Effect of Montmorency tart cherry juice on cognitive performance in older adults: a randomized controlled trial
Hypertension, inflammation and oxidative stress are important factors in the development of cognitive impairment. Our previous study demonstrated that tart cherry juice can lower systolic blood pressure (BP) and improve inflammatory and oxidative stress status in older adults. As part of our previous trial, we explored whether daily consumption of tart cherry juice would improve cognitive abilities. In this randomized controlled trial, 37 adults between the ages of 65–80 with normal cognitive function were recruited and randomly assigned to consume two cups of Montmorency tart cherry juice for 12 weeks. Subjective memory and objective cognitive performance were assessed at baseline and after the 12-week juice supplementation using a validated subjective memory questionnaire and a standardized battery of tests. Daily caloric intake and physical activity levels were assessed throughout the study period. After the intervention, participants in the tart cherry group had higher contentment with memory scores (mean difference of 2.7; 95% CI: 1.2 to 4.2; p = 0.02), lowered their scores of movement time (mean difference of −10.4; 95% CI: −13.4 to −7.5; p = 0.03) as well as performed better on the paired associates learning task (mean difference of −8.5; 95% CI: −12.5 to −4.5; p = 0.02) compared to the control group. The within-group analysis showed that the visual sustained attention (p < 0.0001) and spatial working memory (p = 0.06) improved after the 12-week consumption of tart cherry juice compared with corresponding baseline values. Daily tart cherry juice consumption may improve cognitive abilities. This may be through anti-oxidative and anti-inflammatory properties of tart cherry and its ability to lower BP. Further research is needed to confirm these findings.