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Glycemic index and diabetes
The document explains the glycemic index (GI) as a measure of how carbohydrate-containing foods affect blood glucose levels, categorizing foods into low, medium, and high GI ranges. It discusses various factors influencing GI ranking, including the type of starch, physical entrapment, fiber viscosity, and the impact of food processing and cooking. Additionally, it highlights the limitations of solely using GI for diabetes management, suggesting that glycemic load (GL) and carbohydrate counting may offer more effective strategies.
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Glycemic index and diabetes
- 1. Glycemic Index and Diabetes JOKHAAL-JASSASI DIETITIAN IBRI POLYCLINIC
- 2. Glycemic Index (GI) measures how a carbohydrate-containing food raises blood glucose. Foods are ranked based on how they compare to a reference food — either glucose or white bread.
- 3. GI ranks Key LowMedium High Glycemic Index 55 or less 56 -69 70 or higher Examples • 100% stone- ground whole wheat or pumpernickel bread • Most fruits, • Whole wheat, • Quick oats • Brown, wild or basmati rice, • White bread or bagel • Corn flakes, • Puffed rice, br an flakes, • Shortgrain white rice,
- 4. Factors Influencing GIRanking • Type of starch
- 5. Factors Influencing GIRanking Type of Starch • Absorbs less water • Molecules form tight clumps • Slower rate of digestion • Absorbs more water • Molecules are more open • Faster rate of digestion Amylose Amylopectin Lower GI Kidney beans (28) Higher GI Russet potato (85)
- 6. Factors Influencing GIRanking • Type of starch • Physical entrapment
- 7. Factors Influencing GIRanking Physical Entrapment Endosperm Bran Germ Bran acts as a physical barrier that slows down enzymatic activity on the internal starch layer. Lower GI Pumpernickel bread (50) Higher GI Bagel (72)
- 8. Factors Influencing GIRanking • Type of starch • Physical entrapment • Viscosity of fiber
- 9. Factors Influencing GIRanking Viscosity of Fiber Viscous, soluble fibers transform intestinal contents into gel-like matter that slows down enzymatic activity on starch. Lower GI Apple (40) Higher GI Cheerios (74)
- 10. Factors Influencing GIRanking • Type of starch • Physical entrapment • Viscosity of fiber • Fat and protein content
- 11. Factors Influencing GIRanking Fat & Protein Content Fat and protein slow down gastric emptying, and thus, slows down digestion of starch. Lower GI Potato chips (54) Higher GI Baked potato (85)
- 12. Factors Influencing GIRanking • Type of starch • Physical entrapment • Viscosity of fiber • Fat and protein content • Acid content
- 13. Factors Influencing GIRanking Acid Content Acid slows down gastric emptying, and thus, slows down the digestion of starch. Lower GI Sourdough wheat bread (54) Higher GI Wonder white bread (73)
- 14. Factors Influencing GIRanking • Type of starch • Physical entrapment • Viscosity of fiber • Fat and protein content • Acid content • Food processing
- 15. Factors Influencing GIRanking Food Processing Highly processed foods require less digestive processing. Lower GI Old fashioned, rolled oats (51) Higher GI Quick, 1-minute oats (66)
- 16. Factors Influencing GIRanking • Type of starch • Physical entrapment • Viscosity of fiber • Fat and protein content • Acid content • Food processing • Cooking
- 17. Factors Influencing GIRanking Cooking Cooking swells starch molecules and softens foods, which speeds up the rate of digestion. Lower GI Al dente spaghetti – boiled 10 to 15 minutes (44) Higher GI Over-cooked spaghetti – boiled 20 minutes (64)
- 18. Other Causes ofVariability in the Glycemic Index The particle size of the food The degree of ripeness How long the food has been stored The current meal, or the meal before The pre-meal BG level The procedure for measuring GI can vary from study to study, so GI tables can conflict Both intra-and interpersonal responses can vary significantly
- 19. What are thelimitations of using glycemic index? GI values were determined in studies where volunteers ate portions containing 50 grams of carbohydrate of each test food. 50 grams of carbohydrate from popcorn is ten cups popped, while from white rice is about one cup cooked. There is a wide variation in values assigned to the same food depending on reference source. GI values can vary depending on many factors GI values measured the effect of a test food when that food was eaten alone. The effect of food on blood sugar can vary from person to person. A lower GI value does not necessarily mean the food is a better choice. E.g a chocolate candy bar vs. 1 cup of brown rice have =GI
- 20. glycemic load Theglycemic load (GL) is an equation that takes into account the planned portion size of a food as well as the glycemic index of that food. GL = GI x CHOg per serving/100 Is believed to better represent the glycemic impact of more typical portions of foods Low GL = 10 or less Medium GL = 11-19 High GL = 20 or more
- 21. Example of GL Example using white bread, GI = 70 GL of 1sl = 70 X 15g/100 = 10.5 GL of 2sl = 70 X 30g/100 = 21 GL of 3sl = 70 X 45g/100 = 31.5 So even a low GI food can have a high GL if the portion is big enough. And, a high GI food can have a lower GL if the portion is controlled Because GL is based upon GI, GL values of foods can vary for the same reasons that GI can vary
- 23. Pictures of Low/HighGI Meals & Snacks GI = 60 GL = 48 GI = 42 GL = 31
- 24. Pictures of Low/HighGI Meals & Snacks GI = 85 GL = 48 GI = 39 GL = 22
- 25. Who may beinterested in the glycemic index? People who have diabetes may use GI values as an additional tool for managing blood sugar levels. GI values can also be used when treating reactive hypoglycemia. Studies have shown that when eating low GI foods, people tend to snack less, which may be helpful in weight control as well as blood sugar control.
- 26. GI & Diabetes Most GI studies have been conducted using non-diabetic subjects The measurement of the glycemic response is almost always stopped after 2 hour post-meal Studies which include subject with diabetes show greater variability in GI response among people with diabetes The GI is based on a 50 gram load of carbohydrate -which can be very different from a typical portion Studies demonstrate a small overall improvement in BG control at best 0.27-0.43 % drop in A1c. By contrast, standard Medical Nutritional Therapy has achieved a 1-2% point drop in A1c.
- 27. GI or CarbohydrateCounting? There is no one diet or meal plan that works for everyone with diabetes. The important thing is to follow a meal plan that is tailored to personal preferences and lifestyle Research shows that both the amount and the type of carbohydrate in food affect blood glucose levels. Studies also show that the total amount of carbohydrate in food, in general, is a stronger predictor of blood glucose response than the GI. Based on the research, for most people with diabetes, the first tool for managing blood glucose is some type of carbohydrate counting. Combined GI with carbohydrate counting, it may provide an additional benefit for achieving blood glucose goals for individuals who can and want to put extra effort into monitoring their food choices
- 28. Meats andfats do have a GI ? Yes No
- 29. Case Study –“Amy” Before 38 YO administrative assistant Married, no children Height: 5’7” Weight: 320 lbs.=145kg BMI: 50 (severe obesity) Type 2 DM since age 35 A1c: 6.3 (Glucophage 500 mg) BP: 148/90 (Altace 10 mg)
- 30. Case Study –Amy’s Before Diet Breakfast: toasted bagel with cream cheese, 16 oz. orange juice, large coffee with whole milk Lunch: 6” roast beef & cheese sub sandwich w/ mayo, 20 oz. diet Pepsi Snack: (“all afternoon long”) 13 oz. bag Hershey miniature chocolate bars Dinner: ½ box macaroni & cheese (made w/ 2% milk), 3 beef hot dogs on buns, water Snack: 1 ½ cups ice cream 6250 Kcal: 43% CHO (666g), 11% PRO (173g), 46% fat (321g) GI = 57 (moderate) GL = 352 (very high)
- 31. Case Study –Amy’s After Diet Breakfast: 2 slices 100% WW toast, 1 Tbsp natural, NSA peanut butter, 1 Tbsp all-fruit jelly, 1 cup fresh strawberries, large coffee w/ skim milk Lunch: 4 oz. grilled chicken breast, large green salad with varied fresh vegetables & 2 Tbsp vinaigrette dressing, small boiled sweet potato, orange, diet iced tea Snack: 6 oz. light yogurt, ½ cup cherries (frozen) Dinner: 4 oz. grilled salmon w/ lemon juice, 1 cup pasta w/ 1 cup broccoli rabe, 1 Tbsp olive oil, water Snack: apple 2150 Kcal: 47% CHO (251g), 19% PRO (104g), 34% fat (82g) GI = 39 (low) GL = 61 (low)
- 32. Case Study –“Amy” Before 3 years later…
- 33. Case Study –“Amy” After Weight: 205 lbs=92 kg BMI: 32 (mild obesity) A1c: 5.2 BP: 120/60, RHR 47 Medications: none.
- 34. Referances Johanna Burani,American Diabetes Association, Southern Regional Conference, Marco Island, Florida, May 26, 2006 UCSF Diabetes Center Resources, http://diabetes.ucsf.edu/sites/diabetes.ucsf.edu/files/PEDS %20Glycemic%20Index.pdf , assessed on 28/10/2016 American diabetes Association, Glycemic Index and Diabetes, http://www.diabetes.org/food-and- fitness/food/what-can-i-eat/understanding- carbohydrates/glycemic-index-and- diabetes.html?referrer=https://www.google.com/ Last Edited: May 14, 2014, accessed on 28/10/2016 Patty Haney, GLYCEMICINDEX: FROM RESEARCH TO PRACTICE,
- 35. Thank you Q? You are what you think. So,be positive & optimist ic for future