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1 Tucker Chapter 2 Concepts for Lecture LEARNING OUTCOME 1 To differentiate the types of carbohydrates and list dietary sources of each. Concepts for Lecture 1. Carbohydrates are compounds that contain carbon, hydrogen, and oxygen. The general molecular formula is CH 2O. The formulation Cx(H 2O)y shows how complex or simple a carbohydrate can be. 2. Carbohydrates are classified into groups according to the following factors: the length of the carbon chain, the number of sugar units, and the location of the double bond between the carbon and oxygen molecules. 3. All carbohydrates are formed with a base of at least one sugar molecule, but some have several or hundreds. Some carbohydrates are a straight chain while others are branched. These factors determine whether a carbohydrate is simple or complex. 4. Simple carbohydrates are classified into monosaccharides or disaccharides. The three types of monosaccharides include: glucose: commonly known as blood sugar; provides cells with fuel to make energy fructose: found in fruit and honey; often used to sweeten food galactose: found in milk as a component of lactose and in some fruits 5. Disaccharides are composed of two monosaccharides, and are broken down into these components before being absorbed by the body. The three most common disaccharides are sucrose, lactose, and maltose. Sucrose is a common table sugar usually derived from sugar cane or sugar beets. It is composed of glucose and fructose monosaccharides. Lactose is found in human and animal milk. It is composed of glucose and galactose. Maltose is a preliminary component of starch production. It is the disaccharide found least in nature. 6. Complex carbohydrates, also known as polysaccharides, include starches, glycogen, celluloses, and fibers. 7. Starches are the storage form of energy in plants. Starches are found in two forms: amylose and amylopectin. Amylase is the pancreatic enzyme that breaks down starches so that the body can digest them into glucose and maltose. 8. Starch is stored in the liver and muscles of humans and animals as glycogen. Glycogen can be accessed when the body s glucose level fall too low. 9. Fiber is a form of polysaccharide that is not digested by the body. Fiber moves through the digestive tract until partially fermented by bacteria in the colon.

2 10. Fiber is classified into two categories: insoluble and soluble. Insoluble fiber includes cellulose, hemicelluloses, and lignins. All three components give plant foods texture. Insoluble fibers add bulk to stool by increasing stool volume and absorbing water. This promotes bowel movement, or laxation. Cellulose is the most abundant polysaccharide in nature. The only monosaccharide in cellulose is glucose. The lack of branch chains in cellulose results in compounds that can lie close together, creating a rigid fiber and providing structure to a plant. 11. Soluble fiber includes gums, pectics, some hemicelluloses, and mucilages. Soluble fiber forms a gel in the intestine that slows digestion, diminishing how quickly sugar is absorbed in the intestine. For this reason, patients with diabetes mellitus may benefit by including fiber in their diet. Soluble fiber binds fatty acids in the intestine. This can lower blood cholesterol by reducing the recycling of bile back to the liver after reabsorption. PowerPoint Lecture Slides 1. Carbohydrates are compounds that contain carbon, hydrogen, and oxygen. general molecular formula: CH 2O more accurate formulation shows how complex or simple a carbohydrate can be: Cx(H 2O)y 2. Carbohydrates are classified into groups according to: the length of the carbon chain the number of sugar units the location of the double bond between the carbon and oxygen molecules 3. A carbohydrate is simple or complex, depending on: number of sugar molecules will have at least one, and sometimes hundreds whether it is a straight chain or branched 4. Simple carbohydrates: monosaccharides or disaccharides Three types of monosaccharides: glucose fructose galactose 5. Disaccharides: composed of two monosaccharides broken down into the two monosaccharides before being absorbed by the body Three most common disaccharides: sucrose lactose maltose

3 6. Complex carbohydrates, or polysaccharides, include: starches glycogen celluloses fibers 7. Starches: the storage form of energy in plants Found in two forms: amylose amylopectin 8. Glycogen: form in which starch is stored in the liver and muscles accessed when glucose levels fall too low 9. Fiber: a polysaccharide not digested by the body moves through digestive tract until partially fermented by bacteria in the colon 10. Two categories of fiber: insoluble and soluble Insoluble fiber: o includes cellulose, hemicelluloses, and lignins o gives plant food texture o adds bulk to stool and promotes laxation Cellulose: o the most abundant polysaccharide in nature o contains the monosaccharide glucose o a rigid fiber that provides structure to plants 11. Soluble fiber: includes gums, pectins, some hemicelluloses, and mucilages slows digestion, diminishing how quickly sugar is absorbed in the intestine binds fatty acids in the intestine, resulting in lower blood cholesterol Suggestions for Classroom Activities Have students conduct research on lactose intolerance to determine its prevalence among individuals of various cultural or ethnic groups in the United States. Through their research, students should determine foods that lactose-intolerant individuals may need to avoid. They should then outline dietary advice that a nurse might give to a patient who is lactose intolerant. Assign students the task of researching the dietary benefits of fiber for either individuals who are diabetic or individuals who have high cholesterol. Have each student pair up with another student who researched the opposite subject. Then have each pair of students take turns playing the role of nurse and client. In each case, the nurse should explain to the client why fiber in the diet may be beneficial to health.

4 Suggestions for Clinical Activities Talk with a client who has reported problems with constipation. Ask the client what nonpharmacological measures he or she takes to deal with the problem. Provide dietary suggestions and the rationale for them to the client. Talk with a client who is taking lipid-lowering medication. Find out how long the client has been on the medication and the dietary modifications that have been implemented. Ask which health care professionals have worked with the client on nutrition education. Report your findings to your clinical group. LEARNING OUTCOME 2 To relate the functions of carbohydrates to the body. Concepts for Lecture 1. Simple and complex carbohydrates supply energy to the body in the form of glucose. Glucose is the preferred fuel source for red blood cells, the brain, and the central nervous system. 2. Carbohydrates are broken down by the body into glucose to serve as a source of energy and spare protein for other functions. The synthesis of glucose from protein or glycogen is called gluconeogenesis. When there is insufficient glucose, fat stores can be metabolized, resulting in ketone bodies, which are the by-products of incomplete metabolism. These can be used as a form of energy, but result in reduced function of brain and other tissues that depend on glucose. 3. Carbohydrates are also used to make ribose, keratin, and glycoproteins. 4. Excessive carbohydrate intake results in storage as glycogen in muscles and liver. Excess beyond this is metabolized as triglycerides. 5. Fiber is not absorbed by the small intestine and can be fermented to produce short-chain fatty acids. Fermentation causes bloating as methane and carbon dioxide are produced at different rates, depending upon whether the fibers are fruit, vegetable, or grain. Fiber plays an important role in health maintenance by promoting laxation and controlling blood cholesterol and blood glucose. 6. Carbohydrates are digested through the process of hydrolysis from long chain to enzyme to shortened chain to monosaccharides. Hydrolysis begins in the mouth where an enzyme, salivary amylase, acts on starches and continues in the small intestine where enzymes such as lactase, dextrinase, isomaltase, maltase, and sucrase catalyze polysaccharides and disaccharides into monosaccharides. Deficiencies in any of these enzymes may cause diarrhea, bloating, and flatulence.

5 7. Glucose and galactose move into the capillaries via the GLUT2 transport system. Fructose is transported via GLUT5 and then into the blood by GLUT2. Following absorption, glucose enters the capillaries via the GLUT 2 transport system. The capillaries move the glucose into the hepatic portal vein, where it is directed to the liver. The liver releases the glucose into the bloodstream for the body to use. 8. Insulin and glucagon are the hormones that regulate blood glucose levels. Insulin is released by the pancreas to move the glucose out of the bloodstream when blood glucose levels are too high. Glucagon stimulates the conversion of stored glycogen into glucose when blood glucose levels are too low. 9. The glycemic index refers to the measure of rise in blood glucose during the two hours following ingestion of 50 gm of carbohydrate. High glycemic index foods cause a quick elevation in blood glucose following intake. Low glycemic index foods result in a blunted response following intake. The preparation and cooking method, as well as the presence of protein, fat, fiber, or other meal components may alter the glycemic index of foods. High-fiber foods slow gastric emptying and have a lower glycemic index than low- or no-fiber foods. PowerPoint Lecture Slides 1. Glucose: form of energy supplied by simple and complex carbohydrates Preferred fuel source for: o red blood cells o the brain o the central nervous system 2. Carbohydrates make glucose to: serve as a source of energy spare the use of protein for other functions Gluconeogenesis: synthesis of glucose from protein or glycogen Insufficient glucose body uses protein or ketone bodies for energy reduced function of brain and other tissues that need glucose 3. Carbohydrates also make: ribose keratin glycoproteins 4. Response to carbohydrate intake in excess of body s need for glucose: Glucose is stored as glycogen in muscles and liver. Glucose in excess of the capacity to store glycogen is metabolized into triglycerides.

6 5. Fiber: is not absorbed by the small intestine can be fermented to produce short-chain fatty acids o fermentation bloating as methane and carbon dioxide is produced Function of fiber in health maintenance: promotes laxation controls blood cholesterol and blood glucose 6. Hydrolysis: the process of carbohydrate digestion long-chain carbohydrates shortened chain monosaccharides begins in the mouth where an enzyme, salivary amylase, acts on starches continues in the brush border of the small intestine where enzymes catalyze polysaccharides and disaccharides into monosaccharides for absorption Deficiency in brush border enzymes may cause: diarrhea bloating flatulence 7. Transport through body: glucose and galactose: transported into the capillaries via GLUT2 fructose: transported via GLUT5 and then into the blood by GLUT2 Transport of glucose through the body following absorption: into capillaries via GLUT2 transport system hepatic portal vein liver bloodstream 8. Hormones regulate blood glucose levels insulin: moves glucose out of blood stream when blood glucose levels rise glucagon: stimulates conversion of stored glycogen into glucose when blood glucose levels are too low 9. Glycemic index: measure of rise in blood glucose during two hours after ingestion of 50 gm of carbohydrate High glycemic index foods quick elevation in blood glucose following intake Low glycemic index foods blunted response following intake Factors that alter glycemic index: preparation or cooking method presence of protein, fat, fiber, or other meal components High-fiber foods: slow gastric emptying lower glycemic index than low or no fiber foods Suggestions for Classroom Activities Have each student come to class prepared with a list of five high glycemic index foods and five low glycemic index foods. In class, have students share food items from their lists. From the students findings, create a master list of foods that might be recommended for a diabetic patient and foods that a diabetic patient should avoid.

7 Have students create a visual representation of how glucose is transported through the body. Students may use drawings, magazine cut-outs, pictures from the Internet, or other items in their displays. Suggestions for Clinical Activities Review the menu options for a diabetic client in the acute care setting. Which of the options are high-glycemic foods and which are low-glycemic foods? How can the nurse use knowledge of high- and low-glycemic foods to help the diabetic client make good food selections from the hospital menu? Ask a dietician to show you some materials that are shared with new type 2 diabetics. How is the concept of glycemic index presented in the materials? Share your findings with your clinical group. LEARNING OUTCOME 3 To counsel individuals about the dietary recommendations for carbohydrate intake. Concepts for Lecture 1. Carbohydrates are found in plant-based foods, milk and yogurt, and prepared and processed foods with added sugars. 2. Simple sugar food sources include those that occur naturally in plant-based foods and added sugars. Naturally occurring, or intrinsic, sugars include fructose, lactose, and sucrose. Added, or extrinsic, sugars include sucrose and high-fructose corn syrup. 3. The Nutrition Facts Panel on food labels may not be a clear indicator of overall nutritional value because it does not differentiate between naturally occurring and added sugars. 4. Complex carbohydrates include foods that contain starches and fibers. Starch is the form of carbohydrate stored in plants. 5. Whole grains refer to foods not overly processed during milling. Therefore, they retain outer portions of the grain, known as the germ and bran. Processed, or refined, grains results in the removal of the germ and bran. This causes a loss of fiber and nutrients. Nutrients that are lost are sometimes replaced in a process referred to as enrichment. Nutrients that are not originally present in the food are sometimes added in a process referred to as fortification. 6. Fiber is found in plant-based foods. Foods closer to their original form have higher fiber contents than processed or prepared foods. Most fiber-containing foods include both soluble and insoluble fibers. 7. Recommended Dietary Allowance (RDA) for carbohydrate is a minimum of 130 gm. A range of 45-65% of daily calorie intake should come from carbohydrates. Factors that account for varying carbohydrate needs: weight and activity level pregnant or lactating women have elevated carbohydrate needs

8 8. Simple sugar intake recommendations apply to added sugars. There is no recommended limit to the intake of naturally occurring sugars. recommended daily intake of added sugars: not to exceed 25% of total calories World Health Organization recommendation: not to exceed 10% of total calories 9. The Dietary Guidelines for Americans and Health Canada recommend that foods and drinks with added sugars be limited for dental health and avoidance of excessive calorie intake. The Dietary Guidelines offer suggestions of sugar intake as part of a person s discretionary calories. 10. The Dietary Guidelines for Americans and Health Canada recommendations regarding complex carbohydrates: Intake should come from a variety of food groups. Fiber-rich versions of fruits, vegetables, grains, and legumes are encouraged food sources. Whole grains should comprise at least half of the recommended intake for grains. 11. The recommended daily total fiber intake, based on 14 gm fiber per 1,000 kcalories consumed, is 25 gm for females and 38 gm for males. Total fiber is the sum of dietary fiber and functional fiber. Dietary fibers: the indigestible carbohydrate found in plant cell walls and woody component Functional fibers: the indigestible carbohydrate that also has a physiologic function, such as promoting laxation or reducing blood lipids 12. If more fiber is needed in the diet, it should be increased gradually to avoid intestinal side effects. Adequate fluid intake will improve tolerance to increased fiber. 13. Excessive fiber intake is a self-limiting practice, so no upper limit recommendations for fiber intake have been made. PowerPoint Lecture Slides 1. Food sources of carbohydrates: plant-based foods milk and yogurt prepared and processed foods with added sugars 2. Simple sugar food sources include those with naturally occurring and added sugars: Naturally occurring, or intrinsic, sugars: o fructose o lactose o sucrose Added, or extrinsic, sugars: o sucrose o high-fructose corn syrup 3. Nutrition Facts Panel on food labels does not differentiate between naturally occurring and added sugars may not be a clear indicator of overall nutritional value 4. Complex carbohydrates: foods that contain starches and fibers Starches: the form of carbohydrate stored in plants

9 5. Whole grains: not overly processed during milling retain the germ and bran Processed, or refined, grains: removal of germ and bran cause loss of fiber and nutrients enrichment: nutrients lost during processing are replaced fortification: nutrients not originally present are added 6. Fiber in plant-based foods: most include soluble and insoluble fibers foods closer to original form have greater fiber content than processed or prepared foods 7. Recommended Dietary Allowance (RDA): daily minimum of 130 gm of carbohydrates range of 45 65% of daily calorie intake should come from carbohydrates Factors that affect carbohydrate needs: weight activity level pregnancy and lactation 8. Recommended intake of added sugars: daily intake not to exceed 25% of total calories World Health Organization: not to exceed 10% of total calories 9. Dietary Guidelines for Americans and Health Canada recommendations regarding sugar: limit intake of foods and drinks with added sugars to: o promote dental health o avoid excessive calorie intake Dietary Guidelines recommend sugar as discretionary calories 10. Dietary Guidelines for Americans and Health Canada recommendations regarding complex carbohydrates: Intake should come from a variety of food groups, including: o fruits o vegetables o grains o legumes Whole grains = at least half of the recommended grain intake 11. Recommended daily total fiber intake, based on 14 gm fiber per 1,000 kcalories consumed: 25 gm for females 38 gm for males Total fiber = sum of dietary fiber and functional fiber: Dietary fibers: the indigestible carbohydrate found in plant cell walls and woody component Functional fibers: the indigestible carbohydrate that also has a physiologic function

10 12. Increasing fiber in diet: increase gradually to avoid intestinal side effects take in adequate fluid to improve tolerance 13. Excessive fiber intake: self-limiting practice no upper limit recommendations Suggestions for Classroom Activities Have students monitor their intake of grains for one week to determine how much of their total intake includes whole grains. Have students share their findings as a class. Ask students to infer, based on the information gathered by their classmates, whether most Americans meet, or come close to, their whole grain needs. Then ask students to determine specific suggestions that the nurse might offer individuals to help them increase their intake of whole grains. Have students join in pairs, with one student playing the role of the nurse and the other the role of the client who needs to increase fiber in his or her diet. Ask the nurse to explain to the client why fiber is beneficial in the diet, the possible side effects of increasing fiber intake, and ways in which he or she can safely and comfortably increase fiber intake. Suggestions for Clinical Activities Ask a client to name a high-fiber food that he or she eats daily. Is it really a high-fiber food, or is it one the client thinks is high fiber? Follow up with appropriate teaching to the client. During a postconference, compare the findings to see what responses clients gave. If you are assigned a client who is experiencing constipation or diarrhea, review with that client the role that fiber may play in that situation. Review the client s menu choices, if possible, and make suggestions that may play a role in alleviating the condition. LEARNING OUTCOME 4 To examine the appropriateness of the use of nutritive and nonnutritive sweeteners. Concepts for Lecture 1. Nonnutritive sweeteners are sugar substitutes that contain insignificant or no kcalories. 2. Stevia is a plant-derived, noncaloric sweetener that is not yet approved in the United States or Canada for use as a sweetener or food additive. Concerns exist about a possible link between stevia and infertility and mutagenic risks. 3. Five nonnutritive sweeteners approved for use with guidelines given for Acceptable Daily Intake (ADI) are aspartame, acesulfame potassium, sucralose, neotame, and saccharin. Aspartame is marketed as Nutrasweet and Equal. It is composed of aspartic acid and phenylalanine. Its caloric contribution is insignificant because so little is needed due to its powerful sweetness. Scientific research has not found an association between aspartame and negative health effects. 4. Acesulfame potassium (acesulfame-k) is an all-purpose sweetener marketed as Sunette. Because of its intense sweetness, it is often blended with other nonnutritive sweeteners.

11 5. Sucralose is marketed as Splenda. It is composed of a sucrose molecule chemically combined with chlorine. It is poorly absorbed by the intestines and has no caloric value. It is used in cooking and baking because it is heat stable. Scientific research has not substantiated claims of negative health effects of sucralose. 6. Neotame is not yet widely available in foods. It is 7,000 to 13,000 times sweeter than sucrose. It is chemically similar to aspartame since it contains aspartic acid and phenylalanine. 7. Saccharin is marketed as Sweet N Low and Sugar Twin. It is an artificial sweetener made from synthetic chemicals. It is approved by the FDA for use in beverages, as a packaged sugar substitute, and in some processed foods at controlled levels. 8. Nutritive sweeteners are sugar substitutes that do contain kcalories. Sugar alcohols, also called polyols, are lower calorie sugar replacements that are derived from sugars. Common sugar alcohols include sorbitol, mannitol, and xylitol. These sweeteners are absorbed more slowly and in lesser amounts than simple sugars. This results in an average energy content of 2 kcalories/gm, rather than the 4 kcalories/gm of sugars and other carbohydrates. Excessive intake of sugar alcohols has a laxative effect and may cause diarrhea. Excessive intake may also lead to an increased risk of dental caries. PowerPoint Lecture Slides 1. Nonnutritive sweeteners: sugar substitutes that contain insignificant or no kcalories 2. Stevia: plant-derived, noncaloric sweetener not yet approved in the United States or Canada for use as a sweetener or food additive possible link to infertility and mutagenic risks 3. Five nonnutritive sweeteners approved for use with guidelines given for Acceptable Daily Intake (ADI): aspartame, acesulfame potassium, sucralose, neotame, and saccharin Aspartame marketed as Nutrasweet and Equal: composed of aspartic acid and phenylalanine little caloric contribution no confirmed links to negative health affects 4. Acesulfame potassium (acesulfame-k) marketed as Sunette: all-purpose sweetener blended with other nonnutritive sweeteners because of intense sweetness 5. Sucralose marketed as Splenda: composed of a sucrose molecule chemically combined with chlorine poorly absorbed by intestines, no caloric value heat stable no confirmed links to negative health effects

12 6. Neotame not yet widely available in foods contains aspartic acid and phenylalanine 7,000 to 13,000 times sweeter than sucrose 7. Saccharin marketed as Sweet N Low and Sugar Twin: made from synthetic chemicals FDA approved for use in beverages, packaged sugar substitute, and some processed foods 8. Nutritive sweeteners: sugar substitutes that do contain kcalories Sugar alcohols: lower calorie sugar replacements that are derived from sugars absorbed more slowly and in lesser amounts than simple sugars average energy content of 2 kcalories/gm Common sugar alchohols: sorbitol mannitol xylitol Result of excessive sugar alcohol intake: laxative effect, may cause diarrhea may also lead to an increased risk of dental caries Suggestions for Classroom Activities Have half of the students in the class conduct Internet research to determine the range of ideas that exist regarding the health effects of nonnutritive sweeteners. Have the other students conduct research on specific scientific studies on the health effects of nonnutritive sweeteners. In class, have each half educate the other half on their findings. At the end of the activity, all students should have an understanding of the range of beliefs that exist regarding nonnutritive sweeteners as compared to scientific research regarding these. Suggestions for Clinical Activities Ask several diabetic clients which nonnutritive sweeteners they use. Find out why they selected the one(s) they use. Did a health care provider make a recommendation? If so, was it a physician, dietician, or nurse? Ask a diabetic client who uses a nonnutritive sweetener what he or she knows about the sweetener. How well does what the client knows correlate with what you know about that sweetener? Is there misinformation that you should dispel?

13 LEARNING OUTCOME 5 To formulate nursing interventions that will assist individuals in improving intake of dietary fiber. Concepts for Lecture 1. Carbohydrate intake may increase the risk of dental caries. Altered digestion or metabolism may result from carbohydrate intake in individuals who have lactose intolerance, fructose maldigestion, galactosemia, or diabetes mellitus. There is also a possible relationship between carbohydrate intake and weight gain. Therefore, lowcarbohydrate diets have become more popular. Some side effects of these diets include: changes in blood lipid levels increased loss of urinary calcium insufficient intake of nutrients found in fruits, vegetables, whole grains, and milk 2. Fiber promotes intestinal health in the following ways: normalizes the transit time of substances through the intestinal tract and promotes laxation increases stool bulk and weight and relieves constipation can prevent the development of diverticula Some studies suggests that fiber may have a role in the prevention of colon cancer, but most authorities cite the lack of clear evidence in this area. 3. High-fiber diets may be beneficial in weight management because they have fewer calories than other foods of equal weight, create the feeling of fullness because of their volume, and may delay gastric emptying. 4. Soluble fibers interfere with enterohepatic recycling of bile, leading to a reduction in blood cholesterol levels. 5. Some soluble fibers slow gastric emptying and therefore absorption of glucose following a meal, leading to improved postmeal blood glucose levels in diabetics. PowerPoint Lecture Slides 1. Concerns and potential health effects related to carbohydrate intake include the following: increased risk of dental caries possible relationship between carbohydrate intake and weight gain side effects of low-carbohydrate diets: o changes in blood lipid levels o increased loss of urinary calcium o insufficient intake of nutrients found in fruits, vegetables, whole grains, and milk altered digestion or metabolism: lactose intolerance, fructose maldigestion, galactosemia, diabetes mellitus 2. Fiber promotes intestinal health: normalizes the transit time of substances through the intestinal tract and promotes laxation increases stool bulk and weight and relieves constipation

14 can prevent the development of diverticula may have a role in the prevention of colon cancer, but there is a lack of clear evidence 3. High-fiber diets may help manage weight because they: have fewer calories than other foods of equal weight create the feeling of fullness because of their volume may delay gastric emptying 4. Soluble fibers: interfere with enterohepatic recycling of bile reduction in blood cholesterol levels 5. Some soluble fibers: slow gastric emptying and absorption of glucose improved postmeal blood glucose levels in diabetics Suggestions for Classroom Activities Have students conduct a survey in which they ask twenty other college students the following questions: o Do you think that eliminating carbohydrates from one s diet is a safe way to lose weight? o Do you think that eliminating carbohydrates from one s diet is an effective way to lose weight? o Do you think that limiting the number of carbohydrates in one s diet is a safe and effective way to lose weight? o Have you ever used a no- or low-carb diet as a means to lose weight? o Do you know anyone who has used a no- or low-carb diet to lose weight? o Would learning of possible health risks of no- or low-carb diets influence your decision to use such a diet as a means to lose weight? In class, put students in groups to share their findings with one another. Students should determine the implications of their results, especially in terms of how often the nurse may encounter patients who have tried no- or low-carb diets, and ways in which the nurse can educate clients regarding safely limiting their carbohydrate intake. Suggestions for Clinical Activities Ask clients if they read food facts labels. If they do, ask what they know about the recommended amount of fiber that should be consumed daily. How often do clients report looking at the fiber content of foods? Give some simple suggestions to elderly clients who have problems with dentition about how to increase fiber intake.