Health Canada’s evaluation of the use of glycemic index claims on food labels

Abstract

The glycemic index (GI) is a system that ranks foods according to the blood glucose-increasing potential of servings of foods that provide the same amount of available carbohydrate. The GI was originally developed as a tool for carbohydrate exchange in the dietary management of glycemia in persons with diabetes, and studies have generally supported modest benefits of low-GI diets in this population. Despite inconsistent results for the utility of the GI in the nondiabetic population, there is some interest in its universal application on food labels to assist consumers in making food choices that would help them meet their dietary goals. The objective of this review was to evaluate the usefulness of including the GI values of foods as part of the information on food labels in Canada. Health Canada's assessment identified 3 areas of concern with respect to GI labeling: 1) the GI measure has poor accuracy and precision for labeling purposes; 2) as a ratio, the GI does not vary in response to the amount of food consumed and the partial replacement of available carbohydrates with unavailable carbohydrates, whereas the glycemic response does; and 3) an unintended focus on the GI for food selection could lead to food choices that are inconsistent with national dietary guidelines. Hence, Health Canada's current opinion is that the inclusion of the GI value on the label of eligible food products would be misleading and would not add value to nutrition labeling and dietary guidelines in assisting consumers to make healthier food choices.

Estimating the reliability of glycemic index values and potential sources of methodological and biological variability

“…Meta-analysis of prospective studies supports a positive association between high GI diets and increased chronic disease risk (8), but data from randomized clinical trials indicate an inconsistent relation between dietary GI and GL values and insulin sensitivity (9), cardiovascular disease (8,10), weight loss (11,12), and cancer (13,14). Some of this discrepancy in the literature has been attributed to methodologic issues with its measurement (15)(16)(17)(18).…”

“…have been met with varying degrees of success (16). To minimize the intra-individual CV, it is recommended that the GI value of the test food be derived from the ratio of the glycemic response it elicits over the average of 2, preferably 3, glycemic responses to the reference (24).…”

Glycemic index claims on food labels: review of Health Canada's evaluation

“…2 However, a defined method had been published 12 years ago by the Food and Agriculture Organization of the United Nations; 3 now there is an International Standards Organization-approved method. 4 In the current assessment of GI, 1 Health Canada identified three main areas of concern but its discussion of them is inept; Aziz et al 1 provide no valid evidence to support their conclusions regarding issues that are relevant to GI labeling, and the issues with valid evidence are not relevant.…”

“…Unfortunately for the scientists at Health Canada, the paper by Aziz et al, 1 which is now in the public domain, contains numerous errors and several illogical and inconsistent arguments; errors which might have been avoided by a process of consultation.…”

Effect of Macronutrient Composition on Short-Term Food Intake and Weight Loss

“…Its proponents suggest that low-GI diets have favorable effects on weight loss and other biomarkers of metabolic health. Critics of the GI state that the concept is inaccurate, imprecise, and ignores other potentially important components in the food and thus does not confer additional benefits beyond current dietary guidance (66).…”