Title:The Potential Effect of Blueberry on Cognitive Health and Mood State
based on Human Intervention Studies: Systematic Review and Mini
Meta-Analysis
Volume: 22
Issue: 7
Author(s): Neda Soveid, Bahareh Barkhidarian, Sajjad Moradi, Fatemeh Gholami, Niloufar Rasaei, Hubertus Himmerich and Khadijeh Mirzaei*
Affiliation:
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical
Sciences (TUMS), Tehran, Iran
Keywords:
Blueberry, anthocyanin, cognition, mood, intervention, human.
Abstract:
Background: Blueberries are known for their high content of several bioactive compounds,
specifically anthocyanin, which are the most beneficial of the flavonoid family in terms of neuroprotection.
Several human interventional studies have been conducted to assess the effects of blueberry
intake on cognitive performance; however, the results of clinical trials are inconclusive. Therefore, this
systematic review and meta-analysis evaluated the effect of blueberry supplementation on some aspects
of cognitive performance and mood parameters using data from clinical trials based on existing
evidence.
Methods: Relevant studies, published in April 2021, were searched through PubMed/Medline, Scopus,
Embase, and Google Scholar. The random effect size was used to estimate the pooled effect size. Heterogeneity
between studies was evaluated by the Cochrane Q test and I-squared (I2). To detect the
potential source of heterogeneity, a subgroup analysis was conducted.
Results: Fourteenrandomized trials were included in the quantitative analysis, and six were pooled
for statistical analysis. Blueberry intervention resulted in no significant change in mood state score
(WMD = 0.03; 95% CI: -0.80 to 0.87, P = 0.16). Moreover, no significant effect of blueberry intake
was shown in attention task reaction time (WMD = -1.50 ms; 95% CI: -24.75 to -21.75, P = 0.9), percentages
of attention task accuracy (WMD = 0.85; 95% CI: -2.57 to 0.86, P = 0.3), one-back test accuracy
(WMD = 0.03; 95% CI: -0.04 to 0.09, P = 0.4). Significant effect was indicated (WMD = 0.08;
95% CI: 0.02 to 0.13, P = 0.005) in two-back test accuracy.
Conclusion: We found a significant effect of blueberry consumption on two-back test accuracy as a
cognitive outcome. More high-quality clinical trials according to the challenges mentioned seem to indicate
the use of blueberry as a supplement for cognitive and mood health efficiently.