In Vivo Correlation Between Macular Pigment Optical Volume and Retinal Layers Thickness

Purpose

This study aims to investigate the potential in vivo relationship between macular pigment (MP) and retinal layers thickness in healthy subjects and dry, non-advanced age-related macular degeneration (AMD).

Methods

An observational, cross-sectional study was conducted. Healthy subjects >40 years and patients with early or intermediate AMD were recruited. Structural OCT and macular pigment optical volume (MPOV) were collected for each subject. Retinal layers parameters were calculated based on the standard early treatment diabetic retinopathy study (ETDRS) map. Additionally, MPOV within 1°, 2°, and 9° of eccentricity was assessed and associated with retinal layers thickness and volume. Linear mixed-effects models were used to test the relationship between MP and structural OCT parameters, while adjusting for known possible confounding factors.

Results

A total of 144 eyes of 91 subjects (60.4% females) were evaluated, comprising 43% normal eyes and 57% with early/intermediate AMD. Among the retinal layers, only the outer nuclear layer (ONL) thickness and volume appeared to be associated to higher MP levels. Specifically, the central ONL thickness was identified as a significant predictor of the MPOV 1°(P = 0.04), while the parafoveal ONL thickness (inner ETDRS subfield) was identified as a significant fixed effect on the MPOV 9° (P = 0.037). Age and the presence of drusen or subretinal drusenoid deposits were also tested without showing significant correlations.

Conclusions

Among the retinal layers examined, only the ONL thickness demonstrated a significant association with MPOV. Consequently, ONL thickness might serve as a potential biomarker related to MP levels.

Dietary patterns and carotenoid intake: Comparisons of MIND, Mediterranean, DASH, and Healthy Eating Index

The Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) dietary pattern is associated with reduced cognitive decline and dementia risk. However, the nutrient features that distinguish the MIND from other patterns are unknown. We investigated the relationship between accordance to the MIND pattern and carotenoid intake (phytonutrients hypothesized to confer neuroprotection) relative to the Mediterranean, DASH, and Healthy Eating Index (HEI-2020). We hypothesized that MIND diet accordance would be a stronger predictor of carotenoid intake relative to other diet indices. A total of 396 adults (aged 19-82 years) completed the Dietary History Questionnaire to assess carotenoid intake and adherence to each diet index. Stepwise regressions with adjustment for covariates followed by the Meng's Z-test were used to compare correlation strength between each diet pattern and carotenoid. All diet patterns were positively associated with lutein and zeaxanthin, β-carotene, α-carotene, and β-cryptoxanthin (all βs ≥0.38, Ps <.01). Effect size comparisons revealed that MIND accordance predicted a greater proportion of variance in lutein and zeaxanthin (all Zs ≥ 3.3, Ps < .001) and β-carotene (all Zs ≥ 2.6, Ps < .01) relative to the Mediterranean, DASH, and HEI-2020. MIND accordance explained a greater proportion of variance in α-carotene (Z = 3.8, P < .001) and β-cryptoxanthin (Z = 3.6, P < .001) relative to the HEI-2020. MIND diet accordance was disproportionately related to carotenoid intake, indicating the MIND index places greater emphasis on carotenoid-rich foods, particularly those containing lutein, zeaxanthin, and β-carotene, relative to other diet indices. Future research is needed to define the role of these carotenoids in nutritional interventions for cognitive health.

Macular Pigment Optical Density and Skin Carotenoids in a Childhood Sample

BACKGROUND

Carotenoids are plant pigments with light filtering and antioxidant properties that deposit in human tissues, including retina and skin. Descriptive characteristics and covariates of carotenoid status in macula and skin have been examined in adults; however, similar studies in children are limited. Thus, this study aimed to delineate how factors of age, sex, race, weight status, and dietary carotenoid intake relate to macular and skin carotenoids in children.

METHODS

Children (7-13 y, N = 375) completed heterochromatic flicker photometry to assess macular pigment optical density (MPOD). Participants underwent anthropometrics to measure weight status (BMI percentile [BMI%]), and parent/guardian provided demographic information. Subsample data were available for skin carotenoids (N = 181), assessed using reflection spectroscopy, and dietary carotenoids (N = 101) using the Block Food Frequency Questionnaire. Relationships between skin and macular carotenoids were assessed using partial Pearson's correlations controlling for age, sex, race, and BMI%. Relationships between dietary carotenoids and macular and skin carotenoids were assessed using stepwise linear regression including age, sex, race, and BMI% in the model.

RESULTS

Mean MPOD was 0.56 ± 0.22 and skin carotenoid score was 282 ± 94.6. There was no significant correlation between MPOD and skin carotenoids (r = 0.02, P = 0.76). BMI% was negatively associated with skin (stdβ = -0.42, P < 0.001), but not macular carotenoids (stdβ = -0.04, P = 0.70). Neither MPOD nor skin carotenoids were associated with age, sex, or race (all P > 0.10). MPOD was positively associated with energy-adjusted reported lutein + zeaxanthin intake (stdβ = 0.27, P = 0.01). Skin carotenoids were positively associated with energy-adjusted reported carotenoid intake (stdβ = 0.26, P = 0.01).

CONCLUSIONS

The mean MPOD values in children were higher than what has been reported in adult populations. Previous studies in adult samples report an average MPOD of 0.21. Although macular and skin carotenoids were not related, they were associated with dietary carotenoids relevant to the respective tissues; however, skin carotenoids may be more susceptible negative influence from higher weight status.

Endogenous and Exogenous Regulation of Redox Homeostasis in Retinal Pigment Epithelium Cells: An Updated Antioxidant Perspective

The retinal pigment epithelium (RPE) performs a range of necessary functions within the neural layers of the retina and helps ensure vision. The regulation of pro-oxidative and antioxidant processes is the basis for maintaining RPE homeostasis and preventing retinal degenerative processes. Long-term stable changes in the redox balance under the influence of endogenous or exogenous factors can lead to oxidative stress (OS) and the development of a number of retinal pathologies associated with RPE dysfunction, and can eventually lead to vision loss. Reparative autophagy, ubiquitin-proteasome utilization, the repair of damaged proteins, and the maintenance of their conformational structure are important interrelated mechanisms of the endogenous defense system that protects against oxidative damage. Antioxidant protection of RPE cells is realized as a result of the activity of specific transcription factors, a large group of enzymes, chaperone proteins, etc., which form many signaling pathways in the RPE and the retina. Here, we discuss the role of the key components of the antioxidant defense system (ADS) in the cellular response of the RPE against OS. Understanding the role and interactions of OS mediators and the components of the ADS contributes to the formation of ideas about the subtle mechanisms in the regulation of RPE cellular functions and prospects for experimental approaches to restore RPE functions.

The impact of nutrition on visual cognitive performance in the nutrition, vision, and cognition in sport study

Introduction

The purpose of this study was to examine the influence of nutritional intake on visual perceptual-cognitive performance (VCP) in young healthy adults.

Methods

Ninety-eight healthy men (n = 38) and women (n = 60) aged 18-33 years participated and maintained their usual dietary intake throughout the study. VCP was measured using the NeuroTracker^™ CORE (NT) 3-Dimensional (3-D) software program (15 training sessions) over a 15-day period. Food logs and extensive lifestyle measures including body composition, cardiovascular health, sleep and exercise patterns, and general readiness to perform were collected. Mean intake from 10 food logs collected over the 15 days were analyzed using Nutribase software. Statistical analyses were performed in SPSS using repeated measures ANOVA including significant covariates when appropriate.

Results

Males consumed significantly more calories, macronutrients, cholesterol, choline, and zinc and performed significantly better on VCP than the females. Participants who consumed more than 40% of kcals from carbohydrates (p = 0.038), less than 24% of kcals from protein (p = 0.009), more than 2,000 μg/day lutein/zeaxanthin or more than 1.8 mg/ day vitamin B2 performed significantly better on VCP than those who consumed less than those amounts, respectively.

Discussion

VCP is an important dimension of cognitive function and in the present study is influenced by higher carbohydrate, lutein/ zeaxanthin, and vitamin B2 dietary intake while high protein consumption and the female sex negatively impacted VCP.

Neuroprotective influence of macular xanthophylls and retinal integrity on cognitive function among persons with multiple sclerosis

BACKGROUND

No studies to date have examined if macular xanthophyll accumulation and retinal integrity are independently associated with cognitive function in individuals with multiple sclerosis (MS). This study explored whether macular xanthophyll accumulation and structural morphometry in the retina were associated with behavioral performance and neuroelectric function during a computerized cognitive task among persons with MS and healthy controls (HCs).

METHODS

42 HCs and 42 individuals with MS aged 18-64 years were enrolled. Macular pigment optical density (MPOD) was measured using heterochromatic flicker photometry. Optic disc retinal nerve fiber layer (odRNFL), macular retinal nerve fiber layer, and total macular volume were assessed via optical coherence tomography. Attentional inhibition was assessed using an Eriksen flanker task while underlying neuroelectric function was recorded using event-related potentials.

RESULTS

Persons with MS had a slower reaction time, lower accuracy, and delayed P3 peak latency time during both congruent and incongruent trials compared with HCs. Within the MS group, MPOD explained variance in incongruent P3 peak latency, and odRNFL explained variance in congruent reaction time and congruent P3 peak latency.

CONCLUSIONS

Persons with MS exhibited poorer attentional inhibition and slower processing speed, yet higher MPOD and odRNFL levels were independently associated with greater attentional inhibition and faster processing speed among persons with MS. Future interventions are necessary to determine if improvements in these metrics may promote cognitive function among persons with MS.

Low Xanthophylls, Retinol, Lycopene, and Tocopherols in Grey and White Matter of Brains with Alzheimer's Disease

BACKGROUND

Oxidative stress contributes to pathogenesis and progression of Alzheimer's disease (AD). Higher levels of the dietary antioxidants- carotenoids and tocopherols- are associated with better cognitive functions and lower risk for AD, and lower levels of multiple carotenoids are found in serum and plasma of patients with AD. Although brains donated by individuals with mild cognitive impairment had significantly lower levels of lutein and beta-carotene, previous investigators found no significant difference in carotenoid levels of brains with AD and cognitively normal brains.

OBJECTIVE

This study tested the hypothesis that micronutrients are significantly lower in donor brains with AD than in healthy elderly brains.

METHODS

Samples of donor brains with confirmed AD or verified health were dissected into grey and white matter, extracted with organic solvents and analyzed by HPLC.

RESULTS

AD brains had significantly lower levels of lutein, zeaxanthin, anhydrolutein, retinol, lycopene, and alpha-tocopherol, and significantly increased levels of XMiAD, an unidentified xanthophyll metabolite. No meso-zeaxanthin was detected. The overlapping protective roles of xanthophylls, carotenes, α- and γ-tocopherol are discussed.

CONCLUSION

Brains with AD had substantially lower concentrations of some, but not all, xanthophylls, carotenes, and tocopherols, and several-fold higher concentrations of an unidentified xanthophyll metabolite increased in AD (XMiAD).

Macular Pigment, Cognition, and Visual Function in Younger Healthy Adults in Ghana

BACKGROUND

Macular pigment optical density (MPOD) remains an indispensable biomarker to measure fruit and vegetable intake, with a biologically plausible correlation to vision and cognition. However, evidence in the sub-Saharan regions, including Ghana, is lacking.

OBJECTIVE

This study explored dietary carotenoid intake on MPOD and its influence on cognitive and visual function in a healthy Ghanaian sample.

METHODS

The MPOD of 301 healthy subjects (aged 21.1±1.9 years) was evaluated using the customized Macular DensitometerTM. A battery of cognitive tests and standard vision assessments were employed to assess cognition and visual function, respectively. Dietary lutein and zeaxanthin (L and Z) were estimated based on a twenty-four-hour repeated dietary recall.

RESULTS

The mean MPOD at 0.5° and 1.0° eccentricities were 0.37±0.16 and 0.34±0.15 optical density units, respectively. Dietary intake of L (4.06±10.54 mg/day) was considerably higher than Z (0.33±2.25 mg/day), with cumulative L+Z estimated at 4.39±11.58 mg/day. MPOD was not significantly influenced by demographic, dietary, and visual measures (p≥0.05). However, after statistical adjustment, we found a small but statistically significant positive relationship between F-A-S phonemic verbal fluency (Unstandardized co-efficient (β) = 0.002, p = 0.016) and the never consumed alcohol category (β= 0.062, p = 0.02) with MPOD.

CONCLUSION

The findings in this population showed significant positive relationships between measures of cognition and no alcohol intake, with MPOD. These findings necessitate dietary education to augment carotenoid intake and limit alcohol intake for better cognitive functioning.

Enhancing children's cognitive function and achievement through carotenoid consumption: The Integrated Childhood Ocular Nutrition Study (iCONS) protocol

Lutein and zeaxanthin (L + Z) are carotenoids that accumulate in neural tissue and potentially confer benefits to cognition. Whereas cross-sectional studies have revealed positive associations between macular carotenoids (MC) and cognition, no studies have investigated whether L + Z supplementation impacts MC and cognition in childhood. Accordingly, the Integrated Childhood Ocular Nutrition Study aims to investigate the impact of L + Z supplementation over 9-months on academic abilities, attentional control, memory, and MC among preadolescent children. Children 8-10 years (N = 288) will enroll in a 9-month double-blind, placebo-controlled, randomized trial. The study is registered and approved as a clinical trial on the U.S. National Library of Medicine http://ClinicalTrials.gov registry (NCT05177679). Participants will be randomized into an active (10 mg lutein+2 mg zeaxanthin) or waitlist placebo-controlled group. Primary outcomes include hippocampal-dependent memory, attentional inhibition, and academic achievement using a spatial reconstruction task, an Eriksen flanker task, and the Kaufman Test of Academic and Educational Achievement 3rd edition, respectively. Secondary outcomes include event-related brain potentials of attentional resource allocation and information processing speed (i.e., P3/P300 amplitude and latency) recorded during the flanker task. Macular pigment optical density (MPOD) will be assessed using heterochromatic flicker photometry. Cognitive assessments will be completed prior to and after completion of the supplementation period. MPOD will be quantified prior to, at the mid-point of (4-5 months), and after (9 months) the supplementation period. It is hypothesized that L + Z supplementation will improve cognition and academic achievement. Further, benefits for cognition and achievement are anticipated to be mediated by increases in MC among treatment group participants.

Supplementation With Carotenoids, Omega-3 Fatty Acids, and Vitamin E Has a Positive Effect on the Symptoms and Progression of Alzheimer’s Disease

Background: Preliminary work by our center has reported behavior and functional benefits in patients with Alzheimer’s disease (AD) following targeted micronutritional supplementation. Objective: To build on the existing exploratory research and investigate the impact of these micronutrients on the natural progression of AD in a randomized controlled trial. Methods: Patients with mild-moderate AD consumed daily 1 g fish oil (of which 500 mg DHA, 150 mg EPA), 22 mg carotenoids (10 mg lutein, 10 mg meso-zeaxanthin, 2 mg zeaxanthin), and 15 mg vitamin E or placebo for 12 months in a double-blind, placebo-controlled, randomized clinical trial. Carotenoids, ω-3FAs, and vitamin E were quantified in blood. Carotenoids were also measured in skin. AD severity was measured using the mini-mental state examination and dementia severity rating scale tools. Behavior, mood, and memory were measured using an informant-based questionnaire. Results: Following 12 months of supplementation, the active group (n = 50) compared to the placebo group (n = 27), demonstrated statistically significant improvements in skin carotenoid measurements, blood carotenoids, ω-3FAs, and vitamin E concentrations (p <  0.05, for all). The active group also performed better in objective measures of AD severity (i.e., memory and mood), with a statistically significant difference reported in the clinical collateral for memory (p <  0.001). Conclusion: Exponential increases in the prevalence of AD and its relentless progressive nature is driving the need for interventions that help to ameliorate symptoms and improve quality of life in AD patients. Given the positive outcomes demonstrated in this trial, this combined micronutrient dietary supplement should be considered in the overall management of AD.

Early Childhood Lutein and Zeaxanthin Intake Is Positively Associated with Early Childhood Receptive Vocabulary and Mid-Childhood Executive Function But No Other Cognitive or Behavioral Outcomes in Project Viva

BACKGROUND

Lutein and zeaxanthin are carotenoids associated with better cognition in older adults. Recent evidence suggests that their dietary intake may also have cognitive implications in childhood.

OBJECTIVE

The aim was to examine associations of early childhood lutein and zeaxanthin (L/Z) intake with cognition in early and mid-childhood.

METHODS

Among 1378 children in Project Viva, a prospective cohort, mothers reported their child's dietary intake in early childhood (median: 3.2 y) using a food-frequency questionnaire. Child cognition and behavior were assessed at the same time point using the Peabody Picture Vocabulary Test (PPVT-III) and the Wide Range Assessment of Visual Motor Abilities (WRAVMA) and at mid-childhood (median: 7.7 y) using the Kaufman Brief Intelligence Test, the WRAVMA drawing subtest, the Wide Range Assessment of Memory and Learning, the Behavior Rating Inventory of Executive Function (BRIEF), and the Strengths and Difficulties Questionnaire.

RESULTS

Children consumed a daily mean (SD) of 1.0 (0.4) mg L/Z in early childhood. Children in the third-quartile category of L/Z intake had a mean PPVT-III score 2.40 (95% CI: 0.27, 4.53) points higher than children in the lowest quartile category in early childhood, suggesting better receptive vocabulary. Children in the highest quartile category of L/Z intake had a parent-reported mean BRIEF Global Executive Composite score 1.65 (95% CI: -3.27, -0.03) points lower than children in the lowest quartile category in mid-childhood, indicating better executive function. We did not observe associations between L/Z intake and any of the other cognitive or behavioral outcomes assessed.

CONCLUSIONS

The overall findings do not provide strong evidence of an association between child L/Z intake and cognition and behavior. However, the positive associations found between early childhood L/Z intake and early childhood receptive vocabulary and mid-childhood executive function, in addition to previous evidence of neurodevelopmental benefit of L/Z intake, suggest that this relation deserves further investigation.

Effect of macular pigment carotenoids on cognitive functions: A systematic review

Lutein and zeaxanthin-xanthophyll carotenoids with antioxidant and anti-inflammatory characteristics-are present in the retina and the brain. High concentrations of these carotenoids have been positively related to cognitive performance. Therefore, this systematic review analyses the relationship between macular pigment density and cognitive functions. Most relevant databases were scoured for studies on healthy people relating cognitive functions to macular pigment optical density (MPOD). There were no age, sex, or race limitations. PROSPERO registration: CRD42021254833. Nineteen studies were included, seven randomized controlled trials (RCT) and eleven observational studies. The general aim of the studies was to examine the association between carotenoids (lutein, meso‑zeaxanthin and zeaxanthin) and cognitive function. Most observational studies correlates MPOD levels with cognitive function or brain activity. Besides, RCTs compared the cognitive function and/or brain activity after increasing lutein and zeaxanthin intake though dietary supplementation or avocado consumption. Dietary lutein and zeaxanthin intake increased MPOD in six of the seven clinical trials and significantly improved most of the cognitive functions studied. A wide variety of test and methodologies for measuring cognitive functions were observed. Memory, processing speed, attention and reasoning were the cognitive function significantly related to MPOD levels in adults. Brain activity also was related to MPOD, but the results were inconsistent. Only four of the eleven observational studies were based on young people and all studies showed a significant relationship between MPOD and cognitive functions. This systematic review showed a direct relationship among cognitive functions, macular pigment and the intake of lutein and zeaxanthin.

Can Diet Supplements of Macular Pigment of Lutein, Zeaxanthin, and Meso-zeaxanthin Affect Cognition?

Background: Lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) are collectively called macular pigment. MZ can be converted from L in the macula. In the recent decade, many studies have been performed to investigate the effects for taking carotenoids, especially L and Z or L, Z, and MZ, as diet supplements on human health. Objective: We examined if diet supplements of L + Z or L + Z + MZ have effects on cognitive function in adults. Methods: A systemic literature search was performed in March 2021 with the following keywords: lutein, zeaxanthin, meso-zeaxanthin, cognition, cognitive, and macular pigment. The searched databases included Medline EBSCOhost, Scopus, Elsevier, Cochrane Library, ProQuest, and ClinicalTrials.gov. Findings from eight clinical trials were presented as the strongest evidence on the studied topic. Results: Most studies have found that macular pigments (L + Z) in blood or macula are positively correlated with cognitive performance. As an index of the amount of macular pigments in the brain, macular pigment optical density is related to cognitive performance in adults. In addition, there is an inverse relationship between a higher amount of macular pigment in the blood and lower risk of mild cognitive impairments or Alzheimer’s disease. Based on the findings from the clinical trials, diet supplements of L + Z or L + Z + MZ are associated with improved cognition in adults. Conclusion: The diet supplements of L + Z or L + Z+MZ are associated with better cognitive functioning, which may be via their beneficial effects on the vision.

The Effects of Lutein and Zeaxanthin Supplementation on Cognitive Function in Adults With Self-Reported Mild Cognitive Complaints: A Randomized, Double-Blind, Placebo-Controlled Study

Background

Lutein and zeaxanthin are fat-soluble, dietary carotenoids with high concentrations in human brain tissue. There have been a number studies confirming an association between lutein and zeaxanthin and cognitive function.

Purpose

Examine the effects of lutein and zeaxanthin supplementation on cognitive function in adults with self-reported cognitive complaints.

Study Design

Two-arm, parallel-group, 6-month, randomized, double-blind, placebo-controlled trial.

Methods

Ninety volunteers aged 40–75 years received either 10 mg of lutein and 2 mg of zeaxanthin, once daily or a placebo. Outcome measures included computer-based cognitive tasks, the Cognitive Failures Questionnaire, Behavior Rating Inventory of Executive Function, Profile of Mood States, and the Patient-Reported Outcomes Measurement Information System-29.

Results

Compared to the placebo, lutein and zeaxanthin supplementation was associated with greater improvements in visual episodic memory (p = 0.005) and visual learning (p = 0.001). However, there were no other statistically-significant differences in performance on the other assessed cognitive tests or self-report questionnaires. Lutein and zeaxanthin supplementation was well-tolerated with no reports of significant adverse effects.

Conclusion

The results from this trial suggest that 6-months of supplementation with lutein and zeaxanthin may improve visual memory and learning in community-dwelling adults with self-reported cognitive complaints. However, it had no other effect on other computer-based measures of cognitive performance or self-report measures of cognition, memory, mood, or physical function.

Lutein and Zeaxanthin and Their Roles in Age-Related Macular Degeneration-Neurodegenerative Disease

Lutein and zeaxanthin belong to the xanthophyll family of carotenoids, which are pigments produced by plants. Structurally, they are very similar, differing only slightly in the arrangement of atoms. Key sources of these carotenoids include kale, savoy cabbage, spinach, broccoli, peas, parsley, corn, and egg yolks. The recommended daily intake of lutein is approximately 10.0 mg and that of zeaxanthin is 2 mg. Lutein intake in adults varies, with average intakes being 1–2 mg/day. Due to the lack of synthesis of consumption of these compounds in humans, these substances are extremely important for the proper functioning of certain organs of the body (eye, skin, heart, intestines). Eating a lot of dark leafy vegetables and some fruits can help to prevent our bodies from developing diseases. The protective effects of carotenoids are mainly related to their defense against oxidative stress and their ability to scavenge free radicals. Lutein and zeaxanthin are the only dietary carotenoids that accumulate in the retina, specifically the macula, and are called macular pigments. These carotenoids are concentrated by the action of specific binding proteins such as StARD3, which binds lutein, and GSTP1, which binds zeaxanthin and its dietary metabolite, mesozeaxanthin. It has been shown that supportive therapy with lutein and zeaxanthin can have a beneficial effect in delaying the progression of eye diseases such as age-related macular degeneration (AMD) and cataracts. This article presents the current state of knowledge on the role of lutein and zeaxanthin, especially from human studies targeting their metabolism and bioavailability, with recommendations to consume xanthophyll-rich foods.

Identification of Carotenoids in Hairless Canary Seed and the Effect of Baking on Their Composition in Bread and Muffin Products

Carotenoids are essential components in the human diet due to their positive functions in ocular and cognitive health. This study investigated composition of carotenoids in hairless canary seed (HCS) as a novel food and the effect of baking on carotenoids in bread and muffin made from HCS, wheat and corn. Three bread formulations made from wheat and HCS blends were evaluated and compared with control wheat bread. In addition, three low-fat muffin recipes prepared from HCS alone or in blends with corn were assessed. The fate of carotenoid compounds in breads and muffins was monitored after dry mixing, dough/batter formation and oven baking. Carotenoids in products were quantified using UPLC and their identification was confirmed based on LC-MS/MS. Hairless canary seed and corn were fairly rich in carotenoids with a total content of 7.6 and 12.9 µg/g, respectively, compared with wheat (1.3 µg/g). Nineteen carotenoid compounds were identified, with all-trans lutein being the principal carotenoid in HCS followed by lutein 3-O-linoleate, lutein 3-O-oleate and lutein di-linoleate. There were significant reductions in carotenoids in muffin and bread products. It appears that batter or dough preparation causes more reductions in carotenoids than oven baking, probably due to enzymatic oxidation and degradation. Muffin-making resulted in lower lutein reductions compared with the bread-making process. The results suggest that muffins made from hairless canary seed alone or in blends with corn could boost the daily intake of lutein and/or zeaxanthin.

Omega-3 fatty acid, carotenoid and vitamin E supplementation improves working memory in older adults: A randomised clinical trial

BACKGROUND & AIMS

Accumulating evidence suggests that omega-3 fatty acids (ω-3FAs), carotenoids and vitamin E can improve cognitive performance. However, their collective impact on cognition has not yet been investigated in healthy individuals. This study investigated the combined effect of ω-3FA, carotenoid and vitamin E supplementation on the cognitive performance of older adults.

METHODS

Cognitively healthy individuals aged ≥65 years consumed daily 1 g fish oil (of which 430 mg docosahexaenoic acid, 90 mg eicosapentaenoic acid), 22 mg carotenoids (10 mg lutein, 10 mg meso-zeaxanthin, 2 mg zeaxanthin) and 15 mg vitamin E or placebo for 24 months in a double-blind, placebo-controlled, randomised clinical trial.

RESULTS

Following 24-month supplementation, individuals in the active group (n = 30; aged 69.03 ± 4.41 years; 56.7% female) recorded significantly fewer errors in working memory tasks than individuals receiving placebo (n = 30; aged 69.77 ± 3.74 years; 70% female) (point estimate effect sizes ranged 0.090-0.105). Interestingly, as the cognitive load of the working memory tasks increased, the active group outperformed the placebo group. Statistically significant improvements in tissue carotenoid concentrations, serum xanthophyll carotenoid concentrations and plasma ω-3FA concentrations were also observed in the active group versus placebo (point estimate effect sizes ranged 0.078-0.589). Moreover, the magnitude of change of carotenoid concentrations in tissue, and ω-3FA and carotenoid concentrations in blood were related to the magnitude of change in working memory performance.

CONCLUSION

These results support a biologically plausible rationale whereby these nutrients work synergistically, and in a dose-dependent manner, to improve working memory in cognitively healthy older adults. Increasing nutritional intake of carotenoids and ω-3FAs may prove beneficial in reducing cognitive decline and dementia risk in later life.

STUDY ID NUMBER

ISRCTN10431469; https://doi.org/10.1186/ISRCTN10431469.

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

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.

Early Pediatric Benefit of Lutein for Maturing Eyes and Brain-An Overview

Lutein is a dietary carotenoid preferentially accumulated in the eye and the brain in early life and throughout the life span. Lutein accumulation in areas of high metabolism and oxidative stress such as the eye and the brain suggest a unique role of this ingredient during the development and maturation of these organs of common embryological origin. Lutein is naturally provided to the developing baby via the cord blood, breast milk and then infant diet. The presence of this carotenoid depends on fruit and vegetable intakes and its bioavailability is higher in breastmilk. This paper aims to review the anatomical development of the eye and the brain, explore the presence and selective deposition of lutein in these organs during pregnancy and infancy and, based on its functional characteristics, present the latest available research on the beneficial role of lutein in the pediatric population. The potential effects of lutein in ameliorating conditions associated with increase oxidative stress such as in prematurity will be also addressed. Since consumption of lutein rich foods falls short of government guidelines and in most region of the world infant formulas lack this bioactive, dietary recommendations for pregnant and breastfeeding women and their child can help to bridge the gap.

Night Vision and Carotenoids (NVC): A Randomized Placebo Controlled Clinical Trial on Effects of Carotenoid Supplementation on Night Vision in Older Adults

Twilight and low luminance levels are visually challenging environments for the elderly, especially when driving at night. Carotenoid rich diets are known to increase macular pigment optical density (MPOD), which in turn leads to an improvement in visual function. It is not known whether augmenting MPOD can lead to a decrease in vision related night driving difficulties. Additionally, it is unknown if carotenoid supplementation provides additional measurable benefits to one's useful field of view (UFOV) along with a decreased composite crash risk score. The aim of the study was to evaluate changes in night vision function and UFOV in individuals that took carotenoid vitamin supplements for a six-month period compared to a placebo group.

METHODS

A prospective, randomized, double-blind, six-month trial of a 14 mg zeaxanthin/7 mg lutein-based supplement was carried out. Participants were randomized into active or placebo group (approx 2:1).

RESULTS

n = 33 participants (26 males/7 females) participated with 93% capsule intake compliance in the supplemented group (n = 24) and placebo group (n = 9). MPOD (mean/standard error SE) in the active group increased in the Right eye from 0.35 density units (du)/0.04 SE to 0.41 du/0.05 SE; p < 0.001 and in the Left eye from 0.35 du/0.05 SE to 0.37 du, p > 0.05). The supplemented group showed significant improvements in contrast sensitivity with glare in both eyes with improvements in LogMAR scores of 0.147 and 0.149, respectively (p = 0.02 and 0.01, respectively), monocularly tested glare recovery time improved 2.76 and 2.54 s, respectively, (p = 0.008 and p = 0.02), and we also noted a decreased preferred luminance required to complete visual tasks (p = 0.02 and 0.03). Improvements in UFOV scores of divided attention (p < 0.001) and improved composite crash risk score (p = 0.004) were seen in the supplemented group. The placebo group remained unchanged.

CONCLUSIONS

The NVC demonstrates that augmenting MPOD in individuals with difficulty in night vision showed measurable benefits in numerous visual functions that are important for night vision driving in this small sample RCT. Additionally, we observed an improvement in UFOV divided attention test scores and decreased composite risk scores.

Single Nucleotide Polymorphisms in CD36 Are Associated with Macular Pigment among Children

BACKGROUND

High macular pigment optical density (MPOD) has been associated with improved eye health and better cognitive functions. Genetic variations have been associated with MPOD in adults. However, these associations between genetic variations and MPOD have not been studied in children.

OBJECTIVES

This was a secondary analysis of the FK2 (Fitness Improves Thinking in Kids 2) trial (n = 134, 41% male). The aim was to determine differences in MPOD among children (aged 7-9 y) based on genetic variants that either are biologically relevant to lutein (L) and zeaxanthin (Z) accumulation or have been associated with MPOD in adults.

METHODS

MPOD was measured using customized heterochromatic flicker photometry via a macular densitometer. DXA was used to assess whole-body and visceral adiposity. DNA was extracted from saliva samples and was genotyped for 26 hypothesis-driven single nucleotide polymorphisms and 75 ancestry-informative markers (AIMs). Habitual diet history was obtained via 3-d food logs completed by parents (n = 88). General linear models were used to compare MPOD between different genotypes. Principal component analysis was performed for the AIMs to account for ethnic heterogeneity.

RESULTS

Children carrying ≥1 minor allele on β-carotene-15,15'-monooxygenase (BCO1)-rs7501331 (T allele) (P = 0.045), cluster of differentiation 36(CD36)-rs1527483 (T allele) (P = 0.038), or CD36-rs3173798 (C allele) (P = 0.001) had significantly lower MPOD (range: 14.1%-26.4%) than those who were homozygotes for the major alleles. MPOD differences based on CD36-rs3173798 genotypes persisted after adjustment for dietary L and Z intake.

CONCLUSIONS

The findings indicate that genetic variations of CD36 and BCO1 contribute to MPOD in children. The influence of genetic variation in CD36-rs3173798 persisted after adjusting for variation in dietary intake.This trial was registered at clinicaltrials.gov as NCT01619826.

Macular Pigment Reflectometry: Developing Clinical Protocols, Comparison with Heterochromatic Flicker Photometry and Individual Carotenoid Levels

The study was designed to: (1) Analyze and create protocols of obtaining measurements using the Macular Pigment Reflectometry (MPR). (2) To assess the agreement of MPOD measurements obtained using the heterochromatic flicker photometry (MPS II) and MPR. (3) To obtain the lutein and zeaxanthin optical density obtained using the MPR in the central one-degree of the macula. The measurements were performed using the MPR and heterochromatic flicker photometry. The MPR measurements were performed twice without pupillary dilation and twice following pupillary dilation. The MPR measurements were performed for a 40-s period and the spectrometer signal was parsed at different time points: 10–20, 10–30, 10–40, 20–30, 20–40, and 30–40 s. The MPR analyzes the high-resolution spectrometer signal and calculates MPOD, lutein optical density and zeaxanthin optical density automatically. The MPR-MPOD data was compared with MPPS II-MPOD results. The MPR-MPOD values are highly correlated and in good agreement with the MPS II-MPOD. Of the various parsing of the data, the data 10–30 interval was the best at obtaining the MPOD, lutein, and zeaxanthin values (8–12% coefficient of repeatability). The lutein to zeaxanthin ratio in the central one-degree of the macula was 1:2.40. Dilation was not needed to obtain the MPOD values but provided better repeatability of lutein and zeaxanthin optical density. MPR generates MPOD measurements that is in good agreement with MPS II. The device can produce lutein and zeaxanthin optical density which is not available from other clinical devices.

Environmental and Nutritional Determinants of Macular Pigment in a Mexican Population

Purpose

The carotenoids lutein (L), zeaxanthin (Z), and meso-zeaxanthin deposit at the macula as macular pigment (MP) and provide visual benefits and protection against macular diseases. The present study investigated MP, its nutritional and environmental determinants, and its constituent carotenoids in serum from a Mexican sample, in healthy participants and with metabolic diseases. Additionally, we compared these variables with an Irish sample.

Methods

MP was measured in 215 subjects from a rural community in Mexico with dual-wavelength autofluorescence imaging reported as MP optical volume (MPOV). Dietary intake and serum concentrations of L and Z were evaluated.

Results

The mean MPOV was 8429 (95% confidence interval, 8060-8797); range. 1171-15,976. The mean L and Z serum concentrations were 0.25 ± 0.15 µmol/L and 0.09 ± 0.04 µmol/L, respectively. The MPOV was positively correlated with L and Z serum concentrations (r = 0.347; P < 0.001 and r = 0.311; P < 0.001, respectively), but not with L + Z dietary estimates. Subjects with daily sunlight exposure of more than 50% were found to have significantly higher MPOV than those with less than 50% (P = 0.005). MPOV and serum concentrations of L and Z were significantly higher in the Mexican sample compared with the Irish sample, but this difference was not reflected in dietary analysis.

Conclusions

These new data from a Mexican sample provide evidence of the multifactorial interactions and environmental determinants of MP such as sunlight exposure and dietary patterns. These findings will be essential for future studies in Mexico for eye health, visual function, and ocular pathology.

Carotenoid-Rich Brain Nutrient Pattern Is Positively Correlated With Higher Cognition and Lower Depression in the Oldest Old With No Dementia

Background: Healthy dietary patterns are related to better cognitive health in aging populations. While levels of individual nutrients in neural tissues are individually associated with cognitive function, the investigation of nutrient patterns in human brain tissue has not been conducted. Methods: Brain tissues were acquired from frontal and temporal cortices of 47 centenarians from the Georgia Centenarian Study. Fat-soluble nutrients (carotenoids, vitamins A, E, K, and fatty acids [FA]) were measured and averaged from the two brain regions. Nutrient patterns were constructed using principal component analysis. Cognitive composite scores were constructed from cognitive assessment from the time point closest to death. Dementia status was rated by Global Deterioration Scale (GDS). Pearson's correlation coefficients between NP scores and cognitive composite scores were calculated controlling for sex, education, hypertension, diabetes, and APOE ε4 allele. Result: Among non-demented subjects (GDS = 1-3, n = 23), a nutrient pattern higher in carotenoids was consistently associated with better performance on global cognition (r = 0.38, p = 0.070), memory (r = 0.38, p = 0.073), language (r = 0.42, p = 0.046), and lower depression (r = -0.40, p = 0.090). The findings were confirmed with univariate analysis. Conclusion: Both multivariate and univariate analyses demonstrate that brain nutrient pattern explained mainly by carotenoid concentrations is correlated with cognitive function among subjects who had no dementia. Investigation of their synergistic roles on the prevention of age-related cognitive impairment remains to be performed.

Lutein Has a Positive Impact on Brain Health in Healthy Older Adults: A Systematic Review of Randomized Controlled Trials and Cohort Studies

A previous systematic review revealed that lutein intake leads to improved cognitive function among older adults. However, the association between lutein intake and brain health remains unclear.

METHODS

We searched the Web of Science, PubMed, PsycInfo, and Cochrane Library for research papers. The criteria were (1) an intervention study using oral lutein intake or a cross-sectional study that examined lutein levels and the brain, (2) participants were older adults, and (3) brain activities or structures were measured using a brain imaging technique (magnetic resonance imaging (MRI) or electroencephalography (EEG)).

RESULTS

Seven studies using MRI (brain activities during rest, cognitive tasks, and brain structure) and two studies using EEG were included. We mainly focused on MRI studies. Three intervention studies using MRI indicated that 10 mg lutein intake over 12 months had a positive impact on healthy older adults' brain activities during learning, resting-state connectivity, and gray matter volumes. Four cross-sectional studies using MRI suggested that lutein was positively associated with brain structure and neural efficiency during cognitive tasks.

CONCLUSION

Although only nine studies that used similar datasets were reviewed, this systematic review indicates that lutein has beneficial effects on healthy older adults' brain health.

The effects of lutein and zeaxanthin on resting state functional connectivity in older Caucasian adults: a randomized controlled trial

The carotenoids lutein (L) and zeaxanthin (Z) accumulate in retinal regions of the eye and have long been shown to benefit visual health. A growing literature suggests cognitive benefits as well, particularly in older adults. The present randomized controlled trial sought to investigate the effects of L and Z on brain function using resting state functional magnetic resonance imaging (fMRI). It was hypothesized that L and Z supplementation would (1) improve intra-network integrity of default mode network (DMN) and (2) reduce inter-network connectivity between DMN and other resting state networks. 48 community-dwelling older adults (mean age = 72 years) were randomly assigned to receive a daily L (10 mg) and Z (2 mg) supplement or a placebo for 1 year. Resting state fMRI data were acquired at baseline and post-intervention. A dictionary learning and sparse coding computational framework, based on machine learning principles, was used to investigate intervention-related changes in functional connectivity. DMN integrity was evaluated by calculating spatial overlap rate with a well-established DMN template provided in the neuroscience literature. Inter-network connectivity was evaluated via time series correlations between DMN and nine other resting state networks. Contrary to expectation, results indicated that L and Z significantly increased rather than decreased inter-network connectivity (Cohen's d = 0.89). A significant intra-network effect on DMN integrity was not observed. Rather than restoring what has been described in the available literature as a "youth-like" pattern of intrinsic brain activity, L and Z may facilitate the aging brain's capacity for compensation by enhancing integration between networks that tend to be functionally segregated earlier in the lifespan.

Role of nutraceuticals in cognition during aging and related disorders

Cognitive abilities are compromised with advancing age posing a great risk for the development of dementia and other related brain disorders. Genetic susceptibility as well as environmental exposures determine the fate of cognitive aging and its transition to pathological states. Emerging epidemiological and observational studies have revealed the importance of lifestyle factors including dietary patterns and nutritional intake in the maintenance of cognitive health and reducing the risk of neurodegenerative disorders. In this context, nutraceutical interventions have gained considerable attention in preventing age-related cognitive deficits and counteracting pathological processes. Nutraceuticals include dietary plants and derivatives, food supplements and processed foods with nutritional and pharmaceutical values. The present review highlights the importance of nutraceuticals in attenuating cognitive aging and its progression to dementia, with specific emphasis on chemical constituents, neurocognitive properties and mechanism of action.

Visual Function and Macular Carotenoid Changes in Eyes with Retinal Drusen-An Open Label Randomized Controlled Trial to Compare a Micronized Lipid-Based Carotenoid Liquid Supplementation and AREDS-2 Formula

Purpose: To compare the changes in visual and ocular parameters in individuals with retinal drusen who were treated with two commercially available nutritional supplements. Methods: An open-label, single-center, randomized, parallel-treatment with an observational control group design was utilized. The treatment groups included individuals with fine retinal drusen sub-clinical age-related macular degeneration (AMD), while the control group consisted of ocular normal individuals. The treatment groups were randomly assigned to the micronized lipid-based carotenoid supplement, Lumega-Z (LM), or the PreserVision Age-Related Eye Disease Study 2 (AREDS-2) soft gel (PV). Visual performance was evaluated using the techniques of visual acuity, dark adaptation recovery and contrast sensitivity, at baseline, three months, and six months. Additionally, the macular pigment optical density (MPOD) was measured. The control group was not assigned any carotenoid supplement. The right eye and left eye results were analyzed separately. Results: Seventy-nine participants were recruited for this study, of which 68 qualified and 56 participants had useable reliable data. Of the individuals who completed this study, 25 participants belonged to the LM group, 16 belonged to the PV group, and 15 to the control group. The LM group demonstrated statistically significant improvements in contrast sensitivity function (CSF) in both eyes at six months (p < 0.001). The LM group displayed a positive linear trend with treatment time in CSF (p < 0.001), with benefits visible after just three months of supplementation. Although there was a trend showing improvement in CSF in the PV group, the change was not significant after a Bonferroni-corrected p-value of p < 0.00625. Visual acuity, dark adaptation recovery and MPOD did not significantly improve in either treatment groups. Conclusion: The LM group demonstrated greater and faster benefits in visual performance as measured by CSF when compared to the PV group. This trial has been registered at clinicaltrials.gov (NCT03946085).

Macular Pigment Optical Density Fluctuation as a Function of Pupillary Mydriasis: Methodological Considerations for Dual-Wavelength Autofluorescence

PURPOSE OF THE STUDY

Macular pigment (MP), comprising the dietary carotenoids lutein, zeaxanthin and meso-zeaxanthin, is believed to benefit eye health and vision. Numerous clinical and research devices and techniques are currently available to facilitate MP optical density (MPOD) measurement. One of those techniques, dual-wavelength fundus autofluorescence (AF) is being increasingly used for measurement of MP in the eye. There is substantial methodological variation across the published studies that have employed this technique, including in relation to the use of mydriasis, the possible influence of which does not appear to have been addressed in the literature. This prospective cross-sectional study was designed to investigate the effect of mydriasis on MP measurement quality and MPOD values obtained with dual-wavelength AF using the Heidelberg Spectralis HRA+OCT device.

MATERIALS AND METHODS

Twenty-one healthy participants were recruited to the study. The mean age of participants was 44.8 years (± 14.63). Pupil size and MPOD were measured in one eye for each participant, initially under natural pupil conditions and subsequently 30 minutes following instillation of one drop of 0.5% tropicamide.

RESULTS

Despite providing MPOD measurements for the majority of undilated eyes (85.7% of eyes herein), pupillary dilation resulted in statistically significant changes in MPOD (p < .001 for central eccentricities). Our results indicate that the changes in MPOD were not uniform across the spatial profile. Marked improvements were also observed in image quality post-dilation (p < .002 for central eccentricities).

CONCLUSIONS

This study clearly demonstrates that dual-wavelength AF measurements of MPOD in the same eye vary as a function of pupillary dilation status, with MPOD under-estimated across the entire spatial profile of MP for natural relative to dilated pupillary conditions. Mydriasis should, therefore, be used routinely for MPOD measurements using dual wavelength AF, pupil size should be reported and image quality optimized in order to ensure accurate MPOD quantification.

Detrimental Effects of UVB on Retinal Pigment Epithelial Cells and Its Role in Age-Related Macular Degeneration

Retinal pigment epithelial (RPE) cells are an essential part of the human eye because they not only mediate and control the transfer of fluids and solutes but also protect the retina against photooxidative damage and renew photoreceptor cells through phagocytosis. However, their function necessitates cumulative exposure to the sun resulting in UV damage, which may lead to the development of age-related macular degeneration (AMD). Several studies have shown that UVB induces direct DNA damage and oxidative stress in RPE cells by increasing ROS and dysregulating endogenous antioxidants. Activation of different signaling pathways connected to inflammation, cell cycle arrest, and intrinsic apoptosis was reported as well. Besides that, essential functions like phagocytosis, osmoregulation, and water permeability of RPE cells were also affected. Although the melanin within RPE cells can act as a photoprotectant, this photoprotection decreases with age. Nevertheless, the changes in lens epithelium-derived growth factor (LEDGF) and autophagic activity or application of bioactive compounds from natural products can reverse the detrimental effect of UVB. Additionally, in vivo studies on the whole retina demonstrated that UVB irradiation induces gene and protein level dysregulation, indicating cellular stress and aberrations in the chromosome level. Morphological changes like retinal depigmentation and drusen formation were noted as well which is similar to the etiology of AMD, suggesting the connection of UVB damage with AMD. Therefore, future studies, which include mechanism studies via in vitro or in vivo and other potential bioactive compounds, should be pursued for a better understanding of the involvement of UVB in AMD.

Lutein Supplementation for Eye Diseases

Lutein is one of the few xanthophyll carotenoids that is found in high concentration in the macula of human retina. As de novo synthesis of lutein within the human body is impossible, lutein can only be obtained from diet. It is a natural substance abundant in egg yolk and dark green leafy vegetables. Many basic and clinical studies have reported lutein's anti-oxidative and anti-inflammatory properties in the eye, suggesting its beneficial effects on protection and alleviation of ocular diseases such as age-related macular degeneration, diabetic retinopathy, retinopathy of prematurity, myopia, and cataract. Most importantly, lutein is categorized as Generally Regarded as Safe (GRAS), posing minimal side-effects upon long term consumption. In this review, we will discuss the chemical structure and properties of lutein as well as its application and safety as a nutritional supplement. Finally, the effects of lutein consumption on the aforementioned eye diseases will be reviewed.

Ginger and avocado as nutraceuticals for obesity and its comorbidities

Obesity is a worldwide epidemic and is one of the factors involved in the etiology of type 2 diabetes mellitus. Obesity induces low-grade inflammation and oxidative stress. The treatment for obesity involves changes in diet, physical activity, and even medication and surgery. Currently, the use of nutraceutical compounds is associated with health benefits. Ginger and avocado are used for many people all around the world; however, its effect as a nutraceutical compound is less known by the general population. For this reason, we searched information of the literature to point its effects on distinct mechanisms of defense against the obesity its comorbidities. The present review aimed showing that these nutraceuticals may be useful in obesity treatment. Reports have shown that ginger and avocado induce antioxidant and anti-inflammatory effects by improving enzymatic activity and modulating obesity-related impairments in the anti-inflammatory system in different tissues, without side effects. Furthermore, ginger and avocado were found to be effective in reversing the harmful effects of obesity on blood lipids. In conclusion, on the basis of the positive effects of ginger and avocado in in vitro, animal, and human studies, these nutraceuticals may be useful in obesity treatment.

Correlation between Macular Pigment Optical Density and Neural Thickness and Volume of the Retina

Macular pigment (MP), which is composed of lutein/zeaxanthin/mezo-zeaxanthin, is concentrated in the central part of the retina, the macula. It protects the macula by absorbing short-wavelength light and suppressing oxidative stress. To evaluate whether MP levels are related to retinal neural protection and resulting health, we analyzed the association between the MP optical density (MPOD), and the macular thickness and volumes. Forty-three eyes of 43 healthy adult volunteers (21 men and 22 women; age: 22–48 (average 31.4 ± 1.1) years) were analyzed. Highly myopic eyes (<-6 diopters) were excluded. MPOD was measured using MPS2®, and the neural retinal thickness and volume were measured using optical coherence tomography. The mean MPOD was 0.589 ± 0.024, and it positively correlated with the central retinal thickness (P = 0.017, R = 0.360) and retinal volume of the fovea (1-mm diameter around the fovea; P = 0.029, R = 0.332), parafovea (1–3-mm diameter; P = 0.002, R = 0.458), and macula (6-mm diameter; P = 0.003, R = 0.447). In the macular area (diameter: 6 mm), MPOD was correlated with the retinal neural volume of the ganglion cell layer (P = 0.037, R = 0.320), inner plexiform layer (P = 0.029, R = 0.333), and outer nuclear layer (P = 0.020, R = 0.353). Thus, MPOD may help in estimating neural health. Further studies should determine the impact of MP levels on neuroprotection.

Lutein supplementation and retinopathy of prematurity: a meta-analysis

Background: Retinopathy of prematurity (ROP) is a multifactorial retinal disorder characterized by an abnormal vascular development of the retina of the preterm infants. Carotenoids are natural pigments that are synthesized by all plants and some microorganisms where they play a role in photoprotection and coloration. Lutein and zeaxanthin (L/Z) are two carotenoids identified as the major components of the macular pigment. Recently it has been suggested that lutein and its isomer zeaxanthin may act as antioxidant agents and that they may prevent ROP.Objective: The primary objective of this study is to assess the safety and effectiveness of oral lutein in the prevention of retinopathy of prematurity in preterm neonates.Study design: We conducted a systematic search for randomized or quasi-randomized controlled trials without any language or publication year restriction. The studies have to recruit preterm neonates ≤32 completed weeks of gestation and to compare the administration of oral L/Z at any dosage or duration, versus placebo in order to prevent ROP.Result: Data from three RCT with a total of 406 participants failed to show any reduction in ROP incidence nor the risk of BPD, sepsis, NEC and mortality. It may reduce the number of transfusions but this result has to be assessed in a separate ad hoc trial.

Serum Carotenoids, Tocopherols, Total n-3 Polyunsaturated Fatty Acids, and n-6/n-3 Polyunsaturated Fatty Acid Ratio Reflect Brain Concentrations in a Cohort of Centenarians

Investigating the role of nutrition on cognitive health is challenging. Human brain tissue is inaccessible in living humans and is often limited in deceased individuals. Therefore, biomarkers of brain nutrient levels are of interest. The objective of this study was to characterize the relationships between levels of fat-soluble nutrients in serum and matched brain tissues from the frontal and temporal cortices of participants in the Georgia Centenarian Study (n = 47). After adjusting for sex, race, cognitive status (Global Deterioration Scale), body mass index, and presence of hypertension and/or diabetes, there was a significant relationship (p < 0.05) between serum and brain levels of carotenoids (lutein, zeaxanthin, cryptoxanthin, β-carotene), α-, γ-tocopherols, total n-3 polyunsaturated fatty acids (PUFAs), and n-6/n-3 PUFA ratio. The relationship between serum and brain total n-6 PUFAs was inconsistent among the two brain regions. No significant relationship was identified between serum and brain retinol, total saturated fatty acid, total monounsaturated fatty acid, and trans-fatty acid levels. These findings suggest that serum carotenoids, tocopherols, total n-3 PUFAs, and n-6/n-3 PUFA ratio reflect levels in brain and can be used as surrogate biomarkers in older population.

Standardizing the Assessment of Macular Pigment Using a Dual-Wavelength Autofluorescence Technique

PURPOSE

It is essential to have an appropriate measure to assess macular pigment (MP) that can provide an accurate, valid, and reliable representation of the MP within the macula. The aim of this study was to describe and introduce MP optical volume (MPOV) as an optimal value for reporting MP.

METHODS

Three hundred ninety-three subjects were analyzed using the Heidelberg Spectralis with the investigational MP optical density (MPOD) module to measure MPOV and MPOD at four foveal eccentricities (0.23°, 0.51°, 0.98°, 1.76° [7° as reference point]). Lutein (L) and zeaxanthin (Z) dietary intake and serum concentrations were evaluated.

RESULTS

MPOV mean was 5094 (95%CI, 4877-5310); range: 527 to 10,652. MPOV was inversely correlated with body mass index and positively correlated with education (r = -0.156, P = 0.002 and r = 0.124, P = 0.014, respectively). Serum concentrations of L and Z were positively correlated with MPOV (r = 0.422, P < 0.001 and r = 0.285, P < 0.001, respectively). MPOV was positively correlated to MPOD at all measured eccentricities, with the strongest agreement at 1.76° (r = 0.906, P < 0.001). Serum concentrations of L and Z, BMI, education, and age (P < 0.001) were found to be significant predictors of MPOV.

CONCLUSIONS

The Spectralis MPOV measurement provided a comprehensive and detailed evaluation of the MP profile. The Spectralis MPOV should be considered a preferred metric for the assessment of MP.

TRANSLATIONAL RELEVANCE

Applying a standardized method for the assessment and report of MP will allow to fully derive meaning from observational studies and to successfully implement this MP measurement technique in research and clinical settings.

Effects of macular xanthophyll supplementation on brain-derived neurotrophic factor, pro-inflammatory cytokines, and cognitive performance

PURPOSE

Oxidative and inflammatory processes play a major role in stress-induced neural atrophy. There is a wide body of literature linking oxidative and inflammatory stress with reductions in neurotrophic factors, stress resilience, and cognitive function. Based on their antioxidant and anti-inflammatory capacity, we investigated the effect of the dietary carotenoids lutein and zeaxanthin, along with the zeaxanthin isomer meso-zeaxanthin (collectively the "macular xanthophylls" [MXans]) on systemic brain-derived neurotrophic factor (BDNF) and anti-oxidant capacity (AOC), and the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β. To investigate higher-order effects, we assessed cognitive performance.

METHODS

59 young (18-25 yrs.), healthy subjects participated in a 6-month, double-blind, placebo-controlled trial to evaluate the effects of MXan supplementation on the aforementioned serum parameters and cognitive performance. Subjects were randomly assigned to one of three groups: placebo, 13 mg, or 27 mg/day total MXans; all measures were taken at baseline and 6 months. Blood was obtained via fasting blood draw, and MXan concentration in the retina (termed macular pigment optical density [MPOD]) was measured via customized heterochromatic flicker photometry. Serum BDNF and cytokines were assessed via ELISA. Serum antioxidant capacity (AOC) and serum MXan concentrations were quantified via colorimetric microplate assay, and high-performance liquid chromatography, respectively. Cognitive performance was measured via a computer-based assessment tool (CNS Vital Signs).

RESULTS

BDNF, MPOD, serum MXans, and AOC all increased significantly versus placebo in both treatment groups over the 6-month study period (p < .05 for all). IL-1β decreased significantly versus placebo in both treatment groups (p = .0036 and p = .006, respectively). For cognitive measures, scores for composite memory, verbal memory, sustained attention, psychomotor speed, and processing speed all improved significantly in treatment groups (p < .05 for all) and remained unchanged in the placebo group. Several measures were found to be significantly associated in terms of relational changes over the course of the study. Notably, change in BDNF was related to change in IL-1β (r = -0.47; p < .001) and MPOD (r = 0.44; p = .0086). Additionally, changes in serum MXans were strongly related to AOC (r = 0.79 & 0.61 for lutein and zeaxanthin isomers respectively; p < .001). For cognitive scores, change in BDNF was correlated to change in composite memory (r = 0.32; p = .014) and verbal memory (r = 0.35; p = .007), whereas change in MPOD was correlated with change in both psychomotor speed (r = 0.38; p = .003), and processing speed (r = 0.35; p = .007). Change in serum lutein was found to be significantly correlated to change in verbal memory (r = 0.41; p < .001), composite memory (r = 0.31; p = .009), and sustained attention (r = 0.28; p = .036). Change in serum zeaxanthin isomers was significantly correlated with change in verbal memory (r = 0.33; p = .017). Lastly, change in AOC was significantly associated with verbal memory (r = 0.34; p = .021), composite memory (r = 0.29; p = .03), and sustained attention (r = 0.35; p = .016). No significant relational changes in any cognitive parameter were found for the placebo group.

CONCLUSIONS

Six months of daily supplementation with at least 13 mg of MXans significantly reduces serum IL-1β, significantly increases serum MXans, BDNF, MPOD, and AOC, and improves several parameters of cognitive performance. Findings suggest that increased systemic antioxidant/anti-inflammatory capacity (and not necessarily deposition of the carotenoids in neural tissues), may explain many of the effects determined in this study. The significant relationship between change in BDNF and IL-1β over the course of the study suggests that regular consumption of MXans interrupts the inflammatory cascade that can lead to reduction of BDNF. Changes in MPOD and BDNF appear to account for enhancement in cognitive parameters that involve speed of processing and complex processing, respectively. ISRCTN Clinical Trial Registration: ISRCTN16156382.

Nutritional Intervention to Prevent Alzheimer's Disease: Potential Benefits of Xanthophyll Carotenoids and Omega-3 Fatty Acids Combined

BACKGROUND

A growing body of scientific evidence suggests that enrichment of certain nutritional compounds in the brain may reduce the risk of Alzheimer's disease (AD).

OBJECTIVE

To investigate the impact of supplemental xanthophyll carotenoids plus omega-3 fatty acids on disease progression in patients with AD.

METHODS

Three trial experiments were performed. In Trials 1 and 2 (performed on patients with AD over an 18-month period), 12 patients (AD status at baseline: 4 mild and 8 moderate) were supplemented with a xanthophyll carotenoid only formulation (Formulation 1; lutein:meso-zeaxanthin:zeaxanthin 10:10:2 mg/day) and 13 patients (AD status at baseline: 2 mild, 10 moderate, and 1 severe) were supplemented with a xanthophyll carotenoid and fish oil combination (Formulation 2; lutein:meso-zeaxanthin:zeaxanthin 10:10:2 mg/day plus 1 g/day of fish oil containing 430 mg docohexaenoic acid [DHA] and 90 mg eicopentaenoic acid [EPA]), respectively. In Trial 3, 15 subjects free of AD (the control group) were supplemented for 6 months with Formulation 1. Blood xanthophyll carotenoid response was measured in all trials by HPLC. Omega-3 fatty acids were profiled by direct infusion mass spectrometry.

RESULTS

Xanthophyll carotenoid concentration increases were significantly greater for Formulation 2 compared to Formulation 1 (p < 0.05), and progression of AD was less for this group (p = 0.003), with carers reporting functional benefits in memory, sight, and mood.

CONCLUSION

This preliminary report suggests positive outcomes for patients with AD who consumed a combination of xanthophyll carotenoids plus fish oil, but further study is required to confirm this important observation.

Lutein across the Lifespan: From Childhood Cognitive Performance to the Aging Eye and Brain

Lutein is a non-provitamin A dietary carotenoid found in dark green leafy vegetables, corn, eggs, and avocados. Among the carotenoids, lutein and its isomer, zeaxanthin, are the only 2 that cross the blood-retina barrier to form macular pigment in the retina. Lutein also preferentially accumulates in the human brain across multiple life stages. A variety of scientific evidence supports a role for lutein in visual as well as cognitive function across the lifespan. The purpose of this review is to summarize the latest science on lutein's role in the eye and the brain across different ages.

Dietary Carotenoids Lutein and Zeaxanthin Change Brain Activation in Older Adult Participants: A Randomized, Double-Masked, Placebo-Controlled Trial

SCOPE

Steady-state visual evoked potentials (SSVEP) can be used to test the topological response of cortical neurons. Studies have shown that a lutein (L) preferentially accumulates within cortical tissue. L, zeaxanthin (Z), and their isomers can be measured directly in retina (macular pigment optical density, MPOD), and retinal L+Z correlate highly with L+Z levels in cortical visual processing areas. The purpose of this study was to determine the relation between MPOD and SSVEP signal power, cross-sectionally and after supplementation with L+Z.

METHODS AND RESULTS

SSVEP to three different driving frequencies of stimulation (5, 10, and 16.6 Hz) were obtained for community-dwelling older adults, at baseline and after 12 months of supplementation with either 12 mg L+Z or placebo. Power was quantified at the driving frequencies. Non-specific activation was quantified within the 10-15 Hz band. MPOD was measured psychophysically. Subjects with low MPOD had reduced power at 16.6 Hz and reduced non-specific activation, compared with subjects with high MPOD. Supplementation significantly improved signal power at 5 and 10 Hz.

CONCLUSION

Past research suggests that L+Z can improve visual memory, visual processing speeds, etc. One possible mechanism for that improvement may be improving signal-to-noise ratio throughout the vision system.

Lutein and zeaxanthin: The possible contribution, mechanisms of action and implications of modern dietary intake for cognitive development in children

Background:Studies suggest that lutein and zeaxanthin may be important for cognitive development in children, but a comprehensive evidence synthesis is lacking. The purpose of this evidence synthesis was to analyse the available data regarding the role of lutein and zeaxanthin for cognition in children and propose a theoretical basis for future studies.Methods:The PubMed, Scopus, the ISRCTN registry and Cochrane Library databases were searched for studies that evaluated the relationship between lutein and zeaxanthin and cognitive function in children. Reference list and ancestry searches were performed on relevant articles. A total of 543 articles were identified, of which six cross-sectional studies were included.Results:The literature search revealed that the evidence concerning the effect of lutein and zeaxanthin on cognition in children is sparse. However, there is some preliminary evidence indicating a positive association between lutein and zeaxanthin and cognition in childhood.Conclusions:The cross-sectional nature of the few studies available and the lack of RCT data indicates a need for further investigation before any firm conclusions can be drawn.

Neural Activation During Visual Attention Differs in Individuals with High versus Low Macular Pigment Density

SCOPE

The neural efficiency hypothesis for lutein (L) and zeaxanthin (Z) suggests that higher levels of L+Z in the central nervous system (CNS) are predictive of stronger stimulus-specific brain responses. Past research suggests that supplementing L+Z can improve neural processing speed and cognitive function across multiple domains, which supports this hypothesis. The purpose of this study is to determine the extent to which CNS L+Z levels predict brain responses using an attentionally taxing task.

METHODS AND RESULTS

Macular pigment optical density (MPOD) is measured at baseline in 85 participants ranging in age from 18-92 years. Brain activation is measured using dense array electroencephalography. Stimuli evoking the signal include a grating array of vertical bars, oscillating at four driving frequencies. Significant stimulus-specific interactions are detected between attend condition, location, and age (p < .002) for unattended image locations, and between age and location (p < .008) for attended locations. Although no differences are found across age by MPOD, this measure is found to be predictive of neural power at parafoveal bar locations (R² .080).

CONCLUSION

CNS L+Z status is related to differences in brain activation in conditions designed to stress visual attention. These differences are strongest for older subjects.

The Role of Nutrition for the Aging Population: Implications for Cognition and Alzheimer's Disease

Improved life expectancy worldwide has resulted in a significant increase in age-related diseases. Dementia is one of the fastest growing age-related diseases, with 75 million adults globally projected to develop the condition by 2030. Alzheimer's disease (AD) is the most common form of dementia and represents the most significant stage of cognitive decline. With no cure identified to date for AD, focus is being placed on preventative strategies to slow progression, minimize the burden of neurological disease, and promote healthy aging. Accumulating evidence suggests that nutrition (e.g., via fruit, vegetables, fish) is important for optimizing cognition and reducing risk of AD. This review examines the role of nutrition on cognition and AD, with specific emphasis on the Mediterranean diet (MeDi) and key nutritional components of the MeDi, namely xanthophyll carotenoids and omega-3 fatty acids. Given their selective presence in the brain and their ability to attenuate proposed mechanisms involved in AD pathogenesis (namely oxidative damage and inflammation), these nutritional compounds offer potential for optimizing cognition and reducing the risk of AD.

Lutein and Zeaxanthin Isomers Reduce Photoreceptor Degeneration in the Pde6b rd10 Mouse Model of Retinitis Pigmentosa

PURPOSE

Lutein, RR-zeaxanthin, and RS-zeaxanthin (L-Z) are antioxidants which can reduce endoplasmic reticulum stress (ERS) and oxidative stress (OS), and ameliorate neurodegenerative diseases. However, their treatment effect in the Pde6b rd10 (rd10) mouse model of retinitis pigmentosa (RP) and the underlying cellular mechanisms have not been studied. ERS is an important factor which causes photoreceptor apoptosis. The aim of the current project is to test the treatment effect of L-Z in rd10 mice and to investigate the underlying molecular mechanisms of ERS.

METHODS

L-Z (Lutemax 2020, 10 mg/kg) diluted in sunflower oil (SFO, 1 mg/ml) or the same volume of SFO was administrated via gavage from postnatal day 6 (P6) to P20 daily in L-Z group (n=5) or SFO group (n=6) of rd10 mice. At P21, electroretinography (ERG) was performed to show the functional change of retinas. 78 kDa glucose-regulated protein (GRP78) and endoplasmic reticulum protein 29 (ERp29) were tested by western blot and immunostaining.

RESULTS

The ERG amplitudes were larger in the L-Z group than those of the SFO group in all flash luminances of dark-adapted and light-adapted ERG (all p < 0.01). Western blot revealed that GRP78 in the retinas of the L-Z group was significantly downregulated compared to that of the SFO group (p < 0.01). Meanwhile, the retinal ERp29 protein was significantly upregulated in the L-Z treatment group than that of the SFO group (p < 0.01).

CONCLUSIONS

L-Z provide protection to the photoreceptors of rd10 mouse model of RP, which is probably associated with the reduction of ERS.

Relationships of carotenoid-related gene expression and serum cholesterol and lipoprotein levels to retina and brain lutein deposition in infant rhesus macaques following 6 months of breastfeeding or formula feeding

The purpose of this study was to investigate if the enhanced bioaccumulation of lutein in retina and brain of breastfed, compared to formula-fed, infant monkeys was associated with higher levels of serum total and HDL cholesterol, apolipoproteins, or mRNA/protein expression of carotenoid-related genes. Newborn rhesus macaques were either breastfed, fed a carotenoid-supplemented formula, or fed an unsupplemented formula for 6 months (n = 8, 8, 7). Real-time qPCR and western blotting were performed in two brain regions (occipital cortex and cerebellum) and two retina regions (macular and peripheral retina). Breastfed infants had higher serum total cholesterol, HDL cholesterol, apoA-I, and apoB-100 levels than the combined formula-fed groups (P < 0.05). Breast milk or infant formulas did not alter expression of the nine genes (CD36, SCARB1, SCARB2, LDLR, STARD3, GSTP1, BCO1, BCO2, RPE65) examined except for SCARB2 in the retina and brain regions. In conclusion, dietary regimen did not impact the expression of carotenoid-related genes except for SCARB2. However, carotenoid-related genes were differentially expressed across brain and retina regions. Breastfed infants had higher serum total and HDL cholesterol, and apolipoproteins, suggesting that lipoprotein levels might be important for delivering lutein to tissues, especially the macular retina, during infancy.

Intrinsic and Extrinsic Factors Impacting Absorption, Metabolism, and Health Effects of Dietary Carotenoids

Carotenoids are orange, yellow, and red lipophilic pigments present in many fruit and vegetables, as well as other food groups. Some carotenoids contribute to vitamin A requirements. The consumption and blood concentrations of specific carotenoids have been associated with reduced risks of a number of chronic conditions. However, the interpretation of large, population-based observational and prospective clinical trials is often complicated by the many extrinsic and intrinsic factors that affect the physiologic response to carotenoids. Extrinsic factors affecting carotenoid bioavailability include food-based factors, such as co-consumed lipid, food processing, and molecular structure, as well as environmental factors, such as interactions with prescription drugs, smoking, or alcohol consumption. Intrinsic, physiologic factors associated with blood and tissue carotenoid concentrations include age, body composition, hormonal fluctuations, and variation in genes associated with carotenoid absorption and metabolism. To most effectively investigate carotenoid bioactivity and to utilize blood or tissue carotenoid concentrations as biomarkers of intake, investigators should either experimentally or statistically control for confounding variables affecting the bioavailability, tissue distribution, and metabolism of carotene and xanthophyll species. Although much remains to be investigated, recent advances have highlighted that lipid co-consumption, baseline vitamin A status, smoking, body mass and body fat distribution, and genetics are relevant covariates for interpreting blood serum or plasma carotenoid responses. These and other intrinsic and extrinsic factors are discussed, highlighting remaining gaps in knowledge and opportunities for future research. To provide context, we review the state of knowledge with regard to the prominent health effects of carotenoids.

Lutein and Zeaxanthin Isomers Protect against Light-Induced Retinopathy via Decreasing Oxidative and Endoplasmic Reticulum Stress in BALB/cJ Mice

Oxidative stress (OS) and endoplasmic reticulum stress (ERS) are the major factors underlying photoreceptor degeneration. Lutein, RR-zeaxanthin (3R,3’R-zeaxanthin) and RS (meso)-zeaxanthin (3R,3’S-RS- zeaxanthin) (L/Zi) could protect against cell damage by ameliorating OS in retina. In this study, we examined the effect of L/Zi supplementation in a mouse model of photoreceptor degeneration and investigated whether the treatment of L/Zi ameliorated OS and ERS. BALB/cJ mice after light exposure were used as the animal model. The protective effects of L/Zi were observed by electroretinography (ERG) and terminal deoxyuridine triphosphate nick-end labeling (TUNEL) analysis. The underlying mechanisms related to OS and ERS were explored by Western blotting. After L/Zi treatment, the ERG amplitudes were significantly higher, and the number of TUNEL-positive cells was significantly reduced compared to that of the vehicle group. Western blotting results revealed that OS was ameliorated according to the significant downregulation of phosphorylated c-Jun N-terminal kinase (p-JNK), and significant upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, ERS was reduced according to the significant downregulation of 78 kDa glucose-regulated protein (GRP78), phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (p-PERK), activating transcription factor 4 (ATF4) and activating transcription factor (ATF6). Our data shows that L/Zi provided functional and morphological preservation of photoreceptors against light damage, which is probably related to its mitigation of oxidative and endoplasmic reticulum stress.

Lutein, zeaxanthin and mammalian development: Metabolism, functions and implications for health

It is now widely accepted that nutrition during critical periods in early development, both pre- and postnatal, may have lifetime consequences in determining health or onset of major diseases in the adult life. Dietary carotenoids have shown beneficial health effects throughout the life cycle due to their potential antioxidant properties, their ability to serves as precursors of vitamin A and to the emerging signaling functions of their metabolites. The non-provitamin A carotenoids lutein and zeaxanthin are emerging as important modulators of infant and child visual and cognitive development, as well as critical effectors in the prevention and treatment of morbidity associated with premature births. This review provides a general overview of lutein and zeaxanthin metabolism in mammalian tissues and highlights the major advancements and remaining gaps in knowledge in regards to their metabolism and health effects during pre- and early post-natal development. Furthering our knowledge in this area of research will impact dietary recommendation and supplementation strategies aimed at sustaining proper fetal and infant growth.