Chapter 18: Nutrition and Metabolism
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CHAPTER 18: NUTRITION AND METABOLISM OBJECTIVES: 1. Define the terms nutrition, nutrients, and, essential nutrients. 2. Review (from Chapter 2) the three major macromolecules (polymers) that humans ingest, name the building blocks (monomers) that compose each, & give a general function for each. 3. List the major dietary sources for carbohydrates, lipids, and proteins. 4. Compare and contrast the two major divisions of metabolism in terms of: (see Chapter 4) a. b. c. d. e. f. g. Name of division Descriptive sentence for division Other descriptive terms Whether bonds are broken or formed Whether energy is required or released; name that term Whether water is required or released; name that term and write an equation illustrating each division. 5. Review (from chapter 4) the process of cellular respiration in terms of major steps, location of each step in the cell, end-product(s) from each step and finally, explain the significance of cellular respiration. 6. Describe how human cells utilize lipids (i.e. the process of beta-oxidation). 7. Compare the ATP yield obtained from an 18-Carbon lipid with that of an 18-Carbon carbohydrate. 8. Explain how cells utilize amino acids and name the two major metabolic wastes that result. 9. Define the term nitrogen balance. 10. Define the term calorie, kilocalorie, and heat. 11. Explain how the energy values of foods are determined. 12. Discuss the factors that determine an individual’s energy requirements. 13. Define the term energy balance. 14. Explain what is meant by the term desirable weight. OBJECTIVES: 15. Distinguish between fat-soluble and water-soluble vitamins and explain which enters cells more easily. 16. Make a list of fat-soluble vitamins and give a function for each. 17. Make a list of water-soluble vitamins and give a function for each. 18. Distinguish between a vitamin and mineral in terms of size and function. 19. Explain what is meant by the term trace mineral. 20. List the major minerals and trace minerals and give a function for each. 21. Discuss the major disorders/diseases that result from an insufficiency of the above listed vitamin/mineral. 22. Discuss the components of an adequate diet. 23. Distinguish between primary and secondary malnutrition. 24. Compare and contrast anorexia and bulimia nervosa in terms of behavior(s) exhibited, and prospective health dangers. CHAPTER 18: NUTRITION AND METABOLISM I. WHY WE EAT We eat to obtain the nutrients that power the activities of life. The macronutrients that are needed in large amounts include carbohydrates, proteins and lipids, while micronutrients include vitamins and minerals. Metabolism refers to the ways that nutrients are chemically altered and used in anabolism (synthesis reactions) and catabolism (breakdown reactions) to support the activities of life. Control of eating occurs in the hypothalamus of the brain. Here, a molecule called neuropeptide Y, links messages concerning nutrient use to regulators of food intake. II REVIEW MACROMOLECULE SUMMARY TABLE (Keyed at the end of this outline) Organic Molecule Composed of what atoms? Building Blocks (monomers) Specific types & functions of monomers Specific types and functions of polymers OTHER II REVIEW METABOLISM SUMMARY TABLE (Keyed at the end of this outline) ANABOLIC REACTIONS CONSTRUCTIVE RXN'S GENERAL DESCRIPTION DESCRIPTIVE TERMS BOND FORMATION OR BREAKING? IS ENERGY REQUIRED OR RELEASED? NAME THAT TERM HOW IS WATER INVOLVED? NAME THAT TERM EXAMPLE IN HUMAN METABOLISM CATABOLIC RXNS DEGRADATION RXNS III MACRONUTRIENTS A. Carbohydrates: Carbohydrates are organic compounds and include sugars and starches. The energy held in their chemical bonds is used to power cellular processes. 1. 2. Carbohydrate Sources See Fig 18.2, page 696. a. Complex carbohydrates/polysaccharides o starch from grains and vegetables o glycogen from meats o These foods usually contain rich vitamins and minerals. b. Simple carbohydrates o disaccharides from dairy products, cane sugar, beet sugar, molasses o monosaccharides from honey and fruits. c. Cellulose is a structural polysaccharide in plants. o Humans do not possess enzymes to digest cellulose. o important in providing bulk fiber (roughage) to aid in movement of intestinal contents. Carbohydrate Utilization a. b. Monosaccharides absorbed from small intestine are transported to the liver via the hepatic portal vein include: o fructose o galactose o glucose. Liver enzymes See Fig 18.1, page 696. o convert fructose and galactose into glucose (oxidation releases energy from glucose in cellular respiration). o polymerize excess glucose as glycogen (glycogenesis). The body can only store a certain amount of glycogen, so further excesses of glucose are converted to fat and stored in adipose tissue. See box on page 696 that discusses liver and muscle glycogen. III MACRONUTRIENTS A. Carbohydrates: 2. Carbohydrate Utilization: c. SUMMARY OF CELLULAR RESPIRATION: Keyed at the end of this outline. GLYCOLYSIS CONVERSION STEP KREBS CYCLE ELECTRON TRANSPORT CHAIN LOCATION in cell Is Oxygen Required? Starting Product(s) EndProducts TOTAL 3. Carbohydrate Requirements: a. Vary with activity of individual. Some cells need continuous glucose supply to survive. Amino acids may be converted to glucose if glucose is scarce. Average diet includes 200-300 grams carbohydrates daily. Poor nutrition status usually not related to insufficient carbohydrate intake. CHAPTER 18: NUTRITION AND METABOLISM III. MACRONUTRIENTS (continued) B. Lipids Lipids are organic molecules that include fats, phospholipids, and cholesterol. They supply energy for cellular processes and building blocks for cell membranes, steroid hormones, etc. The most common dietary lipids are the fats called triglycerides. 1. Lipid Sources a. b. Triglycerides o Saturated fats are found in foods from Mainly animal origin: Meats, Egg, Milk, and Lard. Some plant origin: palm & coconut oil. o Unsaturated fats are contained in Seeds Nuts Plant oils. Cholesterol o o o 2. comes from foods of animal origin only. is abundant in liver and egg yolk in trace amounts in whole milk, butter, cheese, and meats. Lipid Utilization a. See Fig 18.3, page 697. Triglycerides are broken down into fatty acids and glycerol in the duodenum, and these are absorbed by lacteals in the distal small intestine and are transported to tissues. Beta Oxidation decomposes fatty acids into 2-carbon units. These segment are converted to acetyl CoA, which enters the Citric acid cycle, where energy is released from their bonds. Glycerol becomes an intermediate in glycolysis. CHAPTER 18: NUTRITION AND METABOLISM III. MACRONUTRIENTS (continued) B. Lipids: 2. Lipid Utilization: b. Liver See Fig 18.4, page 698. o o o o c. Absorbed lipids are transported to Converts fatty acids from one form to another, except it cannot synthesize linolenic acid (i.e. essential F.A.). Required for the synthesis of phospholipids. Needed for the formation of cell membranes. Needed for the transport of circulating lipids. Good sources include corn, cottonseed & soy oils. Other essential FA’s linolenic acid arachadonic acid Uses free FA’s to synthesize a variety of lipids that are then released into the blood (i.e. regulates circulating lipid concentration). Triglycerides Phospholipids Lipoproteins. Controls the total amount of cholesterol in the body by: synthesizing cholesterol and releasing it into blood. removing cholesterol from the blood and excreting it into the bile. The liver uses cholesterol to make bile salts: It is not used for energy. It is used for construction of: cell components hormones. Adipose tissue o o Excess lipids are stored in adipose tissue. During fasting, stored triglycerides may be hydrolyzed into glycerol and fatty acids and released into blood. III. MACRONUTRIENTS (continued) B. Lipids 3. Lipid requirements a. b. c. d. C. vary among individuals. The amounts and types needed for health are unknown and are accordingly a “hot” research topic. Intake must sustain production of fat-soluble vitamins. American Heart Association: “Diet should not exceed 30% of total daily calories from fat”. PROTEINS: Proteins are organic compounds that serve several functions in human cells. The most important proteins are enzymes that regulate metabolism, but others serve roles in structure (i.e. keratin), transport (i.e. hemoglobin), storage (i.e. albumin), movement (i.e. myosin), and energy. The building blocks of proteins are amino acids. During starvation (i.e. carbohydrate and lipid sources are depleted), tissue proteins may be used as energy source causing tissue wasting. 1. Protein Sources a. b. From meats, fish, poultry, dairy products, cereals and legumes. During digestion, proteins are broken into amino acids. o These amino acids can then be used as building materials for cellular proteins and enzymes. See Fig 18.5, page 699. energy sources. Deamination is required before the cell can use amino acids are energy source. See Fig 18.6, page 700. The deaminated portions of amino acids can be 1. converted to CO2 and water, 2. used to produce glucose or fat. o Essential amino acids: See Table 18.3, page 700. Ten in growing children Eight in adults. All must be present simultaneously for growth and tissue repair to occur. III. MACRONUTRIENTS (continued) C. PROTEINS: 1. Protein Sources c. 2. Classified as either complete or incomplete o Complete include those from meat, fish, & dairy. contain adequate amounts of essential amino acids to maintain tissues and promote normal growth and development. o Incomplete include protein in corn. Contain inadequate essential amino acids Tryptophan and lysine and therefore do not maintain tissues or promote growth or development. Nitrogen balance a. Catabolism and anabolism of proteins occur simultaneously, but at different rates in different tissues. o Overall gain of body proteins equals the overall loss = dynamic equilibrium. o Because proteins contain such a high content of nitrogen, dynamic equilibrium leads to nitrogen balance. Definition: Nitrogen balance (NB) is a condition when the nitrogen intake (via proteins) equals nitrogen excretion. Positive NB occurs in growing children, pregnant women and athletes. Negative NB occurs in starving individuals. 3. Protein requirements a. Proteins and amino acids are necessary to build enzymes, hormones, and other cellular proteins. b. vary among individuals. c. Nutritionists recommend that an average adult take in 0.8g/kg body weight. d. Protein deficiencies: o tissue wasting o decreased levels of plasma proteins: Albumin: osmotic pressure abnormalities and nutritional edema. Globulins: decreased immunity. Fibrinogen: bleeding disorders. * See Table 18.4 on page 701 to summarize nutrient sources, utilization and requirements. IV ENERGY EXPENDITURES The amount of potential energy a food contains can be expressed as calories, which are units of heat. A. Important definitions 1. 2. Calorie = the amount of heat required to raise the temperature of one gram of water by 1 degree Celsius (°C). Kilocalorie = the amount of heat required to raise the temperature of a kilogram of water by 1 degree Celsius (°C). a. b. B. Energy Values of Foods 1. 2. The caloric contents of food can be measured with a “bomb calorimeter” (See Fig 18.7, page 702). Energy yield via cellular oxidation: a. b. c. C. used to measure food energy in nutritional studies, simply referred to as a calorie. 1 gram of carbohydrate = 4.1 Calories. 1 gram of protein = 4.1 Calories. 1 gram of fat = 9.5 Calories. Energy Requirements The energy needs of individuals vary and are based on several factors including the individual’s basal metabolic rate, degree of muscular activity, body temperature, and rate of growth. 1. Basal Metabolic Rate (BMR) a. b. c. d. e. 2. BMR measures the rate at which the body expends energy under basal conditions (i.e. awake, at rest, comfortable, et cetera). Tests of thyroid function can be used to estimate a person’s BMR. BMR is affected by sex, temperature, size, and endocrine activity. BMR represents the energy necessary to sustain activities of the brain, heart, lungs, kidneys & liver. BMR maintenance requires the body’s greatest energy expenditure. Energy required to support muscular activity: See Table 18.5, page 703. IV ENERGY EXPENDITURES D. E. Energy Balance a. Definition: a state of energy balance (EB) exists when caloric intake in the form of food equals caloric output resulting from BMR and muscular activity. b. Under these conditions, body weight would remain constant. 1. Positive EB = increases body weight o Excess of 3500 calories can be stored as a pound of fat. 2. Negative EB = decreases body weight o Stored materials are mobilized from tissues for oxidation. Desirable Weight See Clinical Application 18.1 on pages 704 and 705. This application addresses obesity, however a chart illustrating body mass index (BMI) is helpful in understanding what desirable weight really means. Also see Figure 18.8, page 703. V. MICRONUTRIENTS Micronutrients include vitamins and minerals, which essentially aid our cells in metabolism. As discussed in Chapter 4 of this text, enzymes regulate metabolism however they are not always activated and may require a substance called a coenzyme or cofactor. Vitamins serve as coenzymes and minerals serve as cofactors. In addition, vitamins and minerals may themselves be necessary for important body functions (i.e. bone growth, nerve impulse transmission, muscle contraction, et cetera). A. VITAMINS 1. General characteristics a. organic b. required in small amounts, but body cells cannot synthesize vitamins in adequate amounts and therefore they must be obtained from foods. c. classified based on solubility o Fat soluble vitamins include A, D, E, and K o Water-soluble vitamins include the B vitamins and C. fairly resistant to heating (i.e. not destroyed in cooking). d. 2. See Table 18.6 on page 706 concerning vitamin fallacies. FAT-SOLUBLE VITAMINS a. VITAMIN A o occurs in several forms including retinol & retinal. o is synthesized from carotenes (See Fig 18.9, page 706). o is stored in liver. o functions in the production of pigments necessary for vision. b. VITAMIN D o is group of steroids in structure. o is found in foods such as dairy products. o can be produced commercially. o can be synthesized by skin (using sunlight). o functions as hormone that promotes the intestine’s absorption of calcium and phosphorus (i.e. bone growth and remodeling). o Deficiency in children causes rickets (See Fig 18.10, page 707). V. MICRONUTRIENTS A. VITAMINS 2. FAT-SOLUBLE VITAMINS c. VITAMIN E o antioxidants. o stored in muscle and adipose. o precise function unknown. o seems to prevent polyunsaturated and vitamin A oxidation, and stabilize cell membranes. o may play a role in defense in aging, and several other diseases. d. VITAMIN K o K1 occurs in foods. o K2 occurs in intestinal bacterial flora. o stored in the liver. o functions in the production of prothrombin necessary for normal blood clotting. o See box discussing newborn Vitamin K deficiencies on 709. See Table 18.8, page 708 for a summary of the fat-soluble vitamins. See Clinical Application 18.2 on page 720, Dietary Supplements-Proceed with CAUTION 3. WATER-SOLUBLE VITAMINS a. VITAMIN B-COMPLEX o In general, the B vitamins: occur together in many foods (i.e. complex). function as coenzymes or a part of coenzymes that is necessary for the metabolism of proteins, lipids, or carbohydrates. They aid in either the: synthesis of a macromolecule or the oxidization of a macromolecule. V. MICRONUTRIENTS A. VITAMINS 3. WATER-SOLUBLE VITAMINS a. VITAMIN B-COMPLEX o The B vitamins include: Thiamin (B1) aids in cellular respiration (required for pyruvic acid to enter the Krebs Cycle) and aids in the synthesis of the sugar ribose (RNA); Deficiency = beriberi (page 709). Riboflavin (B2) includes FAD that transport electrons through the electron transport chain (ETC) & therefore aids in the oxidation of glucose & fatty acids. Niacin (Nicotinic Acid) includes NAD and NADP which are important electron carriers in glycolysis, Krebs Cycle and the ETC, as well as for the synthesis of proteins and fats; See Fig 18.11 and 12, page 710; deficiency = pellagra (page 710). Pantothenic Acid (B5) functions as part of coenzyme A (i.e. needed for formation of acetyl CoA that enters the Krebs Cycle in cellular respiration). Vitamin B6 aids in the synthesis of proteins, certain amino acids, antibodies, and nucleic acids; See Fig 18.13, page 710. Vitamin B12 (Cyanocobalamin) contains cobalt and is needed for the synthesis of nucleic acids and for the metabolism of carbohydrates and fats; See Fig 18.14, page 711 and pernicious anemia on page 711. Folacin (Folic acid) aids in the metabolism of certain amino acids, the synthesis of DNA, and erythropoiesis; deficiencies have been linked to neural tube defects during pregnancy. Biotin is needed for the metabolism of amino acids and fatty acids and for the synthesis of nucleic acids; See Fig 18.16, page 715. V. MICRONUTRIENTS A. VITAMINS 3. WATER-SOLUBLE VITAMINS b. Ascorbic Acid (Vitamin C) o is closely related chemically to monosaccharides (i.e. contains 6 carbons; hexose). See Fig 18.15, page 712. o is needed for the production of the connective tissue collagen (i.e. bone matrix, ligaments, tendons, others), the metabolism of certain amino acids, and iron absorption. o prolonged deficiencies lead to scurvy. See Table 18.9, page 713 for a summary of the water-soluble vitamins. V. MICRONUTRIENTS B. MINERALS In contrast to carbohydrates, lipids, proteins, and vitamins, which are organic molecules, minerals are very small inorganic elements. Humans obtain these essential minerals by eating plants, or by eating herbivorous animals. 1. Characteristics of Minerals a. Compose 4% of body weight o o b. Usually incorporated into organic molecules o o c. calcium phosphate of bone. Some are free ions in the blood: o o o e. iron in hemoglobin iodine in thyroxine (T4). Some compose of inorganic molecules o d. concentrated in bones & teeth Calcium and phosphorus are the most abundant. Sodium (Na+); Chloride (Cl-); Potassium (K+). Present in all body cells where they provide many functions: o o o o o o o structure; cofactors for enzymes; maintain osmotic pressure (0.9%); are involved in transmission of nerve impulses; are involved in muscle contraction; are involved in blood clotting; maintain pH. V. MICRONUTRIENTS B. MINERALS Summary Table of MAJOR Minerals Mineral Sym -bol Major Trace Primary Distribution Major Function(s) Major Sources Conditions Calcium Ca Major Bones & Teeth Structure of bone/teeth; nerve impulse conduction; muscle contraction milk; + kidney stones - stunted growth Phosphorus P Major Bones & Teeth Structure of bone/teeth; ATP; Nucleic acid & proteins meats; cheese; milk + none - stunted growth Potassium K Major Intracellular Fluid maintenance of resting membrane potential (RMP) avocados ; bananas; potatoes + none - muscular & cardiac problems Sulfur S Major skin, hair, nails essential part of amino acids, thiamine, insulin, biotin, and MPS meats; milk; eggs + none - none Sodium Na Major Extracellular Fluid maintenance of RMP, electrolyte, water, & pH balance table salt; cured ham + hypertension, edema - cramps, convulsions Chlorine Cl Major Extracellular Fluid maintenance of RMP, electrolyte, water, & pH balance table salt; cured ham + vomiting - muscle cramps Magnesium Mg Major Bones needed in mitochondria for cellular respiration; ATP/ADP conversion milk; dairy; legumes + diarrhea - neuromuscular problems Summary Table of TRACE Minerals Mineral Sym bol Major Trace Primary Distribution Major Function(s) Sources Conditions Iron Fe Trace Blood part of hemoglobin liver + liver damage - anemia Manganese Mn Trace liver, kidneys occurs in many enzymes nuts + none - none Copper Cu Trace liver, heart, brain essential in synthesis of hemoglobin, bone, melanin, myelin liver; oysters crabmeat + rare - rare Iodine I Trace thyroid essential in the synthesis of thyroid hormones iodized table salt + thyroid hormone imbalance - goiter Cobalt Co Trace widely distributed component of Cyanocobalamin (B12) liver; lean meats + heart disease - pernicious anemia Zinc Zn Trace liver, kidneys, brain wound healing; part of several enzymes meats; cereals + slurred speech - decreased immunity Fluorine F Trace bones & teeth tooth structure fluoridated water + mottled teeth - none Selenium Se Trace liver & kidney occurs in enzymes lean meats cereals + vomiting, fatigue - none Chromium Cr Trace widely distributed essential for use in carbohydrates liver; lean meats + none - none VI. HEALTHY EATING A. An adequate diet provides sufficient energy and essential nutrients to support 1. optimal growth of tissues 2. maintenance of tissues 3. repair of tissues. B. Individual dietary needs vary greatly 1. impossible to devise adequate diet for every human. 2. Devices to assist consumers in healthy eating include: a. Recommended Daily Allowances (RDA) b. Recommended Dietary Allowances c. Food group plans d. Food pyramid, See Fig 18.18 on page 721. e. Food labels C. Malnutrition: 1. D. Poor nutrition may be due to either: a. Lack of foods or b. Failure to make best use of available foods. c. Poor nutrition is classified in two ways: o Primary = poor diet. o Secondary = some characteristic that makes a normal diet inadequate. Starvation: 1. A person can survive 50-70 days without food. 2. A starving body digests itself. a. starts with carbohydrate stores in liver & muscle b. continues with protein digestion in many tissues including muscle c. continues with fat digestion including adipose but also myelin that surround nerve fibers. 3. Starvation symptoms are numerous and progress in the following order: low blood pressure and pulse chills, dry skin, hair loss poor immunity death due to malfunction of vital organ(s). a. b. c. d. VI. HEALTHY EATING (continued) D. Starvation (continued) 4. In the young, starvation may be due to total vs. specific deficiencies. a. b. c. 5. Marasmus is due to lack of all nutrients. Kwashiorkor is due to a protein deficiency. See Fig 18.19 on page 723 comparing these two deficiencies. In teens or adults, starvation may be self-inflicted as eating disorders: a. Anorexia Nervosa is self-starvation. o o b. See introduction to chapter on page 694. Read progression of disease on page 723-724. Bulimia nervosa o characterized by binge eating followed by purging: o VII. vomiting or use of laxatives or through excessive exercise. See page 724. LIFE SPAN CHANGES A. Nutritional and energy requirements change with age and also depend upon 1. medical conditions 2. social and economic conditions. 3. See Table 18.12, page 724. B. BMR: 1. 2. 3. 4. C. rises in early childhood declines in mid-late childhood peaks again in adolescence declines with age thereafter. At any age: 1. Weight gain occurs when energy in exceeds energy out 2. Weight loss occurs when energy out exceeds energy in. VIII. OTHERS: A. B. C. D. E. F. G. Clinical Application 18.2, “Dietary Supplements - Proceed with Caution”, page 720. Clinical Application 18.3, “Nutrition and the Athlete”, page 722. Sugar substitutes. See box on page 696. Fat-free foods. See box on page 697. Ketone formation in Diabetes. See Box on page 698. BUN. See box on page 699. PICA (eating dirt, etc). See box on page 718. IX. Clinical Terms Related to Nutrition and Metabolism See page 725. KEY TO MACROMOLECULE SUMMARY TABLE (outline page 3) Organic Molecule Carbohydrates (sugars) Lipids (Fats) Proteins Nucleic Acids Composed of what atoms? C, H, 0 C, H, O C, H, O, N, S C, H, O, N, P Building Blocks (monomers) Monosaccharides or hexoses Triglycerides: glycerol and 3 fatty acids amino acids nucleotides: pentose sugar, phosphate, nitrogen base Specific types & functions of monomers glucose, fructose, galactose: TG = energy 20 different amino acids N/A proteins (>100 amino acids); Many functions: ENZYMES, antibodies, structure, transport, chemical messengers, storage DNA = deoxyribonucleic acid; genetic material; RNA= ribonucleic acid; aids DNA in protein synthesis. energy Phospholipid = cell membrane component Steroid = cell membrane component and chemical messenger (i.e. cholesterol) Specific types and functions of polymers Other Disaccharides: sucrose, lactose, maltose; energy _____________ Polysaccharides : Starch (plant); Glycogen (animal); energy storage. N/A Saturated (only single bonds between C’s in fa chain) vs. Unsaturated (at least 1 double bond in fa chain) DNA controls cellular activity by instructing our cells what proteins to make (i.e. Enzymes). Key to Metabolism Comparison Table (outline page 4) Anabolism SYNTHESIS REACTIONS Catabolism DEGRADATION RXN'S GENERAL DESCRIPTION Synthesis involves the building of a large molecule (polymer) from smaller building blocks (monomer). Degradation involves the breakdown of polymer into individual monomers. DESCRIPTIVE TERMS building constructive anabolic breakdown digestive decomposition catabolic BOND FORMATION OR BREAKING? Bonds are formed. Bonds are broken. IS ENERGY REQUIRED OR RELEASED? NAME THAT TERM. Energy is required to form the bond. Endergonic Energy is released when the bond is broken. Exergonic HOW IS WATER INVOLVED? NAME THAT TERM. Water is released when he bond is formed. Dehydration Water is required to break the bond. Hydrolysis EXAMPLE Building a protein from individual amino acids; Building a triglyceride from glycerol and 3 fatty acids, etc. Breaking a protein into individual amino acids; Breaking starch down into monosaccharides, etc. KEY TO CELLULAR RESPIRATION SUMMARY TABLE (outline page 6) LOCATION GLYCOLYSIS CONVERSION STEP KREBS CYCLE ELECTRON TRANSPORT CHAIN cytoplasm mitochondria mito matrix mito inner membrane Oxygen Required? no yes yes yes Starting Product glucose (6-C) 2 pyruvates (2 x 3C) Acetyl CoA (2 x 2C) 10 NADH 2 FADH2 EndProducts 2 pyruvates (2 x 3-C) 2 ATP 2 NADH 2 Acetyl CoA 2 NADH 2 CO2 6 NADH 2 FADH2 2 ATP 4 CO2 30 ATP 4 ATP 4 ATP TOTAL 38 ATP Chapter 18: Nutrition and Metabolism I. Why We Eat A. Nutrients are chemical substances supplied from the environment that an organism requires for survival. B. Macronutrients are carbohydrates, proteins, and fats. C. Micronutrients are essential in small daily doses and include vitamins and minerals. D. Besides nutrients, the body also requires water. E. Digestion breaks down nutrients to sizes that can be absorbed and transported in the bloodstream. F. Metabolism refers to the ways that nutrients are altered chemically and used in anabolism and catabolism of chemical compounds to support the activities of life. G. Anabolism is the synthesis part of metabolism. H. Catabolism is the decomposition part of metabolism. I. Essential nutrients are nutrients that human cells cannot synthesize. J. Leptin regulates fat stores in the long term. K. Cholecystokinin stimulates satiety after eating while ghrelin stimulates appetite. II. Carbohydrates A. Introduction 1. Carbohydrates are organic compounds and include the sugars and starches. 2. The body uses carbohydrates for energy. B. Carbohydrate Sources 1. Sources of polysaccharides are starch from grains and vegetables and glycogen from meats. 2. Sources of disaccharides are milk, sugar, cane sugar, beet sugar, and molasses. 3. Sources of monosaccharides are honey and fruits. 4. Digestion breaks carbohydrates into monosaccharides. 5. Cellulose provides bulk against which the muscular wall of the digestive system can push. 6. Other sources of fiber are hemicellulose, pectin, and lignin. C. Carbohydrate Utilization 1. Monosaccharides that are absorbed from the digestive tract are fructose, galactose, and glucose. 2. The liver converts galactose and fructose to glucose. 3. Glycogenesis is the formation of glycogen and occurs in the liver and muscles. 4. Glycogenolysis is the break down of glycogen into glucose and occurs in most body cells. 5. Excess glucose that cannot be stored as glycogen is converted to fat. 6. Cells use some carbohydrates to produce RNA and DNA. 7. Gluconeogenesis is the formation of glucose from noncarbohydrate sources and occurs in the liver. D. Carbohydrate Requirements 1. A recommended daily carbohydrate intake is about 125-175 grams. 2. The average diet contains 200-300 grams of carbohydrates daily. III. Lipids A. Introduction 1. Lipids are organic substances that include fats, oils, phospholipids, and cholesterol. 2. The functions of lipids are to supply energy for cellular processes and to help build cellular structures. B. Lipid Sources 1. Triglycerides are found in plant and animal based foods. 2. Saturated fats are found in foods of animal origin. 3. Unsaturated fats are found in seeds, nuts, and plant oils. 4. Cholesterol is found in liver, egg yolks, whole milk, butter, cheese, and meats. C. Lipid Utilization 1. Fats are primarily used to supply energy. 2. Gram for gram, fats contain more than twice as much chemical energy as carbohydrates or proteins. 3. Before a triglyceride molecule can release energy, it must undergo hydrolysis. 4. Digestion breaks triglycerides down into fatty acids and glycerol. 5. Glycerol and fatty acids are transported to blood through lymph. 6. Beta-oxidation is a series of reactions that converts some fatty acids to acetyl coenzyme A. 7. Fatty acid oxidases function to break down fatty acids. 8. Excess acetyl CoA is converted to ketone bodies. 9. Glycerol is used to synthesize glucose or can enter metabolic pathways leading to the citric acid cycle. 10. Glycerol and fatty acids can react together to form fat molecules and can be stored in fat tissue. 11. The liver can convert fatty acids to other forms of fatty acids. 12. Essential fatty acids are fatty acids that the liver cannot synthesize. 13. The liver uses free fatty acids to synthesize triglycerides, phospholipids, and lipoproteins. 14. The liver regulates the amount of cholesterol in the body by synthesizing cholesterol and releasing it into the blood or by removing cholesterol from the blood and excreting it into the bile. 15. Cholesterol is not an energy source but it used to build cell and organelle membranes and certain hormones. D. Lipid Requirements 1. The American Heart Associate recommends that the diet not exceed 30% from fat. 2. Dietary fats must supply the required amounts of fat-soluble vitamins. IV. Proteins A. Introduction 1. Proteins are polymers of amino acids. 2. Functions of proteins are to make cellular structures, act as enzymes, act as antibodies, act as clotting factors, etc. 3. Deamination is the removal of nitrogen containing portions from amino acids and occurs in the liver. 4. Urea is a waste product from deamination. 5. Using structural proteins to generate energy causes the tissue-wasting characteristic of starvation. B. Protein Sources 1. Foods rich in proteins are meats, fish, poultry, cheese, nuts, milk, eggs, can cereals. 2. Essential amino acids are amino acids the body cannot synthesize. 3. All twenty amino acids must be present in the body for growth and tissue repair to occur. 4. Complete proteins contain adequate amounts of essential amino acids to maintain human body tissues and promote normal growth and development. 5. Incomplete proteins have too little of the essential amino acids and are unable by themselves to maintain human tissues or to support normal growth and development. 6. Sources of complete proteins are milk, eggs, and meats. 7. Sources of incomplete proteins are corn and legumes. C. Nitrogen Balance 1. Nitrogen balance is a condition in which the amount of nitrogen taken in is equal to the amount excreted. 2. A person who is starving has a negative nitrogen balance because the amount of nitrogen excreted as a result of amino acid oxidation exceeds the amount the diet replaces. 3. Examples of persons with positive nitrogen balances are growing children, a pregnant woman, or an athlete in training. D. Protein Requirements 1. The amount of protein required varies according to body size, metabolic rate, and nitrogen balance condition. 2. The recommended intake of protein per day is 0.8 gram per kilogram of body weight. 3. A pregnant woman requires 30 extra grams per day and a nursing mother requires 20 extra grams per day. 4. Nutritional edema results from a decrease in the level of plasma proteins needed to maintain colloid osmotic pressure of plasma. V. Energy Expenditures A. Introduction 1. Carbohydrates, fats, and proteins supply energy. 2. If the diet is deficient of energy-supplying nutrients, structural molecules may be gradually consumed. 3. Excess intake of energy supplying nutrients may lead to obesity. B. Energy Values of Foods 1. The amount of potential energy a food contains can be expressed as calories. 2. A calorie is defined as the amount of heat required to raise the temperature of a gram of water by 1 degree Celsius. 3. A large calorie is 1,000 times greater than a calorie. 4. A kilocalorie is the amount of heat needed to raise the temperature of a kilogram of water by 1 degree Celcius. 5. A bomb calorimeter is used to measure caloric contents of food. 6. Caloric values determined in a bomb calorimeter are somewhat higher than the amount of energy that metabolic oxidation actually releases because nutrients generally are not completely absorbed from the digestive tract. 7. Cellular oxidation yields on average about 4.1 calories from 1 gram of carbohydrate, about 4.1 calories from one gram of protein, and 9.5 calories from one gram of fat. C. Energy Requirements 1. The factors that influence energy needs are basal metabolic rate, degree of muscular activity, body temperature, and rate of growth. 2. Basal metabolic rate is the rate at which the body expends energy under resting conditions. 3. Tests of thyroid function can be used to estimate a person’s BMR. 4. The BMR reveals the total amount of energy expended in a given time period to support the activities of such organs as the brain, heart, lungs, liver, and kidneys. 5. The average adult BMR indicates a requirement for about 1 calorie or energy per hour for each kilogram of body weight. 6. BMR varies with sex, body size, body temperature, and level of endocrine gland activity. 7. Maintaining the basal metabolic rate usually requires the body’s greatest expenditure of energy. 8. Growing children and pregnant women require more calories because their bodies are actively producing new tissues. D. Energy Balance 1. A state of energy balance exists when caloric intake in the form of foods equals caloric output from the basal metabolic rate and muscular activities. 2. A positive energy balance is when caloric intake exceeds the output and body weight increases. 3. A negative energy balance is when the caloric output exceeds intake and body weight decreases. E. Desirable Weight 1. The most common nutritional disorders reflect calorie imbalances. 2. Overweight is defined as exceeding desirable weight by 10% to 20%. 3. Obesity is defined as exceeding desirable weight by more than 20%. 4. When a person needs to gain weight, diet can to altered to include more calories and to emphasize particular macronutrients. VII. Vitamins A. Introduction 1. Vitamins are organic compounds other than carbohydrates, lipids, and proteins required in small amounts for normal metabolic processes but that body cells cannot synthesize in adequate amounts. 2. Provitamins are precursors to vitamins. 3. Vitamins can be classified based on solubility. 4. Fat-soluble vitamins are vitamins A, D, E and K. 5. Water-soluble vitamins are the B vitamins and vitamin C. B. Fat-Soluble Vitamins 1. The factors that affect fat-soluble vitamin absorption are the same factors that affect lipid absorption. 2. Fat-soluble vitamins are stored in various tissues and cooking generally does not destroy them. 3. Vitamin A is synthesized from carotenes and is stored in the liver. 4. Vitamin A is stable in heat, acids, and bases and unstable in light. 5. Functions of vitamin A are to help synthesize visual pigments, mucoproteins, and mucopolysaccharides. It is also needed for normal bone and teeth development and for maintenance of epithelial cells. 6. Sources of vitamin A are liver, fish, whole milk, butter, leafy green vegetables, yellow and orange vegetables, and fruits. 7. Excess vitamin A produces nausea, headache, dizziness, hair loss and birth defects and a deficiency produces night blindness and degeneration of epithelial tissues. 8. Vitamin D is a group of steroid and is stored in the liver, skin, brain, spleen, and bones. 9. Vitamin D is resistant to heat, oxidation, acids, and bases. 10. The functions of vitamin D are to promote absorption of calcium and phosphorus the development of teeth and bones. 11. Sources of vitamin D are skin, milk, egg yolk, fish, liver oils, and fortified foods. 12. An excess of vitamin D produces diarrhea, calcification of soft tissues, and renal damage and a deficiency produces rickets, bone decalcification, and weakening. 13. Vitamin E is stored in muscles and adipose tissue. 14. Vitamin E is resistant to heat and visible light and unstable in oxygen and UV light. 15. Functions of vitamin E are to prevent oxidation of vitamin A and polyunsaturated fatty acids and to maintain stability of cell membranes. 16. Sources of vitamin E are cereal seeds, salad oils, margarine, shortenings, fruits, nuts, and vegetables. 17. An excess of vitamin E produces hypertension and a deficiency produces rare, uncertain effects. 18. Vitamin K is stored in the liver. 19. Vitamin K is resistant to heat and destroyed by acids, bases, and light. 20. Functions of vitamin K are to promote blood clotting. 21. Sources of vitamin K are leafy green vegetables, egg yolk, pork liver, soy oil, tomatoes, and cauliflower. 22. A deficiency of vitamin K produces easy bruising and bleeding. C. Water-Soluble Vitamins 1. Thiamine is vitamin B1 and is destroyed by heat and oxygen. 2. The functions of thiamine are to aid in oxidation of carbohydrates and ribose synthesis. 3. Sources of thiamine are lean meats, liver, eggs, whole-grain cereals, and legumes. 4. Deficiencies of thiamine produce beriberi, muscular weakness, and enlargement of heart. 5. Riboflavin is vitamin B2, is stable to heat, acids, and oxidation and unstable in bases and UV light. 6. The functions of riboflavin are to help in oxidation of glucose and fatty acids. 7. Sources of riboflavin are meats, dairy products, leafy green vegetables, and whole-brain cereals. 8. Deficiencies of riboflavin produce dermatitis and blurred vision. 9. Niacin is stable in heat, acids, and bases and is synthesized from tryptophan. 10. The functions of niacin are to help in the oxidation of glucose and the synthesis of proteins, fats, and nucleic acids. 11. Sources of niacin are liver, lean meats, peanuts, and legumes. 12. An excess of niacin produces hyperglycemia, vasodilation and gout and a deficiency produces pellagra, photosensitive dermatitis, diarrhea, and mental disorders. 13. Pantothenic acid is destroyed by heat, acids, and bases. 14. The functions of pantothenic acid are to aid in oxidation of carbohydrates and fats. 15. Sources of pantothenic acid are meats, whole-grain cereals, legumes, milk, fruits, and vegetables. 16. Deficiencies of pantothenic are produce loss of appetite, mental depression, and mental disorders. 17. Vitamin B6 is stable in heat and acids and unstable in bases and UV light. 18. The functions of vitamin B6 are to promote synthesis of various amino acids, niacin, antibodies, and nucleic acids. 19. Sources of vitamin B6 are liver, meats, bananas, avocadoes, beans, peanuts, whole-grain cereals, and egg yolk. 20. An excess of vitamin B6 produces numbness and a deficiency produces convulsions, vomiting, and seborrhea lesions. 21. Cyanocobalamin is vitamin B12 and is stable in heat. 22. The absorption of cyanocobalamin is regulated by intrinsic factor. 23. The functions of cyanocobalamin are to promote synthesis of nucleic acids, metabolism of carbohydrates, synthesis of myelin, and red blood cells. 24. Sources of cyanocobalamin are liver, meats, milk, eggs, and cheese. 25. A deficiency of cyanocobalamin produces pernicious anemia. 25. Folacin is stored the liver and is unstable in acids, heat, and bases. 26. The functions of folacin are to promote metabolism of certain amino acids, DNA, and red blood cells. 27. Sources of folacin are liver, leafy green vegetables, whole-grain cereals, and legumes. 28. A deficiency of folacin produces megaloblastic anemia. 29. Biotin is stable in heat, acids, and light and unstable in bases. 30. The functions of biotin are to promote metabolism of amino acids and fatty acids and synthesis of nucleic acids. 31. Sources of biotin are liver, egg yolk, nuts, legumes, and mushrooms. 32. A deficiency of biotin produces elevated blood cholesterol, nausea, fatigues, and anorexia. 33. Ascorbic acid is vitamin C and is stable in acids but unstable in heat, light, and bases. 34. Functions of ascorbic acid are to promote synthesis of collagen, folinic acid, metabolism of certain amino acids, absorption of iron and synthesis of hormones from cholesterol. 35. Sources of ascorbic acid are citrus fruits, tomatoes, potatoes, and leafy green vegetables. 36. An excess of ascorbic acid produces gout and kidney stones and a deficiency produces scurvy, a lowered resistance to infection, and slow wound healing. VIII. Minerals A. Introduction 1. Minerals are inorganic elements that are essential in human metabolism. 2. Minerals are usually extracted from the soil by plants, and humans obtain them by eating plants or animals that have eaten the plants. B. Characteristics of Minerals 1. Minerals are responsible for about 4% of body weight and are most concentrated in the bones and teeth. 2. The minerals calcium and phosphate are very abundant in bones and teeth. 3. Minerals are usually incorporated into organic molecules. 4. Minerals comprise parts of the structural materials of all cells. 5. Other functions of minerals are to assist enzymes, contribute to osmotic pressure of body fluids, help conduct nerve impulses, contract muscle fibers, coagulate blood, and maintain pH. 6. The physiologically active form of minerals is the ionized form. C. Major Minerals 1. The major minerals are calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium. 2. Calcium and phosphorus are the most abundant of the major minerals accounting for nearly 75% by weight of the mineral elements in the body. 3. Calcium is primarily distributed in bones and teeth. 4. Functions of calcium are to serve as structural material for bones and teeth, to promote nerve impulse conduction, muscle fiber contraction, blood coagulation, membrane permeability, and activation of certain enzymes. 5. Sources of calcium are milk products and leafy green vegetables. 6. An excess of calcium produces kidney stones and a deficiency produces stunted growth, misshapen bones, and fragile bones. 7. Phosphorus is primarily distributed bones and teeth. 8. Functions of phosphorus are to serve as structural materials for bones and teeth, and to promote nearly all metabolic reactions, synthesis of nucleic acids, proteins, some enzymes, and some vitamins. It is also a component of cell membranes and ATP. 9. Sources of phosphorus are meats, cheeses, nuts, whole-grain cereals, milk and legumes. 10. A deficiency of phosphorus produces stunted growth. 11. Potassium is distributed widely throughout the body but mostly inside cells. 12. Functions of potassium are to help maintain intracellular osmotic pressure and regulate pH, to promote metabolism, nerve impulse conduction, and muscle fiber contraction. 13. Sources of potassium are avocados, dried apricots, meats, nuts, potatoes, and banana. 14. A deficiency of potassium produces muscular weakness, cardiac abnormalities, and edema. 15. Sulfur is distributed widely but is abundant in skin, hair, and nails. 16. Functions of sulfur are to serve as structural parts of certain amino acids, thiamine, insulin, biotin, and mucopolysaccharides. 17. Sources of sulfur are meats, milk, eggs, and legumes. 18. Sodium is distributed widely but mostly occurs in extracellular fluids. It is also bound to organic salts of bone. 19. Functions of sodium are to help maintain osmotic pressure of extracellular fluids and to regulate water movement. It also promotes nerve impulse conduction and muscle contraction and aids in regulation of pH and in transport of substances across cell membranes. 20. Sources of sodium are table salt, ham, sauerkraut, cheese, and graham crackers. 21. An excess of sodium produces hypertension and edema and a deficiency produces nausea, muscle cramps, and convulsions. 22. Chlorine is distributed closely associated with sodium and in cerebrospinal fluid and gastric juice. 23. Functions of chlorine are to help maintain osmotic pressure of extracellular fluids, to regulate pH, and to maintain electrolyte balance. It also is essential for the formation of hydrochloric acid and aids in the transport of carbon dioxide by red blood cells. 24. Sources of chlorine are table salt, ham, sauerkraut, cheese, and graham crackers. 25. An excess of chlorine produces vomiting and a deficiency produces muscle cramps. 26. Magnesium is distributed in bones. 27. Functions of magnesium are to promote metabolic reactions in mitochondria associated with ATP production and to help breakdown ATP to ADP. 28. Sources of magnesium are milk, dairy products, legumes, nuts, and leafy green vegetables. 29. An excess of magnesium produces diarrhea and a deficiency produces neuromuscular disturbances. D. Trace Elements 1. Trace elements are essential minerals found in minute amounts. 2. Examples of trace elements include iron, manganese, copper, iodine, cobalt, zinc, fluorine, selenium, and chromium. 3. Iron is distributed in blood, liver, spleen, and bone marrow. 4. Functions of iron are to promote formation of hemoglobin, vitamin A, and various enzymes. 5. Sources of iron are liver, meats, apricots, raisins, cereals, legumes, and molasses. 6. An excess of iron produces liver damage and a deficiency produces anemia. 7. Manganese is distributed in liver, kidneys, and the pancreas. 8. Functions of manganese are to synthesize certain enzymes. 9. Sources of manganese are nuts, legumes, cereals, and leafy green vegetables. 10. Copper is distributed in liver, heart and brain. 11. Functions of copper are to promote hemoglobin synthesis, bone development, melanin production, and myelin formation. 12. Sources of copper are liver, oysters, crabmeat, nuts, cereals, and legumes. 13. Iodine is concentrated in the thyroid gland. 14. Functions of iodine are to synthesize thyroid hormones. 15. Sources of iodine are iodized table salt. 16. An excess of iodine produces decreased synthesis of thyroid hormones and a deficiency produces goiter. 17. Cobalt is widely distributed. 18. Functions of cobalt are to synthesize several enzymes. 19. Sources of cobalt are liver, meats, and milk. 20. An excess of cobalt produces heart disease and a deficiency produces pernicious anemia. 21. Zinc is distributed in liver, kidneys, and the brain. 22. Functions of zinc are to synthesize several enzymes. 23. Sources of zinc are meats, cereals, legumes, nuts, and vegetables. 24. An excess of zinc produces slurred speech and problems walking and a deficiency produces depressed immunity, loss of taste and smell, and learning difficulties. 25. Fluorine is distributed in teeth and bones. 26. Functions of fluorine are to serve as structural materials for teeth. 27. Sources of fluorine are fluoridated water. 28. An excess of fluorine produces mottled teeth. 29. Selenium is distributed liver and kidneys. 30. Functions of selenium are to promote formation of various enzymes. 31. Sources of selenium are meats, fish, and cereals. 32. An excess of selenium produces vomiting and fatigue. 33. Chromium is distributed widely. 34. Functions of chromium are to promote metabolism of carbohydrates. 35. Sources of chromium are liver, meats, and wine. IX. Healthy Eating – The Food Pyramid and Reading Labels A. Introduction 1. An adequate diet provides sufficient energy, essential fatty acids, essential amino acids, vitamins, and minerals to support optimal growth and to maintain and repair body tissues. 2. It is not possible to design one diet for everyone because individual nutrient requirements vary greatly with age, sex, growth rate, amount of physical activity, and level of stress, as well as with genetic and environmental factors. 3. RDA stands for United States Recommended Daily Allowance. 4. RDA values are set high because this ensures that most people who follow them are receiving sufficient amounts of each nutrient. 5. According to the 1992 food pyramid, carbohydrates should make up the bulk of a diet. 6. According to the 1992 food pyramid, fats, oils, and sweets should be used most sparingly in a diet. 7. According to the 1992 food pyramid, a daily diet should consist of 6-11 servings of bread, cereal, rice and pasta, 2-4 servings of fruit, 2-3 servings of meat, poultry, fish, dry beans, eggs, and nuts, and 3-5 servings of vegetables. B. Malnutrition 1. Malnutrition is poor nutrition that results from a lack of essential nutrients or a failure to utilize them. 2. Undernutrition is an inadequate intake of nutrients and overnutrition is excess nutrient intake. 3. Primary malnutrition is malnutrition from diet alone. 4. Secondary malnutrition is when an individual’s characteristics make a normally adequate diet insufficient. C. Starvation 1. Introduction a. A healthy person can stay alive for 50 to 70 days without food. b. Starvation is seen in hunger strikes, in prisoners of concentration camps, and in sufferers of psychological eating disorders. c. After one day without eating, the body’s reserves of sugar and starch are gone. d. By the third day of starvation, hunger ceases as th body uses energy from fat reserves. e. Gradually during starvation, metabolism slows to conserve energy, blood pressure drops, the pulse slows, and chills set in. f. Eventually skin becomes dry and hair falls out because the proteins in these structures are broken down to release amino acids that are used for more vital functions in the body. g. Near the end of starvation, the human is blind, deaf, and emaciated. 2. Marasmus and Kwashiorkor 1. Marasmus is a lack of nutrients. 2. Children under the age of two with marasmus often die of measles and other infections because their immune systems are very weak. 3. Kwashiorkor is characterized by protruding bellies and develops when a child has recently been weaned from breast milk. 4. Ascites is the swelling of a child’s belly due to a lack of plasma proteins. 3. Anorexia Nervosa a. Anorexia nervosa is self-imposed starvation. b. Anorexia nervosa is most common in adolescent females from affluent families. c. Treatments of anorexia nervosa are intravenous feedings and therapy. 4. Bulimia a. Bulimia is a condition in which a person binges and purges food. b. A dentist is sometimes the first to spot a person with bulimia because teeth often decay from frequent vomiting. X. Life-Span Changes A. Throughout life, dietary requirements generally remain the same but the ability to acquire those nutrients may change drastically. B. Changing nutrition with age often reflects effects of medical conditions and social and economic circumstances. C. Medical conditions that affect the ability to obtain adequate nutrition are depression, tooth decay, periodontal disease, diabetes mellitus, lactose intolerance, and alcoholism. D. The BMR rises from birth to about age 5 and declines until adolescence, when it peaks again. Chapter 18: Nutrition and Metabolism I. Why We Eat A. Nutrients are ________________________________________________________________________ B. Macronutrients are ___________________________________________________________________ C. Micronutrients are ____________________________________________________________________ D. Besides nutrients, the body also requires __________________________________________________ E. Digestion breaks down ________________________________________________________________ F. Metabolism refers to __________________________________________________________________ G. Anabolism is ________________________________________________________________________ H. Catabolism is _______________________________________________________________________ I. Essential nutrients are _________________________________________________________________ J. Leptin regulates ______________________________________________________________________ K. Cholecystokinin stimulates ____________________________________________________ after eating while _________________________________________________________________ stimulates appetite. II. Carbohydrates A. Introduction 1. Carbohydrates are ________________________________________________________________________ 2. The body uses carbohydrates for _____________________________________________________________ B. Carbohydrate Sources 1. Sources of polysaccharides are ___________________________________________________ 2. Sources of disaccharides are _____________________________________________________ 3. Sources of monosaccharides are __________________________________________________ 4. Digestion breaks carbohydrates into _______________________________________________ 5. Cellulose provides _____________________________________________________________ 6. Other sources of fiber are _______________________________________________________ C. Carbohydrate Utilization 1. Monosaccharides that are absorbed from the digestive tract are __________________________ ______________________________________________________________________________ 2. The liver converts ____________________________________________________ to glucose. 3. Glycogenesis is ____________________________________________________________ and occurs in _______________________________________________________________________ 4. Glycogenolysis is __________________________________________________________ and occurs in _______________________________________________________________________ 5. Excess glucose that cannot be stored as glycogen is converted to ________________________ 6. Cells use some carbohydrates to produce ___________________________________________ 7. Gluconeogenesis is _________________________________________________________ and occurs in _______________________________________________________________________ D. Carbohydrate Requirements 1. A recommended daily carbohydrate intake is ________________________________________ 2. The average diet contains ____________________________________ of carbohydrates daily. III. Lipids A. Introduction 1. Lipids are ____________________ that include _____________________________________ ______________________________________________________________________________ 2. The functions of lipids are_______________________________________________________ ______________________________________________________________________________ B. Lipid Sources 1. Triglycerides are found in __________________________________________________________________ 2. Saturated fats are found in __________________________________________________________________ 3. Unsaturated fats are found in ________________________________________________________________ 4. Cholesterol is found in _____________________________________________________________________ C. Lipid Utilization 1. Fats are primarily used to _______________________________________________________ 2. Gram for gram, fats contain _____________________________________________________ as carbohydrates or proteins. 3. Before a triglyceride molecule can release energy, it must undergo _______________________ ______________________________________________________________________________ 4. Digestion breaks triglycerides down into ___________________________________________ 5. Glycerol and fatty acids are transported to blood through ______________________________ 6. Beta-oxidation is ______________________________________________________________ 7. Fatty acid oxidases function to ___________________________________________________ 8. Excess acetyl CoA is converted to ________________________________________________ 9. Glycerol is used to_____________________________________________________________ 10. Glycerol and fatty acids can react together to form _______________________________ and can be stored in _________________________________________________________________ 11. The liver can convert fatty acids to _______________________________________________ 12. Essential fatty acids are ________________________________________________________ 13. The liver uses free fatty acids to synthesize ________________________________________ ______________________________________________________________________________ 14. The liver regulates the amount of cholesterol in the body by ___________________________ ______________________________________________________________________________ 15. Cholesterol is not an energy source but it used to ____________________________________ ______________________________________________________________________________ D. Lipid Requirements 1. The American Heart Associate recommends that the diet not exceed _____________________ _______________________________________________________________________ from fat. 2. Dietary fats must supply the required amounts of _____________________________ vitamins. IV. Proteins A. Introduction 1. Proteins are polymers of ________________________________________________________ 2. Functions of proteins are ________________________________________________________ ______________________________________________________________________________ 3. Deamination is ____________________________________________________________ and occurs in the ____________________________________________________________________ 4. Urea is ______________________________________________________________________ 5. Using structural proteins to generate energy causes ___________________________________ ______________________________________________________________________________ B. Protein Sources 1. Foods rich in proteins are _______________________________________________________ ______________________________________________________________________________ 2. Essential amino acids are _______________________________________________________ 3. All twenty amino acids must be present in the body for ________________________________ ______________________________________________________________________________ 4. Complete proteins contain_______________________________________________________ 5. Incomplete proteins has too little _________________________________________________ ______________________________________________________________________________ 6. Sources of complete proteins are _________________________________________________ 7. Sources of incomplete proteins are ________________________________________________ C. Nitrogen Balance 1. Nitrogen balance is ____________________________________________________________ 2. A person who is starving has a negative nitrogen balance because _______________________ ______________________________________________________________________________ 3. Examples of persons with positive nitrogen balances are` ______________________________ ______________________________________________________________________________ D. Protein Requirements 1. The amount of protein requires varies according to ___________________________________ ______________________________________________________________________________ 2. The recommended intake of protein per day is _______________________________________ ______________________________________________________________________________ 3. A pregnant woman requires __________________________________ extra grams per day and a nursing mother requires _________________________________________ extra grams per day. 4. Nutritional edema results from ___________________________________________________ ______________________________________________________________________________ V. Energy Expenditures A. Introduction 1. ___________________________________________________________________________ supply energy. 2. If the diet is deficient of energy-supplying nutrients, _____________________________________________ _________________________________________________________________________________________ 3. Excess intake of energy supplying nutrients may lead to___________________________________________ B. Energy Values of Foods 1. The amount of potential energy a food contains can be expressed as ______________________ ______________________________________________________________________________ 2. A calorie is defined as __________________________________________________________ 3. A large calorie is ______________________________________________________________ 4. A kilocalorie is _______________________________________________________________ 5. A _______________________________________ is used to measure caloric contents of food. 6. Caloric values determined in a bomb calorimeter are somewhat higher than ________________ _______________________________________________________________________ because ______________________________________________________________________________ 7. Cellular oxidation yields on average about __________________________________________ from 1 gram of carbohydrate, ___________________________ from one gram of protein, andfrom one gram of fat. C. Energy Requirements 1. The factors that influence energy needs are _________________________________________ ______________________________________________________________________________ 2. Basal metabolic rate is _________________________________________________________ ______________________________________________________________________________ 3. _______________________________________________________ can be used to estimate a person’s BMR. 4. The BMR reveals _____________________________________________________________ ______________________________________________________________________________ 5. The average adult BMR indicates _________________________________________________ ______________________________________________________________________________ 6. BMR varies with ______________________________________________________________ ______________________________________________________________________________ 7. _____________________________________________________ requires the body’s greatest expenditure of energy. 8. Growing children and pregnant women require more calories because ____________________ ______________________________________________________________________________ D. Energy Balance 1. A state of energy balance exists when _____________________________________________ ______________________________________________________________________________ 2. A positive energy balance is __________________________________________________ and body weight ____________________________________________________________________ 3. A negative energy balance is __________________________________________________ and body weight ____________________________________________________________________ E. Desirable Weight 1. The most common nutritional disorders reflect ______________________________________ 2. Overweight is defined as ________________________________________________________ 3. Obesity is ___________________________________________________________________ 4. When a person needs to gain weight, diet can to altered to include _______________________ ______________________________________________________________________________ VII. Vitamins A. Introduction 1. Vitamins are _________________________________________________________________ ______________________________________________________________________________ 2. Provitamins are _______________________________________________________________ 3. Vitamins can be classified based on _______________________________________________ 4. Fat-soluble vitamins are ________________________________________________________ 5. Water-soluble vitamins are ______________________________________________________ B. Fat-Soluble Vitamins 1. The factors that affect fat-soluble vitamin absorption are _______________________________ ______________________________________________________________________________ 2. Fat-soluble vitamins are stored ________________________________________________ and cooking ________________________________________________________________________ 3. Vitamin A is synthesized from ________________________________________________ and is stored in _____________________________________________________________________ 4. Vitamin A is stable in _______________________________________________________ and unstable in _____________________________________________________________________ 5. Functions of vitamin A are ______________________________________________________ ______________________________________________________________________________ 6. Sources of vitamin A are ________________________________________________________ ______________________________________________________________________________ 7. Excess vitamin A produces ______________________________________________________ ____________________ and a deficiency produces ____________________________________ ______________________________________________________________________________ 8. Vitamin D is a group of ______________________________________________________ and is stored _______________________________________________________________________ 9. Vitamin D is resistant to ________________________________________________________ 10. The functions of vitamin D are __________________________________________________ ______________________________________________________________________________ 11. Sources of vitamin D are _______________________________________________________ ______________________________________________________________________________ 12. An excess of vitamin D produces ________________________________________________ _____________________ and a deficiency produces ___________________________________ ______________________________________________________________________________ 13. Vitamin E is stored in _________________________________________________________ 14. Vitamin E is resistant to ____________________________________________________ and ______________________________________________________________________________ 15. Functions of vitamin E are _____________________________________________________ ______________________________________________________________________________ 16. Sources of vitamin E are _______________________________________________________ ______________________________________________________________________________ 17. An excess of vitamin E produces _____________________________________________ and a deficiency produces _____________________________________________________________ 18. Vitamin K is stored ___________________________________________________________ 19. Vitamin K is resistant to ____________________________________________________ and destroyed by ____________________________________________________________________ 20. Functions of vitamin K are _____________________________________________________ ______________________________________________________________________________ 21. Sources of vitamin K are _______________________________________________________ ______________________________________________________________________________ 22. A deficiency of vitamin K produce _______________________________________________ ______________________________________________________________________________ C. Water-Soluble Vitamins 1. Thiamine is vitamin _______ and is destroyed by ____________________________________ 2. The functions of thiamine are ____________________________________________________ ______________________________________________________________________________ 3. Sources of thiamine are _________________________________________________________ ______________________________________________________________________________ 4. Deficiencies of thiamine produce _________________________________________________ ______________________________________________________________________________ 5. Riboflavin is vitamin ________, is stable to ______________________________________ and unstable in _____________________________________________________________________ 6. The functions of riboflavin are ___________________________________________________ ______________________________________________________________________________ 7. Sources of riboflavin are ________________________________________________________ ______________________________________________________________________________ 8. Deficiencies of riboflavin produce _________________________________________________ 9. Niacin is stable in __________________________________________________________ and is synthesized from_______________________________________________________________ 10. The functions of niacin are _____________________________________________________ ______________________________________________________________________________ 11. Sources of niacin are __________________________________________________________ ______________________________________________________________________________ 12. An excess of niacin produces ________________________________________________ and a deficiency produces _____________________________________________________________ 13. Pantothenic acid is destroyed by _________________________________________________ 14. The functions of pantothenic acid are _____________________________________________ ______________________________________________________________________________ 15. Sources of pantothenic acid are __________________________________________________ ______________________________________________________________________________ 16. Deficiencies of pantothenic are produce ___________________________________________ ______________________________________________________________________________ 17. Vitamin B6 is stable in______________________________________________________ and unstable in _____________________________________________________________________ 18. The functions of vitamin B6 are _________________________________________________ ______________________________________________________________________________ 19. Sources of vitamin B6 are ______________________________________________________ ______________________________________________________________________________ 20. An excess of vitamin B6 produces_____________________________________________ and a deficiency produces _____________________________________________________________ 21. Cyanocobalamin is vitamin _________ and is stable in _______________________________ ______________________________________________________________________________ 22. The absorption of cyanocobalamin is regulated by ___________________________________ 23. The functions of cyanocobalamin are _____________________________________________ ______________________________________________________________________________ 24. Sources of cyanocobalamin are __________________________________________________ ______________________________________________________________________________ 25. A deficiency of cyanocobalamin produces _________________________________________ ______________________________________________________________________________ 25. Folacin is stored ___________________________________________________________ and is unstable in ___________________________________________________________________ 26. The functions of folacin are ____________________________________________________ ______________________________________________________________________________ 27. Sources of folacin are _________________________________________________________ ______________________________________________________________________________ 28. A deficiency of folacin produces ________________________________________________ ______________________________________________________________________________ 29. Biotin is stable in__________________________________________________________ and unstable in _____________________________________________________________________ 30. The functions of biotin are _____________________________________________________ ______________________________________________________________________________ 31. Sources of biotin are __________________________________________________________ ______________________________________________________________________________ 32. A deficiency of biotin produces _________________________________________________ ______________________________________________________________________________ 33. Ascorbic acid is vitamin _________ and is stable in _________________________________ _________________ but unstable in ________________________________________________ 34. Functions of ascorbic acid are ___________________________________________________ ______________________________________________________________________________ 35. Sources of ascorbic acid are ____________________________________________________ ______________________________________________________________________________ 36. An excess of ascorbic acid produces ______________________________________________ ____________________________ and a deficiency produces ____________________________ ______________________________________________________________________________ VIII. Minerals A. Introduction 1. Minerals are _________________________________________________________________ 2. Minerals are usually extracted from ___________________________________________ , and humans obtain them by ___________________________________________________________ B. Characteristics of Minerals 1. Minerals are responsible for _________________________________________________ of body weight and are most concentrated in ______________________________________________________________________ 2. The minerals______________________________________________________________ are very abundant in bones and teeth. 3. Minerals are usually incorporated into _________________________________________________________ 4. Minerals comprise parts of __________________________________________________________________ 5. Other functions of minerals are ______________________________________________________________ _________________________________________________________________________________________ 6. The physiologically active form of minerals is __________________________________________________ C. Major Minerals 1. The major minerals are _________________________________________________________ ______________________________________________________________________________ 2. _______________________________________________ are the most abundant of the major minerals accounting for ___________________________________________________________ 3. Calcium is primarily distributed __________________________________________________ ______________________________________________________________________________ 4. Functions of calcium are ________________________________________________________ ______________________________________________________________________________ 5. Sources of calcium are _________________________________________________________ ______________________________________________________________________________ 6. An excess of calcium produces ________________________________________________ and a deficiency produces _____________________________________________________________ 7. Phosphorus is primarily distributed________________________________________________ ______________________________________________________________________________ 8. Functions of phosphorus are _____________________________________________________ ______________________________________________________________________________ 9. Sources of phosphorus are ______________________________________________________ ______________________________________________________________________________ 10. A deficiency of phosphorus produces _____________________________________________ ______________________________________________________________________________ 11. Potassium is distributed________________________________________________________ ______________________________________________________________________________ 12. Functions of potassium are _____________________________________________________ ______________________________________________________________________________ 13. Sources of potassium are _______________________________________________________ ______________________________________________________________________________ 14. A deficiency of potassium produces ______________________________________________ ______________________________________________________________________________ 15. Sulfur is distributed ___________________________________________________________ ______________________________________________________________________________ 16. Functions of sulfur are ________________________________________________________ ______________________________________________________________________________ 17. Sources of sulfur are __________________________________________________________ 18. Sodium is distributed _________________________________________________________ ______________________________________________________________________________ 19. Functions of sodium are _______________________________________________________ ______________________________________________________________________________ 20. Sources of sodium are _________________________________________________________ ______________________________________________________________________________ 21. An excess of sodium produces __________________________________________________ ____________________ and a deficiency produces ____________________________________ ______________________________________________________________________________ 22. Chlorine is distributed _________________________________________________________ ______________________________________________________________________________ 23. Functions of chlorine are _______________________________________________________ ______________________________________________________________________________ 24. Sources of chlorine are ________________________________________________________ ______________________________________________________________________________ 25. An excess of chlorine produces _____________________________________________ and a deficiency produces ______________________________________________________________ 26. Magnesium is distributed ______________________________________________________ ______________________________________________________________________________ 27. Functions of magnesium are ____________________________________________________ ______________________________________________________________________________ 28. Sources of magnesium are _____________________________________________________ ______________________________________________________________________________ 29. An excess of magnesium produces __________________________________________ and a deficiency produces ______________________________________________________________ D. Trace Elements 1. Trace elements are ____________________________________________________________ 2. Examples of trace elements include _______________________________________________ ______________________________________________________________________________ 3. Iron is distributed in ___________________________________________________________ ______________________________________________________________________________ 4. Functions of iron are ___________________________________________________________ ______________________________________________________________________________ 5. Sources of iron are ____________________________________________________________ ______________________________________________________________________________ 6. An excess of iron produces _________________________________________________ and a deficiency produces ______________________________________________________________ 7. Manganese is distributed ________________________________________________________ ______________________________________________________________________________ 8. Functions of manganese are _____________________________________________________ ______________________________________________________________________________ 9. Sources of manganese are _______________________________________________________ ______________________________________________________________________________ 10. Copper is distributed __________________________________________________________ ______________________________________________________________________________ 11. Functions of copper are ________________________________________________________ ______________________________________________________________________________ 12. Sources of copper are _________________________________________________________ ______________________________________________________________________________ 13. Iodine is concentrated in _______________________________________________________ 14. Functions of iodine are ________________________________________________________ 15. Sources of iodine are __________________________________________________________ ______________________________________________________________________________ 16. An excess of iodine produces ______________________________________________ and a deficiency produces ______________________________________________________________ 17. Cobalt is __________________________________________________________ distributed. 18. Functions of cobalt are ________________________________________________________ ______________________________________________________________________________ 19. Sources of cobalt are __________________________________________________________ ______________________________________________________________________________ 20. An excess of cobalt produces ______________________________________________ and a deficiency produces ______________________________________________________________ 21. Zinc is distributed ____________________________________________________________ 22. Functions of zinc are __________________________________________________________ ______________________________________________________________________________ 23. Sources of zinc are ___________________________________________________________ ______________________________________________________________________________ 24. An excess of zinc produces ________________________________________________ and a deficiency produces ______________________________________________________________ 25. Fluorine is distributed _________________________________________________________ 26. Functions of fluorine are _______________________________________________________ 27. Sources of fluorine are ________________________________________________________ 28. An excess of fluorine produces __________________________________________________ 29. Selenium is distributed ________________________________________________________ 30. Functions of selenium are ______________________________________________________ 31. Sources of selenium are _______________________________________________________ 32. An excess of selenium produces _________________________________________________ 33. Chromium is distributed _______________________________________________________ 34. Functions of chromium are _____________________________________________________ 35. Sources of chromium are ______________________________________________________ IX. Healthy Eating – The Food Pyramid and Reading Labels A. Introduction 1. An adequate diet provides _______________________________________________________ ______________________________________________________________________________ 2. It is not possible to design one diet for everyone because ______________________________ ______________________________________________________________________________ 3. RDA stands for _______________________________________________________________ 4. RDA values are set _______________ because ______________________________________ ______________________________________________________________________________ 5. According to the 1992 food pyramid, ______________________________________________ ___________________________________________________ should make up the bulk of a diet. 6. According to the 1992 food pyramid, _____________________________________ should be used most sparingly in a diet. 7. According to the 1992 food pyramid, a daily diet should consist of 6-11 servings of ________________________, 2-4 servings of _______________________________ , 2-3 servings of _________________________________________________________________ , and 3-5 servings of ______________________________________________________________ B. Malnutrition 1. Malnutrition is _______________________ that results from ___________________________ ______________________________________________________________________________ 2. Undernutrition is ________________________________________________ and overnutrition is _____________________________________________________________________________ 3. Primary malnutrition is _________________________________________________________ 4. Secondary malnutrition is _______________________________________________________ ______________________________________________________________________________ C. Starvation 1. Introduction a. A healthy person can stay alive for ________________________________________________ without food. b. Starvation is seen in ____________________________________________________ _______________________________________________________________________ c. After one day without eating, the body ______________________________________ _______________________________________________________________________ d. By the third day of starvation,_____________________________________________ _______________________________________________________________________ e. Gradually during starvation, metabolism ______________________________ , blood pressure, __________________, the pulse _________________________________ , and __________________________________________________________________ set in. f. Eventually skin becomes dry and hair falls out because _________________________ _______________________________________________________________________ g. Near the end of starvation, the human is _____________________________________ _______________________________________________________________________ 2. Marasmus and Kwashiorkor 1. Marasmus is __________________________________________________________ 2. Children under the age of two with marasmus often die of ______________________ ____________________________ because ___________________________________ 3. Kwashiorkor is characterized by ________________________________________ and develops when ___________________________________________________________ _______________________________________________________________________ 4. Ascites is _____________________________________________________________ _______________________________________________________________________ 3. Anorexia Nervosa a. Anorexia nervosa is _____________________________________________________ b. Anorexia nervosa is most common in _______________________________________ _______________________________________________________________________ c. Treatments of anorexia nervosa are ________________________________________ _______________________________________________________________________ 4. Bulimia a. Bulimia is a condition in which ___________________________________________ _______________________________________________________________________ b. A dentist is sometimes the first to spot a person with bulimia because _______________________________________________________________________ X. Life-Span Changes A. Throughout life, dietary requirements _________________________________________________ but the ability to ___________________________________________________________________________ B. Changing nutrition with age often reflects _________________________________________________ _____________________________________________________________________________________ C. Medical conditions that affect the ability to obtain adequate nutrition are _________________________ _____________________________________________________________________________________ D. The BMR rises ____________________ and declines _______________________________________
