Dietary Lutein and Cognitive Function in Adults: A Meta-Analysis of Randomized Controlled Trials.

Jeffrey Li,El-Sayed M Abdel-Aal

doi:10.3390/molecules26195794

Jeffrey Li, El-Sayed M Abdel-Aal

Open Access

https://doi.org/10.3390/molecules26195794

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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.

Highlights

2c), the studies were around the average tive function (Figure 2b) and memory (Figure 2c), the studies were around the average an acceptable precision placed inside a symmetric funnel plot except effecteffect with with an acceptable precision beingbeing placed inside a symmetric funnel plot except for for the executive function domain in two studies
Discussion complex attention domain includes processes such as sustained attention, divided attention,Inselective attention speed processing, while memory cognitive domain entails the current study,and we evaluated the overall effect of lutein on the three cognitive functions of free recall, cued recall, recognition memory, long-term memory and implicit domains of complex attention, executive function and memory in adults who have conlearning
Our results suggest that dietary lutein and its isomers could maintain cognitive functions and brain health, but it did not significantly improve cognitive function in complex attention (Figure 3a), executive function (Figure 3b) or memory (Figure 3c), as indicated by the overall effect size measured by standardized mean difference (SMD)

Summary

Introduction

Zeaxanthin and meso-zeaxanthin, are xanthophyll carotenoids found commonly in green leafy vegetables, avocados and eggs which play significant roles in human health, the health of eyes and brain, due to their antioxidant attributes [1,2,3,4]. Unlike β–carotene, does not have vitamin A activity, it is exclusively accumulated in the retina and forms macular pigment [5,6,7,8,9]. Epidemiological studies have shown that macular pigment optical density (MPOD) status is strongly correlated with lutein intake [1,5,6,7,8,10]

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