1. Carbohydrates

2. Intended Learning Outcomes - -By the end of this lecture, students will have a general overview on the carbohydrates.

3. Can you live without sugar? SSSSoda/Punch CCCCookies CCCCandy CCCChocolate DDDDesserts SSSSugary Cereals IIIIce cream

4. CARBOHYDRATES 1. 60% of our food should come from carbohydrates.

5. 2. Carbohydrates are grains, fruits, vegetables, legumes and sugar.

6. Carbohydrates  glucose provides energy for the brain and ½ of energy for muscles and tissues  glycogen is stored glucose  glucose is immediate energy  glycogen is reserve energy

7. CARBOHYDRATES 3. Carbohydrates give the body energy. They are the best source of fuel for the body. Carbohydrates also help to digest protein and fat.

8. Carbohydrates  2. Carbohydrates also play a vital part of the metabolism and oxidation of protein  Carbs help feed the brain and nervous system and helps keep the body lean.

9. CARBOHYDRATES 4. If we eat more carbohydrates than are needed for energy, the extra is stored in the liver or in the tissues as fat.

10. Carbohydrates  5. all plant food  Milk (LACTOSE)  carbohydrates are not equal –simple carbohydrates –complex carbohydrates

11. Simple Carbohydrates 6. Simple carbohydrates are quick energy sources. They come from sugar. They do not usually supply any other nutrients or fiber.

12. Simple Carbohydrates  sugars –monosaccharides – single sugars –disaccharides – 2 monosaccharides

13. Simple Carbs  monosaccharides –all are 6 carbon hexes  6 carbons  12 hydrogens  6 oxygens  arrangement differs –accounts for varying sweetness –glucose, fructose, galactose

14. Glucose  mild sweet flavor  10. known as blood sugar  essential energy source  found in every disaccharide and polysaccharide

15. Fructose  sweetest sugar  found in fruits and honey  added to soft drinks, cereals, deserts

16. Galactose  hardly tastes sweet  rarely found naturally as a single sugar

17. Disaccharides  pairs of the monosaccharides –glucose is always present –2 nd of the pair could be fructose, galactose or another glucose –taken apart by hydrolysis –put together by condensation –hydrolysis and condensation occur with all energy nutrients –maltose, sucrose, lactose

18. Maltose  2 glucose units  produced when starch breaks down  not abundant

19. Sucrose  fructose and glucose  tastes sweet –fruit, vegetables, grains  table sugar is refined sugarcane and sugar beets  brown, white,powdered

20. Lactose  glucose and galactose  main carbohydrate in milk –known as milk sugar

21. Simple Sugars 7. Glucose or blood sugar is the basic source of energy for all living things. 8. Sucrose or table sugar is made from sugar beets or sugar cane. 9. Fructose is sugar found in fruit, honey and vegetables. 11. Maltose is grain starch broken down into sugar. 12. Lactose is milk sugar.

22. Complex Carbohydrates  starches and fibers  polysaccharides –chains of monosaccharides

23. Complex Carbohydrates 13. Complex carbohydrates supply longer lasting energy, as well as other nutrients and fiber that the body needs. They are a better choice.

24. Condensation  making a disaccharide –chemical reaction linking 2 monosaccharides

25. Hydrolysis  breaking a disaccharide –water molecule splits –occurs during digestion

26. Complex Carbohydrates  polysaccharides –1.glycogen and 2.starch  built entirely of glucose –3.fiber  variety of monosaccharides and other carbohydrate derivatives

27. Glycogen  limited in meat and not found in plants –not an important dietary source of carbohydrate  BUT –all glucose is stored as glycogen –long chains allow for hydrolysis and release hydrolysis and release of energy of energy

28. Starches  stored in plant cells  body hydrolyzes plant starch to glucose

29. STARCHES  14. Starch in the body breaks down simple sugars. The body has to break down all sugar and starch into glucose to use it.

30. Starchy Foods  15. All starchy foods are plant foods, seeds are the richest source; 70% of their weight is starch

31. Fiber  structural parts of plants –found in all plant derived food  bonds of fibers cannot be broken down during the digestive process –minimal or no energy available

32. Fiber types  cellulose  pectins  lignins  resistant starches –classified as fibers –escape digestion and absorption

33. Fiber Characteristics  soluble fibers, viscous, fermentable –easily digested by bacteria in colon –associated with protection against heart disease and diabetes  lower cholesterol and glucose levels –found in legumes and fruits

34. Fiber 1.The average American does not get enough FIBER in their diets. 2.The National Cancer Institute recommends that the average person gets 20-35 GRAMS of fiber every day. 3.Two other common names for fiber are: ROUGHAGE or CELLULOSE.

35. 4.Fiber is important because it attracts WATER to the INTESTINES and helps move food through our systems faster. You have to have water along with fiber or it is not as effective. 5.Benefits of fiber include a lowered risk of DIVERTICULITUS, HEMORRHOIDS and COLON or RECAL CANCER.

36. 6. List the two types of fiber and the main functions they perform:

37. 7.Fiber only comes from PLANT food sources. You CANNOT get fiber from animal food sources. 8.Foods that are high in fiber include: Fruits and Veggies (Especially the Skins!)Fruits and Veggies (Especially the Skins!) Whole GrainsWhole Grains Legumes/Beans - BranLegumes/Beans - Bran 9.Ways to increase fiber in the diet include: Add Whole Grains (At least 3 oz. per day)Add Whole Grains (At least 3 oz. per day) Use Whole Wheat FlourEat the SkinsUse Whole Wheat FlourEat the Skins

38. 10. Label the Wheat Kernel below: A.__ENDOSPERM___ Provides: Starch Protein B.__GERM___ Provides: Unsaturated Fatty Acids “B” Vitamins Vitamin E Iron Zinc Other Trace Minerals C.__Bran___ Provides: Fiber Vitamins Minerals

39. 11.When a product claims that it is “Whole Wheat” or “Whole Grain”, it must use the ENTIRE wheat kernel, or ALL THREE parts. 12.Other products, like white bread and rice, usually only use the ENDOSPERM, which is the LEAST beneficial part of the wheat kernel. 13.ENRICHED: some of the nutrients that were lost in processing are added back into the product. 14.FORTIFIED: 10% more of the Daily Value for the nutrient is being added.

40. Fiber  insoluble and not easily fermented –promote bowel movements –alleviate constipation –found in grains and vegetables

41. DRI and Fiber  distinguish fibers by source –dietary fibers: naturally in intact plants –functional fibers: extracted from plants or manufactured –total fiber: sum of the 2

42. Carbohydrate Digestion  break down into glucose –body is able to absorb and use  large starch molecules – extensive breakdown  disaccharides –broken once  monosaccharides –don’t need to be broken down

43. Carbohydrate Digestion  begins in mouth –chewing releases saliva –enzyme amylase hydrolyzes starch to polysaccharides and maltose  stomach –no enzymes available to break down starch –acid does some breakdown –fibers in starch provide feeling of fullness

44. small intestine majority of carbohydrate digestion takes place here pancreatic amylase reduces carbs to glucose chains or disaccharides specific enzymes finish the job maltase maltose into 2 glucose sucrase sucrose into glucose and fructose lactase lactose into glucose and galactose

45. large intestine 1-4 hours for sugars and starches to be digested only fibers remain attract water, which softens stool bacteria ferment some fibers water, gas, short-chain fatty acids (used for energy)

46. Carbohydrate Absorption  glucose can be absorbed in the mouth  majority absorbed in small intestine –active transport  glucose and galactic –facilitated diffusion  fructose  smaller rise in blood glucose

47. Lactose Intolerance  more lactose is consumed than can be digested –lactose molecules attract water  cause floating, abdominal discomfort, diarrhea –intestinal bacteria feed on undigested lactose  produce acid and gas

48. Lactose Intolerance  age, damage, medication, diarrhea, malnutrition  management requires dietary change –6 grams (1/2 cup) usually tolerable –take in gradually –hard cheeses & cottage cheese –enzyme drops or tablets  lactose free diet is extremely difficult to accomplish

50. Carbohydrate Metabolism  1/3 of body’s glycogen is stored in liver –released as glucose to bloodstream 1.eat – intake glucose 2.liver condenses extra glucose to glycogen 3.blood glucose falls 4.liver hydrolyzes glycogen to glucose Glycogen is bulky, so we store only so much: short term energy supply Fat is the long term energy supply.

51. Glucose for Energy  enzymes break apart glucose – yielding energy  inadequate supply of carbohydrates –ketone bodies (fat fragments) are an alternate energy source during starvation –excess ketones can lead to ketosis: imbalance of acids in body  minimum of 50 – 100 grams of carbs/day are needed to avoid ketosis

52. Glucose Homeostasis  maintaining an even balance of glucose is controlled by insulin and glucagon –insulin  moves glucose into the blood –glucagon  brings glucose out of storage

53. maintaining balance balanced meals at regular intervals fiber and some fat slow the digestive process down glucose gets into the blood slow and steady

54. Maintaining Blood Glucose Homeostasis Intestine When a person eats, blood glucose rises. 1 2 Insulin stimulates the uptake of glucose into cells and storageas glycogen in the liver and muscles. Insulin also stimulates the conversion of excess glucose into fat for storage. 3 4 5 6 7 Blood glucose begins to rise. a The stress hormone epinephrine and other hormones also bring glucose out of storage. Glucose Insulin Glucagon Glycogen Glucagon stimulates liver cells to break down glycogen and release glucose into the blood. a Liver Low blood glucose stimulates the pancreas to release glucagon into the bloodstream. As the body's cells use glucose, blood levels decline. Glucagon Pancreas Fat cell Liver Muscle High blood glucose stimulates the pancreas to release insulin. Pancreas Insulin

55. Imbalance  diabetes –after food intake, blood glucose rises and is not regulated because insulin is inadequate  hypoglycemia –blood glucose drops dramatically  too much insulin, activity, inadequate food intake, illness  diet adjustment includes fiber-rich carbs and protein

56. Glycemic Index  way of classifying food according to their ability to raise blood glucose  much controversy

58. Sugar  ½ comes from natural sources, ½ from refined and added –sucrose, corn syrup, honey  excess can lead to nutrient deficiencies and tooth decay –empty calories –sugar and starch break down in the mouth

59. Sugar  recommended intake –added sugar = no more than 10% of energy intake

61. Starch and Fiber  diet that includes starch, fiber and natural sugars –whole grains, vegetables, legumes, fruits  may protect against heart disease and stroke  reduces the risk of type 2 diabetes  enhances the health of the large intestine  can promote weight loss

62. Starch and Fiber  starch intake –45-65% –225 – 325 grams (DV is 300 grams) –900-1300 kcal/2000 kcal –RDA is 130 grams  fiber intake –Daily Value is 25 grams/2000 kcal

65. Groceries  grains: 1 serving = 15 grams  vegetables –½ cup starchy = 15 grams –½ cup nonstarchy = 5 grams  fruit: 1 serving = 15 grams  milk: 1 cup = 12 grams  meat: none or little  legumes: ½ cup = 15 grams

66. Artificial Sweeteners  help keep sugar and energy intake down  anything we eat has FDA approval –saccharin –aspartame –acesulfame potassium –sucralose –neotame

68. Sugar Replacers  sugar alcohols –provide bulk and sweetness  cookies, gum, candy, jelly –do contain minimal kcal –low glycemic response  absorbed slowly –do not cause dental caries

69. Assignment  Taghreed Mahmoud  Sohila nabil hamed

70. Recommended text book Manual dietetic book