Nutrition Research Reviews

Research Articles

Glycaemic index methodology

F. Brounsa1a2 c1, I. Bjorcka3, K. N. Frayna4, A. L. Gibbsa5, V. Langa6, G. Slamaa7 and T. M. S. Wolevera8

a1 Maastricht University, Nutrition and Toxicology Research Institute, Department of Human Biology, PO Box 616, 6200MD, Maastricht, The Netherlands

a2 Cerestar- Cargill R&D Center, Vilvoorde, Belgium

a3 University of Lund, Department of Applied Nutrition and Food Chemistry, Lund, Sweden

a4 OCDEM, University of Oxford, Oxford, UK

a5 Department of Statistics, University of Toronto, Toronto, Ontario, Canada

a6 Danone Vitapole R&D Center, Palaiseau CEDEX, France

a7 INSERM – Unité 341, Département Diabète, Paris CEDEX 04, France

a8 Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada

Abstract

The glycaemic index (GI) concept was originally introduced to classify different sources of carbohydrate (CHO)-rich foods, usually having an energy content of >80 % from CHO, to their effect on post-meal glycaemia. It was assumed to apply to foods that primarily deliver available CHO, causing hyperglycaemia. Low-GI foods were classified as being digested and absorbed slowly and high-GI foods as being rapidly digested and absorbed, resulting in different glycaemic responses. Low-GI foods were found to induce benefits on certain risk factors for CVD and diabetes. Accordingly it has been proposed that GI classification of foods and drinks could be useful to help consumers make ‘healthy food choices’ within specific food groups. Classification of foods according to their impact on blood glucose responses requires a standardised way of measuring such responses. The present review discusses the most relevant methodological considerations and highlights specific recommendations regarding number of subjects, sex, subject status, inclusion and exclusion criteria, pre-test conditions, CHO test dose, blood sampling procedures, sampling times, test randomisation and calculation of glycaemic response area under the curve. All together, these technical recommendations will help to implement or reinforce measurement of GI in laboratories and help to ensure quality of results. Since there is current international interest in alternative ways of expressing glycaemic responses to foods, some of these methods are discussed.

Correspondence:

c1 *Corresponding author: Dr Fred Brouns, fax +32 2 2570740, email m.brouns@hb.unimaas.nl