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What about the Glycemic Index, from Diabetes Solution Revised and Updated 2007 editionArticles - Dr. Bernstein Shares His Insights Dr. Richard K. Bernstein’s new book is out, Diabetes Solution New and Revised 2007, has more info than ever and we have arranged for a special promotion, go to this URL for more. This week Dr. Bernstein asks the question WHAT ABOUT THE GLYCEMIC INDEX?Diabetes Solution Revised and Updated 2007Complete Guide to Achieving Normal Blood Sugars A P P E N D I X A WHAT ABOUT THE GLYCEMIC INDEX?
This term was, as I recall, first coined by the same Dr. Jenkins mentioned in the above section. The concept is more complicated than the popular press would have you believe. Imagine two graphs, each depicting a curve of a blood sugar increase over a 3-hour time span. The first curve is after eating pure glucose, the standard. The second is after eating any other food of equivalent total carbohydrate content (20 grams glucose versus 20 grams carbohydrate content of, say, rice). Dr. Jenkins defined the glycemic index for a given food in terms of how its curve related to that of the glucose curve. So to arrive at the index for rice, for example, the area under the 3-hour curve of blood sugar increase caused by the rice would be divided by the area under the curve for pure glucose. The measurement is usually made on a number of nondiabetics and then averaged, and finally expressed as a percent. Thus, if a food generates a 3-hour area one-fifth that of glucose, its glycemic index would be 20 percent. So what’s wrong with that? As attractive as it may seem, the concept is clearly flawed in three respects: First, diabetics show much higher blood sugar increases than nondiabetics. Second, digestion of the carbohydrate portion of a meal typically takes at least 5 hours (in the absence of gastroparesis), and the index ignores effects upon blood sugar that last longer than 3 hours. Finally, the index is an average of values for a number of different people, and true numbers have been found to vary considerably from one person to another, from one time to another, and from one study to another. As I’ve pointed out, a food that makes my blood sugar rise dramatically may have little or no effect on that of one of my patients who still makes some insulin. Unfortunately, many dieticians and diabetes educators still recommend foods that have been “shown” to have a “low” glycemic index in some study, and assume that an index of 40 or 50 percent is low. They may thus select apples, lima beans, and the like as appropriate for diabetics, even though consumption of typical portions of these foods will cause considerable blood sugar elevations in diabetics. A “medium-sized” apple, according to one table of food values, contains 21 grams of carbohydrate. It will raise my own blood sugar by 105 mg/dl, and much more rapidly than I can prevent with an injection of rapid-acting insulin. Peanuts usually have the lowest glycemic index in many studies (about 15 percent), yet 1 ounce contains 6 grams of carbohydrate and close to 1 ounce of protein. I’ve found this portion to raise my blood sugar by 80 mg/dl, albeit much more slowly than the apple. Since peanuts work so slowly (more slowly than 3 hours), I can substitute 1 ounce for 6 grams carbohydrate and 1 ounce protein in a meal—but who can eat only one handful of peanuts?* The carbohydrate foods that we recommend, salads and selected vegetables (Chapter 9), have glycemic indices lower than peanuts and work more slowly. Furthermore, they are more filling. The issue here, though, is to understand that such indices are unreliable and won’t help you keep your blood sugars normalized. * As the first edition of this book was going to press, a report appeared entitled “Dietary Fiber, Glycemic Load, and Risk of Non-Insulin-Dependent Diabetes in Women” (Jnl Amer Med Assoc 1997; 277:472–477). This study of 65,173 nurses and former nurses found a strong association between diets high in starch, flour, and sweet foods and the development of type 2 diabetes. Furthermore, consumption of minimally refined grain (such as bran without flour) lowered this risk. The combination of high glycemic foods and low intake of unrefined insoluble fiber was associated with a 2.5-fold higher incidence of diabetes. If you remember our discussion of beta cell burnout (pages 39–42), this should come as no surprise. * By the way, natural peanut butter has a glycemic index much higher than that of the peanuts from which it was created because it is digested more rapidly. DIABETES SOLUTION 2007 Edition
All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means, including information storage and retrieval systems, without permission in writing from the publisher, except by a reviewer who may quote brief passages in a review. Author’s Note For information on how you can purchase Diabetes Solution, go to www.Diabetes911.net Special for $19.95. Regular $29.95 A savings of 10dollars ORDER NOW! www.diabetes911.net or Call 1-800-798-6972 or
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For a number of years, the term “glycemic index” has popped in and out of the popular press. It also has been a pet subject for many dietitians and diabetes educators. I will explain why, but I think it’s important to make clear that there is simply no way to determine objectively
how any given food at any given time is going to behave in any given individual, unless blood sugar is tested before and for a number of hours after its consumption. It sounds like an elegant idea—mashed potatoes do X; table sugar does Y. As with a lot of elegant ideas, however, the reality is far more complex.
We would like to thank the publisher Little Brown and Company and Dr. Richard K. Bernstein, for allowing us to provide excerpts from Diabetes Solution 2007 Edition
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