Section 1 Fundamentals of Nutrition Copyright 2003 Delmar

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Section 1 Fundamentals of Nutrition Copyright © 2003 Delmar Learning, a Thomson Learning company

Section 1 Fundamentals of Nutrition Copyright © 2003 Delmar Learning, a Thomson Learning company

Chapter 4 Carbohydrates Copyright © 2003 Delmar Learning, a Thomson Learning company

Chapter 4 Carbohydrates Copyright © 2003 Delmar Learning, a Thomson Learning company

Objectives § § § Chapter 4 Identify the functions of carbohydrates Name the primary

Objectives § § § Chapter 4 Identify the functions of carbohydrates Name the primary sources of carbohydrates Describe the classification of carbohydrates Copyright © 2003 Delmar Learning, a Thomson Learning company 3

Facts Primary source of energy for the body. Least expensive and most abundant of

Facts Primary source of energy for the body. Least expensive and most abundant of the energy nutrients. Named for the chemical elements they are composed of—carbon, hydrogen, and oxygen. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 4

Functions § § Chapter 4 Provide energy Protein-sparing action Normal fat metabolism Provide fiber

Functions § § Chapter 4 Provide energy Protein-sparing action Normal fat metabolism Provide fiber Copyright © 2003 Delmar Learning, a Thomson Learning company 5

Providing Energy Each gram of carbohydrate provides 4 kcal. A body needs a constant

Providing Energy Each gram of carbohydrate provides 4 kcal. A body needs a constant energy supply. A half day’s supply of carbohydrates is stored in the liver and muscles for use as needed. Stored form is called glycogen. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 6

Protein-Sparing Action The primary function of proteins is to build and repair tissues. When

Protein-Sparing Action The primary function of proteins is to build and repair tissues. When enough carbohydrates (at least 50100 g/day) are ingested, protein is spared. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 7

Normal Fat Metabolism Without an adequate supply of carbohydrates, fat is metabolized to meet

Normal Fat Metabolism Without an adequate supply of carbohydrates, fat is metabolized to meet energy requirements. Ketones are produced as a byproduct of fat metabolism. Ketosis may result. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 8

Stop and Share With a partner role-play the following: A patient asks the nurse

Stop and Share With a partner role-play the following: A patient asks the nurse about starting a high-protein, low-carbohydrate diet. How should the nurse respond? Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 9

Stop and Share Carbohydrates are necessary for energy. Lack of adequate carbohydrate intake may

Stop and Share Carbohydrates are necessary for energy. Lack of adequate carbohydrate intake may result in ketosis (a condition in which acids, called ketones, accumulate in the blood). Protein is best used for building and repairing body tissues. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 10

Providing Fiber Dietary fiber is found in grains, vegetables, and fruits. Recommended intake is

Providing Fiber Dietary fiber is found in grains, vegetables, and fruits. Recommended intake is 20 -35 g/day. Fiber lowers blood glucose levels; may prevent some colon cancers; and helps prevent constipation, hemorrhoids, and diverticular disease by softening stool. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 11

Food Sources Principal sources of carbohydrates are plant foods: • • • Cereal grains

Food Sources Principal sources of carbohydrates are plant foods: • • • Cereal grains Vegetables Fruits Nuts Sugars The only substantial animal source is milk. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 12

Classification Monosaccharides • Simple sugars Disaccharides Polysaccharides • Chapter 4 Complex carbohydrates Copyright ©

Classification Monosaccharides • Simple sugars Disaccharides Polysaccharides • Chapter 4 Complex carbohydrates Copyright © 2003 Delmar Learning, a Thomson Learning company 13

Monosaccharides Simplest form of carbohydrates Absorbed directly into bloodstream from the small intestine Glucose,

Monosaccharides Simplest form of carbohydrates Absorbed directly into bloodstream from the small intestine Glucose, fructose, galactose Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 14

Monosaccharides Glucose • • Chapter 4 Also called dextrose All other forms are converted

Monosaccharides Glucose • • Chapter 4 Also called dextrose All other forms are converted to glucose for eventual metabolism Berries, grapes, sweet corn, corn syrup Central nervous system, red blood cells and brain use only glucose as fuel Copyright © 2003 Delmar Learning, a Thomson Learning company 15

Monosaccharides Fructose • • • Chapter 4 Also called levulose or fruit sugar Ripe

Monosaccharides Fructose • • • Chapter 4 Also called levulose or fruit sugar Ripe fruits, honey, soft drinks Sweetest of all the monosaccharides Copyright © 2003 Delmar Learning, a Thomson Learning company 16

Monosaccharides Galactose • • • Chapter 4 Product of digestion of milk Not found

Monosaccharides Galactose • • • Chapter 4 Product of digestion of milk Not found naturally Source is lactose Copyright © 2003 Delmar Learning, a Thomson Learning company 17

Disaccharides Pairs of monosaccharides Must be changed to simple sugars by hydrolysis before absorption

Disaccharides Pairs of monosaccharides Must be changed to simple sugars by hydrolysis before absorption Sucrose, maltose, and lactose Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 18

Disaccharides Sucrose • • Chapter 4 Composed of glucose and fructose Form of carbohydrate

Disaccharides Sucrose • • Chapter 4 Composed of glucose and fructose Form of carbohydrate present in granulated, powdered, and brown sugar, and in molasses One of the sweetest and least expensive sugars Sources: sugar cane, sugar beets, maple syrup, candy, jams and jellies Copyright © 2003 Delmar Learning, a Thomson Learning company 19

Disaccharides Maltose • • Chapter 4 Intermediary product in the hydrolysis of starch Also

Disaccharides Maltose • • Chapter 4 Intermediary product in the hydrolysis of starch Also created during the fermentation process that produces alcohol Found in some infant formulas, malt beverage products, and beer Less sweet than glucose or sucrose Copyright © 2003 Delmar Learning, a Thomson Learning company 20

Disaccharides Lactose • • Chapter 4 Sugar found in milk Distinct from other sugars

Disaccharides Lactose • • Chapter 4 Sugar found in milk Distinct from other sugars in that it is not found in plants Helps body absorb calcium Less sweet than monosaccharides or other disaccharides Copyright © 2003 Delmar Learning, a Thomson Learning company 21

Stop and Share Your patient complains of bloating, abdominal cramps, and diarrhea after drinking

Stop and Share Your patient complains of bloating, abdominal cramps, and diarrhea after drinking milk or consuming a milk-based food such as processed cheese. What is the likely cause of these symptoms? What causes this condition? What recommendations can be made? Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 22

Stop and Share Lactose intolerance is the likely cause. Caused by insufficient lactase, the

Stop and Share Lactose intolerance is the likely cause. Caused by insufficient lactase, the enzyme required for digestion of lactose. Low-lactose milk products can be used instead of regular milk. Lactase-containing products are also available. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 23

Polysaccharides Complex carbohydrates Compounds of many monosaccharides Important polysaccharides in nutrition: • • •

Polysaccharides Complex carbohydrates Compounds of many monosaccharides Important polysaccharides in nutrition: • • • Chapter 4 Starch Glycogen Fiber Copyright © 2003 Delmar Learning, a Thomson Learning company 24

Polysaccharides Starch • • • Chapter 4 Found in grains and vegetables Storage form

Polysaccharides Starch • • • Chapter 4 Found in grains and vegetables Storage form of glucose in plants Supplies energy over a longer period of time because it takes the body longer to digest polysaccharides than monosaccharides or disaccharides Copyright © 2003 Delmar Learning, a Thomson Learning company 25

Polysaccharides Glycogen • • Chapter 4 Sometimes called animal starch because it is the

Polysaccharides Glycogen • • Chapter 4 Sometimes called animal starch because it is the storage form of glucose in the body Hormone glucagon helps liver convert glycogen to glucose as needed Copyright © 2003 Delmar Learning, a Thomson Learning company 26

Polysaccharides Fiber • • • Chapter 4 It is indigestible because it cannot be

Polysaccharides Fiber • • • Chapter 4 It is indigestible because it cannot be broken down be digestive enzymes Insoluble: does not readily dissolve in water (cellulose, hemicellulose, lignins) Soluble: dissolves in water (gums, pectins, some hemicellulose, mucilages) Copyright © 2003 Delmar Learning, a Thomson Learning company 27

Polysaccharides: Sources Glycogen Starch • Cereals, grains, potatoes, corn, beans, yams Dextrins • Chapter

Polysaccharides: Sources Glycogen Starch • Cereals, grains, potatoes, corn, beans, yams Dextrins • Chapter 4 Starch hydrolysis • Glucose stored in liver and muscles Cellulose • Wheat bran, whole-grain cereals, fruits, green and leafy vegetables Copyright © 2003 Delmar Learning, a Thomson Learning company 28

Digestion and Absorption: Monosaccharides Simple sugars absorbed directly into bloodstream Carried to the liver;

Digestion and Absorption: Monosaccharides Simple sugars absorbed directly into bloodstream Carried to the liver; fructose and galactose changed to glucose Glucose carried to cells Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 29

Digestion and Absorption: Disaccharides Enzymes sucrase, maltase, lactase convert sucrose, maltose, lactose to simple

Digestion and Absorption: Disaccharides Enzymes sucrase, maltase, lactase convert sucrose, maltose, lactose to simple sugars. Simple sugars absorbed directly into bloodstream Carried to the liver; fructose and galactose changed to glucose Glucose carried to cells Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 30

Digestion and Absorption: Polysaccharides More complex; digestibility varies Cellulose wall broken down, starch changed

Digestion and Absorption: Polysaccharides More complex; digestibility varies Cellulose wall broken down, starch changed to intermediate product dextrin, then maltose, and finally glucose Starch digestion begins in mouth where the enzyme salivary amylase begins to change starch to dextrin Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 31

Metabolism Islets of Langerhans in pancreas secrete insulin Insulin is the hormone that controls

Metabolism Islets of Langerhans in pancreas secrete insulin Insulin is the hormone that controls glucose metabolism Impaired or absent insulin secretion results in high blood glucose level (hyperglycemia) Low blood glucose level (hypoglycemia) Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 32

Dietary Requirements Food and Nutrition Board of the National Research Council recommends: • •

Dietary Requirements Food and Nutrition Board of the National Research Council recommends: • • • Chapter 4 Half of one’s energy requirement should come from carbohydrates Complex carbohydrates preferred Weight loss and fatigue can result from a diet deficient in carbohydrates Copyright © 2003 Delmar Learning, a Thomson Learning company 33

Stop and Share Solve the following problem: A patient’s total energy requirement is 2,

Stop and Share Solve the following problem: A patient’s total energy requirement is 2, 000 kcal a day. How many grams of carbohydrate does this patient need per day? Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 34

Stop and Share If a patient’s total energy requirement is 2, 000 kcal/day; ½

Stop and Share If a patient’s total energy requirement is 2, 000 kcal/day; ½ of these should be from carbohydrates. 2, 000 2 = 1, 000 kcal To figure out how many grams are needed, divide 1, 000 by 4 (4 calories per gram of carbohydrate). 1, 000 kcal 4 kcal/g = 250 grams Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 35

Conclusion Carbohydrates provide energy. They should be the major source of energy. These nutrients

Conclusion Carbohydrates provide energy. They should be the major source of energy. These nutrients spare protein, maintain normal fat metabolism, and provide fiber. Excessive carbohydrate intake may lead to obesity, dental caries, and digestive disturbances. Chapter 4 Copyright © 2003 Delmar Learning, a Thomson Learning company 36