Postprandial platelet aggregation: effects of different meals and glycemic index

BACKGROUND/ OBJECTIVES: Hyperglycaemia is associated with increased platelet aggregation that increases the risk of thrombosis in people with type-2 diabetes and cardiovascular disease. Low glycemic index (GI) meals high in carbohydrate or moderately high in protein have been shown to acutely reduce postprandial excursions of plasma glucose and insulin compared with high carbohydrate high GI meals. However, it is not known whether these differences in glucose and insulin profile also impact on postprandial platelet aggregation. This study aimed to investigate the acute effects of three iso-energetic meals, on measures of postprandial platelet aggregation, in healthy individuals. SUBJECTS/METHODS: A randomised cross-over study compared the acute effects of a high GI high carbohydrate (HGI-HC), a low GI high carbohydrate (LGI-HC) and a low GI moderately high in protein and fat (LGI-MPF) meal on postprandial platelet aggregation, glucose, insulin and triglyceride concentrations. Comparisons were made at fasting, 60 and 120 min postprandially. RESULTS: A total of 32 volunteers (mean +/- s.d.; age 59.9 +/- 11.7 years, BMI 27.1 +/- 3.7 kg/m(2)) participated in the study. Results showed significant reductions in maximum platelet aggregation postprandially with nonsignificant differences (all P>0.29) between the three meals. Glucose and insulin were significantly (both P<0.001) higher at 60 min postprandially on the HGI-HC meal compared with both LGI-HC and LGI-MPF meals. Triglycerides were not significantly different (all P>0.25) between the three test meals. CONCLUSION: In healthy individuals platelet aggregation is reduced postprandially but this decrease is similar between meals of different GI that induce different glucose and insulin responses.