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The Carbohydrates

The Carbohydrates. Sugars Starches Fiber. Objectives. After reading Chapter 3 and class discussion, you will be able to: Describe the functions of CHO Identify the classification of CHO Describe CHO digestion & absorption Identify food sources of CHO Calculate calories from CHO.

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The Carbohydrates

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  1. The Carbohydrates Sugars Starches Fiber

  2. Objectives • After reading Chapter 3 and class discussion, you will be able to: • Describe the functions of CHO • Identify the classification of CHO • Describe CHO digestion & absorption • Identify food sources of CHO • Calculate calories from CHO

  3. Objectives • Differentiate between soluble and insoluble fiber • Identify foods that are a significant source of fiber • Discuss health related effects of CHO in • Diabetes -Heart Disease • Obesity -GI -Cancer

  4. Photosynthesis Plants make their own carbohydrates from carbon dioxide in air water from the soil Photosynthesis converts energy from sunlight into energy stored in carbohydrates 4

  5. Categories of Carbohydrate Simple carbohydrates Natural sugars Added (Refined) sugars Complex carbohydrates (polysaccharides) Starch Fiber 5

  6. Carbohydrates • Simple carbohydrates • Monosacchares • Disaccharides • Complex carbohydrates • Glycogen • Starches • Fibers

  7. Glucose

  8. Fructose & Galactose p. 103

  9. Monosaccharides and Disaccharides 9

  10. Disaccharides • Maltose • Glucose + glucose • Starch breakdown; fermentation • Barley • Sucrose • Glucose + fructose • Table sugar from sugarcane, sugar beet • Lactose • Gucose + galactose • Milk

  11. Complex Carbohydrates • Polysaccharides • Glycogen • Storage form of glucose • Stored in liver and muscles • Starches • Long chains of glucose linked together • Straight or branched chains • Fibers • Soluble or viscous • Insoluble or nonviscous

  12. Complex CarbohydratesChemical Structure p. 109 Fig 3-7

  13. Complex Carbohydrate: Starch Amylose - straight glucose chain Amylopectin – branched glucose chain Found only in plant foods: grains, legumes, vegetables, some fruits. Gelatinization – When starches are heated, they absorb water and swell in size. 13

  14. Complex Carbohydrates • Fibers • Cellulose • Hemicelluloses • Pectins • Legnin • Gums and muscilages • Resistant starches p. 108-109

  15. Complex Carbohydrates • Fibers • Soluble fibers-dissolve in water • Viscous-form gels • Fermentable-digested in colon by bacteria

  16. Complex Carbohydrates • Fibers • Insoluble fibers • Nonviscous • Fermented less readily • Phytic acid-binds minerals

  17. Review

  18. Carbohydrate Categories • Sugars • Starches • Fibers OR • Simple • Complex

  19. Carbohydrate Categories • Monosaccharide • Glucose -Fructose -Galactose • Disaccharide • Maltose -Sucrose -Lactose • Polysaccharide • Glycogen -Starches -Fibers

  20. Functions of Carbohydrate Primary source of body’s energy Central nervous system and red blood cells rely almost exclusively on glucose. Glucose stored in liver & muscles as glycogen. Protein sparing Prevents breakdown of protein for energy (gluconeogenesis) Prevents ketone bodies & ketosis Breakdown of fat for energy 20

  21. Digestion • Mouth • Salivary amylase • Mechanical mixing; chewing • Stomach • Continued mixing of bolus • Fibers and satiety • Small intestine • Maltase, Sucrase, Lactase

  22. Digestion • Pancreas • Pancreatic amylase • Large intestine – Colon • Fermentation of viscous fibers • Water, gas, short-chain fatty-acid production

  23. Absorption

  24. Carbohydrates and Health • Lactose Intolerance • Diabetes • Dental caries • Constipation • Hyperactivity • Obesity • Heart Disease

  25. Lactose Intolerance • Symptoms • Abdominal discomfort • Bloating; Intestinal gas formation • Diarrhea • Causes • Primary: Lactase deficiency • Secondary: Mucosal damage p. 110

  26. Lactose Intolerance • Prevalence (p. 111) • Ethnic <10% to >80% • <10% Northern Europeans (Scandinavians) • 20% Caucasians • 50% Hispanics • 60% Inuits • 70% Mediterranean peoples • 75% African Americans • 80% Native Americans • >80% Southeast Asians

  27. Lactose Content of Food • Whole wheat bread 1 slice 0.5gm • Cheese 1 oz 0.5-0.8 • Cheddar/American • Parmesan/Cream • Doughnut, cake type 1.2 • Chocolate 1 oz 2.3 • Sherbet 1 c 4.0 • Cottage cheese 7.5 • Ice Cream 1 c 9.0 • Milk 1 c 12.0 • Yogurt 1 c 15.0

  28. Lactose Intolerance • Dietary changes • May not require the elimination of milk/milk products • Acidophilus milk • Kefir, yogurt • Adequate calcium intake • Conservative vs liberal approach

  29. Lactose Learning Activity

  30. Blood Glucose • Regulating hormones • Insulin • Controls transport of glucose • Glucagon • Release glycogen from liver stores • Epinephrine • Signals liver to release glucose p. 104

  31. How the body regulates blood glucose p. 114

  32. Blood Glucose • Hypoglycemia • Rare in healthy people • Diabetes • Type 1 diabetes • Failure of insulin production • Type 2 diabetes • Obesity

  33. Blood Glucose • Glycemic response • How quickly and how high blood sugar rises after eating • Glycemic index • Method of classifying foods according to their potential for raising blood glucose p. 118

  34. Blood Glucose Glycemic Load Refers to both the Glycemic Index and the total amount of carbohydrate contained in the food Factors Influencing Glycemic Index Effect of mixed meal Fat, fiber, protein content of food Amount and type of CHO eating CAUTION

  35. Added Sugars Sugars added to a food for sweetening or other purposes Do not include natural sugars Other purposes: Prevent spoilage Browning Food for yeast Hold moisture p. 100-102

  36. Examples of Added Sugars White sugar (sucrose) High-fructose corn syrup or corn syrup Invert sugar Brown sugar Molasses Honey Powdered sugar Raw sugar Demerara sugar 38

  37. Sugars • Nutrient density • Overused in USA p. 101

  38. Sugars • Health effects of sugars • Dental caries • Dental plaque p. 102

  39. Controversies Of Sugar • Sugar causes obesity • Sugar causes heart disease p. 104

  40. Controversies Of Sugar • Sugar causes misbehavior in children and criminal behavior in adults • Sugar causes cravings and addictions • Serotonin- mood elevator p. 105

  41. Recommended Intakes of Sugars • DRI • No more than 25% of total daily energy intake • Average U.S. Intake=105#/yr • 30 teaspoons/day

  42. Starch and Fiber • Health effects • Heart disease • Diabetes • GI health • Cancer • Weight management

  43. Viscous Fibers • SOLUBLE and more fermentable • Gums and mucilages • Pectins • Psyllium • Some hemicelluloses

  44. Viscous Fibers • Sources • Whole-grains, fruits, legumes, seeds and husks, vegetables

  45. Viscous Fibers • Lower blood cholesterol • Slow glucose absorption • Slow transit of food through upper GI tract • Holds moisture in stools, softening them

  46. Viscous Fibers • Yield small fat molecules that the colon can use for energy • Lower risk of heart disease • Lower risk of diabetes

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