1.
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.
2.
Effects of soy isoflavones on cognitive function: a systematic review and meta-analysis of randomized controlled trials.
Cui, C, Birru, RL, Snitz, BE, Ihara, M, Kakuta, C, Lopresti, BJ, Aizenstein, HJ, Lopez, OL, Mathis, CA, Miyamoto, Y, et al
Nutrition reviews. 2020;(2):134-144
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Abstract
CONTEXT The results of preclinical and observational studies support the beneficial effect of soy isoflavones on cognition. OBJECTIVE This review aimed to evaluate the effects of soy isoflavones on cognition in adults. DATA SOURCES The PUBMED, EMBASE, Ovid Medline, Cochrane Library, and clinicaltrials.gov databases were searched. STUDY SELECTION Two researchers independently screened 1955 records, using the PICOS criteria: participants were adults; intervention was dietary sources with soy isoflavones or isolated soy isoflavones; comparator was any comparator; outcome was cognitive function; study type was randomized controlled trials (RCTs). A third researcher was consulted to resolve any discrepancies. Sixteen RCTs were included and their quality assessed. DATA EXTRACTION Information on study design, characteristics of participants, and outcomes was extracted. PRISMA guidelines were followed. DATA ANALYSIS A random-effects meta-analysis was used to pool estimates across studies. In the 16 RCTs (1386 participants, mean age = 60 y), soy isoflavones were found to improve overall cognitive function (standardized mean difference [SMD], 0.19; 95% confidence interval [CI], 0.07-0.32) and memory (SMD, 0.15; 95%CI, 0.03-0.26). CONCLUSION The results showed that soy isoflavones may improve cognitive function in adults. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration no. CRD42018082070.
3.
Omega-3 and its domain-specific effects on cognitive test performance in youths: A meta-analysis.
Emery, S, Häberling, I, Berger, G, Walitza, S, Schmeck, K, Albert, T, Baumgartner, N, Strumberger, M, Albermann, M, Drechsler, R
Neuroscience and biobehavioral reviews. 2020;:420-436
Abstract
Omega-3 fatty acids are vital for brain development. The aim of this meta-analysis was to broaden current knowledge of the effects of omega-3 supplementation on cognitive test performance in youths. Randomized controlled trials (RCTs) meeting selection criteria were identified through two independent literature searches on PubMed, Cochrane Library, PsycARTICLES and PsycINFO (last search June 2019). Twenty-nine out of 1126 studies assessing 4247 participants met all selection criteria. A meta-analysis using random-effects model was performed for eight different cognitive domains. This first analysis revealed no main effect of omega-3 fatty acid supplementation on domain-specific cognitive test performance in youths. Subgroup analyses identified beneficial effects of eicosapentaenoic acid (EPA)-rich but not docosahexaenoic acid (DHA)-rich formulations in the domains of long-term memory, working memory and problem solving and a tendency towards beneficial effects in clinical rather than non-clinical populations. Future research should investigate differential effects of EPA and DHA and consider their baseline levels, other nutritional components and interactions with gene variations as potential predictors of response.