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. 2013;2013:946298.
doi: 10.1155/2013/946298. Epub 2013 Jul 22.

Pomegranate Juice Augments Memory and FMRI Activity in Middle-Aged and Older Adults With Mild Memory Complaints

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Free PMC article

Pomegranate Juice Augments Memory and FMRI Activity in Middle-Aged and Older Adults With Mild Memory Complaints

Susan Y Bookheimer et al. Evid Based Complement Alternat Med. .
Free PMC article

Abstract

Despite increasing emphasis on the potential of dietary antioxidants in preventing memory loss and on diet as a precursor of neurological health, rigorous studies investigating the cognitive effects of foods and their components are rare. Recent animal studies have reported memory and other cognitive benefits of polyphenols, found abundantly in pomegranate juice. We performed a preliminary, placebo-controlled randomized trial of pomegranate juice in older subjects with age-associated memory complaints using memory testing and functional brain activation (fMRI) as outcome measures. Thirty-two subjects (28 completers) were randomly assigned to drink 8 ounces of either pomegranate juice or a flavor-matched placebo drink for 4 weeks. Subjects received memory testing, fMRI scans during cognitive tasks, and blood draws for peripheral biomarkers before and after the intervention. Investigators and subjects were all blind to group membership. After 4 weeks, only the pomegranate group showed a significant improvement in the Buschke selective reminding test of verbal memory and a significant increase in plasma trolox-equivalent antioxidant capacity (TEAC) and urolithin A-glucuronide. Furthermore, compared to the placebo group, the pomegranate group had increased fMRI activity during verbal and visual memory tasks. While preliminary, these results suggest a role for pomegranate juice in augmenting memory function through task-related increases in functional brain activity.

Figures

Figure 1
Figure 1
Metabolite results. (a) The pomegranate juice group had significantly higher change in TEAC after day 28 compared with baseline than the placebo group (*unpaired t = 2.8, df = 25,  p < .05). (b) Plasma urolithin A-glucuronide significantly increased in the pomegranate juice group (**paired t = 3.93, df = 13, p < .00064), but not in the placebo group (paired t = 1.7, df = 11, p > .09).
Figure 2
Figure 2
Buschke selective reminding test results. (a) On the total recall measure, the t2 versus t1 change in memory scores was significantly greater in the pomegranate juice group compared to the placebo group (mean change, number of items recalled: PJ = 7.7, placebo = −2.77; t = 2.3; P = .029). (b) Similarly, on the consistent long-term retrieval score the pomegranate juice group recalled more items compared to the placebo group (mean change, number of items consistently recalled: PJ = 15.2, placebo = −9.7; t = 2.4; P = .022).
Figure 3
Figure 3
Visual memory fMRI task: between-groups T2 versus T1 ANOVA. Regions showing greater activation for t2 > t1, for the pomegranate juice group > placebo group (group by time interaction), were found bilaterally in the basal ganglia and thalamus, including caudate, putamen, and pallidum (ANOVA, Z > 2.0, P = .05, corrected for multiple comparisons). Additional regions significant at an uncorrected threshold (Z > 1.7) are listed in Table 2.
Figure 4
Figure 4
Visual memory fMRI task: between-groups T2. Activations for time point, t2, for pomegranate > placebo. For the visual memory task, at t2, between groups, pomegranate > placebo, there were significant activations in right lateral occipital cortex and fusiform gyrus (unpaired t-test, Z > 2.0, P = .05, corrected for multiple comparisons).
Figure 5
Figure 5
Verbal memory fMRI task: within-group activations at t2. Comparing the within-group results for time point t2, there were activation similarities and differences in the placebo group ((a): top) and the pomegranate group ((b): bottom). Only the pomegranate group recruited the hippocampus, bilaterally (group mean: placebo, Z > 2.0, P = .05, corrected for multiple comparisons, pomegranate, Z > 2.0, P = .05, corrected for multiple comparisons).
Figure 6
Figure 6
Verbal memory fMRI task: between-groups T2 versus T1 ANOVA. Regions showing greater activation for t2 > t1, for pomegranate group > placebo group, were found in the left hemisphere in occipital polar regions (ANOVA, Z > 2.0, P = .05, corrected for multiple comparisons).
Figure 7
Figure 7
Verbal memory fMRI task: activations for the pomegranate group for t2 > t1. For the pomegranate group in the verbal memory task, there were significant activations between sessions, in the left inferior temporal gyrus and right occipital lobe (paired t-test between time points, Z > 2.0, P = .05, corrected for multiple comparisons). No regions were more active for t2 versus t1 in the placebo group.
Figure 8
Figure 8
Summary of study results. Our data suggest that the antioxidant properties of pomegranate produce increased task related cerebral blood flow, with lateralized effects for verbal versus visual memory challenge, which in turn increased cerebral blood flow facilitates memory performance. Metabolic measures confirm the increase in polyphenols among the experimental group.

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