection: There are many factors that influence a person’s usual food selections What influences your eating practices?

Biological and Psychological Factors: Age Ability to perceive external sensory information ● Taste ● Smell ● Texture Internal sensations ● Hunger ● Thirst Age Influences Food Choice: Infants and young children: ● Rely on caregivers Teenagers: ● More control over diet Young adults: ● Broaden food choices Older adults:

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May have limited food choices due to health issues

Sensory Information: Humans rely on sensory information to develop personal food likes and dislikes: ● Taste ● Texture ● Odor ● Appearance Cognitive and Psychological Factors: Cognitive factors: ● Past experiences ● Cultural practices ● Religious teachings Psychological factors: ● Stress level ● Mood ○ Depression ○ Anxiety Environmental Factors: Environmental factors: ● Income ● Location of home ● Availability of food ● Relationships ● Marketing 1.6 Key Nutrition Concepts: Key Nutrition Concepts: Concept 1: Most foods are mixtures of nutrients. Concept 2: Variety, moderation, and balance can help ensure a diet’s nutritional adequacy. Concept 3: Food is the best source of nutrients. Concept 4: Foods and the nutrients they contain are not cure‐alls. Concept 5: Malnutrition includes overnutrition as well as undernutrition. Concept 6: Nutrition is a dynamic science. Concept 1: Most foods are mixtures of nutrients ● Water is the major nutrient in most foods All foods have some nutritional value ● Some are healthier than others Nutrient-Dense Food:

Nutrient‐dense food supplies more key beneficial nutrients in relation to total calories ● Broccoli ● Leafy greens ● Fat‐free milk ● Oranges ● Lean meats ● Whole‐ grain cereals Energy-Dense Food: Energy density refers to the amount of energy a food provides per given weight of the food ● Fatty foods are more energy‐ dense because fat supplies the most energy per gram ● Fruits and vegetables have low energy density because water supplies no energy for the body Energy‐ dense food has a kcal‐ to‐ weight ratio of 4.0 or higher Energy Density: Although each of these portions of food supplies about 400 kcal, they differ in their energy density (doughnut vs strawberries) Empty Calories: An empty‐ calorie food supplies excessive calories from unhealthy types of fat, added sugar, and/or alcohol ● Not all energy‐ dense foods are empty‐ calorie foods Examples include: ● Candy ● Snack chips ● Alcoholic or sugar‐ sweetened drinks Concept 2: Variety, moderation, and balance can help ensure a diet’s nutritional adequacy ● Variety‐ a diet that contains foods from each food group ● Moderation‐ eating reasonable amounts of each food ● Balance‐ a level of calorie intake that enables a person to maintain a healthy weight MyPlate Food Groups: People can add variety to their diets by choosing different foods from each of these five food groups

Beverage Comparision: Although equivalent amounts of fat‐ free milk and a sugar‐ sweetened soft drink have similar calorie contents, the milk contains considerably more protein, riboflavin, vitamin A, calcium, and phosphorus

Concept 3: Food is the best source of nutrients ● Reliable ● Economical ● Contains phytochemicals Some individuals need higher amounts of vitamins and other nutrients than those found in food ● In these cases, supplemental nutrients may be required Dietary Supplements: A dietary supplement is a product that contains a vitamin, mineral, herb or other plant product, an amino acid, or a dietary substance that supplements the diet by increasing total intake The Dietary Supplement Health and Education Act of 1994 allows manufacturers to classify nutrient supplements and herbal products as foods ● Do not undergo rigorous testing before being marketed The FDA and Dietary Supplements: The Food and Drug Administration (FDA) does not regulate dietary supplements as strictly as prescription medications

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If a supplement presents risk of harm, FDA alerts consumers and seeks to recall product

Range of Safe Intake: “More is not always better” The physiological dose of a nutrient is the amount of a nutrient that is within the range of safe intake and enables the body to function optimally

Most foods do not contain toxic levels of vitamins and minerals A megadose is an amount of a vitamin or mineral that is very high, generally at least 10 times the recommended amount of the nutrient ● When taken in high amounts, many vitamins behave like drugs and can produce unpleasant and even toxic side effects Compared to vitamins, minerals generally have very narrow ranges of safe intakes Concept 4: Foods and the nutrients they contain are not cure‐alls ● Diet is only one aspect that influences a person’s health Functional foods are manufactured to boost nutrient intake or help manage specific health problems What About Special Diets? Medical nutrition therapies are nutritionally modified diets for people with chronic health conditions ● Can be planned by registered dieticians or registered dietitian nutritionists

Many factors are considered: ● Current health status ● Occupation ● Food likes and dislikes ● Budget ● Support systems ● Ability to access and prepare food Concept 5: Malnutrition‐ a state of health that occurs when the body is improperly nourished ● Overnutrition ● Undernutrition Nutritionally inadequate diets may be selected because of: ● Lack of knowledge ● Low or fixed income ● Eating disorders ● Alcohol or drug addiction ● Medical problems Concept 6: Nutrition is a dynamic science ● Researchers continue to explore the relationships between diet and health ● Dietary practices and recommendations are constantly changing...