EFFECTS OF DIFFERENT GLYCEMIC INDEX FOODS AND DIETARY FIBER INTAKE ONGLYCEMIC CONTROL IN TYPE-1 DIABETIC-PATIENTS ON INTENSIVE INSULIN THERAPY

To evaluate the influence of a low glycaemic index (GI), high CI and h igh fibre diet on glycaemic control and insulin requirement in Type 1 diabetic patients on intensive insulin therapy, nine well-controlled, highly-motivated Type 1 diabetic patients were put on a control diet f or 12 days and then randomized in a consecutive manner to 12 days of e ach diet, in a crossover design. During each experimental diet, the st udy subjects adjusted their premeal insulin (soluble) dose to maintain their 1-h postprandial capillary glucose at or below 10 mmol l(-1). A t the end of each experimental diet, they were submitted to a standard ized breakfast of the diet under study, using the same premeal insulin dose as that required for the control diet. The control diet containe d 16.0 +/- 3.0 g of fibre day(-1) with a GI of 77.4+/-2.7 compared to 15.3+/-6.3 and 66.2+/-11.2 for the low CI diet, 17.1 +/- 7.2 and 92.9 +/- 3.6 for the high GI diet, and 56.1 +/- 3.6 (including 15 g of guar ) and 73.5 +/- 2.1 for the high fibre diet. Prebreakfast capillary blo od glucose (6.2 +/- 1.2 mmol l(-1)) on the low CI diet and postbreakfa st capillary blood glucose (8.7 +/- 1.8 mmol l(-1)) on the high fibre diet were significantly lower than the values obtained with the contro l diet (8.0 +/- 1.8 and 10.6 +/- 2.4, respectively; p < 0.05). No chan ge in premeal or basal insulin dose was required. During the standardi zed breakfasts, the incremental area under the curve was 1.6 +/- 1.5 m mol l(-1) min(-1) for the control diet compared to 1.1 +/- 1.8 for the low GI diet, 3.2 +/- 1.4 for the high CI diet (p <0.05 versus low CI and high fibre; p= 0.08 versus control), and 1.0 +/- 0.9 for the high fibre diet. These observations indicate that in well-controlled Type 1 diabetic subjects on intensive insulin therapy, major alterations in the CI and fibre content of meals induce small but significant changes in glucose profile. In everyday life, however, these differences are blunted, and plasma glucose remains within the target range for optima l metabolic control. (C) 1998 John Wiley & Sons, Ltd.