Slowly digested and absorbed carbohydrate in traditional bushfoods: a protective factor against diabetes?

The aim of this study was to compare the digestibility and metabolic responses of western foods with traditional staples of two populations that show a susceptibility to diabetes, namely Australian Aborigines and Pacific islanders. Rate of starch digestion was studied in vitro in 37 foods (20 Australian Aboriginal bushfoods, 10 Pacific island foods, and 7 western foods), and rate of absorption of 9 foods (8 bushfoods and 1 western food) was studied in human volunteers. In vitro studies showed that 23 of 30 traditional foods were digested more slowly than 7 western foods. Six of 8 bushfoods produced significantly smaller areas under 3-h postprandial plasma glucose curves than potatoes in seven healthy Caucasian volunteers. There was a good correlation between starch digestibility and plasma glucose response. Our findings are consistent with the hypothesis that carbohydrate in traditional diets is slowly digested and absorbed and may once have been protective against diabetes.