The effects of chronictrans-resveratrol supplementation on aspects of cognitive function, mood, sleep, health and cerebral blood flow in healthy, young humans

Abstract

Single doses of resveratrol have previously been shown to increase cerebral blood flow (CBF) with no clear effect on cognitive function or mood in healthy adults. Chronic resveratrol consumption may increase the poor bioavailability of resveratrol or otherwise potentiate its psychological effects. In this randomised, double-blind, placebo-controlled, parallel-groups study, a total of sixty adults aged between 18 and 30 years received either placebo or resveratrol for 28 d. On the 1st and 28th day of treatment, the performance of cognitively demanding tasks (serial subtractions, rapid visual information processing and 3-Back) (n 41 complete data sets) was assessed, alongside blood pressure (n 26) and acute (near-IR spectroscopy (NIRS)) and chronic (transcranial Doppler) measures of CBF (n 46). Subjective mood, sleep quality and health questionnaires were completed at weekly intervals (n 53/54). The results showed that the cognitive effects of resveratrol on day 1 were restricted to more accurate but slower serial subtraction task performance. The only cognitive finding on day 28 was a beneficial effect of resveratrol on the accuracy of the 3-Back task before treatment consumption. Subjective ratings of 'fatigue' were significantly lower across the entire 28 d in the resveratrol condition. Resveratrol also resulted in modulation of CBF parameters on day 1, as assessed by NIRS, and significantly increased diastolic blood pressure on day 28. Levels of resveratrol metabolites were significantly higher both before and after the day's treatment on day 28, in comparison with day 1. These results confirm the acute CBF effects of resveratrol and the lack of interpretable cognitive effects.

Health benefits of resveratrol: Evidence from clinical studies

“…In this study, two doses of trans ‐resveratrol (250 and 500 mg) on two separate occasions, caused increased cerebral blood flow in a dose‐dependent manner . Conversely, at a dose of 500 mg/d for 28 days, no change in sleep or chronic cerebral blood flow was found despite the increasing presence of the resveratrol metabolite in the plasma . Resveratrol has been proposed to assist in conditions such as anxiety and depression.…”

Impact of Resveratrol on Glucose Control, Hippocampal Structure and Connectivity, and Memory Performance in Patients with Mild Cognitive Impairment

“…First interventional studies have shown that resveratrol supplementation over 18 and 6 months, respectively, improved spatial memory performance in non-human primates (Dal-Pan et al, 2011), and increased the number of words retained over 30 min in healthy older adults (Witte et al, 2014). In contrast, in a recently published randomized-controlled trial, resveratrol intervention over 28 days was not sufficient to induce clear improvements in cognitive function, showing merely improvements in working memory performance (i.e., accuracy in the 3-back task), but not in tasks related to attention and executive function (Wightman et al, 2015). In the current study, we did not detect resveratrol-related beneficial effects on learning and memory performance in MCI patients, possibly due to the small sample size and still relatively short intervention time [6 months as compared to 24 months in a nutritional study with B-vitamin supplementation that demonstrated improvement in episodic memory performance (de Jager et al, 2012)].…”

“…No beneficial effects on brain volume have been found in human trials so far (Witte et al, 2014; Turner et al, 2015). In sum, beneficial effects in healthy adults are not yet conclusive (Wong et al, 2013; Witte et al, 2014; Wightman et al, 2015), possibly due to short intervention times of 4–6 weeks in trials with a negative outcome (Wong et al, 2013; Wightman et al, 2015). Moreover, studies that investigate the impact of resveratrol on cognition and brain networks in individuals at high-risk for dementia, like MCI patients, are missing so far.…”

Does phytoestrogen supplementation improve cognition in humans? A systematic review

“…Eight of the 23 studies in this review evaluated the effects of resveratrol or grape formulation on cognition with mixed outcomes . Kennedy et al .…”

“…In a follow‐up study using 250 mg resveratrol combined with 20 mg piperine (to aid bioavailability and efficacy by inhibiting resveratrol metabolism), they found no acute effect on cognitive performance . In the following year, the same group reported that supplementation with a combination of 20 mg of piperine and 500 mg of resveratrol for 28 days resulted in a medium effect size improvement of 0.62 on the 3‐back test (a measure of working memory and attentional function) accompanied by augmentation of cerebral blood flow at rest and during mental activation . Witte et al .…”