The glycaemic index: an overview of its possible role in the prevention and treatment of chronic disease

Abstract

Summary The concept of a glycaemic index owes much to the dietary fibre hypothesis; that fibre would reduce the rate of nutrient absorption and increase the value of carbohydrate foods in the maintenance of health and treatment of disease. However, several aspects of food other than its fibre content contribute to the glycaemic and endocrine responses postprandially. The aim of the glycaemic index classification of foods was therefore to assist in the physiological classification of carbohydrate foods that, it was hoped, would be of relevance in prevention and treatment of chronic diseases such as diabetes. In the last 20 years, low glycaemic index diets have been reported to improve glycaemic control in patients with diabetes and reduce serum lipids in hyperlipidaemic subjects. Low glycaemic index or glycaemic load diets (glycaemic index multiplied by total carbohydrates) have also been associated with higher levels of high-density lipoprotein cholesterol, reduced C-reactive protein concentrations and, in large cohort studies, with decreased risk of developing diabetes and cardiovascular disease. Some case-control and cohort studies have also found positive associations between dietary glycaemic index and the risk of colon and breast cancer. Although there are inconsistencies in the data, sufficient positive findings have emerged to suggest that the dietary glycaemic index is an aspect of diet with potential importance in the treatment and prevention of chronic diseases.