Glycaemic Index (GI) may be used to guide choice of carbohydrate containing foods. GI has typically been determined in small groups of European volunteers and the value thus obtained is assumed to apply to all populations. The aim of this study was to determine whether there are ethnic differences in glycaemic responses and GI to various varieties of rice in people of European and Chinese ethnicity.
Sixty-two healthy volunteers, 31 Chinese and 31 Europeans (18-50yr) consumed 50g of available carbohydrate portions on separate mornings after a 10hr overnight fast. Capillary blood glucose was measured at baseline and over a 2hr period following ingestion of foods (glucose beverage, tested two occasions, and five rice varieties: Jasmine, Basmati, Brown, Doongara® and Parboiled, each tested on a single occasion).
Age, height, and sex distribution were not different between the two groups, but body weight and body mass index (BMI) were significantly lower in the Chinese than the European group (p<0.05). Incremental blood glucose areas under the curve (iAUC) of all tested foods were greater in Chinese than in Europeans (p<0.05). The largest difference was for Parboiled rice for which the Chinese iAUC was 77% (95%CI: 38, 226, p<0.001) higher than the European iAUC. In the Chinese and European groups, respectively, the GI of Doongara® (67, 55), Jasmine (81, 68), and Parboiled rice (72, 57) were significantly higher in the Chinese.
The greater glycaemic response to carbohydrate in Chinese compared with Europeans and the higher glycaemic index for several rice varieties has potential clinical relevance. Regression analysis including variables which might have explained the ethnic differences suggested that age, sex, salivary alpha-amylase and extent of chewing contributed little to the ethnic difference.
