Effect of Pseudocereal-Based Breakfast Meals on the First and Second Meal Glucose Tolerance in Healthy and Diabetic Subjects

BACKGROUND: Many studies have indicated that the incidence of serious diabetic complications may be reduced through strict glycemic control. A low glycemic index diet is one tool to improve insulin resistance and improve glycemic control in type 2 diabetes mellitus (T2DM). AIM: The objective was to study the effect of pseudocereals-based breakfasts (quinoa and buckwheat) on glucose variations at first meal (breakfast) and second meal (standardised lunch) in healthy and diabetic subjects. SUBJECTS AND METHODS: Twelve healthy subjects and 12 patients with Type 2 DM (not- insulin dependent) were recruited in the study. Subjects were provided with quinoa and buckwheat breakfast meals. A standardised lunch was provided 4 h after breakfast. Postprandial blood glucose response after breakfast and the second meal effect was measured in healthy and diabetic subjects. Incremental area under the curve (IAUC) values for glucose was measured in response to the breakfast and lunch. The glycemic index of the 2 pseudocereals-based test breakfasts was determined. A white wheat bread (WWB) was served as a reference breakfast meal. RESULTS: In post-breakfast analyses, healthy subjects showed that buckwheat meal had significantly lower IAUC values for blood glucose compared to WWB reference meal (P < 0.001) while quinoa meal showed no significance. In diabetic subjects, buckwheat and quinoa meals had significantly lower IAUC values for blood glucose compared to WWB reference meal (P < 0.001 and P < 0.05 respectively). Blood glucose concentrations started to decline gradually for the quinoa and buckwheat but not for WWB in all healthy and diabetic subjects and returned to near-fasting baseline levels by 210 min. Post-lunch analyses indicated higher IAUC for the two breakfast types in healthy and diabetic subjects. In addition, the quinoa and buckwheat breakfast meals were followed by a significantly flatter blood glucose response to the second meal for the period between 270 and 330 min. At the end of the second meal period, values were below or near-fasting baseline levels in the breakfast period. The blood glucose concentration after consuming quinoa meal showed a high peak at 30 min similar to that of WWB reference meal. This peak resulted in a high glycemic index (GI) for quinoa (89.4). The GI of buckwheat recorded a low value (26.8). CONCLUSION: The two studied pseudocereals; quinoa and buckwheat have high potential to improve glucose tolerance at the first and second meal (lunch) and are recommended to be introduced in our daily diet for healthy and diabetic subjects.