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Xanthophylls lutein and zeaxanthin (L, Z) and ω-3 fatty acids (FAs), are optimally positioned in retina and cortex to protect from oxidative damage. Research suggests that this placement in retinal tissue is related to reduced risk for acquired retinal diseases and improved visual function (e.g., reduced glare disability, scotopic noise). Whether L, Z and FAs in the cortex are capable of similarly influencing cognitive function (CF) is unknown. The purpose of this investigation was to determine the relation between L, Z and FAs and CF in a healthy cohort of older adults. 118 subjects in the Memphis, TN area, aged 76–85 yrs, with approx. equal numbers of males/females. Retinal L, Z levels (i.e., macular pigment density, MPOD) were significantly related to performance on a variety of indices designed to assess processing speed, accuracy and completion ability (p<0.05). These relations remained significant after adjusting for age, sex and ethnicity. Serum xanthophyll and fatty acid levels were not related to CF. MPOD, unlike serum xanthophylls, is a reflection of L and Z embedded into CNS tissue. The relation between MPOD and CF suggests that L and Z embedded in cortical tissue are capable of influencing cortical function. Additional research will be necessary to confirm these relations.

Background: Evidence continues to accumulate that oxidative stress is etiologically important in the pathogenesis of age-related maculopathy (ARM) and that appropriate antioxidants of dietary origin may protect against this condition. Objective: Risk factors for ARM may be classed as established or putative. We report a study designed to investigate whether such risk factors are associated with a dietary lack of antioxidants relevant to retinal health. Design: Dietary, anthropometric, and sociodemographic details relating to 828 healthy Irish subjects aged 20-60 y were recorded in a cross-sectional fashion and analyzed for associations between risk factors for ARM and dietary intake of relevant nutrients. Results: Of the established risk factors for ARM, increasing age was associated with a relative lack of dietary zeaxanthin (P < 0.05) and tobacco use with a relative lack of dietary vitamin C (P < 0.05). Of the putative risk factors for ARM, alcohol consumption was associated with a relative lack of dietary -linoleic acid (P < 0.05), and female sex was associated with a relative lack of dietary zinc (P < 0.05). Conclusions: We showed that several variables related to risk for ARM are associated with a relative dietary lack of key nutrients. Our finding that age, the most important and universal risk factor for ARM, is associated with a relative lack of dietary zeaxanthin, is an important finding that warrants further investigation.

Purpose. Many parameters of visual performance (e.g., contrast sensitivity) are compromised under glaring light conditions. Recent data indicate that macular pigment (MP) is strongly related to improvements in glare disability and photo stress recovery based on a filtering mechanism. In this study, we assessed the causality of this relation by supplementing lutein and zeaxanthin for 6 months while measuring MP, glare disability, and photo stress recovery.

Methods. Forty healthy subjects (mean age = 23.9) participated in the study. Subjects were followed for 6 months and assessed at baseline, 1, 2, 4, and 6 months. Spatial density profiles of MP were measured using heterochromatic flicker photometry. Disability glare was measured using a 1 degree-diameter circular grating surrounded by a broadband glare source (a xenon-white annulus). The intensity of the annulus (11 degree inner and 12 degree outer diameters) was adjusted by the subject until the grating target was no longer seen. For the photo stress recovery experiment, the time required to detect a 1 degree-diameter grating stimulus after a 5-s exposure to a 2.5 [mu]W/cm2, 5 degree-diameter disk was recorded. Subjects were tested under central viewing and eccentric viewing (10 degree temporal retina) conditions.

Results. At the baseline time point, MP optical density (OD) at 30' eccentricity ranged from 0.08 to 1.04, and was strongly correlated with improved visual performance in the two glare tasks. After 6 months of lutein (L) and zeaxanthin (Z) supplementation, average MPOD (at 30' eccentricity) had increased from 0.41 to 0.57, and was shown to significantly reduce the deleterious effects of glare for both the visual performance tasks assessed.

Conclusions. MP is strongly related to improvements in glare disability and photo stress recovery in a manner strongly consistent with its spectral absorption and spatial profile. Four to 6 months of 12 mg daily L + Z supplementation significantly increases MPOD and improves visual performance in glare for most subjects.

Journal of Gerontology : MEDICAL SCIENCES
2007, Vol. 62A, No. 3, 308-316
 
Plasma Carotenoid levels and Cognitive Performance in an Elderly Population: Results of the EVA study
N. T. Akbaraly, H. Faure, V. Gourlet, A. Favier, C. Berr
 
The EVA Study is a 9 year longitudinal study with 6 waves of follow up that looked primarily at the aging of the arteries. The analysis presented here was restricted to 589 participants in the last follow up of the EVA study conducted between June 2000 and December 2001. The study included volunteers with higher education, higher incomes and grater cognitive function than the average elderly French population.
Trained neuropsychologists evaluated cognition using a battery of tests that included the Mini Mental State Examination. Visual conceptual and visiomotor tracking were assessed with Trail Making Test Part A (which measures motor speed, control and working memory) and Trail Making Test Part B (which assess executive functioning, like set shifting). The maximum time allotted for completion of TMTA was 180 seconds; for TMTB 240 seconds.
Digit Symbol Substitution from the Wechsler Adult Intelligence Scale-Revised was used to measure sustained attention and logical reasoning. Manual dexterity and psychomotor speed were evaluated with Finger Taping Test,  verbal fluency with the Word Fluency Test  and finally Depression symptoms were assessed by the Center for Epidemiological Studies-Depression scale.
 
Significant Associations were observed between low levels of Zeaxanthin and low performance in ALL cognitive tests except MMSE.

After taking into account socio-demographic factors (sex, age, education), consumption habits (tobacco, alcohol), diabetes, hypertension and body mass index, associations between Zeaxanthin and cognitive performance remained significant for all the parameters in the table except TMTB.
Of all the carotenoids tested, only lycopene showed significant associations with TMTB and DSS after adjustment by the above mentioned factors. Total plasma carotenoids, α-carotene, β carotene, lutein and β-cryptoxanthin showed no statistically significant association with low cognitive performance.
 
The same analyses were performed by removing first participants with depressive symptomatology, then participants that were underweight and finally adjusting for levels of plasma retinol. In the three situations the researchers obtained the same results. They also made sure that their findings were not driven by the chosen dichotomous classifications for cognition and carotenoid levels.

IOVS, June 2006, Vol. 47, No. 6
Plasma Lutein and Zeaxanthin and Other Carotenoids as Modifiable Risk factors for Age Related Maculopathy and Cataract: the POLA study
Cecile Delcourt, Isabelle Carriere, Martine Delage, Pascale Barberger-Gateau, Wolfgang Schalch and the POLA Study Group
 
Epidemiological data on the association of xanthophylls and the risk of Age Related Macular Degeneration (AMD) and cataract remain scarce, and are partly inconsistent. Also, until recently, most studies assessed the association of AMD or cataract with the combined plasma concentration of  lutein and zeaxanthin, thereby limiting the chances of finding specific associations of lutein or zeaxanthin with these diseases. This study separately assessed these associations in a Mediterranean population study.
The researchers found that plasma lutein and zeaxanthin showed a strong inverse association with AMD, and that the association with plasma zeaxanthin was particularly strong. Compared with subjects that had low levels of zeaxanthin (<0.04 μM), subjects with high levels of plasma zeaxanthin (>0.9μM) had a 93% reduced risk of AMD. Globally, subjects with high total plasma lutein and zeaxanthin (>0.56μM) had a 79% reduced risks of AMD compared with subjects with low total plasma lutein and zeaxanthin (<0.25μM).
With respect to cataract, after adjustment for age and gender, only plasma zeaxanthin showed a strong inverse association with nuclear cataract. Compared with subjects with low plasma zeaxanthin (<0.04μ), those with high plasma zeaxanthin (>0.9μM) had a 75% decrease risk of nuclear cataract. The other types of cataract did not show any significant association with plasma zeaxanthin. Similarly, subjects with high plasma dehydro-lutein had a significant (66%) reduced risk of nuclear cataract. By contrast plasma lutein was not significantly associated with any type of cataract.
 The results of this study are consistent with those of a recent cross sectional study performed in the United Kingdom. The authors reported a significant (50%) reduced risk of early or late AMD in subjects with high plasma zeaxanthin (>0.05μM), compared with subjects with low levels (<0.03μ). The associations in this study were even stronger, perhaps because of the higher values in the highest quintile of zeaxanthin and lutein in this Mediterranean population, probably associated with higher dietary intakes of these xanthophylls.
Previous studies may have obscured the association with cataract, if only zeaxanthin is associated with cataract, by given results for pooled lutein and zeaxanthin.
The hypothesis of a more important role of zeaxanthin in retina and lens health is supported by several lines of evidence. First, the ratio of zeaxanthin to lutein is much higher in the central retina (1:1 in the macula, 2:1 in the fovea) and in the lens (1:1) than it is in the plasma (~1-5) suggesting that the eye preferentially accumulates zeaxanthin. Moreover, although both lutein and zeaxanthin protect liposomal membranes from light inductive oxidative stress, zeaxanthin appears to be a better photoprotector during prolonged UV exposure, perhaps because there is a different orientation of lutein and zeaxanthin in the biological membranes. Zeaxanthin is also particularly effective in protecting lipid membranes against oxidation by peroxyl radicals.

Ophthal. Physiol. Opt 2006:137-147
The effects of supplementation with lutein and/or zeaxanthin on human macular pigment density and color vision
M. Rodriguez Carmona, J. Kvansakul, J. Alister Harlow, W. Kopcke, W. Schalch and J. Barbur
 
Yellow-Blue discrimination thresholds and Macular Pigment Optical Density (MPOD) measurements in the eye exhibit large variability in the normal population. Although it is well established that selective absorption of blue light by the Macular Pigment (MP) can significantly affect trichromatic color matches, the extent to which the MP affects color discrimination sensitivity remains controversial.
 
The purpose of this study was to assess how the spatial distribution of the Macular Pigment changes as a result of Lutein and/or Zeaxanthin supplementation and to establish if increased MPOD values reduce yellow-blue chromatic sensitivity. It also wanted to establish if red-green chromatic sensitivity may benefit also from increased amounts of MP in the eye
 
Conclusions: The spatial Macular Pigment Optical Density (MPOD) profiles measured after 6 months of supplementation of Lutein (10 mg/day) and Zeaxanthin (10 mg/day) show a significant increase in MPOD, even at 6º eccentricity, making it essential to reference such measurements with respect to a larger eccentricity of 8º. Failure to do so underestimates uniformly the increase in MPOD as a result of supplementation.
Supplementation with a combination of Lutein (10 mg/day) and Zeaxanthin (10 mg/day) over a period of 6 months, increases Macular Pigment (MP) distribution over plus and minus 8º around the macula, causing an almost uniform reduction in the percentage of blue light over the center plus or minus 4º. Although a significant reduction in MP is observed in the supplemented group 4 months after supplementation has stopped, MPOD profiles in this group continue to remain higher than those in the placebo group. These findings are consistent with the measured increase in plasma levels of Lutein and Zeaxanthin during supplementation and the significant reduction observed 4 months after supplementation was stopped.
For the stimulus conditions employed in this study, Yellow-Blue chromatic detection thresholds do not differ significantly within the center plus or minus 5º and do not correlate with the measured MPOD values, either at the fovea or in the periphery. All subjects showed high Red-Green chromatic sensitivity (well within normal range), but no correlation with MPOD was found.

Anticancer Research 25: 3871-3876 (2005)
The photoreceptor Protector Zeaxanthin Induces Cell Death in Neuroblastoma Cells
Mauro Macarrone, Monica Bari, Valeria Gasperi and Barbara Demmig-Adams
Department of Biomedical Sciences, University of Teramo, Teramo Italy
 
In plants, Zeaxanthin protects against the formation of potentially destructive reactive oxygen species in leaves exposed to intense sunlight or moderate levels of sunshine in the presence of environmental conditions unfavorable for plant growth. Zeaxanthin facilitates the harmless dissipation of excess energy absorbed by chlorophyll via a mechanism that involves a reversible electron exchange between chlorophyll and zeaxanthin (with zeaxanthin transiently reducing chlorophyll). Zeaxanthin’s close isomer lutein also plays a role, albeit a minor one, in this dissipation process. In addition, zeaxanthin serves in photo protection via a second, poorly understood mechanism that involves an inhibition of lipid peroxidation.
 
Zeaxanthin protects lipids against photosensitized, singlet oxygen-catalyzed peroxidation in vitro and, while this ability is enhanced by vitamin E, zeaxanthin has a more potent, primary effect. In both plants and animals, lipids can be oxidized by several classes of enzymes including lipoxygenases (LOX). Plant and animal lipoxygenases produce lipid derivatives with both pro- and anti- apoptotic functions.
 
This study examined the effect of zeaxanthin -as an inhibitor of photoreceptor cell death in the eye- on neuroblastoma, a childhood cancer affecting neurons and the eye that is rather resistant to programmed cell death. The researchers chose a neuroblastoma cell line in which 5-Lox activity is present and in which apoptosis had previously been stimulated by treatments with LOX-5 products.
 
The effect of zeaxanthin on the activity of two model lipoxygenases, soybean LOX-1 and barley 5-LOX, was assessed in liposomes by following the conversion of lipoxygenase substrate linoleic acid (LA) to the corresponding hydroperoxide. No significant effects of zeaxanthin on these two LOX forms tested after incorporation of their LA substrate into a liposome system were identified over a range of zeaxanthin concentrations. This indicates that zeaxanthin does not operate via direct effects of these LOX types (5- and 15- LOX).
 
Treatment of neuroblastoma cells with zeaxanthin resulted in a significant and strong induction of programmed cell death in Human CHP100 neuroblastoma cells over a concentration range of 0.5-10 μM zeaxanthin. The effect was assessed as DNA fragmentation via an immunoassay for histone-associated DNA fragments in the cell cytoplasm and apoptotic body formation after staining and visualization via cytofluorometric analysis. Both these features are hallmarks of programmed cell death.
 
This result is consistent with the other study’s finding: that zeaxanthin does not inhibit CHP100 neuroblastoma cell apoptosis, which can also be induced by a range of LOX products. In this neuroblastoma cell system, an inhibition of LOX would not be expected to induce apoptosis. In turn, there is also no evidence that zeaxanthin further stimulates LOX activity.
 
The study demonstrated a strong induction of apoptosis in neuroblastoma cells by zeaxanthin. Zeaxanthin induced apoptosis of these unwanted cells while preventing apoptosis of ‘needed’ cells such as the photoreceptor cells in the eye. The pro-apoptotic effect of zeaxanthin is remarkable in light of the fact that neuroblastoma cells are rather resistant to apoptosis.
Zeaxanthin can be added to the list of phytochemicals that have the ability to kill cancer cells while promoting the survival of healthy cells.

Dietary Modulation of lens Zeaxanthin in quail

Although higher dietary intake of lutein/zeaxanthin has been associated with reduced risk for cataracts, the impact of dietary supplements on lens lutein (L) or zeaxanthin (Z) has not been examined. If higher lens carotenoids do reduce risk for cataract, it would be essential to know whether dietary carotenoids can elevate carotenoids in the adult vertebrate lens. In this study, a covey of Japanese quail were hatched and raised 6 months on carotenoid-deficient diet, then switched to deficient diet supplemented with low or high 3R-3 'R zeaxanthin (5 or 35 mg/kg food) or ß-carotene (50 mg/kg feed). Controls included a group of covey-mates that remained on the deficient diet and another raised from birth on the high Z (35 mg Z per kg of feed) diet. At 1 year of age, carotenoids and tocopherols in the lens and in the serum were analyzed by HPLC, and compared by analysis of variance. Serum Z was significantly elevated in deficient birds fed the lower or higher Z supplement for 6 months (P<0.0001 for each). Serum Z in birds maintained on the higher Z supplement for 1 year was much higher than that in deficit birds (P<0.0001), but not different from deficient birds given the high Z supplement. As in humans, the predominant lens carotenoids were lutein (L) and zeaxanthin (Z), and the total carotenoid concentration was of lower magnitude than the concentration of a-tocopherol. Responses to Z supplementation were sex related. Female quail had 5-10 times higher serum concentrations of both Z and L than males (P<0.0001, <0.001), and they also had higher lens Z concentrations than males (P<0.0006); possible effects of estrogen on lens carotenoids are discussed. Lens Z concentration was strongly and positively correlated with serum Z in females (r=0.77; P<0.002). Deficient adult females supplemented with the 35 mg/kg dose of Z for 6 months had a mean lens Z concentration (0.252 ±0.06 ug per gram of protein) close to that in females fed with the supplement from birth (0.282 ± 0.15ug per g protein). Birds fed with the higher dietary Z supplement for 6 or 12 months had significantly higher lens Z than birds fed lower or no dietary Z (P<0.0001). Lens L was not altered by dietary supplementation of Z or ß-carotene. ß-carotene supplements did not result in detectable lens ß-carotene, and had no effect on lens Z. Neither Z nor ß-carotene supplementation had a significant effect on serum or lens tocopherol concentrations.
These studies in quail provide the first experimental evidence that lens carotenoids in adult vertebrates can be manipulated by dietary Z supplements.

Experimental Eye Research 2005
C. K. Dorey, L. Granata, C.R. Nichols, K.M. Cheng and N. E. Craft

2005 (back to top)

Obesity, Lutein Metabolism, and Age Related Macular Degeneration: a Web of Connections

Age Related Macular Degeneration (AMD) is a major cause of visual impairment in the United States. Currently there is no effective cure for this disease. Risk factors include decreased lutein and zeaxanthin status and obesity. Obesity is also an increasing public health concern. The alarming increase in the prevalence of obesity further exacerbates the public health concern of AMD. The mechanism by which obesity increases the risk of AMD might be related to the physiologic changes that occur with this condition. These include oxidative stress, changes in the lipoprotein profile, and increased inflammation. These changes will also result in an increased destruction and a decreased circulatory delivery of lutein and zeaxanthin to the macula of the eye. Therefore, the mechanism by which obesity is related to AMD risk may be through indirect effects on changes in lutein and Zeaxanthin metabolism.

Nutrition Reviews, Vol. 63, No 1 (2005), Elizabeth Johnson, PhD

Nutritional manipulation of primate retinas, II: effects of age, n-3 fatty acids, lutein, and zeaxanthin on retinal pigment epithelium.

Purpose: To study the effects of age and of n-3 fatty acids, lutein, and zeaxanthin on the retinal pigment epithelium (RPE).

Methods: Rhesus monkeys (age range, 7-17 years; n = 18) were fed xanthophyll-free semipurified diets from birth. The diets had either low or adequate amounts of n-3 fatty acids. Six monkeys remained xanthophyll-free until death. Six received supplements of pure lutein and six of pure zeaxanthin for 6 to 24 months. The central retina was serially sectioned, and the number of RPE cells were counted in an 8-microm strip along the vertical meridian. Cell counts were compared with data from control monkeys (n = 15) fed a standard laboratory diet.

Results: Foveal and parafoveal RPE cell densities increased with age. Xanthophyll-free monkeys had a dip in the RPE cell density profile at the foveal center, rather than the normal peak. After supplementation with xanthophylls, the RPE profile of animals low in n-3 fatty acids no longer had a dip at the foveal center but became asymmetric, with higher densities in the inferior retina. In animals with adequate n-3 fatty acid levels, xanthophyll supplementation did not restore the foveal peak, and resulted in an asymmetric profile with higher densities in the superior retina.

Conclusions: RPE cells are sensitive to the absence of macular pigment. Supplemental xanthophylls interact with n-3 fatty acid levels to produce asymmetries in the RPE profile. Xanthophylls and n-3 fatty acids are essential for the development and/or maintenance of a normal distribution of RPE cells.

Invest Ophthalmol Vis Sci. 2004 Sep;45(9):3244-56. Leung IY, Sandstrom MM, Zucker CL, Neuringer M, Snodderly DM., Schepens Eye Research Institute, Boston, MA, USA.

Purpose: to investigate the relationship between percentage of body fat and macular pigment (MP) optical density.

Results: There was a significant inverse relationship between the percentage of body fat and MP optical density in males and after correcting for age and dietary lutein and zeaxanthin, this inverse relationship remained significant. The relationship between MP optical density and percentage of body fat in females was inverse but not significant. A significant and inverse relationship between serum zeaxanthin and percentage of body fat was observed for females only. Dietary intake of fat was inversely related to serum lutein and zeaxanthin, and significantly so for lutein. However, dietary fat was unrelated to MP optical density

Conclusions: A relative lack of MP is associated with adiposity in men, and may underlie the association between body fat and risk for AMD progression in males. Further, the processes governing accumulation and/or stabilization of lutein and zeaxanthin in fat tissue appear to differ for males and females

IOVS, November 2004, Vol. 45, No 11, J. Nolan, O. O’Donovan, H. Kavanagh, J.Stack, M. Harrison, A.Muldoon, J. Mellerio and S. Beatty

The antioxidant action of carotenoids is believed to involve quenching of singlet oxygen and scavenging of reactive oxygen radicals. However, the exact mechanism by which carotenoids protect cells against oxidative damage, particularly in the presence of other antioxidants remains to be elucidated. This study was carried out to examine the ability of exogenous zeaxanthin alone and in combination with vitamin E or C, to protect cultured human retinal pigment epithelium cells against oxidative stress. The survival of ARPE-19 cells, subjected to merocyanine 540-mediated photodynamic action, was determined by the MTT test and the content of lipid hydroperoxydes in photosensitized cells was analyzed by HPLC with electrochemical detection. We found that zeaxanthin-supplemented cells, in the presence of either α-tocopherol or ascorbic acid, were significantly more resistant to photoinduced oxidative stress. Cells with added antioxidants exhibited increased viability and accumulated less lipid hydroperoxides than cells without the antioxidant supplementation. Such a synergistic action of zeaxanthin and vitamin E or C indicates the importance of the antioxidant interaction in efficient protection of cell membranes against oxidative damage induced by photosensitive reactions.

Free Radical Biology & Medicine, Vol. 36, No 9, pp. 1094-1101, 2004, M. Wrona, M. Rozanowska and T Sarna

Uptake, metabolism, and stabilization of xanthophyll carotenoids in the retina are thought to be mediated by specific xanthophyll-binding proteins (XBPs). A membrane-associated XBP was purified from human macula using ion-exchange chromatography followed by gel-exclusion chromatography. Two-dimensional gel electrophoresis showed a prominent spot of 23 kDa and an isoelectric point of 5.7. Using mass spectral sequencing methods and the public NCBI database, it was identified as a Pi isoform of human glutathione S-transferase (GSTP1). Dietary (3R,3'R)-zeaxanthin displayed the highest affinity with an apparent Kd of 0.33 microm, followed by (3R,3'S-meso)-zeaxanthin with an apparent Kd of 0.52 microm. (3R,3'R,6'R)-Lutein did not display any high-affinity binding to GSTP1. Other human recombinant glutathione S-transferase (GST) proteins, GSTA1 and GSTM1, exhibited only low affinity binding of xanthophylls. (3R,3'S-meso)-Zeaxanthin, an optically inactive nondietary xanthophyll carotenoid present in the human macula, exhibited a strong induced CD spectrum in association with human macular XBP that was nearly identical to the CD spectrum induced by GSTP1. Like-wise, dietary (3R,3'R)-zeaxanthin displayed alterations in its CD spectrum in association with GSTP1 and XBP. Other mammalian xanthophyll carrier proteins such as tubulin, high-density lipoprotein, low-density lipoprotein, albumin, and beta-lactoglobulin did not bind zeaxanthins with high affinity, and they failed to induce or alter xanthophyll CD spectra to any significant extent. Immunocytochemistry with an antibody to GSTP1 on human macula sections showed highest labeling in the outer and inner plexiform layers. These results indicate that GSTP1 is a specific XBP in human macula that interacts with (3R,3'S-meso)-zeaxanthin and dietary (3R,3'R)-zeaxanthin in contrast to apparently weaker interactions with (3R,3'R,6'R)-lutein.

J Biol Chem. 2004 Nov 19;279(47):49447-54. Epub 2004 Sep 07. Bhosale P, Larson AJ, Frederick JM, Southwick K, Thulin CD, Bernstein PS. Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA

Antioxidants, such as tocopherols and carotenoids, have been implicated in the prevention of degenerative diseases. Although correlations have been made between diseases and tissue levels of antioxidants, to date there are no reports of individual carotenoid concentrations in human brain.

Ten samples of brain tissue from frontal lobe cortex and occipital cortex of five cadavers were examined. Sections were dissected into gray and white matter, extracted with organic solvents, and analyzed by HPLC.

Results: At least 16 carotenoids, 3 tocopherols, and retinol were present in human brain. Major carotenoids were identified as lutein, zeaxanthin, anhydrolutein, alpha- cryptoxanthin, beta- cryptoxanthin, alpha-carotene, cis- and trans-betacarotene, and cis- and trans-lycopene. Xanthophylls (oxygenated carotenoids) accounted for 66-77% of total carotenoids in all brain regions examined. Similar to neural retina, the ratio of zeaxanthin to lutein was high and these two xanthophylls were significantly correlated (p <0.0001).

Conclusions: The frontal cortex, generally vulnerable in Alzheimer's disease, had higher concentrations of all analytes than the occipital cortex which is generally unaffected. Moreover, frontal lobes, but not occipital lobes, exhibited an age-related decline in retinol, total tocopherols, total xanthophylls and total carotenoids. The importance of these differences and the role(s) of these antioxidants in the brain remain to be determined.

J Nutr Health Aging. 2004;8(3):156-62. Craft NE, Haitema TB, Garnett KM, Fitch KA, Dorey CK.

Age-related macular degeneration (AMD) is one of the most common eye diseases of elderly individuals. It has been suggested that lutein and zeaxanthin may reduce the risk for AMD. Information concerning the absorption of non-esterified or esterified zeaxanthin is rather scarce. Furthermore, the formation pathway of meso (3R,3_S)-zeaxanthin, which does not occur in plants but is found in the macula, has not yet been identified. Thus, the present study was designed to assess the concentration of 3R,3R_-zeaxanthin reached in plasma after the consumption of a single dose of native 3R,3_R-zeaxanthin palmitate from wolfberry (Lycium barbarum) or non-esterified 3R,3_R-zeaxanthin in equal amounts. In a randomised, single-blind cross-over study, twelve volunteers were administered non-esterified or esterified 3R,3_R-zeaxanthin (5mg) suspended in yoghurt together with a balanced breakfast. Between the two intervention days, a 3-week depletion period was inserted. After fasting overnight, blood was collected before the dose (0h), and at 3, 6, 9, 12, and 24h after the dose. The concentration of non-esterified 3R,3_R-zeaxanthin was determined by chiral HPLC. For the first time, chiral liquid chromatography–atmospheric pressure chemical ionization-MS was used to confirm the appearance of 3R,3_R-zeaxanthin in pooled plasma samples. Independent of the consumed diet, plasma 3R,3_R-zeaxanthin concentrations increased significantly (P=0·05) and peaked after 9–24h. Although the concentration curves were not distinguishable, the respective areas under the curve were distinguishable according to a two-sided F and t test (P=0·05). Thus, the study indicates an enhanced bioavailability of 3R,3_R-zeaxanthin dipalmitate compared with the non-esterified form. The formation of meso-zeaxanthin was not observed during the time period studied.

British Journal of Nutrition Volume 91, Issue 5, May (2004), pp. 707-713. Dietmar E. Breithaupt, Philipp Weller, Maike Wolters and Andreas Hahn

Some epidemiological studies suggest that consumption of fruits and vegetables with a high carotenoid content may protect against colon cancer (CC). The evidence, however, is not completely consistent. Given the inconsistencies in findings in previous studies and continued interest in identifying modifiable risk factors for CC, a case-control study of French-Canadian in Montreal, Canada, was undertaken to examine the possible association between dietary carotenoids and CC risk and to investigate whether this association varies in relation to lifestyle factors such as smoking or diet, and particularly the high consumption of long-chain polyunsaturated fatty acids (LCPUFA). A total of 402 colorectal cases (200 males and 202 females) and 688 population-based controls matched for age, gender and place of residence were interviewed. Dietary intake was assessed through a validated food frequency questionnaire that collected information on over 200 food items and recipes. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in unconditional logistic regression models. After adjustment for important variables such as total energy intake, no association was found between dietary intake of carotenoids and CC risk. For women with high intakes of LCPUFA, an inverse association was found between lutein + zeaxanthin and CC risk. ORs were 0.41; 95%CI (0.19-0.91), p=0.03 for eicosapentaenoic acid, and OR=0.36, 95%CI (0.19-0.78), p=0.01 for docosahexaenoic acid, when the upper quartiles of intake were compared to the lower. Among never-smokers, a significantly reduced risk of CC was associated with intake of beta-carotene [OR=0.44, 95%CI (0.21-0.92) and p=0.02], whereas an inverse association was found between lycopene intake and CC risk [OR=0.63, 95%CI (0.40-0.98) and p=0.05] among smokers. The results of our study suggest that a diet rich in both lutein + zeaxanthin and LCPUFAs may help prevent CC in French-Canadian females.

Int J Cancer. 2004 May 20;110(1):110-6. Nkondjock A, Ghadirian P., Epidemiology Research Unit, Research Centre, CHUM-Hotel-Dieu, Pavillon Masson, 3850 St. Urbain, Montreal, Quebec, Canada H2W 1T7.

Purpose: Macular pigment (MP) is composed of the xanthophylls lutein (L) and zeaxanthin (Z) and may help to prevent age-related macular degeneration or retard its progression. In this study the effects of L or Z supplementation on carotenoid levels was examined in serum, adipose tissue, and retina in rhesus monkeys with no previous intake of xanthophylls.

Methods: From birth to 7 to 16 years of age, 18 rhesus monkeys were fed semipurified diets containing all essential nutrients but no xanthophylls. Six were supplemented with pure L and 6 with pure Z at 3.9 micromol/kg per day for 24 to 101 weeks. At baseline and at 4- to 12-week intervals, carotenoids in adipose tissue were measured by HPLC. At study completion, carotenoids in serum and retina (central 4 mm, 8-mm annulus, and the periphery) were determined. Results were compared with data from control monkeys fed a standard laboratory diet.

Results: Monkeys fed xanthophyll-free diets had no L or Z in serum or tissues. After L or Z supplementation, serum and adipose tissue concentrations significantly increased in the supplemented groups. Both L and 3R,3'S-Z (RSZ or meso-Z, not present in the diet) were incorporated into retinas of monkeys supplemented with L, with RSZ present only in the macula (central 4 mm). All-trans Z, but no RSZ, accumulated in retinas of monkeys supplemented with Z.

Conclusions: L is the precursor of RSZ, a major component of macular pigment. Xanthophyll-free monkeys can accumulate retinal xanthophylls and provide a valuable model for examining their uptake and conversion.

Invest Ophthalmol Vis Sci. 2005 Feb;46(2):692-702. Johnson EJ, Neuringer M, Russell RM, Schalch W, Snodderly DM. Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA.

Recent epidemiologic and animal model data suggest that oxygenated carotenoids are protective against early atherosclerosis. We assessed the association between atherosclerotic progression, measured by carotid intima-media thickness (IMT), and plasma levels of oxygenated and hydrocarbon carotenoids, tocopherols, retinol, and ascorbic acid.

Methods and results: Participants were from an occupational cohort of 573 middle-aged women and men who were free of symptomatic cardiovascular disease at baseline. Ultrasound examination of the common carotid arteries, lipid level determination, and risk factor assessment were performed at baseline and 18-month follow-up. Plasma levels of antioxidants were determined at baseline only. Change in IMT was related to baseline plasma antioxidant levels in regression models controlling for covariates. In models adjusted for age, sex, and smoking status, 18-month change in IMT was significantly inversely related to the 3 measured oxygenated carotenoids (lutein, beta-cryptoxanthin, zeaxanthin; P<0.02 for all) and one hydrocarbon carotenoid, alpha-carotene (P=0.003). After adjusting for additional cardiac risk factors and potential confounders, including high-sensitivity C-reactive protein, these associations remained significant (P<0.05).

Conclusions: These findings suggest that higher levels of plasma oxygenated carotenoids (lutein, zeaxanthin, beta-cryptoxanthin) and alpha-carotene may be protective against early atherosclerosis.

Arterioscler Thromb Vasc Biol. 2004 Feb;24(2):313-9. Epub 2003 Dec 01. Dwyer JH, Paul-Labrador MJ, Fan J, Shircore AM, Merz CN, Dwyer KM. Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.

Lutein and zeaxanthin status and risk of Age-Related Macular Degeneration.

Risk of Age Related macular degeneration (early or late) was significantly higher in people with lower plasma concentrations of zeaxanthin. Compared with those whose plasma concentrations of zeaxanthin were in the highest third of the distribution, people whose plasma concentration was in the lowest third had an odds ratio for risk of age related macular degeneration of 2.0 (95% confidence interval [CI] 1.0-4.1), after adjustment for age and other risk factors.

Risk of age-related macular degeneration was increased in people with the lowest concentrations of lutein plus zeaxanthin (odd ratio [OR] 1.9, 95% CI 0.9-3.5) and in those with the lowest concentrations of lutein (OR 1.7, 95%CI 0.9-3.3), but neither of these relations was statistically significant

Invest Ophtalmol Vis Sci 2003;44:2461-2465, C. Gale, Nigel F. Hall, David Phillips and C. Martins. From the Medical Research Council Environmental Epidemiology Unit, University of Southampton, Southampton General Hospital, UK.

The results of Z supplementation on Macular Pigment optical density for both eyes of subject A are shown in Figure 2. For approximately 40 days of supplementation, no effect was discernible, and the optical densities were essentially the same as those observed during the ~70 day period before supplementation. Thereafter the optical densities increased in a more or less linear fashion in the left and right eyes. This trend continued throughout the 120 day supplementation period and during the 20 days following, before leveling off.

Lutein increases the Optical density in a more impressive way. The article says that bioavailability might have played an important role: lutein was esterified and prepared as an oleoresin that was easily solubilized in vegetable oil; zeaxanthin was crystalline, unesterified and incorporated in gelatin/starch beadlets.

The high rate of nonresponse of MP optical density among subjects who consumed the low Lutein dosage (2.4 mg/day) is not altogether unexpected.

There may be a very slow turnover of carotenoids in the retina.

A high dose could be employed initially to produce a timely increase in MP density; thereafter a lower maintenance dose may be adequate to prevent any decrease from occurring.

J. Nutr. 133:992-998, 2003, Richard Bone, John Landrum, Luis Guerra and Camilo Ruiz.

Lutein and zeaxanthin are found in the macula in high concentrations and may play a role in the pathogenesis of age related macular degeneration (ARMD). Lutein and zeaxanthin may protect the macula and photoreceptor outer segments throughout the retina from oxidative stress and play a role in an antioxidant cascade that safely disarms the energy of reactive oxygen species. Although lutein and zeaxanthin are not essential nutrients, studies are beginning to suggest that they fit the criteria for conditionally essential nutrients. Low plasma lutein and zeaxanthin concentrations or dietary intake are associated with low macular pigment density and increased risk of ARMD. Dietary deprivation of lutein and zeaxanthin in primates causes pathological changes in the macula. Should controlled clinical trials show lutein and/or zeaxanthin supplementation protects against the development or progression of ARMD and other eye diseases, then lutein and zeaxanthin could be considered as conditionally essential nutrients for humans.

Medical Hypothesis (2003) 61(4), 465-472, R.D. Semba and G. Dagnelle, Johns Hopkins University School of Medicine

Resonance Raman measurement of macular carotenoids in normal and age-related macular degeneration patients.

Bernstein et al demonstrated that eyes with AMD have 32% lower levels of macular carotenoids than do age-matched control eyes when measured in vivo by resonance Raman spectroscopy.

Ophthalmology. 2002; 109: 1778-1785, Berstein PS, Zhao DY, Wintch SW, Ermakov IV, McClane RW, Gellerman W.

Groups of quail were raised for 6 months on carotenoid-deficient, normal or zeaxanthin-supplemented diets before exposure to brighter light. The results showed extensive damage to the retina in the carotenoid-deficient animals, as evidenced by large numbers of both dying photoreceptors and gaps or ‘ghosts’ marking sites where photoreceptors have died. The group with quail with normal dietary levels of zeaxanthin showed significantly less retinal damage that did the zeaxanthin-deprived group, while the quail group receiving high levels of zeaxanthin had few ghosts in their retinas.

These experiments by Dr. Dorey showed protection of both cone and rod photoreceptors. The research further demonstrated that retinas were protected by both zeaxanthin and vitamin E. Damage in these experiments was clearly reduced by zeaxanthin and tocopherol but not lutein.

Investigative Ophthalmology & Visual Science. 2002 Nov, v 43, n 11, p 3538-3549, Thompson, L.R.; Toyoda, Y.; Langner, A. ; Delori, F.C.; Garnett, K.M.;Ccraft, N.; Nichols, C.R.; Cheng, K.M.; Dorey, C.K.

Recent evidence introduces the possibility that lutein and zeaxanthin may protect against the development of the two common eye diseases of aging, cataract and macular degeneration. This potential and the lack of other effective means to slow the progression of macular degeneration have fueled high public interest in the health benefits of lutein and zeaxanthin and the proliferation of supplements containing them on pharmacy shelves. An understanding of the biologic consequences of limiting or supplementing with these carotenoids is only beginning to emerge. Some epidemiologic evidence supports a role in eye disease and, to a lesser extent, cancer and cardiovascular disease. However, the overall body of evidence is insufficient to conclude that increasing levels of lutein and zeaxanthin, specifically, will confer an important health benefit. Future advances in scientific research are required to gain a better understanding of the biologic mechanisms of their possible role in preventing disease. Additional research is also required to understand the effect of their consumption, independent of other nutrients in fruits and vegetables, on human health. The newly advanced ability to measure levels of lutein and zeaxanthin in the retina in vivo creates a unique opportunity to contribute some of this needed evidence.

J Nutr 2002 Mar;132(3):518S-524S, Mares-Perlman JA, Millen AE, Ficek TL, Hankinson SE., Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison Medical School, Madison, WI

Objective: To investigate whether nutritional factors and possible risk factors for cataract influence the lens optical density (LOD). DESIGN: Three hundred seventy-six subjects, aged 18 to 75 years, were recruited. In a cross-sectional design, serum was analyzed for lutein, zeaxanthin, vitamin C, alpha-tocopherol, and cholesterol levels. Adipose tissue (n = 187) was analyzed for lutein level. The LOD and the macular pigment optical density (MPOD) were measured by spectral fundus reflectance.

Results: The mean +/- SD LOD at 420 nm was 0.52 +/- 0.17. It showed a significant association with age (beta =.008, P<001) and MPOD (beta = -.096, P =.02). For subjects 50 years and younger (mean +/- SD LOD, 0.45 +/- 0.11), we found only a single significant beta coefficient, for age (beta =.006, P<.001). For subjects older than 50 years (mean +/- SD LOD, 0.68 +/- 0.16), we found significant beta coefficients for age (beta =.011, P<.001) and MPOD (beta = -.240, P =.005). Controlling for age, we found no associations between LOD and other possible risk factors for age-related cataract or serum or adipose tissue concentrations of carotenoids, vitamin C, and alpha-tocopherol.

Conclusions: Macular pigment is composed of lutein and zeaxanthin, the only carotenoids found in human lenses. The inverse relationship between LOD and MPOD suggests that lutein and zeaxanthin may retard aging of the lens.

Arch Ophthalmol 2002 Dec;120(12):1732-7, Berendschot TT, Broekmans WM, Klopping-Ketelaars IA, Kardinaal AF, Van Poppel G, Van Norren D., Department of Ophthalmology, Universitair Medisch Centrum Utrecht

The prevalence rate of AMD in patients with low antioxidant intake and low lutein intake (dichotomized at the median value) was about twice as high as that in patients with high intake: OR = 1.7, 95% CI (0.8-3.7), and OR = 2.4, 95% CI (1.1-5.1). Further specification of intake data into quartiles of antioxidant intake and lutein/zeaxanthin intake showed a clear dose-response relationship. CONCLUSION: The effect of dietary antioxidants upon macular health warrants preventive studies.

Acta Ophthalmol Scand 2002 Aug;80(4):368-71, Snellen EL, Verbeek AL, Van Den Hoogen GW, Cruysberg JR, Hoyng CB., Department of Epidemiology and Biostatistics, University Medical Centre, Nijmegen, Netherlands.

There is increasing evidence that the macular pigment (MP) carotenoids lutein (L) and zeaxanthin (Z) protect the retina and lens from age-related loss. As a result, the use of L and Z supplements has increased dramatically in recent years. An increasing number of reports have suggested that L and Z supplementation (and increased MP density) are related to improved visual performance in normal subjects and patients with retinal and lenticular disease. These improvements in vision could be due either to changes in the underlying biology and/or optical changes. The optical mechanisms, i.e., preferential absorption of short-wave light, underlying these putative improvements in vision, however, have not been properly evaluated. Two major hypotheses are discussed. The acuity hypothesis posits that MP could improve visual function by reducing the effects of chromatic aberration. The visibility hypothesis is based on the idea that MP may improve vision through the atmosphere by preferentially absorbing blue haze (short-wave dominant air light that produces a veiling luminance when viewing objects at a distance).

Prog Retin Eye Res 2002 Mar;21(2):225-40, Wooten BR, Hammond BR., Walter S. Hunter Laboratory, Brown University, Box 1853, Providence, RI 02912, USA

The photoreceptors in the retina, designed to initiate the cascade of events which link the incoming light to the sensation of 'vision', are susceptible to damage by light, particularly blue light. The damage can lead to cell death and diseases. The turnover of retinal, an essential element of the visual process, is the basis of the events that lead to damage. Free retinal, absorbing in the blue region of the visible spectrum, is phototoxic, and is a precursor of the (photo)toxic compound A2E, which specifically targets cytochrome oxidase and thereby induces cell death by apoptosis. Cell death induced by A2E in the dark is prevented by negatively charged phospholipids. The blue light-filtering molecules lutein and zeaxanthin are tailor-made substances protecting the retina. In vitro, they protect cytochrome oxidase against the permanent damage caused by A2E in combination with light. These novel findings should enable us to prevent or cure the dry form of age-related macular degeneration, the leading cause of severe visual impairment in humans living in developed countries.

Biol Chem 2002 Mar-Apr;383(3-4):537-45, Shaban H, Richter C., Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), Zurich.

Supplementation of Carotenoid Depleted Rhesus monkeys with Lutein or Zeaxanthin: Effects on Serum and Adipose Tissue Carotenoids and Macular Pigment.

Normal macular pigment density can be induced by Lutein or Zeaxanthin supplements in non human primates with life long carotenoid deficiency. Carotenoid-depleted monkeys provide a valuable model for examining the importance of these nutrients for macular health.

IOVS March 15, 2001, Vol. 42, No. 4, M. Neuringer, E.J. Johnson, D.M. Snodderly, M.M. Sandstrom, W. Schalch

L and Z levels in all concentric regions were less, on average, for the AMD donors than for the controls. The differences decreased in magnitude from the inner to the medial to the outer regions. The lower levels found in the inner and medial regions for AMD donors may be attributable, in part, to the disease. Comparisons between AMD donors and controls using the outer (peripheral region) were considered more reliable. For this region, logistic regression analysis indicated that those in the highest quartile of L and Z level had 82% lower risk for AMD compared with those in the lowest quartile.

The results are consistent with a theoretical model that proposes an inverse association between risk of AMD and the amounts of L and Z in the retina. The results are inconsistent with a model that attributes a loss of L and Z in the retina to the destructive effects of AMD.

Invest Ophthalmol Vis Sci 2001; 42: 235-240, Richard Bone, John Landrum, ST Mayne, CM Gomez, SE Tibor and EE Twaroska

Relations of the carotenoids lutein and zeaxanthin in the diet and serum to photographic evidence of early and late age-related maculopathy (ARM) among persons over age 40 years (n = 8,222) were examined. Inverse relations of these carotenoids in the diet or serum to any form of ARM were not observed overall. There was a direct relation of dietary levels to one type of early ARM (soft drusen). However, relations differed by age and race. In the youngest age groups who were at risk for developing early (ages 40-59 years) or late (ages 60-79 years) ARM, higher levels of lutein and zeaxanthin in the diet were related to lower odds for pigmentary abnormalities, one sign of early ARM (odds ratio among persons in high vs. low quintiles = 0.1, 95 percent confidence interval: 0.1, 0.3) and of late ARM (odds ratio = 0.1, 95 percent confidence interval: 0.0, 0.9) after adjustment for age, gender, alcohol use, hypertension, smoking, and body mass index. Relations of these carotenoids to ARM may be influenced by age and race and require further evaluation in separate populations and in prospective studies.

Am J Epidemiol 2001 Mar 1;153(5):424-32 , Mares-Perlman JA, Fisher AI, Klein R, Palta M, Block G, Millen AE, Wright JD., Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, WI

Macular Pigment Optical Density in a Southwestern Sample.

Macular pigment density was lower than average levels obtained from the Northeast but similar to average values obtained in a recent study of adults recruited from Indianapolis. Consistent with past studies, MP density was 13% lower in women and 18% lower in individuals with light versus dark-colored irises. The relation of smoking to macular pigment density was only significant for those current smokers who smoke more than 10 cigarettes per day (about a 25% reduction). The large number of individuals in this sample with low macular pigment density motivates the need for population based assessment of the possible poor nutritional state of the average American’s retina.

Investigative Ophthalmology & Visual Science, May 2000, Vol 41. No. 6, Billy R. Hammond Jr. and Mary Caruso-Avery

There was an age related decline in the optical density of macular pigment among volunteers with no ocular disease (right eye: r2 = 0.29, P = 0.0006; left eye: r2 = 0.29, P < 0.0001). Healthy eyes predisposed to AMD had significantly less MP than healthy eyes at no such risk (Wilconxon’s signed rank test: P = .015).

The two most important risk factors for AMD (AMD in the fellow eye and increasing age) are associated with a relative absence of macular pigment. These findings are consistent with the hypothesis that supplemental lutein and zeaxanthin may delay, avert or modify the course of this disease.

Investigative Ophthalmology & Visual Science, May 2000, Vol 41. No. 6, S. Beaty, Ian Murray, David Henson, Dave Carden, Hui-Hiang Koh and Michael Boulton

The carotenoid xanthophylls, lutein and zeaxanthin, accumulate in the eye lens and macular region of the retina. Lutein and zeaxanthin concentrations in the macula are greater than those found in plasma and other tissues. A relationship between macular pigment optical density, a marker of lutein and zeaxanthin concentration in the macula, and lens optical density, an antecedent of cataractous changes, has been suggested. The xanthophylls may act to protect the eye from ultraviolet phototoxicity via quenching reactive oxygen species and/or other mechanisms. Some observational studies have shown that generous intakes of lutein and zeaxanthin, particularly from certain xanthophyll-rich foods like spinach, broccoli and eggs, are associated with a significant reduction in the risk for cataract (up to 20%) and for age-related macular degeneration (up to 40%). While the pathophysiology of cataract and age-related macular degeneration is complex and contains both environmental and genetic components, research studies suggest dietary factors including antioxidant vitamins and xanthophylls may contribute to a reduction in the risk of these degenerative eye diseases. Further research is necessary to confirm these observations.

J Am Coll Nutr 2000 Oct;19(5 Suppl):522S-527S, Moeller SM, Jacques PF, Blumberg JB., Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston

Inverse associations have been reported between the incidence of advanced, neovascular, age-related macular degeneration (AMD) and the combined lutein (L) and zeaxanthin (Z) intake in the diet, and L and Z concentration in the blood serum. We suggest that persons with high levels of L and Z in either the diet or serum would probably have, in addition, relatively high densities of these carotenoids in the macula, the so-called 'macular pigment'. Several lines of evidence point to a potential protective effect by the macular pigment against AMD. In this study we examined the relationship between dietary intake of L and Z using a food frequency questionnaire; concentration of L and Z in the serum, determined by high-performance liquid chromatography, and macular pigment optical density, obtained by flicker photometry. Nineteen subjects participated. We also analysed the serum and retinas, as autopsy samples, from 23 tissue donors in order to obtain the concentration of L and Z in these tissues. The results reveal positive, though weak, associations between dietary intake of L and Z and serum concentration of L and Z, and between serum concentration of L and Z and macular pigment density. We estimate that approximately half of the variability in the subjects' serum concentration of L and Z can be explained by their dietary intake of L and Z, and about one third of the variability in their macular pigment density can be attributed to their serum concentration of L and Z. These results, together with the reported associations between risk of AMD and dietary and serum L and Z, support the hypothesis that low concentrations of macular pigment may be associated with an increased risk of AMD.

Exp Eye Res 2000 Sep;71(3):239-45., Bone RA, Landrum JT, Dixon Z, Chen Y, Llerena CM., Department of Physics, Florida International University, Miami, FL 33199, USA.

Decrease in serum levels of vitamin A and zeaxanthin in patients with colorectal polyp.

Several retrospective and prospective epidemiological investigations have demonstrated that a diet rich in carotenoids could prevent the development of pre-cancerous and neoplastic lesions of the digestive tract. The aim of this examination was to analyse the correlation between colorectal polyps with different histological classifications and serum carotenoid levels.

Results: The serum levels of vitamin A and zeaxanthin were significantly lower in all patients with polyps (vitamin A: 0.913 +/- 0.112 micromol/l, zeaxanthin: 0.071 +/- 0.012 micromol/l) than in the control healthy group (vitamin A: 2.036 +/- 0.354 micromol/l, zeaxanthin: 0.138 +/- 0.048 micromol/l). The lowest levels were found in patients with focal adenocarcinoma in the polyp. There were no significant differences in the serum levels of other carotenoids. The serum levels of cholesterol, haemoglobin, total protein and albumin were normal in these patients.

Conclusions: There are close and inverse correlations between the serum level of carotenoids and colorectal polyps with different histological grades. The low mean carotenoid levels in patients with adenocarcinoma in the polyp indicate that deficiency of carotenoids may be an important factor in the development of colorectal cancer.

Eur J Gastroenterol Hepatol. 1999 Mar;11(3):305-8. Rumi G Jr, Szabo I, Vincze A, Matus Z, Toth G, Rumi G, Mozsik G., First Department of Medicine, University Medical School of Pecs, Hungary.

Background: Dietary antioxidants, including carotenoids, are hypothesized to decrease the risk of age-related cataracts by preventing oxidation of proteins or lipids within the lens. However, prospective epidemiologic data concerning this phenomenon are limited.

Objective: Our objective was to examine prospectively the association between carotenoid and vitamin A intakes and cataract extraction in men.

Design: US male health professionals (n = 36644) who were 45-75 years of age in 1986 were included in this prospective cohort study. Others were subsequently included as they became 45 years of age. A detailed dietary questionnaire was used to assess intake of carotenoids and other nutrients. During 8 years of follow-up, 840 cases of senile cataract extraction were documented.

Results: We observed a modestly lower risk of cataract extraction in men with higher intakes of lutein and zeaxanthin but not of other carotenoids (alpha-carotene, beta-carotene, lycopene, and beta-cryptoxanthin) or vitamin A after other potential risk factors, including age and smoking, were controlled for. Men in the highest fifth of lutein and zeaxanthin intake had a 19% lower risk of cataract relative to men in the lowest fifth (relative risk: 0.81; 95% CI: 0.65, 1.01; P for trend = 0.03). Among specific foods high in carotenoids, broccoli and spinach were most consistently associated with a lower risk of cataract.

Conclusions: Lutein and zeaxanthin may decrease the risk of cataracts severe enough to require extraction, although this relation appears modest in magnitude. The present findings add support for recommendations to consume vegetables and fruit high in carotenoids daily.

Am J Clin Nutr 1999 Oct;70(4):517-24. Brown L, Rimm EB, Seddon JM, Giovannucci EL, Chasan-Taber L, Spiegelman D, Willett WC, Hankinson SE., Departments of Epidemiology, Nutrition, and Biostatistics, Harvard School of Public Health, Boston, MA

Human monocyte-macrophages were incubated for 24 h in Ham's F-10 medium with human low-density lipoprotein (LDL) in the presence or absence of beta-carotene, canthaxanthin or zeaxanthin, at final concentrations of 2.5, 12.5 and 25 mg/l. LDL oxidation, measured by agarose gel electrophoresis, the thiobarbituric acid assay and gas chromatography, was inhibited by each of the carotenoids in a concentration-dependent manner. Canthaxanthin was more effective when incorporated into LDL before addition to the cultures whereas beta-carotene and zeaxanthin were more effective when added simultaneously with LDL. The results suggest that dietary carotenoids might help slow atherosclerosis progression.

FEBS Lett. 1997 Jan 20;401(2-3):262-6. Carpenter KL, Van der Veen C, Hird R, Dennis IF, Ding T, Mitchinson MJ., Department of Pathology, University of Cambridge, UK

Epidemiologic data indicate that individuals with low plasma concentrations of carotenoids and antioxidant vitamins and those who smoke cigarettes are at increased risk for age-related macular degeneration (AMD). Laboratory data show that carotenoids and antioxidant vitamins help to protect the retina from oxidative damage initiated in part by absorption of light. Primate retinas accumulate two carotenoids, lutein and zeaxanthin, as the macular pigment, which is most dense at the center of the fovea and declines rapidly in more peripheral regions. The retina also distributes alpha-tocopherol (vitamin E) in a nonuniform spatial pattern. The region of monkey retinas where carotenoids and vitamin E are both low corresponds with a locus where early signs of AMD often appear in humans. The combination of evidence suggests that carotenoids and antioxidant vitamins may help to retard some of the destructive processes in the retina and the retinal pigment epithelium that lead to age-related degeneration of the macula.

Am J Clin Nutr 1995 Dec;62(6 Suppl):1448S-1461S, Snodderly DM., Schepens Eye Research Institute, Macular Disease Research Center, Boston