Research Letter

Age-related differences in postprandial glycaemia and glycaemic index SIR—The glycaemic index (GI) is a concept that ranks the glycaemic potency of foods [1]. Postprandial hyperglycaemia following consumption of a food is measured over time and expressed as incremental area under the blood glucose curve (iAUC). GI is then calculated as the iAUC of a test food rela-tive to the iAUC of a reference food (normally a glucose bever-age containing the same amount of carbohydrate). Some evidence is suggestive that dietary GI is positively associated with risk of several chronic diseases including type 2 diabetes [2, 3]. Additionally, the prevalence of impaired fasting glucose and diabetes increases with age [4]. There is debate as to the necessity of including GI in dietary recommendations [5] but if GI is to be used it is important to confirm that the GI of th