AIMS: The aim of this study is to compare the efficacy of low glycaemic index (GI) vs. conventional carbohydrate exchange (CCE) dietary advice on glycaemic control and metabolic parameters in patients with type 2 diabetes.
METHODS: A total of 104 patients with type 2 diabetes were randomly assigned to either a low GI (GI) or CCE dietary advice over a 12-week period. The primary end-point was glycaemic control as assessed by glycated haemoglobin A1c (HbA1c), fructosamine level and plasma glucose. The secondary end-points were anthropometric measurements and metabolic parameters that include blood pressure, lipid profile and insulin levels. The oral antidiabetic medications remained unchanged throughout the duration of the study.
RESULTS: A low-GI diet was associated with significant changes in the fructosamine level (DeltaGI = -0.20 +/- 0.03; DeltaCCE = -0.08 +/- 0.03 mmol/l, p < 0.01) and waist circumference (DeltaGI group = -1.88 +/- 0.30 cm; DeltaCCE group: -0.36 +/- 0.4 cm, p < 0.05) at week 4. At week 12, the changes in fasting glucose (DeltaGI = -0.03 +/- 0.3; DeltaCCE = 0.7 +/- 0.3 mmol/l; p < 0.05) and waist circumference (DeltaGI = -2.35 +/- 0.47 cm; DeltaCCE group = -0.66 +/- 0.46 cm; p < 0.05) in the GI group was significantly lower than the CCE group. With the low-GI diet, the changes in postprandial glycaemia at time 0, 60, 150 and 180 min after consuming the standard test meal was lower than with the CCE diet (p < 0.05). No significant differences were found between the groups for the remaining parameters that were measured.
CONCLUSIONS: Use of a low-GI diet resulted in significant changes of serum fructosamine level, plasma glucose and waist circumference in Asian patients with type 2 diabetes over a 12-week period compared with those following a CCE diet. The effect on HbA1c and other metabolic parameters was not significantly different between the two study groups but the improvement within the GI group was more pronounced and of clinical benefit.
Diabetes-specific nutritional formulas (DSNFs) are frequently used as part of medical nutrition therapy for patients with diabetes. This study aims to evaluate postprandial (PP) effects of 2 DSNFs; Glucerna (GL) and Ultra Glucose Control (UGC) versus oatmeal (OM) on glucose, insulin, glucagon-like peptide-1 (GLP-1), free fatty acids (FFA) and triglycerides (TG). After an overnight fast, 22 overweight/obese patients with type 2 diabetes were given 200 kcal of each of the three meals on three separate days in random order. Blood samples were collected at baseline and at 30, 60, 90, 120, 180 and 240 min. Glucose area under the curve (AUC0-240) after GL and UGC was lower than OM (p < 0.001 for both). Insulin positive AUC0-120 after UGC was higher than after OM (p = 0.02). GLP-1 AUC0-120 and AUC0-240 after GL and UGC was higher than after OM (p < 0.001 for both). FFA and TG levels were not different between meals. Intake of DSNFs improves PP glucose for 4 h in comparison to oatmeal of similar caloric level. This is achieved by either direct stimulation of insulin secretion or indirectly by stimulating GLP-1 secretion. The difference between their effects is probably related to their unique blends of amino acids, carbohydrates and fat.