Chp 4 - Nutrition: Concepts & Controversies, 12e Sizer /Whitney

1. HUN 4296 Nutrition & Health IssuesWeek 2 Day 1 Part 2Carbohydrates: Sugar, Starch, Glycogen, and Fiber Chp 4 - Nutrition: Concepts & Controversies, 12eSizer/Whitney

2. Basics on Carbohydrates • Green plants capture energy from sun via photosynthesis • Plants do not use all of the energy stored in their sugars

3. The Need for Carbohydrates • Critical energy source • Nerve cells and brain • Preferred dietary sources • Starchy whole foods • Complex carbohydrates • Vital roles in the functioning body

4. How Monosaccharides Join to Form Disaccharides

5. How Glucose Molecules Join to Form Polysaccharides

6. Fiber – Undigested Carbohydrate • Human digestive enzymes cannot break bonds • Bacteria in large intestine • Fermentation • Soluble vs. insoluble fibers

7. Why Do Nutrition Experts Recommend Fiber-Rich Foods? • Health benefits • Reduced risk of heart disease • Reduced risk of hypertension • Reduced risk of diabetes • Reduced risk of bowel disease • Promotion of healthy body weight • Sources of fiber

8. Characteristics, Sources, and Health Effects of Fibers(“brooms & sponges”)

10. One Way Fiber in Food May Lower Cholesterol in the Blood

11. Why Do Nutrition Experts Recommend Fiber-Rich Foods? • Maintenance of digestive tract health • All kinds of fiber • Ample fluid intake • Benefits of fiber • Constipation, hemorrhoids, appendicitis, diverticulosis

12. Diverticula

13. Why Do Nutrition Experts Recommend Fiber-Rich Foods? • Digestive tract cancer and inflammation • Ways fiber works against cancer • Dilution • Folate • Resident bacteria • Butyrate • Recommended dietary sources • Healthy weight management • Appetite control

14. Fiber Recommendations and Intakes • Few people in U.S. meet recommendations • 20-35 grams of fiber daily • Based on energy needs, age, and gender • Adding fiber to diet • Too much fiber? • Dangers of excess • Binders in fiber • Chelating agents • Cause of deficiencies

16. Refined, Enriched, and Whole-Grain Foods • Bread – “the staff of life” • Kernel (whole grain) has four main parts • Germ • Endosperm • Bran • Husk

17. Refined, Enriched, and Whole-Grain Foods • U.S. Enrichment Act of 1942 • Required additives • Addition in 1996 • Advantages of whole grains vs. enriched grains • Finding the whole grains in foods

18. Nutrients in Whole-Grain, Enriched White, and Unenriched White Breads

19. Bread Labels Compared

20. Carbohydrate →Fuel

21. From Carbohydrates to Glucose – Digestion & Absorption • Starch and disaccharides are broken down • Monosaccharides for absorption • Starch • Begins in the mouth • Splits starch into maltose • Digestion ceases in the stomach • Digestion resumes in small intestine • Pancreas • Resistant starch

22. From Carbohydrates to Glucose – Digestion & Absorption • Sugars • Split to yield free monosaccharides • Enzymes on small intestine lining • Travel to the liver • Fiber • Fermented by bacteria in the colon • Odorous gas • Gradually increase fiber intakes

23. Splitting Glucose for Energy • Glucose can be converted to fat • Fat cannot be converted to glucose • Dependence on protein when insufficient carbohydrate • Protein-sparing action • Ketosis • Shift in body’s metabolism • Disruption of acid-base balance • DRI minimum of digestible carbohydrate

24. How Is Glucose Regulated in the Body? • Two safeguard activities • Siphoning off excess blood glucose • Replenishing diminished glucose • Two hormones • Insulin • Signals body tissues to take up glucose • Glucagon • Triggers breakdown of glycogen • Epinephrine

25. Handling Excess Glucose • Body tissue shift • Burn more glucose • Fat is left to circulate and be stored • Carbohydrate storage as fat • Liver breakdown and assembly • Costs a lot of energy • Weight maintenance • Dietary importance and composition

26. Glycemic Index of Food • Elevation of blood glucose and insulin • Food score compared to standard food • Diabetes • Glycemic load (GL) • Lower GL = less glucose guild up and less insulin needed • Limitations of glycemic index • Resist notion of “good” or “bad” foods

27. Glycemic Index of Selected Foods

28. Diabetes • Prevalence of diabetes • Adults • Children • Prediabetes • Importance of testing • Perils of diabetes • Toxic effects of excess glucose • Inflammation • Circulation problems

29. Prevalence of Diabetes Among Adults in the United States

30. Warning Signs of Diabetes

31. Type 1 Diabetes • 5 to 10 percent of cases • Common age of occurrence • Autoimmune disorder • Own immune system attacks pancreas • Lose ability to produce insulin • External sources of insulin • Fast-acting and long-acting forms

32. Type 2 Diabetes • Predominant type of diabetes • Lose sensitivity to insulin • Obesity underlies many cases • Other factors foreshadowing development • Middle age and physical inactivity • Body fat accumulation • Genetic inheritance • Prevention

33. Type 1 and 2 Diabetes Compared

34. An Obesity-Diabetes Cycle

35. Management of Diabetes • Controlling blood glucose is key • Monitoring blood glucose levels • Taking medications • Control body fatness • Establish good eating patterns

36. Management of Diabetes • Nutrition • Goal: blood glucose levels in normal range • Control carbohydrate intake • Amount rather than source seems to matter • Carbohydrate recommendations • Varies with glucose tolerance • Exchange system

37. Management of Diabetes • Nutrition • Carbohydrate timing • Evenly spaced • Sugar alcohols • Advantages • Artificial sweeteners • Weight control

38. Management of Diabetes • Physical activity • Benefits of regular activity • Type 2 diabetes vs. type 1 diabetes

39. Hypoglycemia • Rare, but true disease • Abnormally low blood glucose • Postprandial hypoglycemia • Requires test to detect • Fasting hypoglycemia • Symptoms • Methods to reduce symptoms

40. Finding Carbohydrates in Foods • Fruits • Vary in water, fiber, & sugar concentrations • Juice • Vegetables • Breads, grains, cereals, rice, & pasta • Brown color does not equal whole grain • Low-fat and low-sugar choices

41. Finding Carbohydrates in Foods • Meat, poultry, fish, dry beans, eggs, & nuts • Nuts and legumes • Milk, cheese, & yogurt • High-quality protein • Oils, solid fats, & added sugars • Naturally occurring vs. added sugars • Honey

42. Finding Carbohydrates in Foods • The nature of sugar • Teaspoon values • High-fructose corn syrup • Concentrated juice sweeteners • Ways to magnify sweetness without calories

43. Are Carbohydrates “Bad” for Health Controversy 4

44. Accusation 1: Carbohydrates Are Making Us Fat • Americans are fatter • Greater consumption of calories • 300-500 per day • Epidemiological studies • Weight loss

45. Percentage of Calories from Energy Nutrients, U.S., 1977-2006

46. Daily Energy Intake Over Time

47. Accusation 2: Carbohydrates Cause Diabetes • Obesity and diabetes • Refined carbohydrates and diabetes • Native Americans • Glycemic load and diabetes • Whole foods

48. Accusation 3: Added Sugars Cause Obesity and Illness • Current trends • Daily • Per year • Relationship with disease

49. Added Sugars: Average U.S. Supply per Person Compared with USDA Prudent Upper Intake Limits

50. Accusation 4: High-Fructose Corn Syrup Harms Health • Villainy has been exaggerated • Nature of HFCS • Half of added sugar in U.S. food supply • Obesity • HCFS not a proven cause • Liquid sugar and calorie control • Appetite regulation • Fructose does not stimulate insulin release