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Polyphenol supplementation and executive functioning in overweight and obese adults at risk of cognitive impairment: A systematic review and meta-analysis.
Farag, S, Tsang, C, Murphy, PN
PloS one. 2023;18(5):e0286143
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It is recognised that overweight and obesity pose an increased risk for the development of cardiometabolic disease, and increasing evidence indicates a link to cognitive impairment associated with early onset dementia in such populations. This study's aim was to elaborate on existing knowledge of the effectiveness or otherwise of polyphenols in general to improve executive function (EFs) in an obese/ overweight population at risk of cognitive impairment. This study was a systematic review and meta-analysis of twenty-three randomised controlled trials. Results showed a nonsignificant effect of polyphenols on EFs. Authors concluded that further research should consider investigating polyphenols supplementation in a younger population at risk of cognitive impairment.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Overweight and obesity have increasing evidence that indicates a link to compromised executive functions such as memory and decision-making processes and cognitive impairment
- This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations with a susceptibility to cognitive impairment.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
A systematic review and meta-analysis were undertaken to investigate the impact of polyphenol supplementation on executive functions (cognitive functions which constitute part of the working memory and decision-making processes) among overweight and/or obese populations.
Method:
A comprehensive literature search was conducted using four electronic databases: PubMed/Medline, PsycInfo, Scopus and the Cochrane Trials Library. Inclusion criteria encompassed primary research studies which investigated the impact of polyphenols versus placebo on executive function in overweight or obese adults.
The review comprised a total of 23 randomised controlled trials (RCTs), incorporating a participant pool of N = 1,976 individuals. The mean ages of participants in all 23 studies receiving polyphenol supplementation were 62.92 years (SD = 8.06 years) and the mean BMIs ranged from 25.5 kg/m2 to 33.7 kg/m2. Various dietary polyphenols were investigated in the studies, with the main groups being isoflavones, flavonoids, resveratrol, phenolic acid, curcumin, walnuts and blueberry powder.
- The JADAD scale was employed to assess the methodological quality of the incorporated studies
- Hedges g, accompanied by 95% confidence intervals (CI) for endpoints, was computed utilising a random effects model whenever applicable
- Various statistical methods were considered for potential application in evaluating publication bias
- Sensitivity analysis was conducted to assess the robustness of the obtained results.
Results
- Meta analysis of the 23 primary studies produced a non-significant effect of polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170)
- A double-blind, randomised, placebo-controlled parallel study reported significant benefits in 60 participants (mean age 67 years) taking 80mg of curcumin over placebo for digital vigilance and serial subtraction tasks (p=0.041)
- A double-blind, randomised, placebo-controlled parallel intervention trial showed significant benefits in 79 patients (mean age of 61 years) taking 150mg of resveratrol for visuospatial working memory double span and trail making test (p= 0.012).
Conclusion:
This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations.
Clinical practice applications:
- Research has documented the association between compromised executive functions and obesity/overweight, emphasising neuroinflammation and oxidative stress as potential mechanisms
- A plausible intervention involves the utilisation of polyphenols, known for their antioxidant and anti-inflammatory properties
- This systematic review and meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions
- A potential beneficial impact for 80mg of curcumin and 150mg of resveratrol was revealed in younger populations (mean ages of 67 and 61 years).
Considerations for future research:
- A potential beneficial impact of 80mg of curcumin and 150mg of resveratrol supplementation was revealed in a younger population (mean ages of 67 and 61 years), highlighting the necessity for in-depth exploration in subsequent studies
- The diversity in tasks employed for assessing executive functions and the comprehensive reporting of the phenolic composition of supplements had limitations that warrant consideration in future research
- The exact constituent and dose of supplementation needs to be described as this is necessary for the identification of the potential beneficial compounds for cognitive health and to support clinical practice.
Abstract
BACKGROUND AND OBJECTIVES Increasing evidence indicates a link between obesity and cognitive impairment. Furthermore, there is limited literature regarding the effect of polyphenols, a plant derived compounds, on executive functioning in an overweight/obese population at-risk of cognitive impairment. The aim of the present systematic review and meta-analysis of randomized controlled trials is to examine the effect of polyphenol supplementation on executive functions in overweight and/or obese populations at risk of cognitive impairment. METHODS A comprehensive literature search was conducted from inception to March 2023 using four electronic databases: PubMed/Medline, PsycInfo, Scopus and Cochrane trials library. Published primary research studies in English that compared the effect of polyphenols with placebo on executive function in overweight/obese adults were considered eligible for the meta-analysis. Jadad scale was used for the methodological quality rating of the included studies. Hedges g with 95% confidence intervals (CI) for endpoints were calculated using random effect model where applicable. Rosenthal's Fail-safe N, funnel plots, the Begg and Mazumdar's rank correlation test (Kendall's S statistic P-Q), Egger's linear regression test, and Duval and Tweedie's trim-and-fill test were identified for potential use as appropriate, to examine publication bias. Sensitivity analysis was conducted to examine the robustness of the results. RESULTS AND CONCLUSION A total of 23 RCT studies involving N = 1,976 participants were included in the review. The results of the meta-analysis revealed a non-significant effect for polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170). Observations from primary studies within the meta-analysis showed a potential positive effect of polyphenol supplementation in a younger population at-risk of cognitive impairment and it is recommended to investigate this further in future studies. Moreover, the variability of the tasks used to examine executive functions as well as the adequate reporting of supplement's phenolic composition is a limitation that future work should also consider.
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Headache Associated with Coeliac Disease: A Systematic Review and Meta-Analysis.
Zis, P, Julian, T, Hadjivassiliou, M
Nutrients. 2018;10(10)
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Coeliac disease (CD) is the best-recognised gluten-related disorder (GRD), and it is characterized by a small bowel enteropathy occurring in genetically susceptible individuals whilst exposed to the protein gliadin. The aim of this study was to systematically review the current literature in order to establish the relationship between headache and CD. This study is a systematic review of 40 articles, studying a total of 42,388 individuals with either headache or GRD. Results show that: - There is an increased prevalence of headache amongst patients with CD. - There is an increased prevalence of CD amongst patients with idiopathic headache. - Headaches associated with CD are mainly migraines. - Gluten-free diet is a very effective treatment for headaches associated with CD. Authors conclude that further studies on the prevalence of gluten sensitivity in patients with idiopathic headache are needed, including further research on the pathogenetic mechanisms.
Abstract
OBJECTIVE The aim of this systematic review was to explore the relationship between coeliac disease (CD) and headache. The objectives were to establish the prevalence of each entity amongst the other, to explore the role of gluten free diet (GFD), and to describe the imaging findings in those affected by headaches associated with CD. METHODOLOGY A systematic computer-based literature search was conducted on the PubMed database. Information regarding study type, population size, the age group included, prevalence of CD amongst those with headache and vice versa, imaging results, the nature of headache, and response to GFD. RESULTS In total, 40 articles published between 1987 and 2017 qualified for inclusion in this review. The mean pooled prevalence of headache amongst those with CD was 26% (95% CI 19.5⁻33.9%) in adult populations and 18.3% (95% CI 10.4⁻30.2%) in paediatric populations. The headaches are most often migraine-like. In children with idiopathic headache, the prevalence of CD is 2.4% (95% CI 1.5⁻3.7%), whereas data for adult populations is presently unavailable. Brain imaging can be normal, although, cerebral calcifications on CT, white matter abnormalities on MRI and deranged regional cerebral blood flow on SPECT can be present. GFD appears to be an effective management for headache in the context of CD, leading to total resolution of headaches in up to 75% of patients. CONCLUSIONS There is an increased prevalence of CD amongst idiopathic headache and vice versa. Therefore, patients with headache of unknown origin should be screened for CD, as such patients may symptomatically benefit from a GFD.
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Body composition status and the risk of migraine: A meta-analysis.
Gelaye, B, Sacco, S, Brown, WJ, Nitchie, HL, Ornello, R, Peterlin, BL
Neurology. 2017;88(19):1795-1804
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Both migraine and obesity are conditions associated with substantial personal and societal burdens. The aim of this study was to evaluate the pooled risk of migraine by body composition status as characterized by the WHO physical status categories and the influence of age and sex on this relationship. This study is a meta-analysis of twelve studies with data from 288,981 unique participants. The age of the participants ranged between 18 and 98 years. Results indicate that obesity and underweight status are associated with an increased risk of migraine, and that age and sex are important covariates for the increased risk. Authors conclude that further research to better understand the mechanisms underlying the association between body composition and migraine, has the potential to advance the understanding of migraine and lead to the development of targeted therapeutic strategies based on obesity status.
Abstract
OBJECTIVE To evaluate the association between migraine and body composition status as estimated based on body mass index and WHO physical status categories. METHODS Systematic electronic database searches were conducted for relevant studies. Two independent reviewers performed data extraction and quality appraisal. Odds ratios (OR) and confidence intervals (CI) were pooled using a random effects model. Significant values, weighted effect sizes, and tests of homogeneity of variance were calculated. RESULTS A total of 12 studies, encompassing data from 288,981 unique participants, were included. The age- and sex-adjusted pooled risk of migraine in those with obesity was increased by 27% compared with those of normal weight (odds ratio [OR] 1.27; 95% confidence interval [CI] 1.16-1.37, p < 0.001) and remained increased after multivariate adjustments. Although the age- and sex-adjusted pooled migraine risk was increased in overweight individuals (OR 1.08; 95% CI 1.04, 1.12, p < 0.001), significance was lost after multivariate adjustments. The age- and sex-adjusted pooled risk of migraine in underweight individuals was marginally increased by 13% compared with those of normal weight (OR 1.13; 95% CI 1.02, 1.24, p < 0.001) and remained increased after multivariate adjustments. CONCLUSIONS The current body of evidence shows that the risk of migraine is increased in obese and underweight individuals. Studies are needed to confirm whether interventions that modify obesity status decrease the risk of migraine.
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Do implementation intentions help to eat a healthy diet? A systematic review and meta-analysis of the empirical evidence.
Adriaanse, MA, Vinkers, CD, De Ridder, DT, Hox, JJ, De Wit, JB
Appetite. 2011;56(1):183-93
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Eating a healthy diet reduces the likelihood of becoming overweight or chronically ill. Many people are aware of the health benefits of eating a healthy diet, and are hence motivated to eat healthily. This study is a review and meta-analysis with the aim to evaluate the effectiveness of setting implementation intentions (the where, when and how planning in goal setting) in promoting healthy eating behaviour. Results indicate that implementation intentions can be effective in increasing healthy eating behaviours with 12 studies showing an overall medium size effect on increasing fruit and vegetable consumption. Authors conclude that implementation intentions to promote healthy eating have more promising effects that those aiming to diminish unhealthy eating patterns.
Abstract
OBJECTIVE This systematic review and meta-analysis examined whether implementation intentions are an effective tool to help people put their intentions to eat a healthy diet into practice. Additionally, it was investigated whether the quality of the outcome measures and the quality of the control conditions that are used in these studies influence implementation intentions' effectiveness. METHODS Twenty three empirical studies investigating the effect of implementation intentions on eating behavior were included. In assessing the empirical evidence, a distinction was made between studies that aim to increase healthy eating (i.e., eating more fruits) and studies that aim to diminish unhealthy eating (i.e., eating fewer unhealthy snacks). RESULTS Implementation intentions are an effective tool for promoting the inclusion of healthy food items in one's diet (Cohen's d=.51), but results for diminishing unhealthy eating patterns are less strong (Cohen's d=.29). For studies aiming to increase healthy eating, it was found that higher quality outcome measures and lower quality control conditions tended to yield stronger effects. CONCLUSION Implementation intentions are somewhat more effective in promoting healthy eating than in diminishing unhealthy eating, although for some studies promoting healthy eating effect sizes may have been inflated due to less than optimal control conditions.