Postprandial hyperglycemia and insulin response are affected by sea buckthorn (Hippophae rhamnoides ssp turkestanica) berry and its ethanol-soluble metabolites

Background/Objectives: Repeated postprandial hyperglycemia and subsequent mild, late hypoglycemia as well as high postprandial insulin response lead to metabolic events that may eventually develop into type 2 diabetes. The aim of this study was to assess how sea buckthorn berries as well as two sea buckthorn extraction residues modulate the postprandial metabolism after a high-glucose meal. Subjects/Methods: Ten healthy normal-weight male volunteers consumed four study breakfasts, one control (A) and three sea buckthorn meals on four distinct study days. All the meals contained yoghurt and glucose (50 g). The sea buckthorn ingredients used were dried and crushed whole berries (meal B1), supercritical fluid (SF)-carbon dioxide (CO2)-extracted oil-free berries (meal B2) or ethanol-extracted SF-CO2-extraction residue (meal B3). Blood samples for glucose, insulin and tumor necrosis factor-a analyses were collected before and during the 6-h study period. Results: Meal B1 suppressed the postprandial peak insulin response when compared with meal A (Delta concentration of 30-min peak value -21.8 mU/l, P = 0.039), and stabilized postprandial hyperglycemia and subsequent hypoglycemia (Dconcentration of 30-min peak value-120-min value -30.4 mU/l, P = 0.036). Furthermore, meal B2 resulted in a more stable insulin response than the control meal (Delta concentration of 30-min peak value-120-min value -25.9 mU/l, P = 0.037). Conclusions: Removal of the CO2-soluble oil component from the berries did not show a significant change in the studied postprandial effects of the berries. The EtOH soluble components, again showed advantageous properties in both insulin and glucose responses. European Journal of Clinical Nutrition (2010) 64, 1465-1471; doi: 10.1038/ejcn.2010.173; published online 8 September 2010