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Useful Facts about Sugars, Starches, and Fiber

Useful Facts about Sugars, Starches, and Fiber. Unit 12. The Carbohydrates. Carbohydrates Chemical substances in foods that consist of a simple sugar molecule or multiples of them in various forms Primary ingredient of staple foods (pasta, rice, cassava, beans, bread).

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Useful Facts about Sugars, Starches, and Fiber

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  1. Useful Facts about Sugars, Starches, and Fiber Unit 12

  2. The Carbohydrates • Carbohydrates • Chemical substances in foods that consist of a simple sugar molecule or multiples of them in various forms • Primary ingredient of staple foods (pasta, rice, cassava, beans, bread)

  3. Three Types of Carbohydrates • Simple sugars • Complex carbohydrates (starches) • Total fiber

  4. Carbohydrate Sources • Simple sugars (left), starch and fiber (right)

  5. Carbohydrate Functions • Major source of energy • Recommended intake 45-65% of total calories • Simple sugars and complex carbohydrates supply 4 calories/gram • Dietary fiber indirectly supplies 2 calories/gram (when digested by bacteria in colon) • Other functions in immune and reproductive systems, blood clotting, DNA

  6. Alcohol • Alcohol (ethanol) and alcohol sugars have similar structures

  7. Simple Sugar Facts • Simple sugars (sugars) • Carbohydrates that consist of a glucose, fructose, or galactose molecule, or a combination of glucose and either fructose or galactose • Also includes high-fructose corn syrup and alcohol sugars

  8. Two Types of Simple Sugar • Monosaccharides • Consist of one sugar molecule • Glucose, fructose, galactose • Disaccharides • Consist of two monosaccharides linked together • Sucrose, maltose, lactose • Broken into monosaccharides by digestion

  9. Disaccharides

  10. Energy Production • Glucose is the only simple sugar the body can use to form energy • Fructose, galactose are converted to glucose • Excess glucose is converted to fat and glycogen • Body produces glucose by breaking down glycogen, amino acids, glycerol from fats • Cells in brain, blood, and kidneys require a constant supply of energy from glucose

  11. Glycogen Storage form of glucose Complex carbohydrate Long chains of glucose molecules Produced only by animals Stored in liver and muscles Glycogen

  12. Body’s Sources of Glucose

  13. In US, total simple sugar intake averages 23% of total calories 17% of total calories from added sugars Sucrose High-fructose corn syrup Simple Sugar Intake

  14. Added sugars in candy, beverages, cereals Natural sugars in milk, fruit, some vegetables Simple Sugars in Foods

  15. Nutrition Labeling of Sugars • Nutrition labels list total amounts of mono- and diglycerides per serving under “sugars” • All simple sugars must be listed in order of weight in the ingredients

  16. Labeling Sugars

  17. What’s So Bad About Sugar? • Simple sugars provide only calories • Sweetened foods are often high in fat, low in nutrients • Problems associated with high sugar intake: • Increased blood triglycerides • Excessive calorie intake • Tooth decay

  18. Advice on Sugar Intake • Limit added sugars to 10% or less of total calorie intake

  19. Alcohol Sugars • Alcohol sugars (“polyols”) • Simple sugars containing an alcohol group in their molecular structure • Incompletely digested (~2 calories/gram) • Examples: • Xylitol, mannitol, sorbitol • Used as sweetening agents • Do not promote tooth decay

  20. Products With Alcohol Sugars

  21. Artificial Sweetener Facts • Artificial (non-nutritive) sweeteners • Not significant sources of energy or nutrients • 160 to 13,000 time sweeter than sucrose • Do not promote tooth decay

  22. Products with Artificial Sweeteners

  23. Artificial Sweeteners

  24. Artificial Sweeteners • Saccharin • First artificial sweetener (1800s) • 300 times sweeter than sucrose • Aspartame (Nutrasweet) • Contains amino acids phenylalanine, aspartame • 4 calories/gram • 200 times sweeter than sucrose

  25. Is Aspartame Safe? • Products containing aspartame must carry a warning for people with certain conditions • Phenylketonuria (PKU) • Genetic disorder • Lack of enzyme phenylalanine hydroxylase causes phenylalanine buildup in blood

  26. Safe levels of aspartame set at 50 mg/kg body weight/day Some individuals report sensitivity to small amounts Safe Limits for Aspartame

  27. Artificial Sweeteners cont. • Sucralose (Splenda) • Made from sucrose • 600 times sweeter than sucrose • Acesulfame K (Sunette, Sweet One) • Acesulfame potassium • 200 times sweeter than sucrose

  28. Artificial Sweeteners cont. • Neotame • Like aspartame, made from phenylalanine and aspartame, but not harmful to people with PKU • 7,000-13,000 times sweeter than sucrose • Rebiana (Reb-A, Truvia, Purevia) • Derived from herb stevia

  29. Stevia-Based Sweeteners

  30. Artificial and natural sweeteners, in order of sweetness Sweetness Rankings

  31. Complex Carbohydrate Facts • Complex carbohydrates • Form of carbohydrate found in starchy vegetables, grains, dried beans, and many types of dietary fiber • The most common form of starch is made of long chains of glucose units

  32. Complex Carbohydrate Facts • Polysaccharides • Carbohydrates containing many molecules of monosaccharides linked together • 3 major types: starch, glycogen, dietary fiber • Oligosaccharides • Polysaccharides consisting of 3 to 10 monosaccharides

  33. Which Foods Have Carbohydrates?

  34. 4 oz baked potato 122 calories 3 oz lean hamburger 239 calories Which Has More Calories?

  35. US Fiber Facts • Fiber is low in calories, prevents constipation, and may lower risk of heart disease, obesity, and diabetes • Recommended intake 28-35 grams/day • Fiber intake by US children and adults is low: about 15 grams of fiber/day

  36. Good Sources of Fiber

  37. Good Sources of Fiber

  38. Types of Fiber • Edible fibers are classified based on source and effects on body processes • Functional fiber • Dietary fiber • Total fiber

  39. Functional Fiber • Functional fiber • Specific types of nondigestible carbohydrates that have beneficial effects on health • Examples: psyllium, pectin, gels, gums • Effects: • Feeling of fullness, slows glucose absorption, prevents constipation, decreases fat and cholesterol absorption

  40. Dietary Fiber • Dietary fiber • Naturally occurring, intact forms of nondigestible fiber in plants and “woody” plant cell walls • Contains nutrients and other plant substances • Found in oat and wheat bran; plant cellulose, fruits and vegetables, raffinose in beans

  41. Dietary Fiber In Wheat Bran

  42. Total Fiber • The recommended daily intake of fiber is based on total fiber • Total fiber • The sum of functional and dietary fiber

  43. Soluble and Insoluble Fiber • Soluble fibers combine chemically with water • Found in oats, barley, fruit, psyllium • Slows glucose absorption • Reduces fat and cholesterol absorption • Insoluble fibers do not combine chemically with water • Found in bran, some legumes • Same health benefits as soluble fiber

  44. Adding Fiber to Your Diet • Adding too much fiber to the diet too quickly can result in temporary side effects • Increase fluid intake along with fiber intake • Don’t add excessive fiber to children’s diets

  45. Carbohydrates and Blood Glucose • Some types of simple and complex carbohydrates in foods elevate blood glucose levels more than others • Important to people with insulin resistance and type 2 diabetes

  46. Key Terms • Insulin resistance • When cell membranes have reduced sensitivity to insulin, more insulin is required to transport a given amount of glucose into cells • Type 2 diabetes • High blood glucose levels due to the body’s inability to use insulin normally, or to produce enough insulin

  47. Glycemic Index • Carbohydrate-containing foods are classified by how much they increase blood glucose • Glycemic index • Measure of how much blood glucose is raised by a 50-gram portion of a carbohydrate-containing food, compared to 50 grams of glucose or white bread

  48. Glycemic Index of Foods • Some high glycemic-index foods: • Glucose, white bread, baked potatoes, jelly beans • Some low glycemic-index foods: • Fructose, xylitol, hummus, apples, all-bran cereal

  49. Low Glycemic Index Diets • Diets with low glycemic index carbohydrates: • Improve blood glucose control • Reduce elevated blood cholesterol and triglycerides • Increase beneficial HDH cholesterol • Decrease risks of type 2 diabetes, some types of cancer, and heart disease

  50. Carbohydrates and Your Teeth • Tooth decay did not become a problem until sugar became widely available • Tooth decay (dental caries, cavities) • Disintegration of teeth due to acids produced by bacteria in the mouth that feed on sugar

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