Glycemic Index

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Glycemic Index

• What is its role in a diet for diabetes?
• Amy Olson, RD, CDE
• FCS 5152

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A Diet For Diabetes

• 1500 B.C.--High Carbohydrate
• Late 1700s--Low carbohydrate
• 1912-- near starvation diet
• 1921 20 CHO, 10 pro
• 70 fat

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A Diet for Diabetes cont.

• CHO PRO FAT
• 1950 40 20 40
• 1971 45 20 35
• 1986 ?60 12-20
• 1994 A 10-20 A,B
• A Based on assessment and goals
• B

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Diet for Diabetes

• Is the type of carbohydrate important?

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Glycemic index of foods
Brand Miller The New Glucose Revolution 2003
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Definition

• Incremental area under the glucose response curve
  to 50 g carbohydrate from test food
• Incremental area under the glucose response curve
  to 50 g carbohydrate standard

• x 100 GI

Jenkins et al. Am J Clin Nutr 1981
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Summary of Results

• Food Group
• Root vegetables
• Sugars
• Vegetables
• Breakfast cereals
• Cereals
• Biscuits
• Fruit
• Dairy Products
• Legumes

• GI
• 72 6
• 71 20
• 65 14
• 65 5
• 60 3
• 60 3
• 50 5
• 35 1
• 31 3

Jenkins et al. Am J Clin Nutr 1981
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Description of Glycemic Index

• The degree to which carbohydrates in different
  foods raise blood glucose levels
• Considers quality rather than quantity of
  carbohydrate
• Brand-Miller, The New Glucose Revolution 2003

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Factors Affecting Glycemic Index

• Chain length and composition
• Amyloseamylopectin
• Amount of viscous soluble fiber
• Cooking and processing
• Acidity
• Ripeness and food storage
• Fat content

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High, low or in between?

• Food Glycemic Index
• Instant Rice 91
• Baked Potato 85
• Corn Flakes 84
• White Bread 70
• Rye Bread 65
• Banana 53
• Spaghetti 41
• Apple 36
• Lentils 29
• Milk 27
• Peanuts 14

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Glycemic Index

• Does it help control diabetes?

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Nine Clinical Trials 1988-1994
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Luscombe 1999

• 21 Type 2 DM adults
• 4 weeks each diet
• high carb/high GI (63)
• high carb/low GI (43)
• high MUFA/high GI (59)
• Luscombe et al. 1999 Euro J Clin Nutr

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Luscombe 1999 Results

• No effect on fasting plasma glucose, 24 h urinary
  glucose excretion, total glycosylated plasma
  protein or fructosamine
• Increase of 6 in HDL (p

Author conclusion Both the low-GI and high-mono
high-GI diet appear to be only marginally better
dietary choices than the high-GI diet--and only
in terms of HDL.
Luscombe et al. 1999 Euro J Clin Nutr
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Järvi 1999

• 20 Type 2 DM adults age 50-77
• 24 days each diet
• low GI (57)
• high (83) GI

Jarvi et al. 1999 Diab Care
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Jarvi 1999 Results
Author conclusion GI is a useful concept in
management of diabetes.
Adapted from Jarvi et al 1999 Diab Care
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Giaco 2000

• 63 Type 1 DM adults age 28.5 9
• 24 week one diet
• low fiber GI63
• high fiber GI49

Giaco et al. 2000 Diab Care
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Giaco 2000 Results
Author conclusion Adult type 1 patients are
able to comply with a long-term dietary treatment
based on a high fiber low glycemic index diet
with significant and long lasting improvement in
glucose control without major drawbacks.
Adapted from Giaco et al. 2000 Diab Care
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Gilbertson2001
Gilbertson et al 2001 Diab Care
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Gilbertson 2001 Results
Author conclusion More flexible dietary
instruction based on the food guide pyramid with
an emphasis on low-GI foods has demonstrable
benefits for children with diabetes.
Gilbertson et al 2001 Diab Care
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Buyken 2001 Study

• 2810 Type 1 DM age 15-60
• cross-sectional clinic-based study analyzed 3-day
  dietary records
• Compared GI quartiles of Southern Europe vs.
  Northern, Western and Eastern Europe
• Adjusted for energy, fiber, alcohol intake,
  overweight, smoking status.

Buyken et al. 2001 Am J Clin Nutr
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Buyken 2001 Results
Author conclusion Type 1 diabetes control
improved as a result of consuming low-GI foods. A
low-GI diet may help HDL cholesterol.
Buyken et al. 2001 Am J Clin Nutr
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Heilbronn 2002

• 45 Type 2 DM diet controlled age 56.7 y
• 12 week energy restricted diet
• high GI 75
• low GI 43
• Participants received foods 60 of energy

Heilbronn et al. 2002 J Am Coll Nutr
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Heilbronn 2002 Results
Author conclusion Lowering the GI of high carb,
low fat diets increases the fall in LDL
cholesterol in Type 2 DM but has little effect on
glycemic control.
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Jiménez-Cruz 2003

• 36 Type 2 DM age 35-75
• randomized, controlled, crossover design
• 6 weeks each diet with 6 week washout
• high GI 56
• low GI 44 (higher in fiber, P0.003)

Jiménez-Cruz et al. 2003 Diab Care
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Jiménez-Cruz 2003 Results

• 8 dropped out of high GI, 4 from low GI, 10 had
  incomplete records so n14
• A1c
• lower after low GI than after high GI (p
  0.019)
• Fasting serum glucose
• lower after low GI than after high GI (p 0.03)
• Lipids
• no significant effect seen

Author conclusion A low-GI diet with
Mexican-style foods may help improve metabolic
control in type 2 obese diabetic subjects.
Jiménez-Cruz et al. 2003 Diab Care
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Summary of Studies
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Meta-Analysis2003
Since 1998
Prior to 1994
Adapted from Brand-Miller et al Diab Care 2003
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Nutrition Recommendations
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Limitations of Glycemic Index

• Does not consider carbohydrate content in meals
• Fasting vs. second meal
• GI curves only cover 2 hours
• Limited reproducibility with varying premeal
  glycemia
• Values exist for 750 foods

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Glycemic Load

• Combines type and amount of carbohydrate
• GI Value x carbohydrate per serving 100

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Compare GI to Glycemic Load

• Food Glycemic Index Glycemic Load Portion
• Instant Rice 87 19.7 1/3 cup
• Baked Potato 85 15.3 3 oz
• Corn Flakes 81 15.8 3/4 cup
• White Bread 70 10.0 1 slice
• Rye Bread 65 9.1 1 slice
• Banana 53 6.2 1/2
• Spaghetti 41 6.5 1/2 cup
• Apple 36 6.0 4 oz
• Lentils 29 3.5 1/2 cup
• Milk 27 3.2 1 cup
• Peanuts 14 0.7 1 oz

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Adjusted carbohydrate exchange
Buchorn, 1997 Aust J Nutr Diet
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What is next?

• American Diabetes Association 64th Scientific
  Sessions June 2004 Program Highlights include
  Glycemic Index What We Know, Dont Know and
  Need to Know

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Popular Books/Diets

• The New Glucose Revolution
• South Beach Diet
• Nutrisystem
• Good Carbs, Bad Carbs
• The Zone
• Sugar Busters

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Questions

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