Background and aims: Dietary berries, such as strawberries, are rich in bioactive compounds and have been shown to lower cardiometabolic risk. We examined the effects of two dietary achievable doses of strawberries on glycemic control and lipid profiles in obese adults with elevated serum LDL cholesterol (LDL-C). Methods: In this 14-week randomized controlled crossover study, participants were assigned to one of the three arms for four weeks separated by a one-week washout period: control powder, one serving (low dose: 13 g strawberry powder/day), or two-and-a -half servings (high dose: 32 g strawberry powder/day). Participants were instructed to follow their usual diet and lifestyle while refraining from consuming other berries and related products throughout the study interval. Blood samples, anthropometric measures, blood pressure, and dietary and physical activity data were collected at baseline and at the end of each four-week phase of intervention. Results: In total, 33 participants completed all three phases of the trial [(mean ± SD): Age: 53 ± 13 y; BMI: 33 ± 3.0 kg/m2). Findings revealed significant reductions in fasting insulin (p = 0.0002) and homeostatic model of assessment of insulin resistance (p = 0.0003) following the high dose strawberry phase when compared to the low dose strawberry and control phases. Glucose and conventional lipid profiles did not differ among the phases. Nuclear magnetic resonance-determined particle concentrations of total VLDL and chylomicrons, small VLDL, and total and small LDL were significantly decreased after the high dose strawberry phase, compared to control and low dose phases (all p < 0.0001). Among the biomarkers of inflammation and adipokines measured, only serum PAI-1 showed a decrease after the high dose strawberry phase (p = 0.002). Conclusions: These data suggest that consuming strawberries at two-and-a-half servings for four weeks significantly improves insulin resistance, lipid particle profiles, and serum PAI-1 in obese adults with elevated serum LDL-C.
Keywords: LDL cholesterol; insulin resistance; obesity; plasminogen activator inhibitor-1; small LDL particles; strawberries.