Chapter 4 Carbohydrates Sugars Starches and Fiber 2012

Chapter 4 Carbohydrates: Sugars, Starches, and Fiber © 2012 Pearson Education, Inc.

Objectives for Chapter 4 1. Compare and contrast the monosaccharides, disaccharides, and polysaccharides. 2. List the functions of carbohydrates in the body. 3. Explain the process of digesting and absorbing dietary carbohydrates. 4. Explain how the body uses, regulates and stores glucose and the hormones involved in the process. 5. Describe the guidelines for carbohydrate intake, including the AMDR for carbohydrates, the DRI for fiber, and the recommendation for consuming simple sugars. 6. Identify good food sources for each type of carbohydrate. 7. Describe the potential health implications of consuming too much or too little added sugar. 8. List alternative sweeteners used as sugar substitutes. 9. Importance of fiber Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. What Are Carbohydrates and Why Do You Need Them? Found primarily in plant-based foods: w Carbon, Hydrogen and Oxygen molecules made from plants converting CO 2 and H 20 into C 6 H 12 O 6 and larger molecules. w Grains, vegetables, fruits, nuts, legumes w Range from simple to complex w Most desirable form of energy for body w Brain, muscles and red blood cells especially rely on glucose for fuel source Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. Photosynthesis: How Glucose Is Made https: //www. youtube. com/watch? v=jo. Z 1 Es. A 5_NY Nutrition and You, 2 e Figure 4. 1 © 2012 Pearson Education, Inc.

1. Where Do Carbohydrates Come From? § Plants use the energy of light to make the energetic monosaccharide glucose. This form of carbohydrate is the most abundant carbohydrate in nature. It is also: w combined with minerals from soil to make other compounds, such as protein and vitamins. w Glucose units linked together and stored in form of starch. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. What Are Simple and Complex Carbohydrates? Simple carbohydrates: monosaccharides and disaccharides w Three monosaccharides: glucose, fructose, galactose w Disaccharides: two monosaccharides joined together w Maltose (beer) = glucose + glucose w Sucrose (table sugar) = glucose + fructose w Lactose (milk sugar) = glucose + galactose Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. Simple Carbohydrates Figure 4. 2 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. What Are Simple and Complex Carbohydrates? Complex carbohydrates: polysaccharides w Long chains and branches of sugars linked together Three forms of carbohydrates Starch, Glycogen & Fiber w Starch is the storage form in plants. w Glycogen is the storage form in animals w Fiber is part of plant that we eat but can’t digest Nutrition and You, 2 e © 2012 Pearson Education, Inc.

1. Complex Carbohydrates Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. Functions of Carbohydrates a. Fiber is part of plant that we eat but can’t digest yet is important to our health. w Examples: cellulose, hemicellulose, pectin w Humans lack digestive enzyme needed to break down fiber w Dietary fiber: naturally found in foods w Functional fiber: added to food for beneficial effect w Example: Psyllium added to cereals w Total fiber = dietary fiber + functional fiber Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. Fiber – soluble and insoluble Fiber is classified by its affinity for water w Soluble fiber: dissolves in water and is fermented by intestinal bacteria w Many are viscous, have thickening properties w Move more slowly through GI tract w Examples: Pectin in fruits and vegetables, betaglucan in oats and barley, gums in legumes, psyllium w Insoluble fiber: cellulose, hemicellulose, lignins w Move more rapidly through GI tract, laxative effect w Examples: bran of whole grains, seeds, fruits, vegetables Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. Most Plant Foods Contain Both Soluble and Insoluble Fibers Figure 4. 3 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. Functions of Carbohydrates b. Glycogen is the storage form of glucose in animals. w Stored in liver and muscle cells w Only limited amounts w Important source of glucose for blood Why don’t animal foods provide a good source of carbohydrates? Answer: Glycogen gets converted to other forms once the animal dies. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. Functions of Carbohydrates c. Starch is the complex carbohydrate that is found ready in plants that are instantly ready to be used as energy w Three edible parts: bran, endosperm, germ Nutrition and You, 2 e © 2012 Pearson Education, Inc.

2. From Wheat Kernel to Flour Refined grains: milling removes bran and germ • Some B vitamins, iron, phytochemicals, and dietary fiber lost as a result • Examples: wheat or white bread, white rice Enriched grains: folic acid, thiamin, niacin, riboflavin and iron added to restore some of the lost nutrition Whole grain foods contain all three parts of kernel Examples: brown rice, oatmeal, whole-wheat bread Nutrition and You, 2 e © 2012 Pearson Education, Inc.

3. DIGESTION: From Carbohydrates to Glucose in Your Body Figure 4. 4 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

3. Carbohydrate Digestion Digesting a meal of pasta (starch), milk (lactose) and cherries (sucrose and fiber): w Carbohydrate digestion starts in your mouth with mechanical and chemical digestion. Saliva contains amylase enzyme (-ase = enzyme) w HCl in your stomach stops carb digestion but begins again in your small intestine. w All complex carbohydrates are now broken down into Monosaccharides. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

3. Some People Cannot Digest Milk Sugar Lactose: Glucose and Galactose w principal carbohydrate found in dairy products w People with a deficiency of the enzyme lactase cannot digest lactose properly w Lactose maldigestion is natural part of aging w As soon as baby stops nursing, body makes less lactase w Lactose intolerance: when lactose maldigestion results in nausea, cramps, bloating, diarrhea, and flatulence Nutrition and You, 2 e © 2012 Pearson Education, Inc.

3. Some People Cannot Digest Milk Sugar Tips for tolerating lactose: w Gradually add dairy products to your diet w Eat smaller amounts throughout day rather than large amount at one time w Eat dairy foods with a meal or snack w Try reduced-lactose milk and diary products w Lactase pills can be consumed with lactose-laden meals or snacks Nutrition and You, 2 e © 2012 Pearson Education, Inc.

3. Do you know how much lactose are in your food? Table 4. 1 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Uses of Carbohydrates Your body only can use glucose as energy. Therefore: w monosaccharides (glucose) are either used immediately for energy in muscles, red blood cells or brian, w Excess monosaccharides (glucose, fructose & maltose) are stored in limited amounts in the liver w Excess monosaccharides (glucose, fructose & maltose) are stored in unlimited amounts as fat Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Uses of Carbohydrates § Glucose supplies energy for body, required for brain, nervous system, red blood cells w Fat can provide fuel for muscle, other tissues w Under starving conditions (18 hours or more) protein can be converted to glucose. § Hormones regulate amount of glucose in blood § Insulin is released by pancreas to convert excess glucose to glycogen (limited amount) or fat (unlimited amount) in response to high blood glucose levels after a carbohydrateheavy meal. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Carbohydrates Fuel Your Body Between Meals § When blood glucose begins to drop, pancreas releases the hormone glucagon to raise blood glucose levels w Directs release of glucose from stored glycogen in liver = glycogenolysis w Signals liver to start gluconeogenesis = making glucose from noncarbohydrate sources, mostly protein § Epinephrine (adrenaline) also stimulates glycogenolysis and increases blood glucose levels w “Fight or flight” hormone: stress, bleeding, low blood glucose levels trigger its release Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Carbohydrates Fuel Your Body During Fasting § Liver glycogen stores depleted after about 18 hours § Without glucose, fat can’t be broken down completely and ketone bodies are produced, which are acidic. w Ketosis: elevated blood levels after fasting about two days w Protein from muscle and organs broken down to make glucose w Brain switches to using ketone bodies for fuel to spare protein-rich tissues. w If fasting continues, protein reserves are depleted and death is inevitable. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Hormones Help Maintain Healthy Blood Glucose Levels in Your Body Figure 4. 6 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

4. Generating Energy from Glucose Figure 4. 5 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

5. How Much Carbohydrate Do You Need and What Are the Best Food Sources? § Minimum amount of carbohydrates needed daily w DRI: 130 grams per day for brain function w Consume diet with low-to-moderate amounts of simple carbohydrates and higher amounts of fiber and other complex carbohydrates w Dairy, whole grains, whole fruits, vegetables, legumes, nuts, and seeds provide natural simple carbohydrates and/or complex carbohydrates Nutrition and You, 2 e © 2012 Pearson Education, Inc.

5. Don’t forget about Fiber! • DRI: 14 grams of fiber per 1, 000 calories to promote heart health • Most Americans fall short: about 15 grams per day • Gradually increasing fiber in your diet will minimize side effects, such as flatulence • As you add fiber to your diet, you should also drink more fluids Table 4. 2 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

6. Food Sources of Carbohydrates Figure 4. 7 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

6. Food Sources of Fiber Figure 4. 8 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What’s the Difference Between Natural and Added Sugars? § Naturally occurring sugars found in fruits and dairy w Usually more nutrient dense; provide more nutrition per bite § Added sugars are added by manufacturers and are often “empty calories” (provide little nutrition). w Examples: soda, candy § Taste buds can’t distinguish between naturally occurring and added sugars Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Slices of an Orange versus Orange Slices Figure 4. 9 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Processed Foods and Sweets Often Contain Added Sugars § Finding the added sugars in your foods: w Sugars on food labels appear under numerous different names w Honey and fructose are not nutritionally superior to sucrose w Naturally occurring sugars are not distinguished from added sugars on the Nutrition Facts panel Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Nutrition in the Real World: Avoiding a Trip to the Dentist § Carbohydrates play a role in dental caries w Fermentable sugars and starch feed bacteria coating teeth, producing acid to erode tooth enamel w To minimize tooth decay: w Eat three balanced meals daily w Keep snacking to a minimum, choosing whole fruits and raw vegetables w Include foods that fight dental caries: cheese, sugarless gum w Regular dental care and good dental hygiene Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Finding Added Sugars on the Label: The Many Aliases of Added Sugar Figure 4. 10 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Where All These Added Sugars Coming From? Figure 4. 11 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. It is getting harder to stay healthy in modern times. Table 4. 3 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. The Many Sizes of Soft Drinks Figure 4. 12 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Diabetes Mellitus and Why Is It an Epidemic? § Diabetes mellitus: individual has high blood glucose levels due to insufficient insulin or insulin resistance w Glucose can’t enter cells, which burn fat for fuel w Without glucose, acidic ketone bodies build up, causing life-threatening diabetic ketoacidosis: untreated can result in coma, death § Type 1 diabetes: 5 to 10 percent of cases w Autoimmune disease: insulin-producing cells in pancreas destroyed—insulin injections required w Develops in childhood, early adult years Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Diabetes Mellitus and Why Is It an Epidemic? § Type 2 diabetes: 90 to 95 percent of cases w Cells are resistant to insulin, eventually insulinproducing cells are exhausted, pancreas decreases and medication and/or insulin is required w People 45 and older or at risk for diabetes should be tested. § Prediabetes: impaired glucose tolerance w Blood glucose higher than normal but not yet high enough to be classified as diabetes w Damage to heart and circulatory system can occur. Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Diabetes Mellitus and Why Is It an Epidemic? § Blood glucose control is key w Nutrition and lifestyle goals: w Physical exercise w Well-balanced diet containing: w High-fiber carbohydrates from whole grains, fruits, vegetables w Low-fat milk w Adequate lean protein sources w Unsaturated fats Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Diabetes Mellitus and Why Is It an Epidemic? § Glycemic index (GI) and glycemic load (GL) classify effects of carbohydrate-containing foods on blood glucose w GI: ranks foods’ effects on blood glucose compared with equal amount of pure glucose w GL: adjusts GI to take into account the amount of carbohydrate consumed § Eating carbohydrate-heavy foods with protein, fat lowers GI Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Glycemic Index • Sugar is not prohibited; starch causes same rise in blood glucose levels Figure 4. 15 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Diabetes Mellitus and Why Is It an Epidemic? § Cases of diabetes are on the rise w Sixth leading cause of death in the United States. w Over 200, 000 Americans die from diabetic complications annually w Rapidly rising in children w Obesity, overweight, and physical inactivity increase risk § Preventing type 2 diabetes: w Losing excess weight, physical exercise, hearthealthy, plant-based diet Nutrition and You, 2 e © 2012 Pearson Education, Inc.

Table 4. 7 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. What Is Hypoglycemia? § Hypoglycemia: blood glucose level below 70 mg/dl w Symptoms: hunger, shakiness, dizziness, perspiration, light-headedness w May occur in people with diabetes when they don’t eat regularly to balance effects of insulin or blood glucose-lowering medication w Can cause fainting, coma Nutrition and You, 2 e © 2012 Pearson Education, Inc.

7. Change in Blood Glucose After Eating a High-Carbohydrate Meal Figure 4. 16 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

8. What Are Sugar Substitutes and What Forms Can They Take? Calorie-Free Sweeteners: w Saccharin (Sweet’N Low): 200 to 700 percent sweeter than sucrose w Aspartame (Nutrasweet, Equal): 200 percent sweeter w People with PKU (disorder where you are unable to digest a certain amino acid) need to monitor all dietary sources of phenylalanine, including aspartame. w Acesulfame-K (Sunette): 200 percent sweeter w Sucralose (Splenda): 600 percent sweeter w Rebaudioside A (Truvia, Pure. Via): 200 percent sweeter Nutrition and You, 2 e © 2012 Pearson Education, Inc.

8. Growing Interest in Sugar-Free Foods and Beverages Figure 4. 13 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

8. Listings of Sugar Substitutes Table 4. 4 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

9. Why Is Fiber So Important? § Fiber is resistant to digestion but has many powerful health effects. § Fiber helps lower risk of developing: w Constipation w Diverticulosis, diverticulitis w Obesity: high-fiber foods add to satiation w Heart disease: soluble fibers lower elevated blood cholesterol levels w Colorectal cancer w Diabetes mellitus: slow digestion and absorption of glucose Nutrition and You, 2 e © 2012 Pearson Education, Inc.

9 Table 4. 5 Nutrition and You, 2 e © 2012 Pearson Education, Inc.

Carbohydrate Assignment http: //ed. ted. com/lessons/how-sugar-affects-the-brain-nicole-avena#review http: //abcnews. go. com/GMA/Recipes/video/stay-healthy-eat-fiber-9976340 Nutrition and You, 2 e © 2012 Pearson Education, Inc.