Tuesday, January 24, 2017

A randomized, double-blind trial reported on January 3, 2017 in the journal Nutrients found an association between supplementation with resveratrol and improvements in cerebrovascular responsiveness and cognitive performance among postmenopausal women between 45 and 85 years of age.

Researchers at the University of Newcastle in New South Wales, Australia randomized 80 postmenopausal women to receive a placebo or 75 milligrams resveratrol twice daily for 14 weeks. Tests to evaluate cognition, followed by questionnaires to assess mood and depressive symptoms, were administered at the beginning and end of the study. Transcranial Doppler ultrasound assessment of the middle cerebral arteries measured cerebrovascular response (indicated by changes in blood flow velocity) to cognitive stimuli and high levels of carbon dioxide (which is a regulator of cerebral blood flow).

Resveratrol supplementation was associated with 17% increases in cerebrovascular responsiveness to cognitive stimuli and elevated carbon dioxide levels (hypercapnia) in comparison with the placebo. Overall cognitive performance, as well as semantic and verbal memory improved to a significantly greater extent among those who received resveratrol compared to the placebo group. Differences in cerebrovascular responsiveness to the cognitive tests were correlated with differences in overall cognitive performance. Mood also tended to improve and anxiety was significantly reduced in women who received resveratrol.

"This is the first study to demonstrate benefits of chronic resveratrol supplementation on cognitive performance and cerebrovascular responsiveness to hypercapnia and cognitive stimuli," authors Hamish M. Evans and colleagues announce. "We hypothesize that resveratrol elicits its benefits on cognition and also mood through its ability to modulate cerebral perfusion during times of demand."

"While the exact mechanisms are still to be confirmed, we have demonstrated that daily resveratrol supplementation for 14 weeks was not only tolerable, but was able to enhance measures of mood and cognitive performance and the latter may be at least partially mediated through improvements in the responsiveness of cerebral vessels to dilate during cognitive demands," they conclude. "Findings of these studies are an important step forward in preventative strategies to delay accelerated cognitive decline in our aging population."