Chapter 4 Carbohydrates Sugars Starches and Fiber 2012 Pearson Education Inc Objectives for Chapter 4 Compare and contrast the monosaccharides disaccharides and polysaccharides List the functions of carbohydrates in the body Describe the differences between insoluble and soluble fibers and their role in promoting health Explain the process of digesting and absorbing dietary carbohydrates Explain how the body regulates blood glucose levels and the hormones involved in the process Describe the guidelines for carbohydrate intake including the AMDR for carbohydrates the DRI for fiber and the recommendation for consuming simple sugars Identify good food sources for each type of carbohydrate Describe the potential health implications of consuming too much or too little added sugar Define type 1 and type 2 diabetes and describe how diabetes differs from hypoglycemia List alternative sweeteners used as sugar substitutes Nutrition and You 2e 2012 Pearson Education Inc What Are Carbohydrates and Why Do You Need Them Found primarily in plant based foods Grains vegetables fruits nuts legumes Carbohydrate based foods are staples in numerous cultures around the world Most desirable form of energy for body In form of glucose ose carbohydrate Brain and red blood cells especially rely on glucose for fuel source Nutrition and You 2e 2012 Pearson Education Inc Where Do Carbohydrates Come From Plants convert the sun s energy into glucose by photosynthesis Glucose is most abundant carbohydrate in nature Used as energy by plants or combined with minerals from soil to make other compounds such as protein and vitamins Glucose units linked together and stored in form of starch Nutrition and You 2e 2012 Pearson Education Inc Animation Hormonal Control of Blood Glucose Nutrition and You 2e 2012 Pearson Education Inc Photosynthesis How Glucose Is Made Figure 4 1 Nutrition and You 2e 2012 Pearson Education Inc What Are Simple and Complex Carbohydrates Simple carbohydrates monosaccharides and disaccharides Three monosaccharides glucose fructose galactose Disaccharides two monosaccharides joined together Maltose glucose glucose Sucrose table sugar glucose fructose Lactose milk sugar glucose galactose Nutrition and You 2e 2012 Pearson Education Inc What Are Simple and Complex Carbohydrates Complex carbohydrates polysaccharides Long chains and branches of sugars linked together Starch fiber and glycogen Starch is the storage form in plants Amylose straight chains of glucose units Amylopectin branched chains of glucose units Nutrition and You 2e 2012 Pearson Education Inc Creating Monosaccharides Disaccharides and Polysaccharides Figure 4 2 Nutrition and You 2e 2012 Pearson Education Inc Fiber is Nondigestible but Important Fiber is part of plant that we eat but can t digest Examples cellulose hemicellulose lignins gums pectin Humans lack digestive enzyme needed to break down fiber Dietary fiber naturally found in foods Functional fiber added to food for beneficial effect Example Psyllium added to cereals Total fiber dietary fiber functional fiber Nutrition and You 2e 2012 Pearson Education Inc Fiber is Nondigestible but Important Fiber is classified by its affinity for water Soluble fiber dissolves in water and is fermented by intestinal bacteria Many are viscous have thickening properties Move more slowly through GI tract Examples Pectin in fruits and vegetables betaglucan in oats and barley gums in legumes psyllium Insoluble fiber cellulose hemicellulose lignins Move more rapidly through GI tract laxative effect Examples bran of whole grains seeds fruits vegetables Nutrition and You 2e 2012 Pearson Education Inc Most Plant Foods Contain Both Soluble and Insoluble Fibers Figure 4 3 Nutrition and You 2e 2012 Pearson Education Inc What Are Simple and Complex Carbohydrates Glycogen is the storage form of glucose in animals Branched glucose similar to amylopectin Stored in liver and muscle cells Only limited amounts Important source of glucose for blood Nutrition and You 2e 2012 Pearson Education Inc Nutrition in the Real World Grains Glorious Whole Grains Grains important staple and source of nutrition Three edible parts bran endosperm germ 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 2e 2012 Pearson Education Inc From Wheat Kernel to Flour Misc 4 1 Nutrition and You 2e 2012 Pearson Education Inc What Happens to the Carbohydrates You Eat Digesting a meal of pasta starch milk lactose and cherries sucrose and fiber You digest carbohydrates in your mouth and intestines Saliva contains amylase enzyme ase enzyme Starts breaking down amylose and amylopectin in pasta into smaller starch units and maltose Nutrition and You 2e 2012 Pearson Education Inc Animation Carbohydrate Absorption Nutrition and You 2e 2012 Pearson Education Inc Animation Carbohydrate Digestion Nutrition and You 2e 2012 Pearson Education Inc From Carbohydrates to Glucose in Your Body Figure 4 4 Nutrition and You 2e 2012 Pearson Education Inc Some People Cannot Digest Milk Sugar Lactose principal carbohydrate found in dairy products People with a deficiency of the enzyme lactase cannot digest lactose properly Lactose maldigestion is natural part of aging As soon as baby stops nursing body makes less lactase Lactose intolerance when lactose maldigestion results in nausea cramps bloating diarrhea and flatulence Nutrition and You 2e 2012 Pearson Education Inc Some People Cannot Digest Milk Sugar Tips for tolerating lactose Gradually add dairy products to your diet Eat smaller amounts throughout day rather than large amount at one time Eat dairy foods with a meal or snack Try reduced lactose milk and diary products Lactase pills can be consumed with lactose laden meals or snacks Nutrition and You 2e 2012 Pearson Education Inc Table 4 1 Nutrition and You 2e 2012 Pearson Education Inc How Does Your Body Use Carbohydrates Glucose supplies energy for body required for brain nervous system red blood cells Fat can provide fuel for muscle other tissues Hormones regulate amount of glucose in blood Insulin is released by pancreas in response to high blood glucose levels after a carbohydrateheavy meal Directs conversion of glucose in