Anthocyanin-rich plum juice reduces ambulatory blood pressure but not acute cognitive function in younger and older adults: A pilot cross-over dose-timing study

Consumption of anthocyanins from fruit sources may exert protection against hypertension and improve cognition. However, the effect of dose-timing in studies is rarely considered. We hypothesized that timed-dose consumption of juice from an anthocyanin-rich Japanese plum variety (Queen Garnet plum, QGP) will have acute and dose-timing effects on cardiovascular responses, cognition, and urinary anthocyanin excretion profiles. Our study objective was to investigate the impact of plum juice on these health parameters. Twelve (12) older (65y+) and 12 younger (18-45y) adults participated in an acute crossover study. Participants received, randomly, either a 1x300ml or 3x100ml plum juice over 3h on two different occasions with a 2-week washout period. A battery of cognitive tasks was administered at 0h and 6h on each study day. BP and urinary anthocyanin/metabolite excretion profiles were measured over 24h. Area under the Curve for BP was calculated (0-6h). A significant reduction in BP and cardiovascular responses was observed in both age groups which was more obvious in the older age group on the single dose for SBP, DBP, Mean Arterial Pressure and Heart Rate (P values = 0.035, 0.028, 0.017 and 0.006 respectively). No significant difference was observed between dose-timing regimens for either age group. There was no observed effect on cognition. Native QGP anthocyanins, as well as methylated/glucuronidated metabolites were detected in urine with no significant differences between age groups or dose-timing. High anthocyanin plum juice significantly reduced blood pressure but dose-timing did not appear to be a significant factor in the potential acute BP-lowering effect of QGP juice.