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1.
Effect of glucose and sucrose on cognition in healthy humans: a systematic review and meta-analysis of interventional studies.
García, CR, Piernas, C, Martínez-Rodríguez, A, Hernández-Morante, JJ
Nutrition reviews. 2021;(2):171-187
Abstract
CONTEXT Evidence suggests that plasma glucose levels may influence cognitive performance, but this has not been systematically reviewed and quantified. OBJECTIVE The aim of this review was to investigate the potential effects of glucose and sucrose, compared with placebo, on cognition in healthy humans. DATA SOURCES The electronic databases PubMed and Web of Science were searched up to December 2019. Reference lists of selected articles were checked manually. STUDY SELECTION Randomized controlled trials or crossover trials that compared glucose or sucrose with placebo for effects on cognition were eligible. DATA EXTRACTION Potentially eligible articles were selected independently by 2 authors. Risk of bias was assessed through the Cochrane Collaboration tool. Standardized mean differences (SMDs) were obtained from random-effects meta-analyses for a subsample of studies that reported the same outcomes. RESULTS Thirty-seven trials were identified, of which 35 investigated the effect of glucose consumption compared with placebo on cognition. Two studies found no effect of glucose on cognition, while the others found mixed results. Only 3 of the 37 studies investigated the effects of sucrose intake, reporting mixed results. Meta-analyses revealed a significantly positive effect of glucose compared with control, but only when a verbal performance test (immediate word recall) was used in parallel-design studies (SMD = 0.61; 95%CI, 0.20-1.02; I2 = 0%). Twenty-four studies were classified as having high risk of bias for the selection procedure. CONCLUSIONS A limited body of evidence shows a beneficial effect of glucose in individuals performing immediate verbal tasks. High-quality trials with standardized cognitive measurements are needed to better establish the effect of glucose or sucrose on cognition. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration number CRD42019122939.
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2.
Milk Fat Globule Membrane Supplementation in Children: Systematic Review with Meta-Analysis.
Ambrożej, D, Dumycz, K, Dziechciarz, P, Ruszczyński, M
Nutrients. 2021;(3)
Abstract
(1) Background: Milk fat globule membrane (MFGM), composing fat droplets responsible for lipid transport in breast milk, has been shown to possess immunological and antimicrobial effects. Standard formulas (SF) are devoid of MFGMs during the production process. The study's aim was to evaluate the safety and benefits of MFGMs supplementation in children. (2) Methods: We searched four databases for randomized controlled trials evaluating the supplementation of MFGMs in children. Growth parameters were chosen as the primary outcome. (3) Results: Twenty-four publications of seventeen studies were included. Meta-analyses assessing the primary outcomes at the age of 4 months included four studies (814 children) comparing the MFGM-supplemented formulas and SF, and two trials (549 children) comparing the MFGM-supplemented formulas and breastfeeding. The primary outcomes were non-inferior in all the experimental MFGM formulas compared to SF, or even represented more similar results to breastfed infants. The promising effects, including a lower incidence of acute otitis media and improved cognitive development, cannot be firmly confirmed due to the small amount of existing evidence. No significant adverse effects were reported in any of the assessed products. (4) Conclusions: The available data signaled beneficial effects and a good safety profile, requiring future research with well-designed trials.
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3.
Effects of physical education interventions on cognition and academic performance outcomes in children and adolescents: a systematic review and meta-analysis.
García-Hermoso, A, Ramírez-Vélez, R, Lubans, DR, Izquierdo, M
British journal of sports medicine. 2021;(21):1224-1232
Abstract
OBJECTIVE To determine the effects of interventions aimed at optimising the quantity and quality of physical education (PE) on cognition and academic performance in children and adolescents. DESIGN A systematic review and meta-analysis. DATA SOURCES Studies from electronic databases from inception to 3 January 2021 were identified. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Experimental studies that assessed the effect of quantity-based (ie, increasing the amount of curriculum time allocated to PE) or quality-based (ie, increasing students' participation in physical activity during PE) PE interventions, or both, on changes in cognition and/or academic performance in youth (aged 5-18 years) were included. RESULTS 19 trials comprising 8676 youth (46.5% girls) were included. Individual quality-based PE interventions increased cognition performance (Hedges' g=0.38, 95% CI 0.15 to 0.60; I 2=83.70%), mainly in primary education settings (g=0.48, 95% CI 0.07 to 0.89; I 2=90.43%). Academic performance, principally mathematics-related skills, was also increased by quality-based PE interventions (g=0.15, 95% CI 0.06 to 0.24; I 2=41.75%). Among these interventions, teaching strategies favoured similar results, but without heterogeneity in the results (g=0.12, 95% CI 0.05 to 0.18; I 2=0%). In contrast, quantity-based PE interventions had a very small and non-significant effect on academic performance (g=0.09, 95% CI -0.05 to 0.24; Q=11.65; I 2=48.48%). Finally, there were no differences between the three PE interventions (ie, quantity, quality, and combined PE interventions) in regard to academic performance. CONCLUSION Improving the quality of PE classes may improve students' cognition and academic performance in children and adolescents. Importantly, allocating more time for PE does not seem to compromise this performance.
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4.
Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis.
Lorenzo Calvo, J, Fei, X, Domínguez, R, Pareja-Galeano, H
Nutrients. 2021;(3)
Abstract
Cognitive functions are essential in any form of exercise. Recently, interest has mounted in addressing the relationship between caffeine intake and cognitive performance during sports practice. This review examines this relationship through a structured search of the databases Medline/PubMed and Web of Science for relevant articles published in English from August 1999 to March 2020. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PICOS model. The identified records reported on randomized cross-over studies in which caffeine intake (as drinks, capsules, energy bars, or gum) was compared to an identical placebo situation. There were no filters on participants' training level, gender, or age. For the systematic review, 13 studies examining the impacts of caffeine on objective measures of cognitive performance or self-reported cognitive performance were selected. Five of these studies were also subjected to meta-analysis. After pooling data in the meta-analysis, the significant impacts of caffeine only emerged on attention, accuracy, and speed. The results of the 13 studies, nevertheless, suggest that the intake of a low/moderate dose of caffeine before and/or during exercise can improve self-reported energy, mood, and cognitive functions, such as attention; it may also improve simple reaction time, choice reaction time, memory, or fatigue, however, this may depend on the research protocols.
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5.
Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.
Markun, S, Gravestock, I, Jäger, L, Rosemann, T, Pichierri, G, Burgstaller, JM
Nutrients. 2021;(3)
Abstract
Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12 deficiency or advanced neurological disorders and the effectiveness of vitamin B12 supplementation in such cases is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to assess the effects of vitamin B12 alone (B12 alone), in addition to vitamin B12 and folic acid with or without vitamin B6 (B complex) on cognitive function, depressive symptoms, and idiopathic fatigue in patients without advanced neurological disorders or overt vitamin B12 deficiency. Medline, Embase, PsycInfo, Cochrane Library, and Scopus were searched. A total of 16 RCTs with 6276 participants were included. Regarding cognitive function outcomes, we found no evidence for an effect of B12 alone or B complex supplementation on any subdomain of cognitive function outcomes. Further, meta-regression showed no significant associations of treatment effects with any of the potential predictors. We also found no overall effect of vitamin supplementation on measures of depression. Further, only one study reported effects on idiopathic fatigue, and therefore, no analysis was possible. Vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.
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6.
The Effects of Fruit-Derived Polyphenols on Cognition and Lung Function in Healthy Adults: A Systematic Review and Meta-Analysis.
Morton, L, Braakhuis, AJ
Nutrients. 2021;(12)
Abstract
Polyphenols are plant derived nutrients that influence oxidative stress and inflammation and therefore may have positive benefits on cognition and lung function. This systematic review and meta-analysis aimed to evaluate the effects of fruit derived polyphenol intakes on cognition and lung capacity in healthy adults. In August 2020 and October 2021, Medline and Google Scholar were used to search for relevant studies examining the effects of fruit derived polyphenol intakes on cognition and/or lung function in healthy adults (<70 years old). Fourteen studies related to cognition (409 healthy subjects) and seven lung/respiratory studies (20,788 subjects) were used for the systematic review using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The meta-analysis (using six cognition and three lung function studies) indicated a protective effect on lung function from dietary intakes of fruit-derived polyphenols. Neither a benefit nor decrement from fruit-derived polyphenol intakes were detected for cognition. Human intervention trials examining the effects of polyphenol supplementation on lung function in healthy adults are scarce and intervention studies are warranted. More conclusive results are needed to provide recommendations for polyphenol supplementation to support aspects of cognition.
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7.
Impact of Lowering Low-Density Lipoprotein Cholesterol with Contemporary Lipid-Lowering Medicines on Cognitive Function: A Systematic Review and Meta-Analysis.
Ying, H, Wang, J, Shen, Z, Wang, M, Zhou, B
Cardiovascular drugs and therapy. 2021;(1):153-166
Abstract
PURPOSE To evaluate the potential association between the lowering of low-density lipoprotein cholesterol (LDL-C) with contemporary lipid-lowering medicines and cognitive function. METHODS Randomized controlled trials (RCTs) in databases including PubMed, Embase, and the Web of Science and all databases in the Cochrane Library and ClinicalTrials.gov were collected from inception to January 1, 2020. The cognitive function of patients receiving proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, statins and ezetimibe was evaluated using meta-analysis. RESULTS A total of 2910 studies were obtained from databases and other sources. Thirty-three studies were selected by screening, including 11 studies on alirocumab, 9 studies on evolocumab, 11 studies on statins and 2 studies on ezetimibe. In our study, a total of 128,691 patients with no cognitive impairment were divided into an intervention group (66,330 patients) and a control group (62,361 patients). The data were subjected to a random-effects model or a fixed-effects model for meta-analysis. The contemporary lipid-lowering medicines significantly reduced LDL-C in terms of both percentage (WMD: -45.06%, 95% CI -50.12% to -40.00%, P < 0.001) and absolute value (WMD: -64.01 mg/dL, 95% CI -72.25 to -55.78, P < 0.001). Compared with the control group, patients receiving treatment with contemporary lipid-lowering medicines did not show a significant difference in the rate of neurocognitive disorder (RR: 1.02, 95% CI 0.90 to 1.16, I2 = 0.0%, p = 0.696). Subgroup analysis was performed according to the intervention and LDL-C stratification. The result of this subgroup analysis was consistent with the main findings. Regarding global cognitive performance, no difference in major cognition was found among the pooled data (SMD: 0.02, 95% CI -0.01 to 0.04, P = 0.002), except for psychomotor speed (SMD: 0.09, 95% CI 0.02 to 0.16, P = 0.0024). CONCLUSIONS Contemporary lipid-lowering medicines were not associated with cognitive impairment in RCTs. A low LDL-C level did not influence the incidence of cognitive disorder or global cognitive performance.
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8.
Effects of Berry Anthocyanins on Cognitive Performance, Vascular Function and Cardiometabolic Risk Markers: A Systematic Review of Randomized Placebo-Controlled Intervention Studies in Humans.
Ahles, S, Joris, PJ, Plat, J
International journal of molecular sciences. 2021;(12)
Abstract
Supplementation with anthocyanins, which are a type of flavonoids mainly found in various berries, is hypothesized to be a promising approach to lower the risk of developing cognitive decline. The aim of this systematic review was to provide a comprehensive overview of dietary intervention trials describing effects of berry anthocyanins on cognitive performance in humans, while also addressing potential underlying mechanisms. A total of 1197 articles were identified through a systematic search, and 49 studies reporting effects on cognitive performance (n = 18), vascular function (n = 22), or cardiometabolic risk markers (n = 32) were included. Significant improvements were observed on memory, while some of the studies also reported effects on attention and psychomotor speed or executive function. Vascular function markers such as brachial artery flow-mediated vasodilation were also affected and consistent evidence was provided for the beneficial effects of berry anthocyanins on endothelial function. Finally, studies reported improvements in blood pressure, but effects on metabolic risk markers (e.g. carbohydrate and lipid metabolism) were less consistent. In conclusion, this review provides evidence for the beneficial effects of berry anthocyanins on cognitive performance as memory improved. Whether observed anthocyanin-induced improvements in vascular function and blood pressure underlie beneficial effects on cognitive performance warrants further study.
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9.
Dietary Lutein and Cognitive Function in Adults: A Meta-Analysis of Randomized Controlled Trials.
Li, J, Abdel-Aal, EM
Molecules (Basel, Switzerland). 2021;(19)
Abstract
Emerging literature suggests that dietary lutein may have important functions in cognitive health, but there is not enough data to substantiate its effects in human cognition. The current study was intended to determine the overall effect of lutein on the main domains of cognition in the adult population based on available placebo randomized-controlled trials. Literature searches were conducted in PubMed, AGRICOLA, Scopus, MEDLINE, and EMBASE on 14 November 2020. The effect of lutein on complex attention, executive function and memory domains of cognition were assessed by using an inverse-variance meta-analysis of standardized mean differences (SMD) (Hedge's g method). Dietary lutein was associated with slight improvements in cognitive performance in complex attention (SMD 0.02, 95% CI -0.27 to 0.31), executive function (SMD 0.13, 95% CI -0.26 to 0.51) and memory (SMD 0.03, 95% CI -0.26 to 0.32), but its effect was not significant. Change-from-baseline analysis revealed that lutein consumption could have a role in maintaining cognitive performance in memory and executive function. Although dietary lutein did not significantly improve cognitive performance, the evidence across multiple studies suggests that lutein may nonetheless prevent cognitive decline, especially executive function. More intervention studies are needed to validate the role of lutein in preventing cognitive decline and in promoting brain health.
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10.
Cognitive function in binge eating disorder and food addiction: A systematic review and three-level meta-analysis.
Iceta, S, Rodrigue, C, Legendre, M, Daoust, J, Flaudias, V, Michaud, A, Bégin, C
Progress in neuro-psychopharmacology & biological psychiatry. 2021;:110400
Abstract
BACKGROUND An extensive body of recent research has focused on the contribution of cognitive functioning to eating behaviors. In binge eating disorder (BED) and food addiction (FA), the extent of cognitive impairment is still unclear. This study aimed to characterize, among those with BED and FA, neurocognitive functions using performances based on neuropsychological tasks in the context of neutral stimuli in adults. METHOD MEDLINE, Embase, PsycINFO, Cochrane Database of Systematic Reviews, CINAHL and gray literature (ProQuest and OpenGrey) were used to identify studies that reported neurocognitive assessments in BED or FA up to December 2019. A three-level meta-analysis was conducted. RESULTS A significant overall effect was found for global cognitive impairments, suggesting that individuals with BED or FA have poorer performances when completing cognitive tasks. Analyses for specific cognitive domains revealed that individuals with BED showed poorer performances at tasks assessing cognitive flexibility, inhibitory control, attention and planning. Analyses regarding FA were inconclusive due to a lack of studies. Thus, the results were described qualitatively. CONCLUSION Our meta-analysis highlighted the cognitive weaknesses that seem to come with BED and the necessity to integrate them in the assessment and treatment of this condition. It also stressed the lack of quality studies surrounding the cognitive features of FA.