Effect of Long-Term Xanthophyll and Anthocyanin Supplementation on Lutein and Zeaxanthin Serum Concentrations and Macular Pigment Optical Density in Postmenopausal Women

Differential Performance of Xanthophylls in Combination with Phenol Classes against H2O2-Induced Oxidative Stress: An In Vitro Analysis Using Retinal Pigment Epithelial Cells

SCOPE

Xanthophylls, vital for ocular defense against blue light and reactive oxygen species, are prone to oxidative degradation; however, they may be regenerated antioxidant-rich plant phenols. Despite certain in vitro evidence, clinical studies show inconsistent findings and this may be due to varying phenolic reduction potentials. Therefore, the current study aims to investigate the ocular protective effect of various plant phenols combined with xanthophyll.

METHODS AND RESULTS

Human retinal pigment epithelial cells (ARPE-19) are subjected to oxidative stress induced by hydrogen peroxide (H2O2) after xanthophyll and phenol pretreatment. Assessments include xanthophyll uptake, total antioxidant capacity, cell viability, intracellular reactive oxygen species levels, apoptosis, phagocytosis, and vascular endothelial growth factor formation. The study finds that while the combination of lutein with phenols does not show significant protective effects compared to lutein-only, zeaxanthin combined with phenols exhibits enhanced protection compared to both the zeaxanthin-only and control groups.

CONCLUSION

The research reveals the complex relationship between xanthophylls and phenols, suggesting that the advantageous effects of their combination might vary among different xanthophylls. Caution is necessary when applying molecular theories to ocular health, and this necessitates further research, serving as a basis for proposing clinical trials to evaluate the efficacy of specific xanthophyll and phenol combinations.

Effect of xanthophyll-rich food and supplement intake on visual outcomes in healthy adults and those with eye disease: a systematic review, meta-analysis, and meta-regression of randomized controlled trials

CONTEXT

Xanthophyll intake is known to improve eye health; however, its benefits on visual outcomes have not been systematically studied, particularly in a population with eye diseases.

OBJECTIVE

A systematic review, meta-analysis, and meta-regression were conducted to investigate the effect of xanthophyll intake on visual outcomes, and further subgroup analysis was performed on the basis of eye disease status.

DATA SOURCES

The PubMed, Scopus, Embase, CINAHL, Cochrane, and Web of Science databases were searched, and relevant randomized controlled trials were identified.

DATA EXTRACTION

For systematic review, meta-analysis, and meta-regression, 43, 25, and 21 articles were selected, respectively.

DATA ANALYSIS

Xanthophyll intake enhanced macular pigment optical density (MPOD) for both heterochromatic flicker photometry (weighted mean difference [WMD], 0.05; 95% confidence interval [CI], 0.03-0.07) and autofluorescence imaging (WMD, 0.08; 95%CI, 0.05-0.11) measurements and decreased photostress recovery time (WMD, -2.35; 95%CI, -4.49 to -0.20). While enhancement in visual acuity logarithm of the minimum angle of resolution was observed in response to the xanthophyll-rich food and supplement intake only for patients with eye disease (WMD, -0.04; 95%CI, -0.07 to -0.01). Meta-regression showed a positive correlation between change in MPOD (heterochromatic flicker photometry) and the corresponding change in serum lutein levels (regression coefficient = 0.068; P = 0.00).

CONCLUSION

Intake of xanthophyll-rich food or supplements can improve eye health. Additional improvement in visual acuity was observed in patients with eye disease. A positive association between MPOD and serum lutein level, while absent with dietary xanthophyll intake, suggests the importance of bioavailability when examining the effect of xanthophyll on eye health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021295337.

Xanthophyll pigments dietary supplements administration and retinal health in the context of increasing life expectancy trend

Introduction

Medicine faces nowadays the trend of increasing life expectancy of human population, with the resulting increase of degenerative age related diseases prevalence, combined with the risks of less tempered sun radiations environment exposure. Under these circumstances, our work pointed out on evaluating the effect of some xanthophyll pigments dietary supplements, actually widely recommended, for prevention of retinal degenerative damages and for slowing down the progression of such age related changes if they have already occurred. These dietary supplements are already well known for their total antioxidant activity, proven by photochemiluminescence method using Total Antioxidant Capacity in Lipid soluble-substances procedure.

Materials and methods

The study recruited a number of 120 subjects equally divided on genders. The lot included a first group of 60 patients with comparable ages (all of them over 50 years and divided in 2 segments of age: 50-60 and over 60) and suffering from comparable retinal age-related degenerative abnormalities (mild/medium severity age-related macular degeneration according to Wisconsin Age-Related Maculopathy Grading System), and a second group, considered control, including a similar number of healthy, normal retina subjects belonging to same age and gender categories. There were evaluated at baseline the eye medical status and the retinal risk by specific methods: complete eye check-up, Amsler grid, specific standardized questionnaires focused on visual function and its impact on the quality of current life. Both groups, patients and control, received similar dosages of xanthophyll pigments dietary supplements including lutein and zeaxanthin during 18 months after baseline; at the end of this supplementation period a new evaluation was conducted. In the second part of the research all subjects involved received a new dietary supplement in which the same xanthophylls were enriched with C and E vitamins and oligo-elements Zinc and Copper. At the end of three years duration supplementation, the subjects were reevaluated and the paper presents the conclusions on the matter, pointing on the impact of xanthophyll supplements on visual health.

Results

Correlation tests were applied to the complete set of data. Correlation tests have values between -1 and +1. The value -1 represents the negative correlation (reverse proportionality) meanwhile the value +1 represents the positive correlation (direct proportionality). The charts show the curves that are fitting experimental data. The dependence is linear in nature, and the value R2, as it approaches more the value 1, represents a better match with the experimental data (the data are in a percentage of approximately 99% on these straight lines of type y = ax + b). In the charts, there were noted the average values of the scores for healthy control patients with "Control", and the average values of the scores for the patients with existing age related degenerative retinal pathology at baseline with "Patients".

Discussion

The retinal function and the impact of visual condition on health were both evaluated at baseline, 18 months and 36 months after baseline, by visual acuity, ophthalmoscopy fundus examination, Amsler test and by asking the subjects to answer the visual function questionnaires: EQ-5D, NEI-VFQ-25, as measures of health status quality and of the influence on welfare. The study revealed that under supplementation both control healthy subjects and patients with known degenerative retinal pathology included in the 50-60 years of age group evolved almost the same way, leading to the conclusion that administered xanthophyll pigments-based supplements, simple or enriched, managed to slow down the progression of abnormal degenerative vision loss to a rate comparable to physiological aging-related vision loss. It was also observed that intake of xanthophyll pigments dietary supplements preserved the general health condition and maintained relatively constant vision on the entire 36th months follow-up research duration in patients presented with existing age related degenerative retinal pathology at baseline. For healthy subjects, evaluation showed an improvement in results after dietary supplementation, with maintenance of constant vision and a significantly increase of general condition, in a positive sense. For subjects over the age of 60 dietary supplements intake was even more effective compared to younger group in providing better control of degenerative processes.

The effect of lutein and Zeaxanthine on dyslipidemia: A meta-analysis study

AIMS

The relationship between circulating Lutein and zeaxanthin (L/Z) concentrations, and plasma lipoproteins has been indicated by observational studies. However, the beneficial impact of L/Z administration on dyslipidemia are unclear. This meta-analysis aimed to investigate the effect of oral intake of L/Z on circulating total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), as well as high-density lipoprotein-cholesterol (HDL-C) levels.

METHODS

We electronically assessed all eligible interventional studies through different electronic databases, including PubMed, Scopus, ISI -Web of Science, and Cochrane library until Jun 2021. After identifying the quality of each included randomized controlled trials, they were evaluated by assessing the risk-difference between treatment and control groups by pooling available data on net change of serum LDL-C, HDL-C, and Cholesterol.

RESULTS

L/Z supplementation has null effect on circulating levels of TC (WMD: -3.82 95% CI: -13.83, 6.18; I-square: 85.2%), and LDL-C (WMD: -4.54; 95% CI: -11.5, 2.48; I-square: 83.9%). In contrast, L/Z treatment could significantly increase HDL-C levels in older adults (WMD: 4.06; 95% CI: 0.64, 7.48; I-square: 50.7%).

CONCLUSION

L/Z administration could be an effective treatment for improving circulating HDL-C concentration in elderly adults.

Combination of Lutein and DHA Alleviate H2O2 Induced Cytotoxicity in PC12 Cells by Regulating the MAPK Pathway

Docosahexaenoic acid (DHA) and lutein are important nutrients for brain health. Whether there were synergistic effects of DHA and lutein on the protection against neuronal cell damage induced by oxidative stress remained unclear. The present study was designed to investigate the synergistic effects of DHA and lutein against hydrogen peroxide (H₂O₂)-induced oxidative challenge in PC12 cells. PC12 cells were divided into different groups and received H₂O₂ (80 μM), lutein (20 μM)+H₂O₂ (80 μM), DHA (25 μM)+H₂O₂ (80 μM), and lutein (20 μM)+DHA (25 μM)+H₂O₂ (80 μM), respectively. The results indicated that pre-treatment of cells with lutein, DHA and DHA+lutein could significantly antagonize the H₂O₂-mediated growth inhibition and morphological changes in PC12 cells (p<0.05). Molecularlevel studies indicated that the DHA+lutein combination can significantly inhibit the mRNA expression of AMAD10 and BAX. Furthermore, Western blot analysis demonstrated that DHA+lutein synergistically inhibits the phosphorylation of JNK1/2. The results of the present study suggest that DHA and lutein in combination may be utilized as potent antioxidative compounds, with potential preventative or palliative effects on age-related neurodegenerative diseases.

The Effect of Lutein/Zeaxanthin Intake on Human Macular Pigment Optical Density: A Systematic Review and Meta-Analysis

Lutein, zeaxanthin, and meso-zeaxanthin are the only carotenoids found in the human macula and may have a role in visual function. These carotenoids are reported to protect the retina, and thus vision, as antioxidants and by acting as a blue light filter. Our objective was to determine a minimum concentration of lutein/zeaxanthin intake that is associated with a statistically significant and/or clinically important change in macular pigment optical density (MPOD) among adults with healthy eyes. We searched Ovid MEDLINE, CENTRAL, and the Commonwealth of Agriculture Bureau for English-language studies through to July 2020. Two reviewers screened results to identify studies that evaluated supplements or dietary sources of lutein/zeaxanthin on MPOD among adults with healthy eyes. One reviewer extracted data and assessed strength of evidence, which was confirmed by a second reviewer. Two independent reviewers assessed the risk of bias. Meta-analyses were stratified by total lutein/zeaxanthin dose. We included 46 studies (N = 3189 participants; mean age = 43 y; 42% male). There was no statistically significant change in MPOD among studies evaluating <5 mg/d of total lutein/zeaxanthin intake which primarily assessed dietary interventions for 3-6 mo (pooled mean difference, 0.02; 95% CI: -0.01 to 0.05). The pooled mean increase in MPOD was 0.04 units (95% CI: 0.02 to 0.07) among studies evaluating 5 to <20 mg/d of lutein/zeaxanthin and was 0.11 units (95% CI: 0.06 to 0.16) among studies evaluating ≥20 mg/d of lutein/zeaxanthin for 3-12 mo. MPOD increased with lutein/zeaxanthin intake, particularly at higher doses, among adults with healthy eyes. The effects of lutein/zeaxanthin intake at doses <5 mg/d or from dietary sources is less clear. Increased lutein/zeaxanthin intake can help with maintaining ocular health. Future research is needed to determine the minimum dose and duration of lutein/zeaxanthin intake that is associated with a clinically important change in MPOD or visual function.

A Randomized Study of Nutritional Supplementation in Patients with Unilateral Wet Age-Related Macular Degeneration

The purpose of this study is evaluate the efficacy and safety of medicinal products containing the original Age-Related Eye Disease group (AREDS) formulation at doses approved in Europe (EU, control group; n = 59) with a product that adds DHA, lutein, zeaxanthin, resveratrol and hydroxytyrosol to the formula (intervention group; n = 50). This was a multicenter, randomized, observer-blinded trial conducted in patients aged 50 years or older diagnosed with unilateral exudative Age related Macular Degeneration AMD. At month 12, the intervention did not have a significant differential effect on visual acuity compared with the control group, with an estimated treatment difference in Early Treatment Diabetic Retinopathy Study (ETDRS) of −1.63 (95% CI −0.83 to 4.09; p = 0.192). The intervention exhibited a significant and, in most cases, relevant effect in terms of a reduction in some inflammatory cytokines and a greater improvement in the fatty acid profile and serum lutein and zeaxantin concentration. In patients with unilateral wet AMD, the addition of lutein, zeaxanthin, resveratrol, hydroxytyrosol and DHA to the AREDS EU recommended doses in the short-term did not have a differential effect on visual acuity compared to a standard AREDS EU formula but, in addition to improving the fatty acid profile and increasing carotenoid serum levels, may provide a beneficial effect in improving the proinflammatory and proangiogenic profile of patients with AMD.

Antioxidant supplements in age-related macular degeneration: are they actually beneficial?

Age-related macular degeneration (ARMD) is one of the prominent causes of central visual loss in the older age group in the urbanized, industrialized world. In recent years, many epidemiological studies and clinical trials have evaluated the role of antioxidants and micronutrients to prevent the progression of ARMD. In this article, we review some of these major studies. In addition, we review the absorption and bioavailability and possible undesirable effects of these nutrients after ingestion. The role of genotypes and inappropriate use of these supplements are also discussed. From all the above evidence, we conclude that it may not be prudent to prescribe these formulations without a proper assessment of the individual's health and dietary status. The effectiveness of all the components in antioxidant formulations is controversial. Thus, these supplements should not be prescribed just for the purpose of providing patients some kind of therapy, which may give a false sense of mental satisfaction.

Antioxidant Phytochemicals in Pulses and their Relation to Human Health: A Review

Pulses are a staple food cultivated since ancient times, which play an important role in the human diet. From a nutritional point of view, pulses are very interesting foods as they are rich in proteins, carbohydrates and dietary fibre. Dietary antioxidants are a complex mixture of hydrophilic and lipophilic compounds usually present in foods of plant origin, including pulses. In the present study, the phytochemical composition of selected pulses (common beans, fava beans, lentils, chickpeas, peas and lupins) has been reviewed in terms of their content of antioxidant compounds. The content of hydrosoluble antioxidants (organic acids, phenolic compounds), liposoluble antioxidants (tocopherols, carotenoids) and other compounds which exert antioxidant properties, such as dietary fibre and minerals (zinc, selenium), has been studied, reporting that pulses are an interesting source of these compounds, which have important health benefits, including a preventing role in cardiovascular diseases, anticarcinogenic or neuroprotective properties. It is important to take into account that pulses are not usually consumed raw, but they must be processed before consumption in order to improve their nutritional quality and their palatability, therefore, the effect of different technological and heat treatments (germination, cooking, boiling, extrusion) on the antioxidant compounds present in pulses has been also reviewed. In this regard, it has been observed that as a consequence of processing, the content of phytochemicals with antioxidant properties is usually decreased, but processed pulses maintain relevant amounts of these compounds, preserving their beneficial health effect.

Dietary β-Cryptoxanthin and α-Carotene Have Greater Apparent Bioavailability Than β-Carotene in Subjects from Countries with Different Dietary Patterns

β-carotene, α-carotene and β-cryptoxanthin are greater contributors to vitamin A intake than retinol in the human diet for most people around the world. Their contribution depends on several factors, including bioavailability and capacity of conversion into retinol. There is an increasing body of research showing that the use of retinol activity equivalents or retinol equivalents could lead to the underestimation of the contribution of β-cryptoxanthin and of α-carotene. The aim is to assess their apparent bioavailability by comparing concentrations in blood to their dietary intakes and identifying the major food contributors to their dietary intake. Dietary intake (3-day 24-h records) and serum concentrations (by HPLC) were calculated in normolipemic subjects with adequate retinol status (≥1.1 µmol/L) from our studies (n = 633) and apparent bioavailability calculated from 22 other studies (n = 29,700). Apparent bioavailability was calculated as the ratio of concentration in the blood to carotenoid intake. Apparent bioavailabilities for α-carotene and β-cryptoxanthin were compared to those for β-carotene. Eating comparable amounts of α-carotene, β-cryptoxanthin and β-carotene foods resulted in 55% greater α-carotene (95% CI 35, 90) and 686% higher β-cryptoxanthin (95% CI 556, 1016) concentrations than β-carotene in blood. This suggests differences in the apparent bioavailability of α-carotene and β-cryptoxanthin and even larger differences with β-cryptoxanthin, greater than that of β-carotene. Four fruits (tomato, orange, tangerine, red pepper) and two vegetables (carrot, spinach) are the main contributors to their dietary intake (>50%) in Europeans.

Feasibility study of a docosahexaenoic acid optimized nutraceutical formulation on the macular levels of lutein in a healthy Mediterranean population

INTRODUCTION

Macular pigment optical density plays a pivotal role in maintaining macular structure and functioning. Research shows that daily consumption of lutein reduces the risk of eye diseases such as age-related macular degeneration.

OBJECTIVE

This study analyzes the influence of a supplementation containing lutein and antioxidant vitamins either with or without docosahexaenoic acid (DHA), with the main objective of identifying macular pigment optical density (MPOD) changes in both eyes at the end of the follow-up using the Visucam® retinograph. The secondary endpoint was to determine variation in the lutein and DHA levels in plasma and red blood cell membranes respectively.

METHODS

One hundred healthy participants (200 eyes) aged 40-70 years (mean age 49.3 years, SEM=13.7) were randomized in a 1:1 ratio to receive daily one of the following supplements for 3 months: Lutein group (LT-G, n=49), Lutein /Docosahexaenoic acid group (LT/DHA-G, n= 51). The MPOD was measured at baseline and end of the follow-up by retinography (Visucam® retinograph). Lutein in plasma was determined by HPLC and DHA in red blood cell membranes was analyzed by gas chromatograph/mass spectrometer.

RESULTS

From baseline, macular pigment optical density showed significantly higher values in the Lutein/DHA group than in the Lutein group at the end of the study (p<0.0001). Significantly higher Lutein in plasma (p<0.0001) and DHA (p<0.0001) levels in the red blood cell membrane were seen in the Lutein/DHA group than in the Lutein group at the 3-month follow-up.

CONCLUSION

Lutein supplementation improves macular pigment optical density in healthy subjects from a Mediterranean population being significantly increased in the presence of DHA. Therefore, our findings highlight the relevance of the adjunctive role of DHA for a better Lutein availability.

Lack of a Synergistic Effect on Cardiometabolic and Redox Markers in a Dietary Supplementation with Anthocyanins and Xanthophylls in Postmenopausal Women

Fruits and vegetables are pivotal for a healthy diet due partly to their content in bioactive compounds. It is for this reason that we conducted a parallel study to unravel the possible effect on cardiometabolic parameters of the ingestion of anthocyanins, xanthophylls, or both groups of bioactives together in postmenopausal women. Seventy-two postmenopausal women were randomized into an 8-month parallel study: a group consuming 60 mg/day anthocyanins (Group A), a group consuming 6 mg lutein and 2 mg zeaxanthin per day (Group X), and a third group consuming a combination of anthocyanins and xanthophylls in the same amounts (Group A+X). Non-targeted metabolomic analysis was done in plasma samples at baseline and after the 8-month intervention by HPLC-QTOF-MS. Inflammatory, antioxidant, and cardiometabolic parameters were measured at the beginning of the study and after 4 and 8-months intervention. Compared with baseline values, none of the 8-month treatments significantly (p < 0.05) changed systolic or diastolic blood pressure (BP), plasma C-reactive protein, interleukin 6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, monocyte chemoattractant protein-1 or matrix metalloproteinases 2 and 9. Only plasma glucose levels were significantly decreased by treatment A+X after 8 months, and the plasma metabolomic profile was clearly affected by all three dietary supplementations after 8 months. In parallel, there was an increase, also for the three groups, in the plasma ferric reducing antioxidant power value that did not show any synergistic effect between the two groups of bioactives. Postmenopausal women could benefit from an increase in anthocyanins and xanthophylls intake, through the consumption of fruits and vegetables rich in these two types of compounds. Accordingly, plasma glucose and, above all, the reducing power in plasma, could be improved.

Nutrients for Prevention of Macular Degeneration and Eye-Related Diseases

The risk of macular degeneration can be reduced through the consumption of antioxidant-rich foods, supplements, and nutraceutical formulas. This review focuses on the antioxidants, vitamins, and minerals that have been reported for reducing the risk of macular degeneration and other eye-related diseases. Antioxidants including anthocyanins, carotenoids, flavonoids, and vitamins have been shown to reduce the risk of eye-related diseases. Anthocyanins extracted from berries are powerful antioxidants. Cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin are anthocyanin aglycones detected in berries, currants, and other colored fruits and vegetables. β-Carotene, as well as xanthophyll lutein and zeaxanthin, have been reported to reduce the risk of macular degeneration. Flavonoids from plants help in the prevention of eye-related diseases through anti-inflammatory mechanisms. A combination of these antioxidants, vitamins, and minerals possess a synergistic effect on the prevention or risk reduction of macular degeneration. Formulas have been developed as dietary supplements to cater to the high demand from consumers and patients with eye problems. Many of the formulated dietary supplements that are sold in the market have been clinically proven for their efficacy to treat eye diseases. Although the bioactivities in the supplement capsules or tablets have been scientifically established for reducing risks of several diseases, which include macular degeneration and other eye-related diseases, knowledge on the right dosage, efficacy, and bioavailability of antioxidants, vitamins, and minerals is important for consumers. The information may help them make the best decision in choosing the right dietary supplements and nutraceuticals following the evidence-based recommended dosages and reference intakes for improving general health and preventing eye-related diseases. This review covers the potential causal factors involved in eye diseases, clinically proven treatments, and controversial findings on the antioxidants in the prevention of macular degeneration. Future studies should consider multiethnic and multicenter trials for eliminating potential bias in research.