Effects of black raspberry on lipid profiles and vascular endothelial function in patients with metabolic syndrome

Black raspberry (Rubus occidentalis) has been known for its anti-inflammatory and anti-oxidant effects. However, short-term effects of black raspberry on lipid profiles and vascular endothelial function have not been investigated in patients with metabolic syndrome. Patients with metabolic syndrome (n = 77) were prospectively randomized into a group with black raspberry (n = 39, 750 mg/day) and a placebo group (n = 38) during a 12-week follow-up. Lipid profiles, brachial artery flow-mediated dilatation (baFMD), and inflammatory cytokines such as IL-6, TNF-α, C-reactive protein, adiponectin, sICAM-1, and sVCAM-1 were measured at the baseline and at the 12-week follow-up. Decreases from the baseline in the total cholesterol level (-22.8 ± 30.4 mg/dL vs. -1.9 ± 31.8 mg/dL, p < 0.05, respectively) and total cholesterol/HDL ratio (-0.31 ± 0.64 vs. 0.07 ± 0.58, p < 0.05, respectively) were significantly greater in the group with black raspberry than in the placebo group. Increases in baFMD at the 12-week follow-up were significantly greater in the group with black raspberry than in the placebo group (0.33 ± 0.44 mm vs. 0.10 ± 0.35 mm, p < 0.05, respectively). Decreases from the baseline in IL-6 (-0.4 ± 1.5 pg/mL vs. -0.1 ± 1.0 pg/mL, p < 0.05, respectively) and TNF-α (-2.9 ± 4.7 pg/mL vs. 0.1 ± 3.6 pg/mL, p < 0.05, respectively) were significantly greater in the group with black raspberry. The use of black raspberry significantly decreased serum total cholesterol level and inflammatory cytokines, thereby improving vascular endothelial function in patients with metabolic syndrome during the 12-week follow-up.