Diet and Serum Carotenoid Concentrations Affect Macular Pigment Optical Density in Adults 45 Years and Older

Macular Pigment Assessment in Indian Population Using Degree of Polarization Threshold: Impact of Diet on Macular Pigment Density

Purpose

To determine macular pigment (MP) density scores in healthy Indians and examine correlations with demographic and lifestyle variables.

Methods

We observed 484 Indians without an ocular pathology. Body mass index (BMI) and self-reported lifestyle factors (sunglasses usage, physical activity, and smoking) were noted. MP density was assessed as the threshold of perception of the shadow of their macular pigments on their retina using a new MP assessment tool (MP-eye). Lutein and zeaxanthin intake was assessed using a prevalidated questionnaire regionally designed for the Indian diet. Clusters of participants were created for statistical analysis based on MP-eye scores secondarily to detect any relevant effects in very low, low, medium, and high ranges of MPs.

Results

Data analyzed included 235 males and 249 females with mean age of 36.1 ± 12.9 years (range, 14-72). The median MP-eye score was 6 (range, 0-10, with 10 being high). Most were non-smokers (413, 85.3%) and did not use sunglasses (438, 90.5%), and 314 (64.9%) had low physical activity. Diabetes was present in 62 participants (12.8%) and hypertension in 53 (10.9%). Advancing age (r = -0.209; P < 0.000) and BMI (r = -0.094; P = 0.038) had weak negative correlation with MP-eye scores. Hypertension was less prevalent (7/88) in the cluster with the highest median MP-eye score (P = 0.033). Dietary intake of MPs and other lifestyle factors did not correlate significantly with MP-eye score overall or when analyzed in clusters.

Conclusions

MP-eye scores of an Indian population were normally distributed. Higher age, high BMI, and presence of hypertension were weakly associated with lower MP-eye scores. The impact of diet on MPs requires further evaluation.

Translational Relevance

This normative regional database enables risk stratification of macular degeneration.

Impacts of regular consumption of grapes on macular pigment accumulation in Singapore older adults: a randomized controlled trial

Background: Oxidative stress is a key risk factor for visual impairment and consuming dietary antioxidant-rich foods may help in managing visual impairments. However, a limited number of studies have investigated the effect of dietary antioxidant-rich food including grapes on eye health in older adults. Objectives: To assess the effects on macular pigment accumulation of regular consumption of grapes in Singapore older adults. Methods: This was a 16 week, double-blind, randomized, placebo-controlled trial. Thirty-four Singapore older adults were randomized into regularly consuming either 46 g day-1 of freeze-dried table grape powder (the intervention group) or the same amount of placebo powder (the control group). Macular pigment optical density (MPOD), skin carotenoid status, advanced glycation end product (AGEs) status and dietary lutein intake were assessed every 4 weeks, and plasma lutein concentration, total antioxidant capacity and total phenolic content were measured every 8 weeks. Results: A significant time effect (p = 0.007) was observed for MPOD, and this is largely attributed to the improvement in the MPOD for the intervention group, as a significant increase was observed only in this group (week 0: 0.56 ± 0.04 D.U.; week 16: 0.61 ± 0.04 D.U., p < 0.01). Additionally, a significant increase in plasma total antioxidant capacity (week 0: 0.26 ± 0.13 mM TEAC; week 16: 0.36 ± 0.20 mM TEAC, p < 0.01) and total phenolic content (week 0: 10.50 ± 0.44 mg L-1 GAE; week 16: 12.58 ± 0.55 mg L-1 GAE, p < 0.001) was observed for the intervention group only. In contrast, a significant increase in skin AGE status was observed in the control group (week 0: 2.47 ± 0.24; week 16: 2.99 ± 0.12, p < 0.05) while this was mitigated in the intervention group. There were no differences in dietary lutein intake, plasma lutein concentration and skin carotenoid status between groups throughout the study. Conclusions: Regular intake of grapes may improve eye health in Singapore older adults, specifically in augmenting MPOD, which can be explained by an increase in plasma total antioxidant capacity and phenolic content, and the downregulation of AGEs. This study was registered at clinicatrials.gov as NCT05064865.

Macular and Plasma Xanthophylls Are Higher in Age-related Macular Degeneration than in Normal Aging: Alabama Study on Early Age-related Macular Degeneration 2 Baseline

Purpose

Quantification of retinal xanthophyll carotenoids in eyes with and without age-related macular degeneration (AMD) via macular pigment optical volume (MPOV), a metric for xanthophyll abundance from dual wavelength autofluorescence, plus correlations to plasma levels, could clarify the role of lutein (L) and zeaxanthin (Z) in health, AMD progression, and supplementation strategies.

Design

Cross-sectional observational study (NCT04112667).

Participants

Adults ≥ 60 years from a comprehensive ophthalmology clinic, with healthy maculas or maculas meeting fundus criteria for early or intermediate AMD.

Methods

Macular health and supplement use was assessed by the Age-related Eye Disease Study (AREDS) 9-step scale and self-report, respectively. Macular pigment optical volume was measured from dual wavelength autofluorescence emissions (Spectralis, Heidelberg Engineering). Non-fasting blood draws were assayed for L and Z using high-performance liquid chromatography. Associations among plasma xanthophylls and MPOV were assessed adjusting for age.

Main Outcome Measures

Age-related macular degeneration presence and severity, MPOV in fovea-centered regions of radius 2.0° and 9.0°; plasma L and Z (μM/ml).

Results

Of 809 eyes from 434 persons (89% aged 60-79, 61% female), 53.3% eyes were normal, 28.2% early AMD, and 18.5% intermediate AMD. Macular pigment optical volume 2° and 9° were similar in phakic and pseudophakic eyes, which were combined for analysis. Macular pigment optical volume 2° and 9° and plasma L and Z were higher in early AMD than normal and higher still in intermediate AMD (P < 0.0001). For all participants, higher plasma L was correlated with higher MPOV 2° (Spearman correlation coefficient [Rs] = 0.49; P < 0.0001). These correlations were significant (P < 0.0001) but lower in normal (Rs = 0.37) than early and intermediate AMD (Rs = 0.52 and 0.51, respectively). Results were similar for MPOV 9°. Plasma Z, MPOV 2°, and MPOV 9° followed this same pattern of associations. Associations were not affected by supplement use or smoking status.

Conclusions

A moderate positive correlation of MPOV with plasma L and Z comports with regulated xanthophyll bioavailability and a hypothesized role for xanthophyll transfer in soft drusen biology. An assumption that xanthophylls are low in AMD retina underlies supplementation strategies to reduce progression risk, which our data do not support. Whether higher xanthophyll levels in AMD are due to supplement use cannot be determined in this study.

Potential roles of dietary zeaxanthin and lutein in macular health and function

Lutein, zeaxanthin, and meso-zeaxanthin are three xanthophyll carotenoid pigments that selectively concentrate in the center of the retina. Humans cannot synthesize lutein and zeaxanthin, so these compounds must be obtained from the diet or supplements, with meso-zeaxanthin being converted from lutein in the macula. Xanthophylls are major components of macular pigments that protect the retina through the provision of oxidant defense and filtering of blue light. The accumulation of these three xanthophylls in the central macula can be quantified with non-invasive methods, such as macular pigment optical density (MPOD). MPOD serves as a useful tool for assessing risk for, and progression of, age-related macular degeneration, the third leading cause of blindness worldwide. Dietary surveys suggest that the dietary intakes of lutein and zeaxanthin are decreasing. In addition to low dietary intake, pregnancy and lactation may compromise the lutein and zeaxanthin status of both the mother and infant. Lutein is found in modest amounts in some orange- and yellow-colored vegetables, yellow corn products, and in egg yolks, but rich sources of zeaxanthin are not commonly consumed. Goji berries contain the highest known levels of zeaxanthin of any food, and regular intake of these bright red berries may help protect against the development of age-related macular degeneration through an increase in MPOD. The purpose of this review is to summarize the protective function of macular xanthophylls in the eye, speculate on the compounds' role in maternal and infant health, suggest the establishment of recommended dietary values for lutein and zeaxanthin, and introduce goji berries as a rich food source of zeaxanthin.

Changes in Aqueous Humor Lutein Levels of Patients with Cataracts after a 6-Week Course of Lutein-Containing Antioxidant Supplementation

PURPOSE

Oxidative damage is known to be an important cause of age-related cataracts and it has been suggested that administration of antioxidants, such as lutein, may delay the onset and progression of cataracts. Our previous investigation of human aqueous humor after the intake of a lutein-containing supplement demonstrated decreases in peroxidative products. This study evaluated the transportation of lutein into aqueous humor which is an important factor when measuring the antioxidant effects of lutein on the lens.

METHODS

This study enrolled 155 patients with binocular cataracts of the same grade. Serum and aqueous humor samples were collected during cataract surgery before (as pre-intake samples) and after 6 weeks of oral intake of Ocuvite + Lutein^® (as post-intake samples). Lutein levels were measured with high-performance liquid chromatography.

RESULTS

Lutein levels in both the serum and aqueous humor were significantly higher in the post-intake than the pre-intake samples. There were significant increases in the lutein levels in patients with lower pre-intake lutein serum levels. There was also a tendency for greater increases in patients with lower pre-intake aqueous humor lutein levels.

CONCLUSIONS

These results demonstrate that oral lutein supplementation increases lutein levels, which further induce decreases in peroxidation in the aqueous humor. Furthermore, lutein supplementation may be more effective in patients with lower serum lutein levels.

Macular pigment optical density assessed by heterochromatic flicker photometry in eyes affected by primary epiretinal membrane

PURPOSE

To compare macular pigment optical density (MPOD) in healthy eyes vs eyes affected by primary epiretinal membrane (ERM) in different stages and to assess the relation between MPOD and optical coherence tomography findings.

METHODS

Prospective cross-sectional study of 62 eyes from 62 patients affected by unilateral primary ERM. Contralateral healthy eyes from the same patients were used as a control group. Main outcome measures were MPOD, ERM stage, central foveal thickness (CFT), outer nuclear layer thickness (ONLT), integrity of outer retinal bands (ORB) and presence of Central Bouquet (CB) abnormalities.

RESULTS

In the study group mean CFT was 444±75 µm and mean ONLT was 245±40 µm, while in the control group mean CFT was 230±21 µm and mean ONLT was 102±14 µm (p<0.001). Mean MPOD was 0.86±0.07 in eyes with ERM and 0.48±0.09 in contralateral healthy eyes (p<0.001). MPOD was associated with CFT (p=0.006) and ONLT (p<0.001) while no significant associations were observed between MPOD and ORB integrity (p=0.14) and CB abnormalities (p=0.08).

CONCLUSIONS

MPOD increased in eyes affected by primary ERM proportionally to CFT and, especially, ONLT. Probably, centripetal forces exerted by ERM contraction on the retinal surface lead to a progressive foveal packing of foveal Muller cells.

Whey- and Soy Protein Isolates Added to a Carrot-Tomato Juice Alter Carotenoid Bioavailability in Healthy Adults

Recent findings suggested that proteins can differentially affect carotenoid bioaccessibility during gastro-intestinal digestion. In this crossover, randomized human trial, we aimed to confirm that proteins, specifically whey- and soy-protein isolates (WPI/SPI) impact postprandial carotenoid bioavailability. Healthy adults (n = 12 males, n = 12 females) were recruited. After 2-week washout periods, 350 g of a tomato-carrot juice mixture was served in the absence/presence of WPI or SPI (50% of the recommended dietary allowance, RDA ≈ 60 g/d). Absorption kinetics of carotenoids and triacylglycerols (TAGs) were evaluated via the triacylglycerol-rich lipoprotein (TRL) fraction response, at timed intervals up to 10 h after test meal intake, on three occasions separated by 1 week. Maximum TRL-carotenoid concentration (C_max) and corresponding time (T_max) were also determined. Considering both genders and carotenoids/TAGs combined, the estimated area under the curve (AUC) for WPI increased by 45% vs. the control (p = 0.018), to 92.0 ± 1.7 nmol × h/L and by 57% vs. SPI (p = 0.006). Test meal effect was significant in males (p = 0.036), but not in females (p = 0.189). In males, significant differences were found for phytoene (p = 0.026), phytofluene (p = 0.004), α-carotene (p = 0.034), and β-carotene (p = 0.031). C_max for total carotenoids (nmol/L ± SD) was positively influenced by WPI (135.4 ± 38.0), while significantly lowered by SPI (89.6 ± 17.3 nmol/L) vs. the control (119.6 ± 30.9, p < 0.001). T_max did not change. The results suggest that a well-digestible protein could enhance carotenoid bioavailability, whereas the less digestible SPI results in negative effects. This is, to our knowledge, the first study finding effects of proteins on carotenoid absorption in humans.

Predictors of macular pigment and contrast threshold in Spanish healthy normolipemic subjects (45-65 years) with habitual food intake

Introduction

The dietary carotenoids lutein (L) and zeaxanthin (Z) are transported in the bloodstream by lipoproteins, sequestered by adipose tissue, and eventually captured in the retina where they constitute macular pigment. There are no L&Z dietary intake recommendations nor desired blood/tissue concentrations for the Spanish general population. Our aim was to assess the correlation of L&Z habitual dietary intake (excluding food supplements), resulting serum concentrations and lipid profile with macular pigment optical density (MPOD) as well as the contrast sensitivity (CT), as visual outcome in normolipemic subjects (n = 101) aged 45–65.

Methods

MPOD was measured by heterochromatic flicker photometry, serum L&Z by HPLC, the dietary intake by a 3-day food records and CT using the CGT-1000-Contrast-Glaretester at six stimulus sizes, with and without glare.

Results

Lutein and zeaxanthin concentrations (median) in serum: 0.361 and 0.078 μmol/L, in dietary intake: 1.1 mg L+Z/day. MPOD: 0.34du. L+Z intake correlates with their serum concentrations (rho = 0.333, p = 0.001), which in turn correlates with MPOD (rho = 0.229, p = 0.000) and with fruit and vegetable consumption (rho = 0.202, p = 0.001), but not with lutein+zeaxanthin dietary intake. MPOD correlated with CT, with and without glare (rho ranges: -0.135, 0.160 and -0.121, –0.205, respectively). MPOD predictors: serum L+Z, L+Z/HDL-cholesterol (β-coeficient: -0.91±0.2, _95%CI: -1.3,-0.5) and HDL-cholesterol (R² = 15.9%). CT predictors: MPOD, mainly at medium and smaller visual angles (corresponding to spatial frequencies for which sensitivity declines with age) and gender (β-coefficients ranges: -0.95,-0.39 and -0.13,-0.39, respectively).

Conclusion

A higher MPOD is associated with a lower ratio of L+Z/HDL-cholesterol and with a lower CT (higher contrast sensitivity). The HDL-cholesterol would also act indirectly on the CT improving the visual function.

From carotenoid intake to carotenoid blood and tissue concentrations - implications for dietary intake recommendations

There is uncertainty regarding carotenoid intake recommendations, because positive and negative health effects have been found or are correlated with carotenoid intake and tissue levels (including blood, adipose tissue, and the macula), depending on the type of study (epidemiological vs intervention), the dose (physiological vs supraphysiological) and the matrix (foods vs supplements, isolated or used in combination). All these factors, combined with interindividual response variations (eg, depending on age, sex, disease state, genetic makeup), make the relationship between carotenoid intake and their blood/tissue concentrations often unclear and highly variable. Although blood total carotenoid concentrations <1000 nmol/L have been related to increased chronic disease risk, no dietary reference intakes (DRIs) exist. Although high total plasma/serum carotenoid concentrations of up to 7500 nmol/L are achievable after supplementation, a plateauing effect for higher doses and prolonged intake is apparent. In this review and position paper, the current knowledge on carotenoids in serum/plasma and tissues and their relationship to dietary intake and health status is summarized with the aim of proposing suggestions for a "normal," safe, and desirable range of concentrations that presumably are beneficial for health. Existing recommendations are likewise evaluated and practical dietary suggestions are included.

A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

A review of the putative causal mechanisms associated with lower macular pigment in diabetes mellitus

Macular pigment (MP) confers potent antioxidant and anti-inflammatory effects at the macula, and may therefore protect retinal tissue from the oxidative stress and inflammation associated with ocular disease and ageing. There is a body of evidence implicating oxidative damage and inflammation as underlying pathological processes in diabetic retinopathy. MP has therefore become a focus of research in diabetes, with recent evidence suggesting that individuals with diabetes, particularly type 2 diabetes, have lower MP relative to healthy controls. The present review explores the currently available evidence to illuminate the metabolic perturbations that may possibly be involved in MP's depletion. Metabolic co-morbidities commonly associated with type 2 diabetes, such as overweight/obesity, dyslipidaemia, hyperglycaemia and insulin resistance, may have related and independent relationships with MP. Increased adiposity and dyslipidaemia may adversely affect MP by compromising the availability, transport and assimilation of these dietary carotenoids in the retina. Furthermore, carotenoid intake may be compromised by the dietary deficiencies characteristic of type 2 diabetes, thereby further compromising redox homeostasis. Candidate causal mechanisms to explain the lower MP levels reported in diabetes include increased oxidative stress, inflammation, hyperglycaemia, insulin resistance, overweight/obesity and dyslipidaemia; factors that may negatively affect redox status, and the availability, transport and stabilisation of carotenoids in the retina. Further study in diabetic populations is warranted to fully elucidate these relationships.

Identification of Surrogate Biomarkers for the Prediction of Patients at Risk of Low Macular Pigment in Type 2 Diabetes

Purpose: This cross-sectional study compared macular pigment (MP) levels among persons with Type 2 diabetes relative to healthy controls. Additionally, a range of behavioral, anthropometric, clinical and serum measures were explored as possible predictors of low MP optical density (MPOD) in diabetes.Methods: Two health status groups; Group 1: Type 2 diabetes (n = 188), and Group 2: Healthy controls (n = 2,594) completed a full MP assessment using customized heterochromatic flicker photometry, as part of The Irish Longitudinal Study on Aging (TILDA). Clinical [blood pressure; cataract status; MPOD] and anthropometric [waist (cm); weight (kg); hip (cm)] measurements were taken, and a blood sample drawn for analysis of serum biomarkers [lipoproteins; inflammatory markers (C reactive protein and vitamin-D)].Results: One-way ANOVA revealed lower MPOD in subjects with Type 2 diabetes relative to controls (p = .047). Amongst participants with diabetes, those with low serum vitamin D (≤50 nmol/L) had significantly lower mean MPOD compared to those with sufficient serum vitamin D levels >50 nmol/L (0.173(0.148) vs. 0.226(0.145); p = .006). Concomitantly, MP was significantly lower in diabetes participants with raised serum triglyceride (TG) to high density lipoprotein (HDL) ratio (TG/HDL); values >1.74 mmol/L (0.172 (0.140) vs 0.215 (0.152); p = .039). Body mass index, waist-to-height ratio and waist circumference, were all significantly negatively correlated with MPOD (Pearson's correlation, p < .05 for all). Significant correlates of MPOD in the multivariate regression model included smoking, cataract, and vitamin D, which collectively contributed 18.5% of the overall variability in MPOD status amongst participants with Type 2 diabetes.Conclusions: This study provides additional evidence that low MP may indeed be a feature of Type 2 diabetes, and further identifies smoking, cataract and vitamin D status as plausible predictors of low MPOD amongst persons with Type 2 diabetes.

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

Xanthophylls (lutein, L; zeaxanthin, Z) and anthocyanins are often included in food supplements to improve ocular health. There are no dietary reference intakes for them. The aim was to assess the effects of L, Z and anthocyanin supplementation on short and long-term lutein status markers (serum concentration and macular pigment optical density (MPOD)). Seventy-two postmenopausal women were randomized into a parallel study of 8 months: Group A-anthocyanines (60 mg/day); Group X-xanthophylls (6 mg L + 2 mg Z/day); Group X+A-anthocyanines (60 mg/day) + xanthophylls (6 mg L + 2 mg Z/day). At the beginning of the study, 4 and 8 month serum L and Z concentrations were determined (HPLC), as well as L, Z and anthocyanine dietary intake and MPOD (heterochromic flicker photometry). Baseline concentrations of L (0.35 ± 0.19 μmol/L), Z (0.11 ± 0.05 μmol/L), L+Z/cholesterol/triglycerides (0.07 ± 0.04 μmol/mmol) increased in Group X (2.8- and 1.6-fold in L and Z concentrations) and in group XA (2- and 1.4-fold in L and Z concentrations). MPOD (baseline: 0.32 ± 0.13 du) was not modified in any of the groups at the end of the study. There were no differences in the dietary intake of L+Z and anthocyanin at any point in time in any group. Supplementation of L and Z at a dietary level provoked an increase in their serum concentration that was not modified by simultaneous supplementation with anthocyanins.

A global perspective on carotenoids: Metabolism, biotechnology, and benefits for nutrition and health

Carotenoids are lipophilic isoprenoid compounds synthesized by all photosynthetic organisms and some non-photosynthetic prokaryotes and fungi. With some notable exceptions, animals (including humans) do not produce carotenoids de novo but take them in their diets. In photosynthetic systems carotenoids are essential for photoprotection against excess light and contribute to light harvesting, but perhaps they are best known for their properties as natural pigments in the yellow to red range. Carotenoids can be associated to fatty acids, sugars, proteins, or other compounds that can change their physical and chemical properties and influence their biological roles. Furthermore, oxidative cleavage of carotenoids produces smaller molecules such as apocarotenoids, some of which are important pigments and volatile (aroma) compounds. Enzymatic breakage of carotenoids can also produce biologically active molecules in both plants (hormones, retrograde signals) and animals (retinoids). Both carotenoids and their enzymatic cleavage products are associated with other processes positively impacting human health. Carotenoids are widely used in the industry as food ingredients, feed additives, and supplements. This review, contributed by scientists of complementary disciplines related to carotenoid research, covers recent advances and provides a perspective on future directions on the subjects of carotenoid metabolism, biotechnology, and nutritional and health benefits.

Lutein and Zeaxanthin Are Positively Associated with Visual-Spatial Functioning in Older Adults: An fMRI Study

Lutein (L) and zeaxanthin (Z) are two xanthophyll carotenoids that have antioxidant and anti-inflammatory properties. Previous work has demonstrated their importance for eye health and preventing diseases such as age-related macular degeneration. An emerging literature base has also demonstrated the importance of L and Z in cognition, neural structure, and neural efficiency. The present study aimed to better understand the mechanisms by which L and Z relate to cognition, in particular, visual–spatial processing and decision-making in older adults. We hypothesized that markers of higher levels of L and Z would be associated with better neural efficiency during a visual–spatial processing task. L and Z were assessed via standard measurement of blood serum and retinal concentrations. Visual–spatial processing and decision-making were assessed via a judgment of line orientation task (JLO) completed during a functional magnetic resonance imaging (fMRI) scan. The results demonstrated that individuals with higher concentrations of L and Z showed a decreased blood-oxygen-level dependent (BOLD) signal during task performance (i.e., “neural efficiency”) in key areas associated with visual–spatial perception, processing, decision-making, and motor coordination, including the lateral occipital cortex, occipital pole, superior and middle temporal gyri, superior parietal lobule, superior and middle frontal gyri, and pre- and post-central gyri. To our knowledge, this is the first investigation of the relationship of L and Z to visual–spatial processing at a neural level using in vivo methodology. Our findings suggest that L and Z may impact brain health and cognition in older adults by enhancing neurobiological efficiency in a variety of regions that support visual perception and decision-making.

Analysis of Lutein, Zeaxanthin, and Meso-Zeaxanthin in the Organs of Carotenoid-Supplemented Chickens

The macular carotenoids (i.e., lutein (L), zeaxanthin (Z) and meso-zeaxanthin (MZ)) exhibit anti-inflammatory, antioxidant and optical properties that are believed to support human health and function. Studying the accumulation and distribution of these nutrients in tissues and organs, in addition to the eye, is an important step in understanding how these nutrients might support global human function and health (e.g., heart and brain). Chicken is an appropriate animal model with which to study the accumulation of these carotenoids in organs, as the relevant transport molecules and carotenoid binding proteins for L, Z and MZ are present in both humans and chickens. In this experiment, a sample of 3 chickens that were supplemented with L and MZ diacetate (active group) and a sample of 3 chickens that received a standard diet (control group) were analysed. Both groups were analysed for L, Z and MZ concentrations in the brain, eyes, heart, lung, duodenum/pancreas, jejunum/ileum, kidney and breast tissue. L, Z and MZ were identified in all the organs/tissues analysed from the active group. L and Z were identified in all of the organs/tissues analysed from the control group; while, MZ was identified in the eyes of these animals only. The discovery that MZ is accumulated in the tissues and organs of chickens supplemented with this carotenoid is important, given that it is known that a combination of L, Z and MZ exhibits superior antioxidant capacity when compared to any of these carotenoids in isolation.

Effect of carotenoids dietary supplementation on macular function in diabetic patients

Background

Diabetic retinopathy is a major cause of visual impairment and blindness among working-age people worldwide. The aim of our study was to investigate the effects of a carotenoid supplementation on retinal thickness and macular function of patients with diabetes using optical coherence tomography (OCT) and multifocal electroretinography (mfERG).

Methods

A retrospective study of one hundred and twenty eyes of sixty patients age between 40 and 60 years with non-insulin dependent type 2 diabetes mellitus without diabetic retinopathy who underwent OCT and mfERG and took vitamin supplements for a period of two years. Patients received a carotenoid supplement containing lutein (10 mg), zeaxanthin (2 mg) and meso-zeaxanthin (10 mg) once a day for two years. The thickness of the fovea was evaluated using OCT and the macular function was tested by mfERG.

Results

OCT showed an increase in the central foveal thickness and mfERG revealed increased retinal response density within the central 13° surrounding the fovea (rings 1 to 3) at two years after the onset of carotenoids supplement intake.

Conclusion

The use of carotenoid supplements may be of benefit for improving visual function of type 2 diabetes patients. However, further study is needed to assess the treatment’s long-term efficacy.

Correlations Between Macular, Skin, and Serum Carotenoids

Purpose

Ocular and systemic measurement and imaging of the macular carotenoids lutein and zeaxanthin have been employed extensively as potential biomarkers of AMD risk. In this study, we systematically compare dual wavelength retinal autofluorescence imaging (AFI) of macular pigment with skin resonance Raman spectroscopy (RRS) and serum carotenoid levels in a clinic-based population.

Methods

Eighty-eight patients were recruited from retina and general ophthalmology practices from a tertiary referral center and excluded only if they did not have all three modalities tested, had a diagnosis of macular telangiectasia (MacTel) or Stargardt disease, or had poor AFI image quality. Skin, macular, and serum carotenoid levels were measured by RRS, AFI, and HPLC, respectively.

Results

Skin RRS measurements and serum zeaxanthin concentrations correlated most strongly with AFI macular pigment volume under the curve (MPVUC) measurements up to 9° eccentricity relative to MPVUC or rotationally averaged macular pigment optical density (MPOD) measurements at smaller eccentricities. These measurements were reproducible and not significantly affected by cataracts. We also found that these techniques could readily identify subjects taking oral carotenoid-containing supplements.

Conclusions

Larger macular pigment volume AFI and skin RRS measurements are noninvasive, objective, and reliable methods to assess ocular and systemic carotenoid levels. They are an attractive alternative to psychophysical and optical methods that measure MPOD at a limited number of eccentricities. Consequently, skin RRS and MPVUC at 9° are both reasonable biomarkers of macular carotenoid status that could be readily adapted to research and clinical settings.

The Role of Retinal Carotenoids and Age on Neuroelectric Indices of Attentional Control among Early to Middle-Aged Adults

One apparent consequence of aging appears to be loss of some aspects of cognitive control. This loss is measurable as early as mid-adulthood. Since, like many aspects of cognition, there is wide variance among individuals, it is possible that behavior, such as one’s diet, could drive some of these differences. For instance, past data on older humans and non-human primates have suggested that dietary carotenoids could slow cognitive decline. In this study, we tested how early such protection might manifest by examining a sample (n = 60) of 25–45 year olds. Carotenoid status was assessed by directly measuring macular pigment optical density (MPOD) which has shown to be highly correlated with the primary carotenoid in brain, lutein. Cognitive control was measured using event-related potentials during the performance of cognitive control tasks designed to tap into different aspects of attentional (i.e., selective attention, attentional inhibition, and response inhibition) control. Our results showed that, across participants, MPOD was related to both age and the P3 component of participants’ neuroelectric profile (P3 amplitude) for attentional, but not response, inhibition. Although younger adults exhibited larger P3 amplitudes than their older adult counterparts, older subjects with higher MPOD levels displayed P3 indices similar to their younger adult counterparts in amplitude. Furthermore, hierarchical regression analyses showed that age was no longer a significant predictor of P3 amplitude when MPOD was included as a predictor in the model, suggesting that MPOD may partially contribute to the relationship between age and P3 amplitude. In addition, age and MPOD were shown to have independent associations with intraindividual variability of attentional control, such that younger individuals and individuals with higher MPOD showed less intraindividual variability. These results show a relationship between retinal carotenoids and neuroelectric indices underlying cognitive control. The protective role of carotenoids within the CNS may be evident during early and middle adulthood, decades prior to the onset of older age.

Non-Dietary Correlates and Determinants of Plasma Lutein and Zeaxanthin Concentrations in the Irish Population

OBJECTIVE

To investigate non-dietary correlates and determinants of plasma lutein (L) and zeaxanthin (Z) concentrations in The Irish Longitudinal Study on Ageing (TILDA) sample.

DESIGN

Cross-sectional study.

SETTING

Community dwelling adults in the Republic of Ireland (ROI).

PARTICIPANTS

3,681 participants aged 50 years and older.

MEASUREMENTS

TILDA is a nationally representative prospective cohort study of community dwelling adults aged 50 years and over in the ROI. Demographic and health variables were collected during a face-to-face interview carried out in the home (n=8175), and a substantial proportion of these (n=5035; 62%) also attended a study visit in a health assessment centre. Blood samples collected at baseline (wave 1, the subject of the current study), were analysed for plasma concentrations of L and Z by reversed-phase high performance liquid chromatography, and macular pigment (MP) optical density was also measured (using customized heterochromatic flicker photometry).

RESULTS

After excluding participants with eye disease, data from 3,681 participants were available for analysis. For this group of participants, plasma L and Z were inversely and significantly associated with body mass index (BMI), and were positively and significantly associated with MP, total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) (p<0.001, for all). Plasma L and Z were significantly lower in males, current smokers, participants reporting less physical exercise, and participants reporting lower levels of education (p<0.05, for all). Plasma L was significantly higher in participants reporting a family history of age-related macular degeneration (AMD) (p=0.001), and in the group of ≥75 years old (p<0.05). For each of these variables, the significant associations remained after controlling for other potential confounding variables.

CONCLUSION

The findings of this large study indicate that plasma concentrations of L and Z were lower in association with indicators of a poor lifestyle (high BMI, tobacco use, and less physical exercise) and in association with lower education, indicating that modifying lifestyle in a positive way is likely to be reflected in higher concentrations of plasma carotenoids, with consequential and putative health benefits.

Relationship of Lutein and Zeaxanthin Levels to Neurocognitive Functioning: An fMRI Study of Older Adults

OBJECTIVES

It is well known that the carotenoids lutein (L) and zeaxanthin (Z) improve eye health and an accumulating evidence base suggests cognitive benefits as well. The present study investigated underlying neural mechanisms using functional magnetic resonance imaging (fMRI). It was hypothesized that lower L and Z concentrations would be associated with neurobiological inefficiency (i.e., increased activation) during cognitive performance.

METHODS

Forty-three community-dwelling older adults (mean age=72 years; 58% female; 100% Caucasian) were asked to learn and recall pairs of unrelated words in an fMRI-adapted paradigm. L and Z levels were measured in retina (macular pigment optical density) and serum using validated procedures.

RESULTS

Following first-level contrasts of encoding and retrieval trials minus control trials (p<.05, family-wise error corrected, minimum voxel cluster=8), L and Z were found to significantly and negatively relate to blood-oxygen-level-dependent signal in central and parietal operculum cortex, inferior frontal gyrus, supramarginal gyrus, planum polare, frontal and middle temporal gyrus, superior parietal lobule, postcentral gyrus, precentral gyrus, occipital cortex bilaterally, and cerebellar regions.

CONCLUSIONS

To the authors' knowledge, the present study represents the first attempt to investigate neural mechanisms underlying the relation of L and Z to cognition using fMRI. The observed results suggest that L and Z promote cognitive functioning in old age by enhancing neural efficiency. (JINS, 2017, 23, 11-22).

Association of macular pigment optical density with early stage of non-proliferative diabetic retinopathy in Chinese patients with type 2 diabetes mellitus

AIM

To detect the association between macular pigment optical density (MPOD), which reflects the antioxidant ability of retina, and diabetic retinopathy (DR) and to investigate the correlated factors of MPOD.

METHODS

Totally 435 subjects of urban Chinese were recruited to the study and divided into 3 groups: non-diabetes mellitus controls (NDM), diabetic patients without retinopathy (DWR), and patients with early stage of non-proliferative diabetic retinopathy (DR). Demographic and lifestyle characteristics were ascertained by questionnaire. A food-frequency questionnaire, general physical and ophthalmic examinations were completed for all participants. MPOD was measured by heterochromatic flicker photometry. Foveal thickness was measured by optical coherence tomography. The difference of MPOD among 3 groups was analyzed by analysis of covariance. The correlation analyses of MPOD with the candidate influence factors were assessed using the generalized estimating equations (GEE) model.

RESULTS

Of the 435 participants, 34 could not perform the MPOD measurements. Final analysis included 401 subjects, including 48 were in DR group, 134 in DWR group, and 219 in NDM group. MPOD was not significantly different among DR (0.49±0.21), DWR (0.45±0.21), and NDM (0.49±0.17) groups (P=0.24) after adjustment for fasting plasma glycemia, central foveal thickness, green vegetables, Chinese wolfberry, carotene and vitamin E. For all the 401 participants included, MPOD was positively associated with central foveal thickness (E=0.0007, P=0.001), Chinese wolfberry (E=0.0345, P=0.01), and green vegetables (E=0.0596, P<0.001) intake.

CONCLUSION

The data suggest that MPOD level is not statistically significantly influenced by the onset of diabetes or early stage of DR in the studied population. MPOD level is positively associated with thicker central foveal thickness and higher intake of foods containing carotenoids.

Lutein and zeaxanthin supplied by red/orange foods and fruits are more closely associated with macular pigment optical density than those from green vegetables in Spanish subjects

Lutein and zeaxanthin (L+Z) accumulate in the retina. Although vegetables are major contributors to their intake, a stronger association between fruits and macular pigment optical density (MPOD) has been reported. We hypothesized that L+Z intake from fruits would have a stronger association with L+Z status markers (MPOD, serum concentrations) than intake from vegetables or eggs, and that those associations would also differ according to plant foods color. One hundred eight subjects (57 men; age groups, 20-35 and 45-65 years) were enrolled in a cross-sectional study. L+Z intake from fruits, vegetables, and eggs was determined using three 24-hour diet recalls and a country-specific carotenoid database. Vegetables were the major contributors (75%) to L+Z intake, followed by eggs (10%) and fruits (4%). Vegetables supplied 86% and 84% of the LandZ intake, respectively, and fruits supplied 3% and 16%. Green foods supplied 78% and 52% of LandZ, respectively, followed by red/orange (9% and 38%) and white/yellow (14% and 9%). Factorial analysis showed associations in older subjects. The explained variance of the first 2 principal components was 54% considering L+Z intake from fruits, vegetables, and eggs, and 55% considering L+Z intake from plant foods grouped by color. Macular pigment optical density is related to L+Z intake from fruits (0.264, P=.003) and is independent of that from vegetables and eggs. It is related to L+Z intake from red/orange foods (0.320, P=.000) and the serum concentrations to that from green foods (0.222, P=.11). Although vegetables and green foods of plant origin are the major contributors to L+Z intake, red/orange foods and fruits have the strongest relationship to MPOD in study participants (45-65 years of age).

Assessment of lutein and zeaxanthin status and dietary markers as predictors of the contrast threshold in 2 age groups of men and women

Lutein and zeaxanthin (L + Z) status is associated with the macular pigment (MP). The relationship between MP and visual function is controversial. We hypothesized that, within the framework of nutrition, visual function was related to MP and nutritional and/or/dietary factors influencing it. A cross-sectional study was performed in 108 volunteers divided into 2 age groups (20-35 years; 45-65 years), each 27 women and 27 men, to assess the relationship between MP optical density (MPOD) and contrast threshold (CT), considering the influence of L + Z and, fruit and vegetable (F + V) intake. MPOD, L + Z in serum and dietary intake were determined using heterochromatic flicker photometry, high-performance liquid chromatography and 3-day food records, respectively. CT was measured with the CGT-1000 Contrast Glaretester at 6 stimulus sizes, with and without glare. Spearman correlation coefficient and a generalized linear model were used for the statistical study. MPOD and CT were higher and lower, respectively in younger than in elder individuals (P < .000) and were correlated only in the older group. CT were higher under glare conditions, at the intermediate and smaller visual angles, with greater differences in the older (P < .003) than the younger group (P < .014). In the total sample, CT correlated inversely with MPOD (correlation coefficients and P values ranging from -.245 to -.152 and from .000 to .026, respectively) and directly with F + V intake (correlation coefficients and P values ranging from -.265 to -.176 and from .000 to .010, respectively). As predictors of CT in the total sample, MPOD, F + V (every 100 g/d) and sex were identified (β coefficients ranged from -0.01 to -1.86; from 0.01 to 0.08 and from 0.01 to 0.40, respectively). CT revealed age-specific nutritional predictors: MPOD and serum lutein in the 45- to 65-year group, and F + V intake in the 20- to 35-year group.

Dietary modification and supplementation for the treatment of age-related macular degeneration

Age-related macular degeneration (AMD) causes a significant proportion of visual loss in the developed world. Currently, little is known about its pathogenesis, and treatment options are limited. Dietary intake is one of the few modifiable risk factors for this condition. The best-validated therapies remain oral antioxidant supplements based on those investigated in the Age-Related Eye Disease Study (AREDS) and the recently completed Age-Related Eye Disease Study 2 (AREDS2). In this review, current dietary guidelines related to AMD, along with the underlying evidence to support them, are presented in conjunction with current treatment recommendations. Both AREDS and AREDS2 are discussed, as are avenues for further research, including supplementation with vitamin D and saffron. Despite the considerable disease burden of atrophic AMD, few effective therapies are available to treat it, and further research is required.

Lutein and preterm infants with decreased concentrations of brain carotenoids

OBJECTIVES

Lutein and zeaxanthin are dietary carotenoids that may influence visual and cognitive development. The objective of this study was to provide the first data on distribution of carotenoids in the infant brain and compare concentrations in preterm and term infants.

METHODS

Voluntarily donated brain tissues from 30 infants who died during the first 1.5 years of life were obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank. Tissues (hippocampus and prefrontal, frontal, auditory, and occipital cortices) were extracted using standard lipid extraction procedures and analyzed using reverse-phase high-pressure liquid chromatography.

RESULTS

Lutein, zeaxanthin, cryptoxanthin, and β-carotene were the major carotenoids found in the infant brain tissues. Lutein was the predominant carotenoid accounting for 59% of total carotenoids. Preterm infants (n = 8) had significantly lower concentrations of lutein, zeaxanthin, and cryptoxanthin in their brain compared with term infants (n = 22) despite similarity in postmenstrual age. Among formula-fed infants, preterm infants (n = 3) had lower concentrations of lutein and zeaxanthin compared with term infants (n = 5). Brain lutein concentrations were not different between breast milk-fed (n = 3) and formula-fed (n = 5) term decedents. In contrast, term decedents with measurable brain cryptoxanthin, a carotenoid that is inherently low in formula, had higher brain lutein, suggesting that the type of feeding is an important determinant of brain lutein concentrations.

CONCLUSIONS

These data reveal preferential accumulation and maintenance of lutein in the infant brain despite underrepresentation in the typical infant diet. Further investigation on the impact of lutein on neural development in preterm infants is warranted.

Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration

Plant-based macular xanthophylls (MXs; lutein and zeaxanthin) and the lutein metabolite meso-zeaxanthin are the major constituents of macular pigment, a compound concentrated in retinal areas that are responsible for fine-feature visual sensation. There is an unmet need to examine the genetics of factors influencing regulatory mechanisms and metabolic fates of these 3 MXs because they are linked to processes implicated in the pathogenesis of age-related macular degeneration (AMD). In this work we provide an overview of evidence supporting a molecular basis for AMD-MX associations as they may relate to DNA sequence variation in AMD- and lipoprotein-related genes. We recognize a number of emerging research opportunities, barriers, knowledge gaps, and tools offering promise for meaningful investigation and inference in the field. Overviews on AMD- and high-density lipoprotein (HDL)-related genes encoding receptors, transporters, and enzymes affecting or affected by MXs are followed with information on localization of products from these genes to retinal cell types manifesting AMD-related pathophysiology. Evidence on the relation of each gene or gene product with retinal MX response to nutrient intake is discussed. This information is followed by a review of results from mechanistic studies testing gene-disease relations. We then present findings on relations of AMD with DNA sequence variants in MX-associated genes. Our conclusion is that AMD-associated DNA variants that influence the actions and metabolic fates of HDL system constituents should be examined further for concomitant influence on MX absorption, retinal tissue responses to MX intake, and the capacity to modify MX-associated factors and processes implicated in AMD pathogenesis.

Markers of lutein and zeaxanthin status in two age groups of men and women: dietary intake, serum concentrations, lipid profile and macular pigment optical density

Background & aims

Lutein and zeaxanthin accumulate in retina (macular pigment). Their nutritional status can be assessed using dietary or biochemical markers and both have been associated with macular pigment optical density. We proposed to assess dietary and status markers of lutein and zeaxanthin in a group of healthy Spanish volunteers, considering the potential influence of age, gender and serum lipids to investigate the predictors of the macular pigment optical density.

Methods

Serum lutein and zeaxanthin concentrations, dietary intake and macular pigment optical density were determined in 108 healthy men and women (20–35 and 45–65 years), using high-performance liquid chromatography, 3-day food records and heterochromic flicker photometry, respectively. Mann–Whitney U-test, Spearman correlation coefficient and multivariate regression analysis were used for the statistical study.

Results

Serum concentrations and dietary intake of lutein plus zeaxanthin (p < 0.0001 and p = 0.001, respectively) were higher in older vs younger subjects, whereas macular pigment optical density was lower (p = 0.038). The highest correlation coefficients between intake and serum were for fruit and serum lutein (ρ = 0.452, p < 0.0001) and for fruit and lutein + zeaxanthin (ρ = 0.431, p < 0.0001) in the younger group. Macular pigment optical density correlated with serum xanthophylls (ρ = 0.223, p = 0.02) and fruit and vegetable intake (ρ = 0.350, p = 0.0002), showing highest correlations when lutein and zeaxanthin were expressed in relation to serum lipids in older subjects (ρ = 0.262, p = 0.006). Multivariate regression analysis identified age and serum lutein as major predictors of macular pigment optical density (total sample), and a coefficient of determination of 29.7% for the model including lutein + zeaxathin/cholesterol + triglycerides, sex and fruit + vegetables in the older group.

Conclusions

The establishment of normal/reference ranges for serum lutein and zeaxanthin should consider age ranges and be expressed in relation to lipid concentrations, at least in subjects over 45 years, as this could influence macular pigment optical density. The macular pigment optical density showed age-specific correlations with lutein plus zeaxanthin expressed in relation to serum lipid concentrations as well as with the fruit and vegetable intake.

Dietary, anthropometric, and lifestyle correlates of serum carotenoids in postmenopausal women

PURPOSE

Concentration of carotenoids in the serum is a biomarker of mainly vegetable and fruit consumption. However, the levels of carotenoids in humans may decline with age and can also depend on body fat, alcohol consumption, and cigarette smoking.

METHOD

Food intake and characteristics of 159 randomly chosen women aged 56-75 years were obtained by a self-administered questionnaire. Serum concentrations of carotenoids were determined by high-performance liquid chromatography. Estimation of fat mass was carried out by dual energy X-ray absorptiometry.

RESULTS

The estimated total daily intake of carotenoids was 9.75 mg: α-carotene 10.6%; β-carotene 35.6%; lutein/zeaxanthin 27.1%; β-cryptoxanthin 4.7%; and lycopene 22.0%. We observed statistically significant positive correlations between concentrations of serum carotenoids and their estimated intakes (r = 0.11 lycopene to 0.38 β-carotene) and fruit and vegetable intake (r = 0.15 lycopene to 0.30 β-carotene). Concentration of serum carotenoids positively correlated with education (r = 0.17 α-carotene to 0.29 lycopene) and alcohol intake (r = 0.02 α-carotene to r = 0.25 lycopene). Inverse correlations were with the age (r = -0.18 α-carotene to -0.42 lycopene) and fat mass (r = -0.15 lycopene to -0.29 α-, β-carotene).

CONCLUSION

In this population of healthy postmenopausal women, serum concentrations of carotenoids declined with increasing age and body fat mass. The concentrations were increased among women with high vegetable and fruit consumption, moderate alcohol intake, and high level of education.

The putative role of lutein and zeaxanthin as protective agents against age-related macular degeneration: promise of molecular genetics for guiding mechanistic and translational research in the field

Age-related macular degeneration (AMD) is the primary cause of vision loss in elderly people of western European ancestry. Genetic, dietary, and environmental factors affect tissue concentrations of macular xanthophylls (MXs) within retinal cell types manifesting AMD pathology. In this article we review the history and state of science on the putative role of the MXs (lutein, zeaxanthin, and meso-zeaxanthin) in AMD and report findings on AMD-associated genes encoding enzymes, transporters, ligands, and receptors affecting or affected by MXs. We then use this context to discuss emerging research opportunities that offer promise for meaningful investigation and inference in the field.

Macular pigment optical density and its relationship with refractive status and foveal thickness in Chinese school-aged children

PURPOSE

To investigate macular pigment optical density (MPOD) and its relationship with refractive status and foveal thickness in Chinese school-aged children.

METHODS

Ninety-four healthy Chinese children, 6 to 12 years old, were recruited to the study. MPOD was measured with a heterochromatic flicker photometer (HFP), and foveal thickness, including both minimum and central foveal thicknesses (MFT and CFT, respectively), were measured by optical coherence tomography (OCT) with fast macular map scan. A noncontact tonometer was used to measure intraocular pressure (IOP) followed by determination of the refraction using an autorefractor after cycloplegia. Information on body mass index (BMI) was obtained. The correlation between MPOD values and foveal thickness, spherical equivalent (SE) refraction, IOP, BMI, sex, and age was statistically analyzed using SAS 8.2 statistical software.

RESULTS

The MPOD in examined school-aged children was 0.56 ± 0.25, without any significant difference between boys and girls (p = 0.12). MPOD showed no significant association with age, BMI, IOP, SE, MFT, or CFT. In the myopia group, however, there was an inverse relationship between MPOD and MFT (R =-0.66, p = 0.028) and a positive relationship between MPOD and CFT (R = 0.67, p = 0.025).

CONCLUSIONS

MPOD was inversely related to MFT and positively related to CFT in Chinese school-age children with low-to-moderate myopia. MPOD showed no significant association with age, BMI, IOP, SE or foveal thickness.

Macular pigment optical density in wet age-related macular degeneration among Indians

PURPOSE

To estimate the value of macular pigment optical density (MPOD) in adult south Indian population with wet age-related macular degeneration (AMD).

METHODS

A total of 33 patients with wet AMD and 29 age-matched controls >50 years of age underwent MPOD measurement with the macular densitometer. The patients were also tested for their dietary intake of carotenoids, smoking history, and lifetime UV exposure.

RESULTS

The mean MPOD values in the Indian population with wet AMD was 0.23 (95% CI: 0.18-0.29) vs control was 0.43 (95% CI: 0.37-0.49), P<0.0001, at 0.5° eccentricity. Ex-smokers had a lower MPOD than non-smokers (0.16 (0.09-0.23) vs 0.28 (0.22-0.34), P=0.026) and the lowest level of carotenoids intake had 48% lower MPOD than the highest level (0.14 (0.08-0.21) vs 0.33 (0.24-0.43), P=0.012). There was no significant age-related decline or gender variation in MPOD.

CONCLUSION

This study establishes the MPOD in adult Indian population with wet AMD, with a lack of macular pigment in association with wet AMD.

Lutein: more than just a filter for blue light

Lutein is concentrated in the primate retina, where together with zeaxanthin it forms the macular pigment. Traditionally lutein is characterized by its blue light filtering and anti-oxidant properties. Eliminating lutein from the diet of experimental animals results in early degenerative signs in the retina while patients with an acquired condition of macular pigment loss (Macular Telangiectasia) show serious visual handicap indicating the importance of macular pigment. Whether lutein intake reduces the risk of age related macular degeneration (AMD) or cataract formation is currently a strong matter of debate and abundant research is carried out to unravel the biological properties of the lutein molecule. SR-B1 has recently been identified as a lutein binding protein in the retina and this same receptor plays a role in the selective uptake in the gut. In the blood lutein is transported via high-density lipoproteins (HDL). Genes controlling SR-B1 and HDL levels predispose to AMD which supports the involvement of cholesterol/lutein transport pathways. Apart from beneficial effects of lutein intake on various visual function tests, recent findings show that lutein can affect immune responses and inflammation. Lutein diminishes the expression of various ocular inflammation models including endotoxin induced uveitis, laser induced choroidal neovascularization, streptozotocin induced diabetes and experimental retinal ischemia and reperfusion. In vitro studies show that lutein suppresses NF kappa-B activation as well as the expression of iNOS and COX-2. Since AMD has features of a chronic low-grade systemic inflammatory response, attention to the exact role of lutein in this disease has shifted from a local effect in the eye towards a possible systemic anti-inflammatory function.

The relation between serum lipids and lutein and zeaxanthin in the serum and retina: results from cross-sectional, case-control and case study designs

Background

The xanthophyll carotenoids lutein (L) and zeaxanthin (Z) are found in and around the macula of the primate retina, where they are termed macular pigment (MP). Dietary L and Z are absorbed with fat in the gut and transported on lipoproteins to the retina. Both MP and serum lipoproteins have been related to risk for neurodegenerative diseases such as age-related macular degeneration (AMD). L and Z are carried on both HDL (related to reduced risk of AMD) and LDL (related to increased risk). The purpose of this set of studies was to analyze the relation between L and Z in the serum and retina with the circulating lipid profile.

Methods

In all experiments, lipoproteins were measured enzymatically from plasma, and MP optical density (MPOD) was measured using customized heterochromatic flicker photometry. Experiment 1: Relations between serum L and Z, MPOD and lipoprotein levels. 108 young, healthy subjects (M = 23.2, SD = 4.12 years) participated. Lipoprotein levels and MPOD were measured. In a subset of 66 participants, serum L and Z levels were also measured using high-performance liquid chromatography. Experiment 2: Relations between lipoprotein levels and MPOD in statin users. 20 subjects (M = 58.05, SD = 11.08 years) taking statin medication and 20 subjects (M = 57.95, SD = 11.03 years) not taking satin were recruited for participation. MPOD and lipoprotein levels were measured. Experiment 3: lowering lipoprotein levels to impact MPOD. One individual (aged 41 years) with high MP density adhered first to an atorvastatin regimen, then, after a wash-out period, to a rosuvastatin regimen.

Results

Experiment 1: HDL were significantly (p < 0.05) related to MPOD (r = 0.33), to serum L (r = 0.36) and to serum Z (r = 0.26). MPOD was also significantly related to total cholesterol (r = 0.19). Experiment 2: MPOD was not lower in statin users when compared to matched non-statin users, but MPOD decreased significantly with increased duration of statin use (r = −0.63). Experiment 3: Administration of a statin regimen reduced MPOD with atorvastatin (p < 0.05) but not with rosuvastatin.

Conclusions

Serum xanthophylls, retinal xanthophylls and lipoprotein concentrations are significantly related, and changing lipoprotein levels may impact levels of retinal xanthophylls.

Measuring macular pigment optical density in vivo: a review of techniques

BACKGROUND

Macular pigment has been the focus of much attention in recent years, as a potential modifiable risk factor for age-related macular degeneration. This interest has been heightened by the ability to measure macular pigment optical density (MPOD) in vivo.

METHOD

A systematic literature search was undertaken to identify all available papers that have used in vivo MPOD techniques. The papers were reviewed, and all relevant information was incorporated into this article.

RESULTS

Measurement of MPOD is achievable with a wide range of techniques, which are typically categorized into one of two groups: psychophysical (requiring a response from the subject) or objective (requiring minimal input from the subject). The psychophysical methods include heterochromatic flicker photometry and minimum motion photometry. The objective methods include fundus reflectometry, fundus autofluorescence, resonance Raman spectroscopy and visual evoked potentials. Even within the individual techniques, there is often much variation in how data is obtained and processed.

CONCLUSION

This review comprehensively details the procedure, instrumentation, assumptions, validity and reliability of each MPOD measurement technique currently available, along with their respective advantages and disadvantages. This leads us to conclude that development of a commercial instrument, based on fundus reflectometry or fundus autofluorescence, would be beneficial to macular pigment research and would support MPOD screening in a clinical setting.

Augmentation of macular pigment following supplementation with all three macular carotenoids: an exploratory study

PURPOSE

At the macula, the carotenoids meso-zeaxanthin (MZ), lutein (L), and zeaxanthin (Z) are collectively referred to as macular pigment (MP). This study was designed to measure serum and macular responses to a macular carotenoid formulation.

MATERIALS AND METHODS

Ten subjects were recruited into this study (five normal and five with early age-related macular degeneration [AMD]). Subjects were instructed to consume a formulation containing 7.3 mg of MZ, 3.7 mg of L, and 0.8 mg of Z everyday over an eight-week period. The spatial profile of MP optical density (i.e., MPOD at 0.25 degrees , 0.5 degrees , 1 degrees , and 1.75 degrees ) was measured using customized heterochromatic flicker photometry, and a blood sample was collected at each study visit in order to analyze serum concentrations of MZ, L, and Z.

RESULTS

There was a significant increase in serum concentrations of MZ and L after two weeks of supplementation (p < 0.05). Baseline serum carotenoid analysis detected a small peak eluting at the same time as MZ in all subjects, with a mean +/- SD of 0.02 +/- 0.01 micromol/L. We report significant increases in MPOD at 0.25 degrees , 0.5 degrees , 1 degree , and average MPOD across its spatial profile after just two weeks of supplementation (p < 0.05, for all). Four subjects (one normal and three AMD) who had an atypical MPOD spatial profile (i.e., central dip) at baseline had the more typical MPOD spatial profile (i.e., highest MPOD at the center) after eight weeks of supplementation.

CONCLUSION

We report significant increases in serum concentrations of MZ and L following supplementation with MZ, L, and Z and a significant increase in MPOD, including its spatial profile, after two weeks of supplementation. Also, this study has detected the possible presence of MZ in human serum pre-supplementation and the ability of the study carotenoid formulation to rebuild central MPOD in subjects who have atypical profiles at baseline.

Consumption of 2 and 4 egg yolks/d for 5 wk increases macular pigment concentrations in older adults with low macular pigment taking cholesterol-lowering statins

BACKGROUND

Lutein and zeaxanthin may reduce the risk of dry, age-related macular degeneration because of their photo-oxidative role as macular pigment.

OBJECTIVE

The present study evaluated serum lutein, zeaxanthin, and macular pigment optical density (MPOD) responses at 0.25 degrees , 0.5 degrees , and 1 degree retinal eccentricities to the consumption of 2 and 4 egg yolks/d by older adults taking cholesterol-lowering medications.

DESIGN

Subjects consumed foods containing 2 followed by 4 egg yolks/d for 5 wk each with a 4-wk egg-free period at baseline and between the 2 interventions.

RESULTS

Changes in MPOD (n = 37) with egg yolk consumption were inversely associated (P < 0.05) with baseline MPOD. Subjects with low-baseline MPOD (defined as MPOD < or =0.5 at 0.25 degrees , < or =0.4 at 0.5 degrees , and < or =0.35 at 1 degrees ) showed increases of < or =50% (P < 0.05) with 4 egg yolks at the 3 retinal eccentricities. MPOD increased by 31% (P = 0.059) at 0.5 degrees with 2 egg yolks. Serum lutein increased by only 16% and 24% (P < 0.05) compared with increases of 36% and 82% (P < 0.001) in serum zeaxanthin (n = 52) after consumption of 2 and 4 egg yolks, respectively. Serum HDL cholesterol increased by 5% (P < 0.05) after consumption of 2 and 4 egg yolks. Serum LDL cholesterol did not change with either egg yolk treatment.

CONCLUSIONS

Consumption of 4 egg yolks/d, and possibly of 2 egg yolks/d, for 5 wk benefited macular health in older adults with low MPOD. Serum HDL cholesterol increased without an increase in LDL cholesterol in this study population, most of whom were taking cholesterol-lowering statins.

[The macular pigment: short- and intermediate-term changes of macular pigment optical density following supplementation with lutein and zeaxanthin and co-antioxidants. The LUNA Study]

BACKGROUND

How long do the elevated concentrations of macular pigment persist after stopping supplementation with lutein and zeaxanthin?

METHODS

One hundred eight (108) probands with and without age-related macular degeneration (68 female, 40 male, age 51-87 years) received a supplement containing 12 mg lutein and 1 mg zeaxanthin once per day (Ocuvite lutein) for 6 months. Analysis of macular pigment optical density (MPOD) was performed during the period of supplementation and again 3, 6, and 9 months following discontinuation of the supplement. A control group of 28 subjects received no dietary supplement.

RESULTS

At baseline, the mean MPOD at 0.5 degrees was 0.50 in the supplemented group. Following supplementation, values rose, and 3 months after discontinuation of supplementation the highest levels of MPOD0.5 degrees (0.59 ODU) were detected (increase of +0.1 ODU, (p<0.001). Six months after supplement discontinuation, a slight decrease of mean MPOD0.5 degrees appeared (to 0.54 ODU), followed again by a slight increase 3 months later (to 0.57 ODU). An increment of MPOD0.5 degrees in the control group was not significant (0.03 ODU, p=0.15).

DISCUSSION

Supplementation of lutein and zeaxanthin leads to an increase of MPOD0.5 degrees . This effect outlasts the duration of intake, and 9 months after supplementation was stopped, the mean MPOD0.5 degrees was still elevated compared with baseline levels. A longer follow-up subsequent to stopping supplementation might clarify whether the values decrease over time or whether a plateau of elevated MPOD levels is reached. High doses of lutein and zeaxanthin seem to be necessary to increase macular pigment density in the retina; afterwards, the amount of carotenoids needed to maintain high concentrations seems to be covered by daily food.

The Effect of the AcrySof natural lens on glare disability and photostress

PURPOSE

To investigate whether implanting "blue-filtering" yellow intraocular lenses (IOL) could provide a visual benefit in terms of glare disability and photostress recovery.

DESIGN

A case-control study.

METHODS

Researchers masked to group assignments tested 58 subjects: 17 with yellow IOLs (AcrySof Natural; SN60WF; Alcon Laboratories Inc, Fort Worth, Texas, USA), 20 with clear IOLs, and 21 phakic controls. Photostress recovery and visual acuity under veiling glare conditions were assessed in a Maxwellian view optical system. Photostress recovery was assessed by measuring the time required to detect a grating stimulus (1 degree diameter) after a 5-second exposure to an intense circular disk (1 degree diameter) of broad-band xenon light. For the veiling glare experiment, subjects fixated on the grating stimulus, and the intensity of a broad-band xenon annulus (the glare source, 10 degrees inner, 12 degrees outer diameter) was adjusted until the grating stimulus was no longer seen.

RESULTS

Subjects with AcrySof Natural (P < .0001) and clear IOLs (P < .035) could withstand significantly more light than the phakic controls. Subjects with the AcrySof Natural lens could withstand significantly more light (P < .02) than subjects with clear IOLs. Photostress recovery was significantly longer for subjects with clear IOLs vs phakic controls (P < .01), but the AcrySof Natural lens was not different from phakic controls (P < .09). Photostress recovery was similar between subjects with clear or AcrySof Natural lens (P < .32).

CONCLUSION

The AcrySof Natural lens is related to reduced glare disability relative to a clear IOL or phakic controls.

Long-term plant stanol and sterol ester-enriched functional food consumption, serum lutein/zeaxanthin concentration and macular pigment optical density

Observational epidemiological studies have shown that low carotenoid intake and/or low carotenoid blood levels increase the risk of degenerative diseases like age-related macular degeneration. Functional foods enriched with plant sterol or stanol esters may lower serum concentrations of fat-soluble carotenoids. Theoretically, as a result the macular pigment optical density (MPOD), a marker for eye health, may change. We carried out a double-blind placebo-controlled human intervention trial with a duration of 18 months to evaluate the possible effects of plant stanol and sterol esters on serum lutein/zeaxanthin concentration in relation to the MPOD. Forty-seven subjects were randomly assigned to one of the three treatment groups: margarine without added plant sterols or stanols, plant sterol-enriched margarine, or plant stanol-enriched margarine. Serum cholesterol and lutein/zeaxanthine concentrations and the MPOD were evaluated at baseline and at study end. Changes in lipid-adjusted serum lutein/zeaxanthine concentrations between baseline and study end differed significantly between the three groups (P = 0.001). We found no differences in the MPOD between the three treatment groups, despite the differences in both absolute and cholesterol-standardized serum lutein/zeaxanthine concentrations. This shows that the observed reduction in serum carotenoid concentrations during 18 months consumption of these functional foods does not affect MPOD.

Monthly Consistency of Macular Pigment Optical Density and Serum Concentrations of Lutein and Zeaxanthin

PURPOSE

This study was undertaken to assess serial month-to-month consistency of macular pigment (MP) optical density and serum concentrations of lutein (L) and zeaxanthin (Z). Four healthy subjects aged between 23 and 51 years volunteered to participate in this study.

METHODS

MP optical density (measured psychophysically using heterochromatic flicker photometry [HFP]), and serum concentrations of L and Z (quantified using high-performance liquid chromatography [HPLC]), were recorded every month for 24 consecutive months.

RESULTS

Mean MP optical density (+/-SD) was 0.361 (0.086) and 0.369 (0.074) for right and left eyes, respectively. There was no statistically significant seasonal variation in MP optical density for the group (two-way ANOVA: p>0.05). Serum concentrations of L and Z demonstrated a statistically significant subject-season interaction effect (two-way ANOVA: p<0.01). Serial serum concentrations of L and Z were positively correlated within all four subjects (r=0.370 to 0.786), and significantly so for three subjects (p<0.05). There was no obvious relationship, synchronous or lagged, between serum concentrations of L (or Z) and MP optical density (r=-0.036 to 0.368).

CONCLUSIONS

MP optical density was relatively stable for all subjects over the 24-month period. Fluctuations in serum concentrations of L and Z, in the absence of dietary modification or supplementation, are associated with stable MP optical density.

Where Do Eggs Fit in a Heart-Healthy Diet?

Eggs make up a relatively small contribution to the energy consumption of the average American, in part because of the perception that the cholesterol content makes them a forbidden food for a heart-healthy diet. The relationship between egg cholesterol, blood cholesterol, and cardiovascular disease risk is complex and not clearly understood. In addition, eggs provide many valuable and bioavailable nutrients. Thus, the place of eggs in meal planning should be reconsidered while keeping in mind the diet and lifestyle recommendations of the American Heart Association.

Associations between lutein, zeaxanthin, and age-related macular degeneration: an overview

Age-related macular degeneration, the leading cause of blindness in the elderly, is a degenerative condition of the macula characterized by death or dysfunction of the photoreceptors. With the aging population growing, the incidence of age-related macular degeneration is expected to increase. This raises concern about the future of visual dysfunction related falls and the resulting injuries in the elderly population. Lutein and zeaxanthin are macular pigments that may play a role in reducing the development and progression of age-related macular degeneration. Evidence is accumulating on the consumption of lutein and zeaxanthin (in whole food or supplemental form), the resulting concentrations in the serum, and tissue distribution throughout the body, particularly in the retina. Lutein and zeaxanthin intake increases serum concentrations which in turn increases macular pigment density. Existing literature focuses on factors affecting macular pigment density, functions of lutein and zeaxanthin as blue-light filters and antioxidants, and risk factors associated with age-related macular degeneration. Few studies have focused on the impact of dietary lutein and zeaxanthin on retinal function and the potential to preserve vision and prevent further degeneration. This presents an opportunity for further research to determine an effective dose that delays the progression of age-related macular degeneration.