Acute and chronic flow-mediated dilation and blood pressure responses to daily intake of boysenberry juice: a preliminary study.

There is an increasing interest in dietary polyphenols for risk reduction in cardiovascular diseases. The aim of this study was to evaluate acute and chronic flow-mediated dilation (FMD) and blood pressure responses to daily intake of boysenberry juice. FMD of the brachial artery was measured in six subjects in the initial, intermediate and follow-up stages of a 4-week open-label intervention study. The intake of boysenberry juice (180 ml/d) increased FMD with progression of intervention stage, and FMD differed in the follow-up stage compared with pre-intake baseline (p = 0.0163 < 0.0167 = 0.1/6) using Bonferroni correction. Changes in systolic blood pressure (SBP) correlated negatively with SBP before intake only in the follow-up stage (r = -0.961 and p = 0.0007 at 3.5 h), indicating a greater SBP reduction in subjects with higher SBP. These results suggest that daily intake of boysenberry juice is beneficial for reducing cardiovascular risk.