The Effect of (Poly)phenol-Rich Interventions on Cognitive Functions and Neuroprotective Measures in Healthy Aging Adults: A Systematic Review and Meta-Analysis
by
Achraf Ammar 1,*,†
, Khaled Trabelsi 2,3,†, Patrick Müller 4,5, Bassem Bouaziz 6, Omar Boukhris 2,3, Jordan M Glenn 7,8, Nick Bott 8,9, Tarak Driss 10, Hamdi Chtourou 11, Notger Müller 4 and Anita Hökelmann 1
Achraf Ammar 1,*,†, Khaled Trabelsi 2,3,†, Patrick Müller 4,5, Bassem Bouaziz 6, Omar Boukhris 2,3, Jordan M Glenn 7,8, Nick Bott 8,9, Tarak Driss 10, Hamdi Chtourou 11, Notger Müller 4 and Anita Hökelmann 1
1
Institute of Sport Sciences, Otto-von-Guericke University, 39104 Magdeburg, Germany
2
UR15JS01: Education, Motricity, Sport and Health (EM2S), High Institute of Sport and Physical Education, University of Sfax, Sfax 3000, Tunisia
3
High Institute of Sport and Physical Education, University of Sfax, Sfax 3000, Tunisia
4
German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
5
Department of Neurology, Medical Faculty, Otto von Guericke University, 39104 Magdeburg, Germany
6
Higher Institute of Computer Science and Multimedia of Sfax, University of Sfax, Sfax 3000, Tunisia
7
Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR 72701, USA
8
Neurotrack Technologies, 399 Bradford St, Redwood City, CA 94063, USA
9
Clinical Excellence Research Center, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
10
Interdisciplinary Laboratory in Neurosciences, Physiology and Psychology: Physical Activity, Health and Learning (LINP2-2APS), UFR STAPS, UPL, Paris Nanterre University, 92000 Nanterre, France
11
Physical Activity, Sport and Health, UR18JS01, National Observatory of Sport, Tunis 1003, Tunisia
*
Author to whom correspondence should be addressed.
†
Equally contributed as first authors.
J. Clin. Med. 2020, 9(3), 835; https://doi.org/10.3390/jcm9030835
Received: 19 February 2020 / Revised: 10 March 2020 / Accepted: 13 March 2020 / Published: 19 March 2020
(This article belongs to the Special Issue Effects of Lifestyle Factors and Exercise on Brain Plasticity and Underlying Neurobiological Mechanisms)
Context: As the food industry is continually involved in the development of new attractive alternative therapeutic agents, the evaluation of the beneficial impact of (poly)phenols on cognitive and brain function during aging has gained increasing interest. Objective: This systematic review and meta-analysis aimed to evaluate the acute and chronic effects of (poly)phenol-rich diet supplementation on cognitive function and brain health in aging adults. Data Sources: PubMed and Web of Science databases were searched for relevant randomized placebo-controlled trials (RCTs) published from inception to July 2019. Study Selection: Two researchers independently screened 4303 records, using the PICOS criteria: Participants were aging adults; Intervention was based on acute and/or chronic (poly)phenols-rich supplementation; Comparator was any comparator; Outcomes included cognitive function and neuroprotective measures; and Study design was RCTs. A third researcher was consulted when discrepancies arose. Fifteen high-quality (mean PEDro score = 8.8 ± 0.56) RCTs (total participants: 918 healthy older adults) were included in the final sample. Data Extraction: Information on study design, employed treatment, characteristics of participants, outcomes, and the correspondent assessing methods were extracted. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Data Analysis and Results: A random-effects meta-analysis was used to pool estimates across studies. Effect size (ES) and its 95% confidence interval (CI) was calculated. Pooled results yielded a trivial ES (−0.2 to 0.03) for brain-derived neurotrophic factor and neuroinflammatory parameters and small (0.36) to moderate (0.82) ES for executive functions. Conclusion: This meta-analysis failed to provide evidence regarding the neuroprotective and anti-inflammatory effect of (poly)phenols supplementation in aging adults. However, findings from individual studies, included in this systematic review, suggest polyphenol-rich supplementation may improve some cognitive and brain functions in older adults. The beneficial effect of polyphenols seems to depend on ingested dose and bioavailability. Results suggest at least an intermediate dose (≥500 mg), and intermediate (≈9%) to high (43%) bioavailability rates are needed to cross the brain blood barrier and to exert a significant effect on cognitive health.
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Keywords:
cognition; neuroplasticity; neuroinflammation; brain; polyphenols; meta-analysis
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MDPI and ACS Style
Ammar, A.; Trabelsi, K.; Müller, P.; Bouaziz, B.; Boukhris, O.; Glenn, J.M.; Bott, N.; Driss, T.; Chtourou, H.; Müller, N.; Hökelmann, A. The Effect of (Poly)phenol-Rich Interventions on Cognitive Functions and Neuroprotective Measures in Healthy Aging Adults: A Systematic Review and Meta-Analysis. J. Clin. Med. 2020, 9, 835.
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