Oleuropein-enriched chocolate by extra virgin olive oil blunts hyperglycaemia in diabetic patients: Results from a one-time 2-hour post-prandial cross over study.

Abstract

Oleuropein, a component of extra virgin olive oil (EVOO), reduces post-prandial glycemia with a mechanism counteracting oxidative stress-mediated incretin down-regulation. In this study we evaluated if the intake of an oleuropein-enriched chocolate could have positive effects on glycaemia and insulin levels in patients with type 2 diabetes mellitus (T2DM) and healthy subjects (HS). Twenty-five consecutive T2DM patients and 20 HS were recruited. Participants were randomized to receive 40g oleuropein-enriched chocolate by EVOO or 40g control chocolate spread in a cross-over design. Serum glucose, insulin, glucagon-like peptide-1 (GLP1), and dipeptidyl-peptidase-4 (DPP4) were measured before and 2h after chocolate intake. In T2DM, the pairwise comparisons showed that intake of oleuropein-enriched chocolate was associated with a significantly less increase of blood glucose compared to control; GLM analysis showed a significant difference for treatments with respect to glucose (p=0.04), GLP1 (p<0.001) and DPP-4 activity (p=0.01). In HS, the pairwise comparisons showed that, after oleuropein-enriched chocolate intake, blood glucose concentration and DPP4 activity did not change; conversely a significant increase was observed for insulin and GLP1. After control chocolate intake, a significant increase for blood glucose, insulin levels and DPP4 activity were observed while GLP1 did not change. The study shows that using EVOO as source of oleuropein administration of 40g oleuropein-enriched chocolate is associated with a modest increase or no change of glycemia in T2DM and HS respectively, via an incretin-mediated mechanism.