Lutein and zeaxanthin intake and the risk of age-related macular degeneration: a systematic review and meta-analysis

Effects of Lutein and Zeaxanthin on LPS-Induced Secretion of IL-8 by Uveal Melanocytes and Relevant Signal Pathways

The effects of lutein and zeaxanthin on lipopolysaccharide- (LPS-) induced secretion of IL-8 by uveal melanocytes (UM) were tested in cultured human UM. MTT assay revealed that LPS (0.01-1 μg/mL) and lutein and zeaxanthin (1-10 μM) did not influence the cell viability of cultured UM. LPS caused a dose-dependent increase of secretion of IL-8 by cultured UM. Lutein and zeaxanthin did not affect the constitutive secretion of IL-8. However, lutein and zeaxanthin decreased LPS-induced secretion of IL-8 in cultured UM in a dose-dependent manner. LPS significantly increased NF-κB levels in cell nuclear extracts and p-JNK levels in the cell lysates from UM, but not p-p38 MAPK and p-ERG. Lutein or zeaxanthin significantly reduced LPS-induced increase of NF-κB and p-JNK levels, but not p38 MAPK and ERG levels. The present study demonstrated that lutein and zeaxanthin inhibited LPS-induced secretion of IL-8 in cultured UM via JNK and NF-κB signal pathways. The anti-inflammatory effects of lutein and zeaxanthin might be explored as a therapeutic approach in the management of uveitis and other inflammatory diseases of the eye.

Adherence to a Mediterranean diet, genetic susceptibility, and progression to advanced macular degeneration: a prospective cohort study

BACKGROUND

Adherence to a Mediterranean-type diet is linked to a lower risk of mortality and chronic disease, but the association with the progression of age-related macular degeneration (AMD) and genetic susceptibility is unknown.

OBJECTIVE

We examined the association of adherence to the Mediterranean diet and genetic susceptibility with progression to advanced AMD.

DESIGN

Among 2525 subjects in the AREDS (Age-Related Eye Disease Study), 1028 eyes progressed to advanced AMD over 13 y. Baseline data for demographic and behavioral covariates were collected by using questionnaires. Dietary data were collected from food-frequency questionnaires. The alternate Mediterranean diet (aMeDi) score (range: 0-9) was constructed from individual intakes of vegetables, fruit, legumes, whole grains, nuts, fish, red and processed meats, alcohol, and the ratio of monounsaturated to saturated fats. Ten genetic loci in 7 genes [complement factor H (CFH), age-related maculopathy susceptibility 2/high-temperature requirement A serine peptidase 1 (ARMS2/HTRA1), complement component 2 (C2), complement factor B (CFB), complement component 3 (C3), collagen type VIII α 1 (COL8A1), and RAD51 paralog B (RAD51B)] were examined. Survival analysis was used to assess individual eyes for associations between incident AMD and aMeDi score, as well as interaction effects between aMeDi score and genetic variation on risk of AMD.

RESULTS

A high aMeDi score (score of 6-9) was significantly associated with a reduced risk of progression to advanced AMD after adjustment for demographic, behavioral, ocular, and genetic covariates (HR: 0.74; 95% CI: 0.61, 0.91; P-trend = 0.007). The aMeDi score was significantly associated with a lower risk of incident advanced AMD among subjects carrying the CFH Y402H nonrisk (T) allele (P-trend = 0.0004, P-interaction = 0.04). The aMeDi score was not associated with AMD among subjects who were homozygous for the risk (C) allele.

CONCLUSION

Higher adherence to a Mediterranean diet was associated with reduced risk of progression to advanced AMD, which may be modified by genetic susceptibility. This trial was registered at clinicaltrials.gov as NCT00594672.

Lutein and Brain Function

Lutein is one of the most prevalent carotenoids in nature and in the human diet. Together with zeaxanthin, it is highly concentrated as macular pigment in the foveal retina of primates, attenuating blue light exposure, providing protection from photo-oxidation and enhancing visual performance. Recently, interest in lutein has expanded beyond the retina to its possible contributions to brain development and function. Only primates accumulate lutein within the brain, but little is known about its distribution or physiological role. Our team has begun to utilize the rhesus macaque (Macaca mulatta) model to study the uptake and bio-localization of lutein in the brain. Our overall goal has been to assess the association of lutein localization with brain function. In this review, we will first cover the evolution of the non-human primate model for lutein and brain studies, discuss prior association studies of lutein with retina and brain function, and review approaches that can be used to localize brain lutein. We also describe our approach to the biosynthesis of ¹³C-lutein, which will allow investigation of lutein flux, localization, metabolism and pharmacokinetics. Lastly, we describe potential future research opportunities.

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.

Effect of supplemental lutein and zeaxanthin on serum, macular pigmentation, and visual performance in patients with early age-related macular degeneration

Purpose. To compare the 2-year effect of multiple doses of lutein/zeaxanthin on serum, macular pigmentation, and visual performance on patients with early age-related macular degeneration (AMD). Methods. In this randomized, double-blinded, and placebo-controlled trial, 112 early AMD patients randomly received either 10 mg lutein, 20 mg lutein, a combination of lutein (10 mg) and zeaxanthin (10 mg), or placebo daily for 2 years. Serum concentration of lutein/zeaxanthin, macular pigment optical density (MPOD), visual functions including best-spectacle corrected visual acuity (BCVA), contrast sensitivity (CS), flash recovery time (FRT), and vision-related quality of life (VFQ25) was quantified. Results. Serum lutein concentration and MPOD significantly increased in all the active treatment groups. Supplementation with 20 mg lutein was the most effective in increasing MPOD and CS at 3 cycles/degree for the first 48 weeks. However, they both significantly increased to the same peak value following supplementation with either 10 mg or 20 mg lutein during the intervention. No statistical changes of BCVA or FRT were observed during the trial. Conclusions. Long-term lutein supplementation could increase serum lutein concentration, MPOD, and visual sensitivities of early AMD patients. 10 mg lutein daily might be an advisable long-term dosage for early AMD treatment.

Lutein and Factor D: two intriguing players in the field of age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive eye disease that impairs central vision among elderly populations in Western, industrialized countries. In this review we will focus on the role of factor D (FD) and lutein in AMD. FD is a rate-limiting enzyme of the alternative complement activation pathway that may play an important role in the development of AMD. Several independent studies have shown a significant increase in the level of a number of complement factors of the alternative pathway, including factor D in the blood of AMD patients as compared to healthy individuals, which suggests a systemic involvement in the pathogenesis of AMD. FD, also called adipsin, is mainly produced by adipose tissue. Besides playing a role in the activation of the alternative pathway, FD is also known to regulate the immune system. Of interest is our preliminary finding that lutein supplementation of early AMD cases was shown to lower the level of systemic FD. If confirmed, these findings provide further support for the application of anti-factor D intervention as a new approach to control the development of this disease.

An Evidence-Based Systematic Review of Lutein by the Natural Standard Research Collaboration

An evidence-based systematic review of lutein by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated, reproducible grading rationale. This article includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

Zeaxanthin inhibits hypoxia-induced VEGF secretion by RPE cells through decreased protein levels of hypoxia-inducible factors-1α

Hypoxia is the most important stimulus leading to upregulation of VEGF in the retina and this is caused by accumulation of hypoxia-inducible factors-1α (HIF-1α) protein. The effects of zeaxanthin, a natural phytochemical, on the VEGF and HIF-1α expression in the primary culture of human retinal pigment epithelial (RPE) cells were studied. An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2) to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without zeaxanthin under normoxic and hypoxic conditions. VEGF and HIF-1α protein and RNA levels were measured by ELISA kits and RT-PCR, respectively. Hypoxia caused a significant increase of VEGF expression and accumulation of HIF-1α in RPE cells. Zeaxanthin at 50-150 μM significantly inhibited the expression of VEGF and accumulation of HIF-1α protein caused by hypoxia but did not affect expression of VEGF and HIF-1α under normoxic conditions. This is the first report on the effect of zeaxanthin on VEGF and HIF-1α levels in cultured RPE cells and suggests that zeaxanthin may have potential value in the prevention and treatment of various retinal diseases associated with vascular leakage and neovascularization.

Nutraceuticals for geriatrics

Geriatrics is a medical practice that addresses the complex needs of older patients and emphasizes maintaining functional independence even in the presence of chronic disease. Treatment of geriatric patients requires a different strategy and is very complex. Geriatric medicines aim to promote health by preventing and treating diseases and disabilities in older adults. Development of effective dietary interventions for promoting healthy aging is an active but challenging area of research because aging is associated with an increased risk of chronic disease, disability, and death. Aging populations are a global phenomenon. The most widespread conditions affecting older people are hypertension, congestive heart failure, dementia, osteoporosis, breathing problems, cataract, and diabetes to name a few. Decreased immunity is also partially responsible for the increased morbidity and mortality resulting from infectious agents in the elderly. Nutritional status is one of the chief variables that explains differences in both the incidence and pathology of infection. Elderly people are at increased risk for micronutrient deficiencies due to a variety of factors including social, physical, economic, and emotional obstacles to eating. Thus there is an urgent need to shift priorities to increase our attention on ways to prevent chronic illnesses associated with aging. Individually, people must put increased efforts into establishing healthy lifestyle practices, including consuming a more healthful diet. The present review thus focuses on the phytochemicals of nutraceutical importance for the geriatric population.

Severity of coronary artery disease is independently associated with the frequency of early age-related macular degeneration

BACKGROUND/AIMS

To describe the prevalence of early, late and any age-related macular degeneration (AMD) in a clinical cohort (Australian Heart Eye Study, AHES) and to determine whether associations exist between extent and severity of coronary artery disease (CAD) and AMD, independent of traditional cardiovascular risk factors.

METHODS

The AHES is an observational study that surveyed 1680 participants between 2009 and 2012 who presented to a tertiary referral hospital for the evaluation of potential CAD by coronary angiography. Severity and extent of CAD was assessed using three scoring systems: (1) segment/vessel scores, (2) Gensini and (3) extent scores.

RESULTS

Prevalence of early and late AMD was 5.8% (n=86) and 1.4% (n=21), respectively. After multivariable adjustment, patients with stenosis >50% in any coronary artery segment (vessel score) had approximately twofold higher odds of early AMD, OR 1.95 (95% CI 1.07 to 3.57). Patients with obstructive coronary stenosis in all three main coronary arteries (segment score) had greater than twofold higher likelihood of early AMD, OR 2.67 (95% CI 1.24 to 5.78). Participants in the highest versus lowest tertile of Gensini scores were also twice as likely to have early AMD, multivariable-adjusted OR 2.27 (95% CI 1.12 to 4.58). Extent scores were not associated with AMD. There was no significant association between CAD and late AMD.

CONCLUSIONS

Severity of coronary stenosis and the presence of stenotic lesions were independently associated with early AMD. These findings could have potential clinical significance as they suggest that individuals with evidence of CAD may be screened for early AMD.

Autofluorescence imaging of macular pigment: influence and correction of ocular media opacities

The healthy adult human retina contains in its macular region a high concentration of blue-light absorbing carotenoid compounds, known as macular pigment (MP). Consisting of the carotenoids lutein, zeaxanthin, and meso-zeaxanthin, the MP is thought to shield the vulnerable tissue layers in the retina from lightinduced damage through its function as an optical attenuator and to protect the tissue cells within its immediate vicinity through its function as a potent antioxidant. Autofluorescence imaging (AFI) is emerging as a viable optical method for MP screening of large subject populations, for tracking of MP changes over time, and for monitoring MP uptake in response to dietary supplementation. To investigate the influence of ocular media opacities on AFI-based MP measurements, in particular, the influence of lens cataracts, we conducted a clinical trial with a large subject population (93 subjects) measured before and after cataract surgery. General AFI image contrast, retinal blood vessel contrast, and presurgery lens opacity scores [Lens Opacities Classification System III (LOCS III)] were investigated as potential predictors for image degradation. These clinical results show that lens cataracts can severely degrade the achievable pixel contrasts in the AFI images, which results in nominal MP optical density levels that are artifactually reduced. While LOCS III scores and blood vessel contrast are found to be only a weak predictor for this effect, a strong correlation exists between the reduction factor and the image contrast, which can be quantified via pixel intensity histogram parameters. Choosing the base width of the histogram, the presence or absence of ocular media opacities can be determined and, if needed, the nominal MP levels can be corrected with factors depending on the strength of the opacity.

Plasma lutein concentrations are related to dietary intake, but unrelated to dietary saturated fat or cognition in young children

Lutein and zeaxanthin are xanthophyll carotenoids present in highly pigmented vegetables and fruits. Lutein is selectively accumulated in the brain relative to other carotenoids. Recent evidence has linked lutein to cognition in older adults, but little is known about lutein in young children, despite structural brain development. We determined lutein intake using FFQ, one 24 h recall and three 24 h recalls, plasma lutein concentrations and their association with cognition in 160 children 5·6–5·9 years of age, at low risk for neurodevelopmental delay. Plasma lutein was skewed, with a median of 0·23 (2·5th to 95th percentile range 0·11–0·53) µmol/l. Plasma lutein showed a higher correlation with lutein intake estimated as the average of three 24 h recalls (r 0·479; P = 0·001), rather than one 24 h recall (r 0·242; P = 0·003) or FFQ (r 0·316; P = 0·001). The median lutein intake was 697 (2·5th to 95th percentile range 178–5287) µg/d based on three 24 h recalls. Lutein intake was inversely associated with SFA intake, but dietary fat or SFA intakes were not associated with plasma lutein. No associations were found between plasma lutein or lutein intake and any measure of cognition. While subtle independent effects of lutein on child cognition are possible, separating these effects from covariates making an impact on both child diet and cognition may be difficult.

Consumption of dairy products and the 15-year incidence of age-related macular degeneration

Habitual consumption of dairy products has been shown to play an important role in the prevention of several chronic diseases. We aimed to prospectively assess the relationship between the change in dairy product consumption (both regular fat and low/reduced fat) and the 15-year incidence of age-related macular degeneration (AMD). In the Blue Mountains Eye Study, 2037 participants aged 49 years or above at baseline were re-examined at follow-up in 1997-9, 2002-4 and/or 2007-9. AMD was assessed from retinal photographs. Dietary data were collected using a semi-quantitative FFQ, and servings of dairy product consumption calculated. Over the 15-year follow-up, there were 352, 268 and eighty-four incident cases of any, early and late AMD, respectively. After adjusting for age, sex, current smoking, white cell count and fish consumption, a significant linear trend (P for trend = 0·003) was observed with decreasing consumption of total dairy foods and the 15-year incidence of late AMD, comparing the lowest v. highest quintile of intake (OR 2·80, 95 % CI 1·21, 3·04). Over the 15 years, decreased consumption of reduced-fat dairy foods was associated with an increased risk of incident late AMD, comparing the lowest to highest quintile of intake (OR 3·10, 95 % CI 1·18, 8·14, P for trend = 0·04). Decreasing total dietary Ca intake over the 15 years was also associated with an increased risk of developing incident late AMD (multivariable-adjusted P for trend = 0·03). A lower consumption of dairy products (regular and low fat) and Ca was independently associated with a higher risk of developing incident late AMD in the long term. Additional cohort studies are needed to confirm these findings.

Optimization of the ultrasound-assisted synthesis of lutein disuccinate using uniform design

The ultrasound-assisted synthesis of lutein disuccinate from all-trans lutein (AL) and succinic anhydride (SA) was investigated in this study. Triethylamine was used as the catalyst. Based on the single-factor experiments, a 7-level-3-factor uniform design and response surface analysis were further employed to evaluate the effects of the selected variables including molar ratio of SA/AL, reaction time and ultrasonic power on the yield of lutein disuccinate. The results indicated that the data were adequately fitted into a second-order polynomial model; the molar ratio of SA/AL significantly affected the synthesis of lutein disuccinate, whereas reaction time and ultrasonic power did not. Based on ridge max analysis, the optimum condition for lutein disuccinate synthesis was predicted to be the molar ratio of SA/AL 265.3:1, ultrasonic power 300 W and reaction time 131.6 min with the lutein disuccinate yield of 80.53±0.18%, which give a 43.8% increase compared with the traditional method, and also significantly shorten the reaction time.

Association of HDL-related loci with age-related macular degeneration and plasma lutein and zeaxanthin: the Alienor study

BACKGROUND

Several genes implicated in high-density lipoprotein (HDL) metabolism have been reported to be associated with age-related macular degeneration (AMD). Furthermore, HDL transport the two carotenoids, lutein and zeaxanthin, which are highly suspected to play a key-role in the protection against AMD. The objective is to confirm the associations of HDL-related loci with AMD and to assess their associations with plasma lutein and zeaxanthin concentrations.

METHODS

Alienor study is a prospective population-based study on nutrition and age-related eye diseases performed in 963 elderly residents of Bordeaux, France. AMD was graded according to the international classification, from non-mydriatic colour retinal photographs. Plasma lutein and zeaxanthin were determined by normal-phase high-performance liquid chromatography. The following polymorphisms were studied: rs493258 and rs10468017 (LIPC), rs3764261 (CETP), rs12678919 (LPL) and rs1883025 (ABCA1).

RESULTS

After multivariate adjustment, the TT genotype of the LIPC rs493258 variant was significantly associated with a reduced risk for early and late AMD (OR=0.64, 95%CI: 0.41-0.99; p=0.049 and OR=0.26, 95%CI: 0.08-0.85; p=0.03, respectively), and with higher plasma zeaxanthin concentrations (p=0.03), while plasma lipids were not significantly different according to this SNP. Besides, the LPL variant was associated with early AMD (OR=0.67, 95%CI: 0.45-1.00; p=0.05) and both with plasma lipids and plasma lutein (p=0.047). Associations of LIPC rs10468017, CETP and ABCA1 polymorphisms with AMD did not reach statistical significance.

CONCLUSION

These findings suggest that LIPC and LPL genes could both modify the risk for AMD and the metabolism of lutein and zeaxanthin.

Review of nutrient actions on age-related macular degeneration

The actions of nutrients and related compounds on age-related macular degeneration (AMD) are explained in this review. The findings from 80 studies published since 2003 on the association between diet and supplements in AMD were reviewed. Antioxidants and other nutrients with an effect on AMD susceptibility include carotenoids (lutein and zeaxanthin, β-carotene), vitamins (vitamin A, E, C, D, B), mineral supplements (zinc, copper, selenium), dietary fatty acids [monounsaturated fatty acids, polyunsaturated fatty acids (PUFA both omega-3 PUFA and omega-6 PUFA), saturated fatty acids and cholesterol], and dietary carbohydrates. The literature revealed that many of these antioxidants and nutrients exert a protective role by functioning synergistically. Specifically, the use of dietary supplements with targeted actions can provide minimal benefits on the onset or progression of AMD; however, this does not appear to be particularly beneficial in healthy people. Furthermore, some supplements or nutrients have demonstrated discordant effects on AMD in some studies. Since intake of dietary supplements, as well as exposure to damaging environmental factors, is largely dependent on population habits (including dietary practices) and geographical localization, an overall healthy diet appears to be the best strategy in reducing the risk of developing AMD. As of now, the precise mechanism of action of certain nutrients in AMD prevention remains unclear. Thus, future studies are required to examine the effects that nutrients have on AMD and to determine which factors are most strongly correlated with reducing the risk of AMD or preventing its progression.

Reflection-based imaging of macular pigment distributions in infants and children

We have developed a reflection-based capability of the RetCam(®) platform, an FDA-cleared pediatric retinal-imaging instrument, for the purpose of measuring macular pigment levels as well as their spatial distributions in infants and children. Our modifications include narrow-band blue-wavelength excitation of the macular pigment absorption in combination with spectrally selective blue-wavelength readout of the reflection signals received by the instrument's CCD detector array. Furthermore, an algorithm is developed that allows the computation of optical density maps for the macular pigment relative to peripheral retinal areas. This made it possible for the first time to directly measure macular pigment levels and their spatial features in the developing human retina. In contrast to adults, infants with measurable pigment levels had almost exclusively a narrow, circularly symmetric, pigment distribution. The described methodology holds promise for future investigations into the role of macular pigment in the developing human retina and the effect of dietary interventions in diseases resulting from a lack of normal carotenoid levels.

Food predictors of plasma carotenoids

Empirical prediction models that weight food frequency questionnaire (FFQ) food items by their relation to nutrient biomarker concentrations may estimate nutrient exposure better than nutrient intakes derived from food composition databases. Carotenoids may especially benefit because contributing foods vary in bioavailability and assessment validity. Our objective was to develop empirical prediction models for the major plasma carotenoids and total carotenoids and evaluate their validity compared with dietary intakes calculated from standard food composition tables. 4180 nonsmoking women in the Nurses’ Health Study (NHS) blood subcohort with previously measured plasma carotenoids were randomly divided into training (n = 2787) and testing (n = 1393) subsets. Empirical prediction models were developed in the training subset by stepwise selection from foods contributing ≥0.5% to intake of the relevant carotenoid. Spearman correlations between predicted and measured plasma concentrations were compared to Spearman correlations between dietary intake and measured plasma concentrations for each carotenoid. Three to 12 foods were selected for the α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, lycopene, and total carotenoids prediction models. In the testing subset, Spearman correlations with measured plasma concentrations for the calculated dietary intakes and predicted plasma concentrations, respectively, were 0.31 and 0.37 for α-carotene, 0.29 and 0.31 for β-carotene, 0.36 and 0.41 for β-cryptoxanthin, 0.28 and 0.31 for lutein/zeaxanthin, 0.22 and 0.23 for lycopene, and 0.22 and 0.27 for total carotenoids. Empirical prediction models may modestly improve assessment of some carotenoids, particularly α-carotene and β-cryptoxanthin.

Zeaxanthin Induces Apoptosis in Human Uveal Melanoma Cells through Bcl-2 Family Proteins and Intrinsic Apoptosis Pathway

The cytotoxic effects of zeaxanthin on two human uveal melanoma cell lines (SP6.5 and C918) and related signaling pathways were studied and compared to effects on normal ocular cells (uveal melanocytes, retinal pigment epithelial cells, and scleral fibroblasts). MTT assay revealed that zeaxanthin reduced the cell viability of melanoma cells in a dose-dependent manner (10, 30, and 100 μM), with IC₅₀ at 40.8 and 28.7 μM in SP6.5 and C918 cell lines, respectively. Zeaxanthin did not affect the viability of normal ocular cells even at the highest levels tested (300 μM), suggesting that zeaxanthin has a selectively cytotoxic effect on melanoma cells. Zeaxanthin induced apoptosis in melanoma cells as indicated by annexin V and ethidium III flow cytometry. Western blot analysis demonstrated that zeaxanthin decreased the expression of antiapoptotic proteins (Bcl-2 and Bcl-xL) and increased the expression of proapoptotic proteins (Bak and Bax) in zeaxanthin-treated melanoma cells. Zeaxanthin increased mitochondrial permeability as determined by JC-1 fluorescein study. Zeaxanthin also increased the level of cytosol cytochrome c and caspase-9 and -3 activities, but not caspase-8, as measured by ELISA assay or colorimetric assay. All of these findings indicate that the intrinsic (mitochondrial) pathway is involved in zeaxanthin-induced apoptosis in uveal melanoma cells.

Diminishing risk for age-related macular degeneration with nutrition: a current view

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. Clinical hallmarks of AMD are observed in one third of the elderly in industrialized countries. Preventative interventions through dietary modification are attractive strategies, because they are more affordable than clinical therapies, do not require specialists for administration and many studies suggest a benefit of micro- and macro-nutrients with respect to AMD with few, if any, adverse effects. The goal of this review is to provide information from recent literature on the value of various nutrients, particularly omega-3 fatty acids, lower glycemic index diets and, perhaps, some carotenoids, with regard to diminishing risk for onset or progression of AMD. Results from the upcoming Age-Related Eye Disease Study (AREDS) II intervention trial should be particularly informative.

Blue-light reflectance imaging of macular pigment in infants and children

PURPOSE

While the role of the macular pigment carotenoids in the prevention of age-related macular degeneration has been extensively studied in adults, comparatively little is known about the physiology and function of lutein and zeaxanthin in the developing eye. We therefore developed a protocol using a digital video fundus camera (RetCam) to measure macular pigment optical density (MPOD) and distributions in premature infants and in children.

METHODS

We used blue light reflectance to image the macular pigment in premature babies at the time of retinopathy of prematurity (ROP) screening and in children aged under 7 years who were undergoing examinations under anesthesia for other reasons. We correlated the MPOD with skin carotenoid levels measured by resonance Raman spectroscopy, serum carotenoids measured by HPLC, and dietary carotenoid intake.

RESULTS

We enrolled 51 infants and children ranging from preterm to age 7 years. MPOD correlated significantly with age (r = 0.36; P = 0.0142), with serum lutein + zeaxanthin (r = 0.44; P = 0.0049) and with skin carotenoid levels (r = 0.42; P = 0.0106), but not with dietary lutein + zeaxanthin intake (r = 0.13; P = 0.50). All premature infants had undetectable macular pigment, and most had unusually low serum and skin carotenoid concentrations.

CONCLUSIONS

Our most remarkable finding is the undetectable MPOD in premature infants. This may be due in part to foveal immaturity, but the very low levels of serum and skin carotenoids suggest that these infants are carotenoid insufficient as a consequence of low dietary intake and/or severe oxidative stress. The potential value of carotenoid supplementation in the prevention of ROP and other disorders of prematurity should be a fruitful direction for further investigation.

Inhibitory effects of astaxanthin, β-cryptoxanthin, canthaxanthin, lutein, and zeaxanthin on cytochrome P450 enzyme activities

Astaxanthin, β-cryptoxanthin, canthaxanthin, lutein and zeaxanthin, the major xanthophylls, are widely used in food, medicine, and health care products. To date, no studies regarding the inhibitory effects of these xanthophylls on the nine CYPs isozymes have been reported. This study investigated the reversible and time-dependent inhibitory potentials of five xanthophylls on CYPs activities in vitro. The reversible inhibition results showed that the five compounds had only a weak inhibitory effect on the nine CYPs. Lutein did not inhibit the nine CYPs activities. Astaxanthin weakly inhibited CYP2C19, with an IC₅₀ of 16.2 μM; and β-cryptoxanthin weakly inhibited CYP2C8, with an IC₅₀ of 13.8 μM. In addition, canthaxanthin weakly inhibited CYP2C19 and CYP3A4/5, with IC₅₀ values of 10.9 and 13.9 μM, respectively. Zeaxanthin weakly inhibited CYP3A4/5, with an IC₅₀ of 15.5 μM. However, these IC₅₀ values were markedly greater than the Cmax values reported in humans. No significant IC₅₀ shift was observed in the time-dependent inhibition screening. Based on these observations, it is unlikely that these five xanthophylls from the diet or nutritional supplements alter the pharmacokinetics of drugs metabolized by CYPs. These findings provide some useful information for the safe use of these five xanthophylls in clinical practice.

Dietary sources of lutein and zeaxanthin carotenoids and their role in eye health

The eye is a major sensory organ that requires special care for a healthy and productive lifestyle. Numerous studies have identified lutein and zeaxanthin to be essential components for eye health. Lutein and zeaxanthin are carotenoid pigments that impart yellow or orange color to various common foods such as cantaloupe, pasta, corn, carrots, orange/yellow peppers, fish, salmon and eggs. Their role in human health, in particular the health of the eye, is well established from epidemiological, clinical and interventional studies. They constitute the main pigments found in the yellow spot of the human retina which protect the macula from damage by blue light, improve visual acuity and scavenge harmful reactive oxygen species. They have also been linked with reduced risk of age-related macular degeneration (AMD) and cataracts. Research over the past decade has focused on the development of carotenoid-rich foods to boost their intake especially in the elderly population. The aim of this article is to review recent scientific evidences supporting the benefits of lutein and zexanthin in preventing the onset of two major age-related eye diseases with diets rich in these carotenoids. The review also lists major dietary sources of lutein and zeaxanthin and refers to newly developed foods, daily intake, bioavailability and physiological effects in relation to eye health. Examples of the newly developed high-lutein functional foods are also underlined.

Lutein supplementation reduces plasma lipid peroxidation and C-reactive protein in healthy nonsmokers

OBJECTIVE

The aim of this study was to determine whether lutein affected biomarkers related to cardiovascular diseases (CVD) in healthy nonsmokers.

METHODS

A randomized, double-blind, placebo-controlled trial of lutein supplementation was conducted in healthy nonsmokers. 117 eligible subjects were randomly assigned to receive 10 or 20 mg/d of lutein or placebo for 12 weeks. Levels of plasma carotenoid concentrations, total antioxidant capacity (TAOC), the lipoprotein profile, and antioxidant enzymes activities were determined at baseline and at 6, and 12 weeks after the initiation of treatment. Biomarkers of oxidative damage to protein and lipids, and C-reactive protein (CRP) concentrations were measured at baseline and after supplementation.

RESULTS

Plasma lutein and TAOC significantly increased in both active treatment groups during 12 weeks. A significant reduction was found in malondialdehyde in the 20 mg lutein group. CRP concentration decreased in a dose-dependent manner for lutein supplementation, and there was a significant between-group difference in CRP between the 20 mg lutein and the placebo group. Serum CRP was directly related to the change in plasma lutein and TAOC for both active treatment groups.

CONCLUSION

The results support the possibility that lutein supplementation reduce biomarkers of CVD risk via decreased lipid peroxidation and inflammatory response by increasing plasma lutein concentrations and antioxidant capacity.

Dietary nutrients associated with short and long sleep duration. Data from a nationally representative sample

Short sleep duration is associated with weight gain and obesity, diabetes, cardiovascular disease, psychiatric illness, and performance deficits. Likewise, long sleep duration is also associated with poor physical and mental health. The role of a healthy diet in habitual sleep duration represents a largely unexplored pathway linking sleep and health. This study evaluated associations between habitual sleep parameters and dietary/nutritional variables obtained via the National Health and Nutrition Examination Survey (NHANES), 2007-2008. We hypothesized that habitual very short (<5h) short (5-6h) and long (9+h) sleep durations are associated with intake of a number of dietary nutrient variables. Overall, energy intake varied across very short (2036kcal), short (2201kcal), and long (1926kcal) sleep duration, relative to normal (2151kcal) sleep duration (p=0.001). Normal sleep duration was associated with the greatest food variety (17.8), compared to very short (14.0), short (16.5) and long (16.3) sleep duration (p<0.001). Associations between sleep duration were found across nutrient categories, with significant associations between habitual sleep duration and proteins, carbohydrates, vitamins and minerals. In stepwise analyses, significant contributors of unique variance included theobromine (long sleep RR=0.910, p<0.05), vitamin C (short sleep RR=0.890, p<0.05), tap water (short sleep RR=0.952, p<0.001; very short (<5h) sleep RR=0.941, p<0.05), lutein+zeaxanthin (short sleep RR=1.123, p<0.05), dodecanoic acid (long sleep RR=0.812, p<0.05), choline (long sleep RR=0.450, p=0.001), lycopene (very short (<5h) sleep RR=0.950, p<0.05), total carbohydrate (very short (<5h) sleep RR=0.494, p<0.05; long sleep RR=0.509, p<0.05), selenium (short sleep RR=0.670, p<0.01) and alcohol (long sleep RR=1.172, p<0.01). Overall, many nutrient variables were associated with short and/or long sleep duration, which may be explained by differences in food variety. Future studies should assess whether these associations are due to appetite dysregulation, due to short/long sleep and/or whether these nutrients have physiologic effects on sleep regulation. In addition, these data may help us better understand the complex relationship between diet and sleep and the potential role of diet in the relationship between sleep and obesity and other cardiometabolic risks.

Insights into the genetic architecture of early stage age-related macular degeneration: a genome-wide association study meta-analysis

Genetic factors explain a majority of risk variance for age-related macular degeneration (AMD). While genome-wide association studies (GWAS) for late AMD implicate genes in complement, inflammatory and lipid pathways, the genetic architecture of early AMD has been relatively under studied. We conducted a GWAS meta-analysis of early AMD, including 4,089 individuals with prevalent signs of early AMD (soft drusen and/or retinal pigment epithelial changes) and 20,453 individuals without these signs. For various published late AMD risk loci, we also compared effect sizes between early and late AMD using an additional 484 individuals with prevalent late AMD. GWAS meta-analysis confirmed previously reported association of variants at the complement factor H (CFH) (peak P = 1.5×10⁻³¹) and age-related maculopathy susceptibility 2 (ARMS2) (P = 4.3×10⁻²⁴) loci, and suggested Apolipoprotein E (ApoE) polymorphisms (rs2075650; P = 1.1×10⁻⁶) associated with early AMD. Other possible loci that did not reach GWAS significance included variants in the zinc finger protein gene GLI3 (rs2049622; P = 8.9×10⁻⁶) and upstream of GLI2 (rs6721654; P = 6.5×10⁻⁶), encoding retinal Sonic hedgehog signalling regulators, and in the tyrosinase (TYR) gene (rs621313; P = 3.5×10⁻⁶), involved in melanin biosynthesis. For a range of published, late AMD risk loci, estimated effect sizes were significantly lower for early than late AMD. This study confirms the involvement of multiple established AMD risk variants in early AMD, but suggests weaker genetic effects on the risk of early AMD relative to late AMD. Several biological processes were suggested to be potentially specific for early AMD, including pathways regulating RPE cell melanin content and signalling pathways potentially involved in retinal regeneration, generating hypotheses for further investigation.

Improvement of retinal function in early age-related macular degeneration after lutein and zeaxanthin supplementation: a randomized, double-masked, placebo-controlled trial

PURPOSE

To examine the effects of lutein and zeaxanthin supplementation on retinal function using multifocal electroretinograms (mfERG) in patients with early age-related macular degeneration (AMD).

DESIGN

Randomized, double-masked, placebo-controlled trial.

METHODS

One hundred eight subjects with early AMD were randomly assigned to receive 10 mg/d lutein (n = 27), 20 mg/d lutein (n = 27), 10 mg/d lutein plus 10 mg/d zeaxanthin (n = 27), or placebo (n = 27) for 48 weeks. Thirty-six age-matched controls without AMD were also enrolled to compare baseline data with early AMD patients. MfERG responses and macular pigment optical densities (MPODs) were recorded and analyzed at baseline and at 24 and 48 weeks.

RESULTS

There were significant reductions in N1P1 response densities in ring 1 to ring 3 in early AMD patients compared with the controls (P < .05), whereas neither N1P1 response densities in ring 4 to ring 6 nor P1 peak latencies significantly changed. After 48-week supplementation, the N1P1 response densities showed significant increases in ring 1 for the 20 mg lutein group and for the lutein and zeaxanthin group, and in ring 2 for the 20 mg lutein group. The increases in MPOD related positively to the increases in N1P1 response density in ring 1 and ring 2 for nearly all active treatment groups. N1P1 response densities in ring 3 to ring 6 or P1 peak latencies in all rings did not change significantly in any group.

CONCLUSION

Early functional abnormalities of the central retina in the early AMD patients could be improved by lutein and zeaxanthin supplementation. These improvements may be potentially attributed to the elevations in MPOD.

Further insights on the carotenoid profile of the echinoderm Marthasterias glacialis L

In this study, the carotenoid profile of the echinoderm Marthasterias glacialis L. was established using HPLC-DAD-APCI-MS/MS equipped with a C₃₀ column. This approach rendered the identification of 20 compounds, eight of them reported for the first time in this marine organism. Differentiation of carotenoid isomers was also achieved.

Carotenoids and chronic diseases

Chronic diseases such as cancer and cardiovascular diseases are the major causes of deaths in North America. Dietary intake of fruits and vegetables has been suggested to have protective effects against such chronic diseases. Carotenoids are important plant pigments which are thought to contribute towards the beneficial effects of fruit and vegetable consumption. This review focuses on the role of carotenoids and particularly lycopene in chronic diseases.