Ch4 Carbohydrates


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Ch4 Carbohydrates

  1. 1. Chapter 4 Carbohydrates Lecture and Animation PowerPoint Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. To run the animations you must be in Slideshow View . Use the buttons on the animation to play, pause, and turn audio/text on or off. Please Note : Once you have used any of the animation controls , you must click in the white background before advancing to the next slide.
  2. 2. Photosynthesis
  3. 3. Monosaccharides <ul><li>Structure </li></ul><ul><li>Glucose </li></ul><ul><li>Fructose </li></ul><ul><li>Galactose </li></ul>
  4. 4. Glucose <ul><li>Major monosaccharide in the body </li></ul><ul><li>Also known as dextrose </li></ul><ul><li>In bloodstream called blood sugar </li></ul><ul><li>Breakdown of starches and sucrose </li></ul><ul><li>Source of fuel for cells </li></ul>
  5. 5. Fructose (fruit sugar) <ul><li>In sucrose </li></ul><ul><li>In fruit, honey, and high-fructose corn syrup </li></ul><ul><li>Converted into glucose in the liver </li></ul>
  6. 6. Galactose <ul><li>In lactose </li></ul><ul><li>Converted to glucose in the liver </li></ul>
  7. 8. Disaccharides <ul><li>“ Simple sugars” </li></ul><ul><li>Sucrose (Gluc + Fruc) </li></ul><ul><ul><li>Sugar </li></ul></ul><ul><li>Lactose (Galactose + Gluc) </li></ul><ul><ul><li>Milk products </li></ul></ul><ul><li>Maltose (Glyc + Gluc) </li></ul><ul><ul><li>Fermentation </li></ul></ul><ul><ul><li>Alcohol production </li></ul></ul>
  8. 9. Complex Carbohydrates <ul><li>Polysaccharides: Starch & Glycogen </li></ul><ul><li>Amylose </li></ul><ul><li>Amylopectin </li></ul><ul><li>Dietary fiber </li></ul>
  9. 11. Oligosaccharides <ul><li>3-10 monosaccharides </li></ul><ul><li>In beans and legumes </li></ul><ul><li>Not digested </li></ul><ul><li>Metabolized by bacteria in the large intestine </li></ul><ul><li>Effect of Beano ® </li></ul>
  10. 12. Polysaccharides: Starch <ul><li>3,000 or more monosaccharides </li></ul><ul><li>Starch </li></ul><ul><ul><li>Amylose--straight chain polymer </li></ul></ul><ul><ul><li>Amylopectin--highly branched polymer </li></ul></ul>
  11. 13. Common Starches
  12. 14. Glycogen <ul><li>Storage form of carbohydrate for animals and human </li></ul><ul><li>Structure similar to amylopectin </li></ul><ul><li>More sites for enzyme action </li></ul><ul><li>Found in the liver and muscles </li></ul>
  13. 15. Dietary Fiber <ul><li>Undigested starch </li></ul><ul><li>Body cannot break the bonds </li></ul><ul><li>Insoluble or Non-fermentable fiber </li></ul><ul><ul><li>Cellulose, hemicellulose, lignin </li></ul></ul><ul><ul><li>Not fermented by the bacteria in the colon </li></ul></ul><ul><li>Soluble or Viscous fiber </li></ul><ul><ul><li>Gum, pectin, mucilage </li></ul></ul><ul><ul><li>Fruit, vegetable, rice bran, psyllium seed </li></ul></ul>
  14. 16. Functional Fiber <ul><li>Fiber added to food </li></ul><ul><ul><li>Provides health benefits </li></ul></ul><ul><li>Prebiotics – Type of functional fiber </li></ul><ul><ul><li>Stimulate growth or activity of beneficial bacteria in the large intestine </li></ul></ul>
  15. 17. Viscous and Non-Fermentable Fiber
  16. 18. Benefits of Dietary Fiber
  17. 19. Carbohydrates in Foods
  18. 20. Sweeteners
  19. 21. High-fructose Corn Syrup <ul><li>55% fructose </li></ul><ul><li>Cornstarch mixed with acid and enzymes </li></ul><ul><li>Starch is broken down to glucose </li></ul><ul><li>Some glucose is converted to fructose </li></ul><ul><li>Cheaper than sucrose </li></ul><ul><li>Does not form crystals </li></ul>
  20. 22. Other Types of Sweeteners <ul><li>Brown sugar </li></ul><ul><li>Turbinado sugar (raw sugar) </li></ul><ul><li>Maple syrup </li></ul><ul><li>Honey </li></ul><ul><li>Sugar alcohols (sorbitol, xylitol) </li></ul><ul><ul><li>~2.6 kcal/g </li></ul></ul><ul><ul><li>Absorbed and metabolized slower </li></ul></ul><ul><ul><li>“ Excess consumption may have a laxative effect” </li></ul></ul>
  21. 23. Sugar Substitutes
  22. 24. Sugar Alcohols <ul><li>Sorbitol, Xylitol </li></ul><ul><li>~2.6 kcals/gram </li></ul><ul><li>Large quantities can cause diarrhea </li></ul><ul><li>Do not promote tooth decay </li></ul>
  23. 25. Saccharin <ul><li>First produced in 1879 </li></ul><ul><li>180-200x sweeter than sucrose </li></ul><ul><li>No potential risk in humans </li></ul>
  24. 26. Aspartame (Equal  , NutraSweet  ) <ul><li>Composed of phenylalanine, aspartic acid, and methanol </li></ul><ul><li>180-200x sweeter than sucrose </li></ul><ul><li>4 kcal/gm </li></ul><ul><li>Not heat stable </li></ul><ul><li>Complaints of sensitivity </li></ul><ul><ul><li>Headaches, dizziness, seizures, nausea, etc. </li></ul></ul><ul><li>Acceptable daily intake: 50 mg per kg body weight (FDA) (~14 cans of diet soda for average adult per day) </li></ul><ul><li>Warning label for Phenylketonuria (PKU) </li></ul>
  25. 27. Sucralose (Splenda  ) <ul><li>600x sweeter than sucrose </li></ul><ul><li>Substitutes chlorines for hydroxyl groups on sucrose </li></ul><ul><li>Heat stable </li></ul><ul><li>Tiny amount digested </li></ul><ul><li>Excreted in the feces </li></ul>
  26. 28. Neotame <ul><li>FDA approved for general-purpose sweetener </li></ul><ul><li>Similar structure to Aspartame </li></ul><ul><li>Is not broken down in the body </li></ul><ul><li>7,000-13,000x sweeter than sucrose </li></ul><ul><li>Heat stable </li></ul><ul><li>Safe for use </li></ul>
  27. 29. Acesulfame-K (Sunette  ) <ul><li>Approved by FAD </li></ul><ul><li>200x sweeter than sucrose </li></ul><ul><li>Not digested by the body </li></ul><ul><li>Heat stable </li></ul><ul><li>Diabetisweet used in baking </li></ul>
  28. 30. Tagatose <ul><li>Altered form of fructose </li></ul><ul><li>1.5 kcals/gram </li></ul><ul><li>Does not increase glucose level </li></ul><ul><li>Does not cause tooth decay </li></ul><ul><li>Is fermented by large intestine </li></ul>
  29. 31. Stevia (Sweet Leaf ® ) <ul><li>100-300X sweeter than sucrose </li></ul><ul><li>Provides no energy </li></ul><ul><li>Generally recognized as safe (GRAS) </li></ul><ul><li>Can not be used as additive in food products </li></ul>
  30. 32. Carbohydrate Digestion
  31. 33. Effects of Cooking <ul><li>Softens fibrous tissues </li></ul><ul><li>Easier to chew and swallow </li></ul>
  32. 34. Digestion of Carbohydrate in the Mouth <ul><li>Salivary amylase </li></ul><ul><ul><li>Breaks starch to shorter saccharides </li></ul></ul><ul><ul><li>Prolonged chewing </li></ul></ul><ul><li>Short duration in the mouth </li></ul>
  33. 35. Digestion of Carbohydrate in the Stomach <ul><li>Acidic environment </li></ul><ul><li>No further starch digestion </li></ul>
  34. 36. Digestion of Carbohydrate in the Small Intestine <ul><li>Pancreas releases enzymes </li></ul><ul><ul><li>Pancreatic amylase </li></ul></ul><ul><li>Absorptive cells release </li></ul><ul><ul><li>Maltase </li></ul></ul><ul><ul><li>Sucrase </li></ul></ul><ul><ul><li>Lactase </li></ul></ul><ul><li>Monosaccharides are absorbed </li></ul>
  35. 37. Carbohydrate Digestion
  36. 38. Lactose Maldigestion <ul><li>Reduction in lactase </li></ul><ul><ul><li>Lactose is undigested and not absorbed </li></ul></ul><ul><ul><li>Lactose is metabolized by large intestinal bacteria </li></ul></ul><ul><ul><ul><li>Causes gas, bloating, cramping, discomfort </li></ul></ul></ul><ul><li>Primary lactose maldigestion </li></ul><ul><li>Secondary lactose maldigestion </li></ul><ul><li>Severe cases are called lactose intolerance </li></ul>
  37. 39. What To Do if You Have Lactose Maldigestion or Lactose Intolerance <ul><li>Determine amount you can tolerate </li></ul><ul><li>Eat dairy with fat </li></ul><ul><li>Cheese & yogurt are usually well tolerated </li></ul><ul><li>Use Lact-Aid  </li></ul>
  38. 40. Absorption <ul><li>Glucose and Galactose </li></ul><ul><ul><li>Active absorption </li></ul></ul><ul><ul><li>Energy is expended </li></ul></ul><ul><li>Fructose </li></ul><ul><ul><li>Facilitated absorption using a carrier </li></ul></ul><ul><ul><li>No energy expended </li></ul></ul>
  39. 41. After Absorption <ul><li>Portal vein to the liver </li></ul><ul><li>Liver can: </li></ul><ul><ul><li>Transform monosaccharide into glucose </li></ul></ul><ul><ul><li>Release glucose back into the bloodstream </li></ul></ul><ul><ul><li>Store as glycogen (or fat) </li></ul></ul>
  40. 42. Undigested Carbohydrates <ul><li>Only a minor amount escapes digestion </li></ul><ul><li>Travels to the colon </li></ul><ul><li>Fermentation by the bacteria </li></ul><ul><li>Acids and gases produced are absorbed </li></ul><ul><li>May promote health of the colon </li></ul>
  41. 43. Functions of Carbohydrate <ul><li>Supplies energy </li></ul><ul><li>Protein sparing </li></ul><ul><li>Prevents ketosis </li></ul><ul><li>Sweetener </li></ul>
  42. 44. Regulation of Blood Glucose <ul><li>Hyperglycemia </li></ul><ul><li>Hypoglycemia </li></ul>
  43. 45. Blood Glucose Control <ul><li>Role of the liver </li></ul><ul><ul><li>Regulates glucose that enters bloodstream </li></ul></ul><ul><li>Role of the pancreas </li></ul><ul><ul><li>Release of insulin </li></ul></ul><ul><ul><li>Release of glucagon </li></ul></ul>
  44. 46. Functions of Insulin <ul><li>Promotes glycogen synthesis </li></ul><ul><li>Increases glucose uptake by the cells </li></ul><ul><li>Reduces gluconeogenesis </li></ul><ul><li>Net effect: lowers blood glucose </li></ul>
  45. 47. Functions of Glucagon <ul><li>Breakdown glycogen </li></ul><ul><li>Enhances gluconeogenesis </li></ul><ul><li>Net effect: raises blood glucose </li></ul>
  46. 48. Epinephrine / Norepinephrine <ul><li>“ Fight or flight” response </li></ul><ul><li>Breakdown glycogen </li></ul><ul><li>Raises blood glucose </li></ul>
  47. 49. Regulation of Blood Glucose
  48. 50. Glycemic Response <ul><li>Glycemic Index </li></ul><ul><ul><li>Ratio of blood glucose response to a given food </li></ul></ul><ul><li>Glycemic Load </li></ul><ul><ul><li>Grams of carbohydrate in a food multiplied by the glycemic index of that food </li></ul></ul><ul><ul><li>Divide result by 100 </li></ul></ul>
  49. 51. High Glycemic Load <ul><li>Large release of insulin </li></ul><ul><ul><li>Increase blood triglycerides level </li></ul></ul><ul><ul><li>Increase Low Density Lipoprotein (LDL) </li></ul></ul><ul><ul><li>Increase fat deposits </li></ul></ul><ul><ul><li>Increase clotting </li></ul></ul><ul><ul><li>Increase fat synthesis </li></ul></ul><ul><ul><li>Rapid return of hunger </li></ul></ul><ul><li>Insulin resistance develops (Type 2 diabetes) </li></ul>
  50. 52. Dietary Fiber and Health
  51. 53. Hemorrhoids <ul><li>Swelling of a large vein </li></ul><ul><li>Result from excessive straining </li></ul>
  52. 54. Diverticula
  53. 55. Can high-fiber diets prevent colon cancer?
  54. 56. Weight Control and Fiber <ul><li>Filling </li></ul><ul><li>Low in kcal </li></ul><ul><li>Satisfied after eating </li></ul>
  55. 57. Colon Cancer and Fiber <ul><li>Controversial </li></ul><ul><li>Focus on fruits, vegetables, beans, and whole grains </li></ul><ul><li>Higher-fiber foods are more nutrient dense </li></ul>
  56. 58. Glucose Absorption and Fiber <ul><li>Soluble fiber slows glucose absorption </li></ul><ul><li>Better blood glucose regulation </li></ul>
  57. 59. Cholesterol and (Soluble) Fiber <ul><li>Absorption of cholesterol inhibited </li></ul><ul><li>Bile acid absorption reduced </li></ul><ul><li>Risk for cardiovascular disease and gallstones reduced </li></ul><ul><li>Insulin release decreased </li></ul><ul><ul><li>Decrease cholesterol synthesis in the liver </li></ul></ul><ul><li>Blood cholesterol lowered </li></ul>
  58. 60. Carbohydrate Needs <ul><li>RDA is 130 grams/day for adults </li></ul><ul><li>Average U.S. intake is 180-330 grams </li></ul><ul><li>Recommendations vary </li></ul><ul><ul><li>FNB: 45%-65% of total calories </li></ul></ul><ul><ul><li>Nutrition Facts panel: 60% </li></ul></ul><ul><li>Focus on fruits, vegetables, whole grains </li></ul>
  59. 61. Recommended Dietary Fiber Intake <ul><li>AI is 25 grams/day for women </li></ul><ul><li>AI is 38 grams/day for men </li></ul><ul><li>(Goal of 14 grams/1000 kcal) </li></ul><ul><li>DV is 25 grams for 2000 kcal diet </li></ul><ul><li>Average U.S. intake: </li></ul><ul><ul><li>14 grams/day for women </li></ul></ul><ul><ul><li>17 grams/day for men </li></ul></ul>
  60. 62. Too Much Fiber <ul><li>> 60 grams/day </li></ul><ul><li>Extra fluid needed </li></ul><ul><li>May decrease availability of some minerals </li></ul><ul><li>Unmet energy needs in children </li></ul>
  61. 63. Recommendation for Simple Sugar Intake <ul><li>Low nutrient density </li></ul><ul><li>Dental caries </li></ul><ul><li>Added to food and beverages </li></ul><ul><li>< 10% of total kcal/day with a maximum of 50 grams (12 tsp) per day--WHO </li></ul><ul><li>Average U.S. intake: 16% of total kcal/day </li></ul><ul><ul><li>~82 grams per day </li></ul></ul>
  62. 64. Diabetes <ul><li>Type 1 Diabetes </li></ul><ul><li>Type 2 Diabetes </li></ul><ul><li>Gestational Diabetes </li></ul>
  63. 67. Type 1 Diabetes <ul><li>Occurs often in children </li></ul><ul><li>Genetic link </li></ul><ul><li>Body stops producing insulin </li></ul><ul><li>Treatment </li></ul><ul><ul><li>Insulin Therapy </li></ul></ul><ul><ul><li>Diet Therapy </li></ul></ul>
  64. 68. Type II Diabetes <ul><li>Generally in people > 40 years of age </li></ul><ul><li>Increasing rates in younger individuals </li></ul><ul><li>Obesity </li></ul><ul><li>Treatment </li></ul><ul><ul><li>Weight loss </li></ul></ul><ul><ul><li>Oral medications </li></ul></ul><ul><ul><li>Diet therapy </li></ul></ul><ul><ul><li>Insulin </li></ul></ul>
  65. 69. Blood Sugar Regulation in Diabetics
  66. 70. Hypoglycemia <ul><li>Reactive hypoglycemia </li></ul><ul><ul><li>Occurs 2-4 hours after eating a meal </li></ul></ul><ul><ul><li>Possibly due to over-secretion of insulin </li></ul></ul><ul><li>Fasting hypoglycemia </li></ul><ul><ul><li>Usually caused by pancreatic cancer </li></ul></ul><ul><ul><li>Leads to overproduction of insulin </li></ul></ul>
  67. 71. Metabolic Syndrome (Syndrome X) <ul><li>25% of adults have it </li></ul><ul><li>High blood triglycerides </li></ul><ul><li>Poor blood glucose regulation </li></ul><ul><li>Hypertension </li></ul><ul><li>Risk factors </li></ul><ul><ul><li>Obesity </li></ul></ul><ul><ul><li>Lack of physical activities </li></ul></ul><ul><ul><li>High simple/refined sugar intake </li></ul></ul><ul><ul><li>Low fiber intake </li></ul></ul>
  68. 72. Metabolic Syndrome (Syndrome X)