The Effects of Sea Buckthorn and Strawberry on Postprandial Glycaemia, Insulinemia and Appetite - A Randomised, Controlled, Crossover Study of Danish Berries 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. Berries may thus improve health in longer studies; however, accurate assessment of berry intake is still problematic. The discovery of objective biomarkers for intake of berries is therefore important in assessing both intake and compliance. The investigators aimed to identify urinary exposure markers of two very different berries, strawberry and sea buckthorn, in humans.

Methods: The study was conducted as a randomised, controlled, single-blinded, 3-way crossover study. Eighteen subjects were studied in three 2 h meal tests followed by a subsequent ad libitum meal. Test meals contained either sea buckthorn, strawberry or no berries and added sucrose to match with respect to sucrose content. 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 measurements analyses or differences in the area under the curve (AUC) for that measure in a linear mixed model. Urine samples were collected on each test day at t=-15min, t=0-1h, t=1-2h, and t=2-24h and were analyzed by untargeted metabolomics. Multivariate analysis was applied to discover markers, followed by molecular fragmentation to ease their chemical identification.