Dietary Strawberries Improve Insulin Resistance in Adults with the Metabolic Syndrome

OBJECTIVES: Dietary berries have been shown to lower cardio-metabolic risks in clinical trials. We examined the dose-response effects of two dietary achievable doses of strawberries on low-density lipoprotein cholesterol (LDL-C) and insulin resistance in adults with metabolic syndrome. METHODS: In this 14-week randomized controlled crossover study, adults with metabolic syndrome were assigned to one of the three arms for 4 weeks separated by a one-week washout period: control powder, one serving strawberries (13 g powder/day), and 2.5 servings strawberries (32 g powder/day). The freeze-dried powders were blended in water, and participants consumed half the daily dose in the morning and half in the evening. Participants were instructed to follow their usual diet and lifestyle while refraining from consuming other berries and related products throughout the study. RESULTS: Thirty participants completed all three phases of the trial (baseline profiles: weight: 90.8 ± 22.4 kg, BMI: 33.1 ± 4.2 kg/m(2), waist circumference: 109 ± 12.5 cm, HbA(1c) : 5.8 ± 0.2%). Outcome measures were analyzed using a multivariate analysis of variance with statistical significance set at P