RESUMO
Low-glycemic index diets are associated with a wide range of benefits when followed on a chronic basis. The chronic effects, however, of the substitution of 1 meal per day are not well known in diabetic subjects. Therefore, we aimed to evaluate whether the chronic use of a low-glycemic index breakfast (low-GIB) rich in low-GI carbohydrates and a modest amount of soluble fibers could have an effect on lipemia at a subsequent lunch, and improve glucose and lipid metabolism in men with type 2 diabetes. A total of 13 men with type 2 diabetes were randomly allocated in a double-blind cross-over design to a 4-week daily intake of a low-GI versus a high-GI breakfast separated by a 15-day washout interval. The low-GI breakfast was composed of whole grain bread and muesli containing 3 g beta-glucan from oats. Low-GIB induced lower postprandial plasma glucose peaks than the high-GIB at the beginning (baseline, P <.001) and after the 4-week intake (P <.001). The incremental area under the plasma glucose curve was also lower (P <.001, P <.01, baseline, and 4 weeks, respectively). There was no effect on fasting plasma glucose, insulin, fructosamine, or glycosylated hemoglobin (HbA(1c)). Fasting plasma cholesterol, as well as the incremental area under the cholesterol curve, were lower (P <.03, P <.02) after the 4-week low-GIB period than after the high-GIB period. Apolipoprotein B (apo B) was also decreased by the 4-week low-GIB. There was no effect of the low-GI breakfast on triacylglycerol excursions or glucose and insulin responses at the second meal. The high-GIB, however, tended to decrease the amount of mRNA of leptin in abdominal adipose tissue, but had no effect on peroxisome proliferator-activated receptor gamma (PPARgamma) and cholesterylester transfer protein (CETP) mRNA amounts. In conclusion, the intake of a low-GI breakfast containing a modest amount (3 g) of beta-glucan for 4 weeks allowed good glycemic control and induced low plasma cholesterol levels in men with type 2 diabetes. The decrease in plasma cholesterol associated with low-GI breakfast intake may reduce the risk of developing cardiovascular complications in subjects with type 2 diabetes.