Effects of a beverage rich in (poly)phenols on established and novel risk markers for vascular disease in medically uncomplicated overweight or obese subjects: A four week randomized placebo-controlled trial.

OBJECTIVE: To determine if (poly)phenols alter cardiovascular risk factors, we assessed the potential of a high (poly)phenol beverage drink, rich in hydroxycinnamates and flavonoids, to modify vascular function in middle aged, overweight or obese subjects without medical co-morbidity in a randomized placebo controlled pilot study. METHODS: Randomly assigned active 250 ml beverages containing 361 mg of (poly)phenols and 120 mg of vitamin C or placebo (no polyphenol/vitamin C) were taken twice daily for 4 weeks. Both beverages contained 40 kcals/250 ml. The primary end-points were pulse wave velocity (PWV) and cutaneous microvascular responses to sodium nitroprusside (SNP) and acetyl choline (ACh) laser doppler iontophoresis. A range of established and novel plasma markers were also measured. RESULTS: Twenty subjects received active beverage and 19 placebo; all completed the study. There was no difference in cutaneous vascular response to either SNP or ACh with mean group differences (logΔ area under perfusion curve) of 0.30 (-0.65, 1.26) and 0.35 (-0.11, 0.81) respectively. Nor was there evidence of a change in log PWV with a mean group difference of 0.029 m/s (-0.042, 0.10). No significant differences were seen in plasma leptin, apolipoproteins, cystatin C, insulin, adiponectin, CRP, ICAM-1, E-Selectin or t-PA, but IL-6 increased in active versus placebo recipients (0.32 vs - 0.18 pg/ml; p=0.010). CONCLUSION: There was no evidence for a short-term beneficial effect of (poly)phenol intervention on microcutaneous vascular response or pulse wave velocity, and no evidence for a benefit on established or novel risk factors in overweight or obese subjects. Our results do not support a short-term benefit of (poly)phenol supplementation on cardiometabolic risk. REGISTRATION: Clinical Trials.gov (NCT00795834).