Age-related differences in postprandial glycaemia and glycaemic index.

摘要

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 relative to the iAUC of a reference food (normally a glucose beverage 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 the food, a value typically obtained in young people, is applicable to an older age group. Guidelines on GI testing do not specify a preferred age of participants [6, 7]. The average age of GI participants has been reported from mid-twenties to mid-fifties [8-10]. Wolever et al. did not find differences in GI for three foods tested in people aged either younger or older than 40 years with a differential in mean age between the groups of 20 years [11]. However, this is a relatively close age gap considering the ageing population living into their seventh decade and older. We have tested two ready-to-eat breakfast cereals in groups of people differing substantially in age to determine whether published data are likely to apply across the age range.