Queen garnet plum juice supplementation does not provide additional cognitive benefits over a group-based memory program in older adults with mild cognitive impairment: A randomized clinical trial

Research suggests a role for inflammation and oxidative stress in mild cognitive impairment (MCI) and its progression. Evidence suggests anthocyanin-rich foods may reduce inflammation and oxidative stress and improve cognition but benefits in MCI are unclear. Therefore, it was hypothesized that daily consumption of anthocyanin-rich Queen Garnet Plum (QGP) juice would improve cognition, mood and blood pressure in people with MCI. Participants diagnosed with MCI (N = 42) participated in a double-blind, randomized controlled trial. Participants were administered either QGP juice or apricot juice (comparator) daily for 8-weeks and participated in a 6-week group-based memory program. Cognitive function was assessed using a battery of cognitive tests, including the Rey Auditory Verbal Learning Test (RAVLT), Complex Figure Test (CFT), Royal Prince Alfred-Prospective Memory Test (RPA-ProMem), and Comprehensive Assessment of Prospective Memory self-report (CAPM-self). Mood and blood pressure were also measured pre- and post-intervention. There was a significant effect of TIME for total RAVLT (P = .028, η 2 = .12), CFT-recall (P = .036, η 2 = .11), RPA-ProMem (P < .001, η 2 = .28), and CAPM-self (P = .007, η 2 = .22) scores. There was a non-significant trend towards an interaction for CFT-recall (p = .063, η 2 = .09), where Bonferroni adjusted pairwise comparisons showed that the QGP group, but not comparators, had significantly improved CFT-recall scores (QGP: +13.93%, P = .007; comparators: +0.84%, P = .855). Overall, QGP consumption during a group-based memory rehabilitation program did not result in additional cognitive benefits in older adults with MCI. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12618001184268.