Sea buckthorn decreases and delays insulin response and improves glycaemic profile following a sucrose-containing berry meal: a randomised, controlled, crossover study of Danish sea buckthorn and strawberries in overweight and obese male subjects

Purpose: Berries and mixed berry products exert acute effects on postprandial glycaemia and insulinemia, but very few berries have been studied, and primarily in normal weight subjects. Sea buckthorn and strawberry are compositionally widely different berries and may likely produce different responses. The effects of strawberry and sea buckthorn on postprandial glycaemia and insulinemia were examined in overweight or obese male subjects. Subjective appetite sensations and ad libitum intake were also examined.

Methods: The study was conducted as a randomised, controlled, single-blinded, three-way crossover study. Eighteen subjects were studied in three 2-h meal tests followed by a subsequent ad libitum meal. Test meals contained added sucrose and either sea buckthorn, strawberry or no berries with added fructose (control). Blood samples were collected at t = 0, 30, 45, 60, 90 and 120 min. Subjective appetite sensations were recorded at t = 0, 15, 30, 45, 60, 90, 120, and 140 min and subsequent ad libitum intake was recorded. Statistical differences in all continuous measures were evaluated based on the existence of a meal or a time-meal interaction by repeated measures linear model analyses or by differences in AUC by linear mixed models.

Results: None of the berries affected postprandial glucose. However, sea buckthorn improved glycaemic profile (44.7%, p < 0.01) compared to control. Sea buckthorn also resulted in a decrease in plasma insulin concentration at 30 min (39.6%, p < 0.01) and at 45 min (16.5%, p < 0.05) compared to control and the maximal increase in plasma insulin was lower following sea buckthorn compared with control (23.6%, p < 0.01). Strawberry did not affect postprandial insulin concentrations compared to control. No differences between control and each of the two berries were observed for any of the appetite parameters, except for desire for something sweet, which was increased following the sea buckthorn meal compared to control.

Conclusions: There was no effect on postprandial glucose response to a sugar challenge given together with purees of strawberry or sea buckthorn. Sea buckthorn decreased and delayed the insulin response and improved glycaemic profile compared with control. Strawberry had no such effects. No important differences were seen for the appetite measures. Sea buckthorn might be useful as a culinary tool for lowering meal insulin response.