Diabetes 2  

Glycemic Index
Alpha Nutrition Health Education Series

 

These discussions of diabetes are from the Book of Diabetes 2. 

You can order an eBook or printed text version separately or as part of a

Diabetes Nutritional Rescue Starter Pack

Topics

Coping with Diet Change

Exercise is Best Medicine

eBook Information

Diabetes Center

 

 

Alpha Nutrition

 

Order Diabetes Rescue Starter Pack

The idea behind the glycemic index is that different foods produce different blood sugar elevations. Studies were undertaken to measure the blood sugar responses to common foods in healthy volunteers. Values from two indices are listed below. 

The  index  in the right column below compares a 50 gram dose of the food to 50 grams of glucose with reference value of 100. 

In the  column on the left, another index uses white bread as a reference with the value of 100; glucose then has a value of 138.

The glycemic index values are useful as guides to food selection, but many factors influence the blood sugar response to foods.

 Combining foods into meals will change the impact of each food on blood sugar. High fiber vegetables have low glycemic indexes and trend to reduce the glycemic effects of the higher rated foods. The method of cooking also influences the blood sugar effect - cooking rice longer, for example liberates more free sugar from starch and increases the glycemic index.

Differences in glycemic response reflects the rate that foods are digested and there are many factors.  Variability of glycemic responses arises from variables in the same subject and variation between different subjects. 

There is less variability between the GI values of different subjects than there is within the same subject from day to day. Starchy foods producing low glycemic responses have been identified, including legumes, pasta, barley, bulgur, parboiled rice and whole grain rye breads such as pumpernickel. Incorporation of these foods into diets have been associated with reduced blood glucose, insulin, and lipid levels. Low GI foods increase colonic fermentation,  increase bacterial urea utilization, and increase production and absorption of short chain fatty acids in the colon.

Alpha Nutrition a Division of
Environmed Research Inc.  British Columbia, Canada
Food Index 1 : White bread reference Index 2: Glucose reference
Glucose 138 100
Potato, Baked 116 98
Parsnips x 97
Carrots (cooked) x 92
Honey 126 87
Potato, Instant mashed 120 80
Cornflakes 121 80
White Bread 100 72
Whole Wheat Bread 100 72
Shredded Wheat 97 72
White Rice Boiled 81 72
Potato, White Boiled 80 70
Brown Rice 81 66
Raisins 93 64
Beets x 64
Bananas 84 62
SUCROSE 83 59
Sweet Corn 80 59
Pastry x 59
Bran x 51
Green Peas 50 51
Potato Chips x 51
Sweet Potato x 51
White Spaghetti 67 50
Oatmeal 78 49
Grapes x 45
Whole Grain Rye Bread 68 42
Whole Wheat Spaghetti 61 42
Orange 59 40
Apples 52 39
Tomatoes x 38
Chick-Peas 47 36
Lima Beans x 36
Kidney Beans 43 29
Lentils 36 29
Pears x 34
Peaches x 26
Grapefruit x 26
Plums x 25
Cherries x 24
Fructose 26 20
Soybeans 20 15
Peanuts 15 13

 

Order Diabetes Rescue Starter Pack

Course Work Abstracts:

Starchy foods and glycemic index.

Jenkins_DJ; Wolever_TM; Jenkins_AL

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.

Diabetes Care, 1988 Feb, 11:2, 149-59

Different starchy foods produce different glycemic responses when fed individually, and there is some evidence that this also applies in the context of the mixed meal. A major reason appears to relate to the rate at which the foods are digested and the factors influencing this. A similar ranking in terms of glycemic response to specific foods is seen independent of the carbohydrate tolerance status of the groups tested. Potentially clinically useful starchy foods producing relatively flat glycemic responses have been identified. Many of these are considered ethnic or traditional and include legumes; pasta; grains such as barley, parboiled rice, and bulgur (cracked wheat); and whole-grain breads such as pumpernickel. Specific incorporation of these foods into diets has been associated with reductions in low-density lipoprotein cholesterol and triglyceride levels in hyperlipidemia and with improved blood glucose control in insulin-dependent diabetic patients. To facilitate identification of such foods, it has been suggested that the glycemic response should be indexed to a standard (e.g., white bread) to allow comparisons to be made between the glycemic index of foods tested in different groups of subjects. The scope of application of this principle is subject to further investigation. It may be used to expand the range of possibly useful starchy foods for trial in the diets of diabetic patients

Foods with a low glycemic index do not improve glycemic control of both type 1 and type 2 diabetic patients after one month of therapy.

Calle-Pascual_AL; Gomez_V; Leon_E; Bordiu_E

Diabete Metab, 1988 Sep-Oct, 14:5, 629-33

Twenty four diabetic patients (12 type 1 and 12 type 2) were studied to determine the influence of using foods rich in carbohydrates with either low or high glycemic indexes on the glycemic control of Diabetes Mellitus. All patients were treated with insulin. During 2 periods of 4 weeks the patients received, at lunch, 2 types of foods rich in carbohydrates as part of their usual diet. Meal A: foods with a low glycemic index and Meal B: foods with a high glycemic index. During the last 7 days of each period the patients determined, at home, their capillary glucose levels before and 1, 2, and 3 hours after lunch by means of a reflectometer. At the end of each period HbA1 levels were also determined. No differences in insulin dose or changes in body weight were found during the two periods of the study for both types of diabetic patients. Capillary glucose levels before lunch were similar on both diets and for both types of diabetic patients. Similarly, postprandial capillary glucose levels 1, 2, and 3 hours later were not different for both died A and diet B. No statistically significant differences were found either in HbA1 values for both periods of the study. These results confirm previous ones obtained in acute studies. The present findings indicate that the glycemic response of foods rich in carbohydrates is modified when included in a mixed meal by the other components of the meal. From these date it can be inferred that the use in a diet of foods with a low glycemic index does not improve the glycemic control of patients affected of Diabetes

The glycemic index: variation between subjects and predictive difference.

Wolever_TM; Csima_A; Jenkins_DJ; Wong_GS; Josse_RG

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.

J Am Coll Nutr, 1989 Jun, 8:3, 235-47

It is not known whether the variability of the glycemic index (GI) in different subjects is due to within- or between-individual variation. In addition, it is not known how large a difference in GI between different meals is clinically important for individuals with diabetes. Therefore, insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetic subjects tested four foods, with each food taken by each subject on two separate occasions. For each food, most of the variation of absolute glycemic responses was due to differences between the subjects. However, when the results were expressed as the GI, there were no significant differences between the subjects, and most of the variation was due to within-individual variation. Using the within-individual variance, we estimated the so-called "predictive difference" of GI values. Its reliability was assessed by consideration of published data from eight studies where different mixed meals were taken by the same group of subjects. There were 37 cases where the difference between the GI of any two meals was greater than the predictive difference. Of these 37 pairs of meals, the GI correctly ranked the glycemic responses in 36 (97%). We conclude that GI values for the same food do not vary significantly between different individuals. For a subject with NIDDM a difference in GI of 34 will predict the ranking of glycemic responses of two meals with 95% probability. The corresponding value for a subject with IDDM is 50.

Glycemic index of foods in individual subjects.

Wolever_TM; Jenkins_DJ; Vuksan_V; Josse_RG; Wong_GS; Jenkins_AL</DD>

Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada.

Diabetes Care, 1990 Feb, 13:2, 126-32

We studied 12 subjects with diabetes to determine how well the glycemic index (GI) predicted the ranking of glycemic responses of different foods in individuals. All subjects ate three mixed meals (bread, rice, or spaghetti with GIs of 100, 79, and 61, respectively) four times in a randomized complete block design. The mean glycemic response areas of the different meals ranked according to the predicted GI in every individual. The observed mean +/- SD GI values of the meals were significantly different from each other (bread 100 +/- 7, rice 75 +/- 9, spaghetti 54 +/- 9), with no significant difference in response between subjects. It is concluded that individuals share common mean GI values for different foods. Within confidence limits determined by the variability of glycemic responses, the number of repeated tests conducted, and the expected GI difference, the GI can be used to predict the ranking of the mean glycemic responses of mixed meals taken by individuals.

The clinical utility of the glycemic index and its application to mixed meals.

Hollenbeck_CB; Coulston_AM

General Clinical Research Center, Stanford University School of Medicine, CA 94305.

Can J Physiol Pharmacol, 1991 Jan, 69:1, 100-7

A classification of carbohydrate-containing foods based on their glycemic response to 50-g carbohydrate portions has recently been developed. The relative glycemic potency of many of these carbohydrate-containing foods have been compared, and these data have been published in the form of a glycemic index. It has been suggested that meals containing low glycemic index foods will result in a lower postprandial glucose response than meals with a higher glycemic index. However, whether or not these data will lead to a clinically useful reduction in postprandial hyperglycemia in individuals with carbohydrate intolerance remains controversial. In this review, we will try to delineate why we believe that the glycemic index, as currently developed, may be a specious tissue. In addition, we will briefly discuss a number of factors that may explain the apparent discrepancy in viewpoints on this issue.

The glycemic index: methodology and clinical implications.

Wolever_TM; Jenkins_DJ; Jenkins_AL; Josse_RG

Department of Nutritional Sciences, Faculty of Medicine, St. Michael's Hospital, University of Toronto, Ontario, Canada.

Jour Clin Nutr, 1991 Nov, 54:5, 846-54

There is controversy regarding the clinical utility of classifying foods according to their glycemic responses by using the glycemic index (GI). Part of the controversy is due to methodologic variables that can markedly affect the interpretation of glycemic responses and the GI values obtained. Recent studies support the clinical utility of the GI. Within limits determined by the expected GI difference and by the day-to-day variation of glycemic responses, the GI predicts the ranking of the glycemic potential of different meals in individual subjects. In long-term trials, low-GI diets result in modest improvements in overall blood glucose control in patients with insulin-dependent and non-insulin-dependent diabetes. Of perhaps greater therapeutic importance is the ability of low-GI diets to reduce insulin secretion and lower blood lipid concentrations in patients with hypertriglyceridemia.

Second-meal effect: low-glycemic-index foods eaten at dinner improve subsequent breakfast glycemic response

Wolever_TM; Jenkins_DJ; Ocana_AM; Rao_VA; Collier_GR

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.

Am J Clin Nutr, 1988 Oct, 48:4, 1041-7

The effects of the glycemic index (GI) of carbohydrate eaten the previous night on the glycemic response to a standard test meal eaten subsequently in the morning (breakfast) was studied. On separate evenings normal subjects ate low- or high-GI test meals of the same nutrient composition. The dinners consisted of single foods in two experiments and mixed meals containing several foods in the third. The differences between the observed glycemic responses to low- and high-GI dinners were predicted by their GIs. The glycemic responses to breakfast were significantly lower on mornings after low-GI dinners than after high-GI dinners. Eating, at dinner, foods with different fiber contents but the same GI had no effect on postbreakfast glycemia. We conclude that the GI predicts the difference between glycemic responses of mixed dinner meals; breakfast carbohydrate tolerance is improved when low-GI foods are eaten the previous evening.

Application of glycemic index to mixed meals.

Chew_I; Brand_JC; Thorburn_AW; Truswell_AS

Department of Biochemistry, University of Sydney, Australia.

Am J Clin Nutr, 1988 Jan, 47:1, 53-6

Plasma glucose and insulin responses to six different meals were determined and compared with values predicted by published glycemic indices of the component foods. The test meals were of different ethnic origins: Indian (lentil curry with rice), Italian (spaghetti bolognaise), Chinese (stir-fried vegetables and chicken with rice), Greek (lentil stew), Western (sirloin chop and vegetables); and Lebanese (sandwich with unleavened bread and hummus). Eight healthy volunteers were given 50 g carbohydrate portions of the above meals after an overnight fast. The glycemic and insulin indices were highest for the Lebanese meal and lowest for the Greek with significant differences among the meals (ANOVA, p less than 0.05). The observed glycemic indices correlated well with the predicted glycemic indices (r = 0.88, p less than 0.01) and insulin responses parallelled the glycemic responses (r = 0.83, p less than 0.05). These results suggest that the glycemic index approach will be useful in planning diets for diabetic people.

  Environmed Research/Alpha Nutrition