Chapter 4

1. Chapter 4 The Carbohydrates: Sugar, Starch, and Fiber

2. Ask Yourself True or False? Fruit sugar (fructose) is less fattening than table sugar (sucrose). Foods high in complex carbohydrate (starch and fiber) are good choices when you are trying to lose weight. People with diabetes should never eat sugar. The primary role of dietary fiber is to provide energy. The brain demands the sugar glucose to fuel its activities.

3. Ask Yourself 6. Honey and refined sugar are the same as far as the body is concerned. 7. Of all the components of foods that increase one’s risk of diseases, sugars are probably the biggest troublemakers. 8. Breads that are brown in color have more fiber than white bread. Some foods labeled sugar-free actually contain calorie-bearing sugars. Artificial sweeteners are safe to use in moderation.

4. The Body’s Need for Carbohydrates The primary role of carbohydrates is to provide the body with energy (calories). Carbohydrates are the preferred fuel for the brain and nervous system. Carbohydrates are the ideal fuel compared to other alternatives: Less expensive than protein. High-fat diets are associated with chronic disease.

6. Carbohydrate Basics Carbohydrates Compounds made of single sugars or multiples of them and composed of carbon, hydrogen, and oxygen atoms. carbo = carbon (C) hydrate = water (H2O) Complex carbohydrates Long chains of sugars (glucose) arranged as starch or fiber. Also called polysaccharides. poly = many saccharides = sugar unit Simple carbohydrates (sugars) Single sugars (monosaccharides) and the pairs of sugars (disaccharides) linked together.

7. Carbohydrate Basics Carbohydrate-rich foods are obtained almost exclusively from plants. Milk is the only animal-derived food that contains significant carbohydrate. All carbohydrates are composed of single sugars, alone or in various combinations.

10. Simple Carbohydrates • Glucose is made of water and carbon dioxide. • Plants use energy from the sun to synthesize it. • The atoms in a glucose molecule can be rearranged by plants to form fructose, too.

11. Simple Carbohydrates Single Sugars - Monosaccharides: Glucose The building block of carbohydrate; a single sugar used in both plant and animal tissues as quick energy. A single sugar is known as a monosaccharide. mono = one Fructose Fruit sugar—the sweetest of the single sugars. Galactose: Another single sugar that occurs bonded to glucose in the sugar of milk.

12. Simple Carbohydrates Double Sugars - Disaccharides: Sucrose: A double sugar composed of glucose and fructose. A double sugar is known as a disaccharide. di = two Maltose A double sugar composed of two glucose units. Lactose A double sugar composed of glucose and galactose; commonly known as milk sugar.

13. Simple Carbohydrates Added Sugars: Sugar cane and sugar beets are purified to make sucrose. Food examples include white (table) sugar, brown sugar, powdered sugar. Sucrose is common in sweets. A sampling of foods providing added sugars to the diet.

14. Simple Carbohydrates Enzymes Protein catalysts. A catalyst facilitates a chemical reaction without itself being altered in the process. Utilized in the brewing process to break down starch in barley and wheat into maltose Lactose intolerance Inability to digest lactose as a result of a lack of the necessary enzyme lactase. Symptoms include nausea, abdominal pain, diarrhea, or excessive gas that occurs anywhere from 15 minutes to a couple of hours after consuming milk or milk products.

17. Complex Carbohydrates: Starch Complex carbohydrates include starch and fiber. All starchy foods are plant foods. • Starch A plant polysaccharide composed of hundreds of glucose molecules, digestible by human beings. • Polysaccharide A long chain of 10 or more glucose molecules linked together in straight or branched chains; another term for complex carbohydrates.

18. Complex Carbohydrates: Starch Sources of starch include: • Seeds such as grains, peas and beans. • Legumes including dried beans, lentils and soybeans. • Root vegetables (yams) and tubers (potatoes).

19. Complex Carbohydrates: Starch • Most societies have a staple grain that provides most of the people’s food energy. • Staple grain A grain used frequently or daily in the diet. Examples include: • Corn in Mexico • Rice in Asia • Wheat in Canada, Europe and USA • Millet, rye, barley, and oats

21. Complex Carbohydrates: Starch • Refined: Refers to the process by which the coarse parts of food products are removed. • Enriched Refers to a process by which the B vitamins thiamin, riboflavin, niacin, folic acid, and the mineral iron are added to refined grains and grain products at levels specified by law. • Fortified foods Foods to which nutrients have been added. Typically, commonly eaten foods are chosen for fortification with added nutrients to help prevent a deficiency of a nutrient (iodized salt, milk with vitamin D) or to reduce the risk of chronic disease (juices with added calcium).

22. Complex Carbohydrate: Starch A Whole Grain: Germ The nutrient-rich and fat-dense inner part of a whole grain. Endosperm Provides energy; contains starch grains embedded in a protein matrix. Bran Fibrous protective covering of a whole grain; source of fiber, B vitamins, and trace minerals. Husk (Chaff) The outer, inedible covering of a grain.

23. Complex Carbohydrates: Starch Whole grain Refers to a grain that is milled in its entirety (all but the husk), not refined. Whole grains include wheat, corn, rice, rye, oats, barley, amaranth, buckwheat, sorghum, and millet; two others—bulgur and couscous—are processed from wheat grains.

25. Complex Carbohydrates: Fiber Fiber: The indigestible residues of food, composed mostly of polysaccharides. The best known fibers are cellulose, hemicellulose, pectin, and gums. Comes from the supporting structures of plants: leaves, stems and seeds. Cannot be broken down by human digestive enzymes although some may be broken down by bacteria residing in the digestive tract. Fiber has few if any calories because it is not digested.

26. Complex Carbohydrates: Fiber Insoluble fiber Includes the fiber types called cellulose, hemicellulose, and lignin. Insoluble fibers do not dissolve in water. Soluble fiber Includes the fiber types called pectin, gums, mucilages, some hemicelluloses, and algal substances (for example, carageenan). Soluble fibers either dissolve or swell when placed in water.

27. Foods rich in insoluble fiber: Foods rich in soluble fiber: Bran Brown rice Green beans Green peas Many veggies Nuts Rice Seeds Skins/peels Wheat bran Whole-grain products Barley Broccoli Carrots Corn Fruits Legumes Oat bran Oats Potatoes Rye Insoluble fiber: • Holds water in the colon and increases bulk to the stool. • Stimulates muscles and helps maintain health and tone. Soluble fiber: • Binds cholesterol compounds and may lower blood cholesterol. • Improves body’s handling of glucose.

30. We are advised to increase our intakes of complex carbohydrates. Choose plenty of whole foods like this… …and fewer foods like these—foods that no longer resemble their original farm-grown products.

31. Choosing Carbohydrates Whole food A food that is altered as little as possible from the plant or animal tissue from which it was taken—such as milk, oats, potatoes, or apples. The more a food resembles the original, farm-grown product, the more nutritious it is likely to be.

32. Choosing Carbohydrates

33. Fiber in the Diet • Diets high in fruits, vegetables and legumes will provide high fiber • Too much fiber can cause dehydration, intestinal discomfort and limit absorption of iron and other nutrients

34. Choosing Carbohydrates Added Sugars: Use Discretion Reduce the intake of calories from added sugars. (Dietary Guidelines). Added Sugar Sugars and other caloric sweeteners that are added to foods during processing or preparation. Added sugars do not include naturally occurring sugars that are found in milk and fruit.

35. Choosing Carbohydrates Choose most often the naturally occurring sugars (DRI). For those who meet their nutrient needs, maintain a “healthy body weight” and still need additional calories--maximum intake = 25% or less for added sugars (DRI).

36. Choosing Carbohydrates Small amounts of added sugars allowed within MyPlate calorie allowance: 3 tsp. for 1,600 calories 5 tsp. for 1,800 calories 8 tsp. for 2,000 calories 9 tsp. for 2,200 calories 12 tsp. for 2,400 calories Consistently build your diet using nutrient-dense foods, low in added sugars.

38. Whole Grains for Health • Incorporate whole grains into your diet. • Count to 3 • Keep it varied • Check the label

39. Breakfast: Try a higher-fiber grain: oatmeal, whole-grain muffin, or whole-grain cereal Whole grains are low in fat and added sugars Baking recipes: Substitute whole-grain flour for 1/4 of all-purpose flour Make a fiber-rich snack mix from whole grain cereals, popcorn, and nuts Try whole-wheat pasta, rice, and breads Combine whole grains in mixed dishes Make Half Your Grains Whole

40. How the Body Handles Carbohydrates Glucose is the basic carbohydrate unit that each cell uses for energy. The task of the digestive system is to disassemble lactose, sucrose and starch into single sugars so they can be absorbed into the blood.

41. Digestive system The body system composed of organs and glands associated with the ingestion and processing of food for absorption of nutrients into the body. Digestion The process by which foods are broken down into smaller absorbable products. Absorption The passage of nutrients or substances into cells or tissues; nutrients pass into intestinal cells after digestion and then into the circulatory system (for example, into the bloodstream). How the Body Handles Carbohydrates

42. If the blood delivers more glucose than the cells need, glycogen will be built. Glycogen A polysaccharide composed of chains of glucose, manufactured in the body and stored in liver and muscle. As a storage form of glucose, liver glycogen can be broken down by the liver to maintain a constant blood glucose level when carbohydrate intake is inadequate. How the Body Handles Carbohydrates

44. Salivary glands 1. Carbohydrate digestion begins in the mouth. The salivary glands secrete a watery fluid into the mouth to moisten the food. An enzyme begins digestion by splitting starch into smaller polysaccharides and maltose. This digestion continues after the food is swallowed until stomach acid and enzymes start to digest the salivary enzymes. 3. These simple sugars are then absorbed into the blood and travel to the liver; the liver regulates the amount of glucose circulating in the blood in response to the hormones insulin and glucagon. Liver Stomach 2. The pancreas produces carbohydrate digesting enzymes and releases them through the common bile duct into the small intestine. These enzymes split polysaccharides into disaccharides. Then enzymes on the surface of the cells of the small intestine break these into simple sugars (monosaccharides). Absorption of the monosaccharides takes place in the small intestine. Pancreas Small intestine Gallbladder Large intestine 4. Most fiber passes intact through the digestive tract through the large intestine, and is eventually excreted with the feces. Some fiber is digested by bacteria in the large intestine.

46. When a person eats, blood glucose rises. High blood glucose stimulates the pancreas to release insulin. Insulin serves as a key for entrance of blood glucose into cells. Liver and muscle cells store the glucose as glycogen. Excess glucose can also be stored as fat.

47. Later, when blood glucose is low, the pancreas releases glucagon, which serves as the key for the liver to break down stored glycogen into glucose and release it into the blood to raise blood glucose levels.

48. Pancreas Insulin Bloodstream Body cells Elevated blood glucose Glucose Digestive tract 110 mg/dL* Normal blood glucose range 70 mg/dL Pancreas Low blood glucose Glucagon Liver Glucose Body cells Bloodstream Glycogen Glucose

49. Insulin: A hormone secreted by the pancreas in response to high blood glucose levels; it assists cells in drawing glucose from the blood. Glucagon A hormone released by the pancreas that signals the liver to release glucose into the bloodstream. How the Body Handles Carbohydrates

50. Carbohydrates--Friend or Foe? Glycemic index (GI) A scale that ranks carbohydrate-containing foods by how much they raise blood glucose levels compared to a standard food such as glucose or white bread. The glycemic load (GL) is a measure of the extent to which blood glucose is raised by a given amount of carbohydrate-containing food. Glycemic effect The effect of food on a person’s blood glucose and insulin response – how fast and high the blood glucose rises and how quickly the body responds by normalizing.