Reply to Byker Shanks et al. Measurement of Fruit and Vegetable Intake Incorporating a Diversity, Equity, and Inclusion Lens. Comment on "Di Noia, J.; Gellermann, W. Use of the Spectroscopy-Based Veggie Meter® to Objectively Assess Fruit and Vegetable Intake in Low-Income Adults. Nutrients 2021, 13, 2270".

We thank Byker Shanks et al. [...].

Lutein and Zeaxanthin Distribution in the Healthy Macula and Its Association with Various Demographic Factors Examined in Pseudophakic Eyes.

The macular pigment consisting of lutein (L) and zeaxanthin (Z) protects photoreceptors via its antioxidative and barrier activities. This study aimed to determine L and Z distribution in the healthy macula and their association with various demographic factors. Macular pigment optical density (MPOD) was measured using fundus autofluorescence spectroscopy in 352 pseudophakic eyes with no fundus diseases. Pseudophakia was chosen to avoid the influence of cataract in the measurement of fundus autofluorescence. The mean patient age was 72.3 ± 8.6 years. MPOD was analyzed separately in three zones, i.e., A: a central area within a radius of 0.5°, mainly containing Z; B: a ring area with radii from 0.5° to 1.3°, containing Z and L; C: a ring area with radii from 1.3° to 9°, containing L. Multivariate analyses were performed with MPOD as the dependent variable and sex, supplement intake, smoking habits, glaucoma, diabetes, age, body mass index (BMI), skin carotenoid levels, retinal thickness, retinal volume, axial length as the independent variables. The mean total MPOD volume within 9° eccentricity was 20,121 ± 6293. Age was positively associated with MPOD in all zones. Supplement and BMI were positively and negatively associated with MPOD in zones B and C. Smoking was negatively associated with MPOD in zone A. This study revealed the standard MP values of aged Japanese, which resulted to be higher than the previously reported values in other races. Age was found to have a positive association with MP values. L in the outer foveola was affected by BMI and supplements, but Z in the foveola was not. The amount of Z in the Müller cell cone may not be changed easily by factors such as hunger and satiety in the context of preservation of homeostasis in the human body, but tobacco had a negative effect on Z.

Use of the Spectroscopy-Based Veggie Meter® to Objectively Assess Fruit and Vegetable Intake in Low-Income Adults.

Reflection spectroscopy is an emerging approach for noninvasively assessing dermal carotenoids as a biomarker of fruit and vegetable (FV) intake. This study sought to profile and identify determinants of scores from a reflection spectroscopy device (the Veggie Meter (VM)®) among 297 urban, primarily Hispanic low-income adults served by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). The repeatability of the scores and bi- and multivariate relationships between VM scores, self-reported FV intake measured by a brief screener, and participant characteristics were examined. The mean VM score was 270 (range 0-695); 3- and 6-month test-retest correlations were positive and strong (r = 0.79 and 0.55, respectively). VM scores were negatively associated with body mass index (BMI; r = -0.22) and were higher among participants of Ecuadorian, Dominican, and Mexican Hispanic origin relative to those of Puerto Rican origin; foreign- vs. US-born participants, breastfeeding vs. non-breastfeeding participants, nonsmokers vs. smokers, and participants who consumed three or more cups of FV/day relative to those who consumed less than three cups of FV/day. Foreign-born nativity, consumption of three or more cups of FV/day, and smaller body size were determinants of increased VM scores. Although replication studies are needed to confirm these findings, investigators working with similar populations are encouraged to use the VM to longitudinally track FV intake and to target determinants of the scores in observational and intervention studies of FV intake as measured by the VM.

Relationships between Skin Carotenoid Levels and Metabolic Syndrome.

Carotenoids have potential antioxidant and anti-inflammatory effects; their protective roles are of particular interest in the pathogenesis of metabolic syndrome (MetS). The reflection spectroscopy method has been recently developed to noninvasively measure skin carotenoid (SC) levels, which highly correlates with serum concentration of carotenoids. The relationship between SC levels and metabolic syndrome has been investigated. We aimed to identify the differences in patient characteristics and SC levels between participants with and without MetS in a large health examination population. In addition, the relationships between SC levels and various clinical parameters related to MetS were investigated. SC levels were measured using a reflection spectroscopy. A total of 1812 Japanese participants (859 male, 953 female; mean age ± standard deviation (SD), 57.8 ± 11.0 years) comprised the study population, i.e., participants with MetS (n = 151) and those without MetS (n = 1661). Multivariate logistic regression analysis was performed to identify variables associated with MetS. Compared to controls (377.3 ± 122.8), SC indices were significantly lower in patients with MetS (340.7 ± 112.5, p = 0.0004). Multivariate models also suggested that lower SC was significantly associated with MetS after adjustment for age, sex, smoking habit, and other potential risk factors for MetS. Furthermore, male gender (p < 0.0001), smoking habit (p < 0.0001) and worse lipid profiles (i.e., serum triglyceride (r = -0.1039, p < 0.0001), high-density lipoprotein (r = 0.1259, p < 0.0001), and usage of hypolipidemic agents (p = 0.0340)) were significantly associated with lower SC levels. The current study indicated that lower SC levels were significantly associated with MetS. This study highlights the antioxidant capacity of carotenoids in patients with MetS and the clinical utility of non-invasive and cost-effective SC measurement to detect participants who are at risk of developing MetS in a large population.

Skin carotenoids are inversely associated with adiposity in breast cancer survivors.

Carotenoids are antioxidants which may mitigate some of the adverse effects of obesity, a condition associated with poor outcomes in breast cancer patients. We hypothesized that baseline skin carotenoids would be inversely associated with adiposity in breast cancer survivors and would increase with weight loss. Skin carotenoid score (SCS) was assessed by resonance Raman spectroscopy in breast cancer survivors (body mass index ≥25 kg/m2) enrolled in a 6-month randomized controlled weight loss trial (n = 47). Measurements included total body fat using dual-energy X-ray absorptiometry, height, weight, waist and hip circumference, dietary intake, and serum biomarkers. Associations between SCS, adiposity measures, and serum biomarkers were assessed at baseline, as was the change in SCS from baseline to 6 months, in the intervention and usual care groups. At baseline, SCS was inversely correlated with all adiposity measures (P ≤ .05). In multivariate analyses, baseline percent body fat had the strongest association with baseline SCS (partial R2= 0.20). Baseline SCS was significantly inversely associated with log C-reactive protein levels (regression coefficient ß ±â€¯SE: -0.051±â€¯0.019; P = .011) and log leptin (ß ±â€¯SE: -0.019±â€¯0.009; P = .046), but the associations were no longer significant after adjustment for adiposity. Over the 6-month study, the intervention group had a 17.6% increase in SCS compared to a 1.5% decrease in the usual care group (P = .28). In our study of overweight and obese breast cancer survivors, dual-energy X-ray absorptiometry-measured body fat explained a large portion of the variation in skin carotenoids at baseline, suggesting a stronger association than that previously seen in studies using less accurate measures of adiposity.

Effect of an antioxidant supplement containing high dose lutein and zeaxanthin on macular pigment and skin carotenoid levels.

The effect of a high dose lutein/zeaxanthin supplement on macular pigment optical density (MPOD) and skin carotenoid (SC) levels in healthy subjects was investigated. This is a prospective, single-arm, open-label study. Subjects were 16 Japanese, age 26-57 years. Subjects took a supplement containing 20 mg/day of lutein, 4 mg/day of zeaxanthin, and other antioxidants (vitamin C, vitamin E, zinc, copper) for 16 weeks. MPOD levels were measured by a two-wavelength autofluorescence imaging technique. SC levels were measured by reflection spectroscopy. Total volume of MPOD within 9° eccentricity significantly increased by week 8 and continued to increase until week 16 (p < 0.0001, two-way factorial ANOVA). The increase rate of MPOD was significantly higher in subjects with body mass index (BMI) less than 25 kg/m2 (n = 13) compared to those of 25 kg/m2 and higher (n = 3). SC levels increased significantly by week 4 and continued to increase until week 16 (p < 0.0001, two-way factorial ANOVA). All subjects completed the study without any serious adverse events. These results demonstrated the effectiveness of a high dose lutein/zeaxanthin supplement for MPOD volume and SC levels without serious adverse events.

Spatial distribution of macular pigment estimated by autofluorescence imaging in elderly Japanese individuals.

PURPOSE: To determine the spatial distribution types of macular pigment (MP) in elderly Japanese individuals and to consider their origin. STUDY DESIGN: Observational case series. METHODS: Local MP optical density (MPOD) at some eccentricities and MP volume were measured using the MPOD module of a MultiColor Spectralis in 96 pseudophakic eyes of 96 participants (age range, 52-86 years; mean age, 72.8 ± 8.3 years). The MP distribution types were determined from the MP spatial profiles. The retinal thickness (RT) at the foveal center, at both 0.5° and 0.9° eccentricities, and the foveal width were measured using optical coherence tomography. RESULTS: The mean local MPOD at the foveal center was 0.79. Spatial distribution was classified into four types: central peak (24.0%), ring-like (40.6%), intermediate (22.9%), and central dip (12.5%). The ring-like type was the most frequent in these Japanese participants. The central-peak type showed lower MPOD than did the other types in the area outside 0.9°. The ring-like type occurred frequently in eyes with small RT at 0.5° and wider foveal width. A rough contour of the Müller cell cone was found more frequently in the central-dip type than in the other types. CONCLUSIONS: The present characteristics of the different distribution patterns could be explained by the hypothesis that MP presents mainly in the Müller cell cone within 0.5° and in Müller cells in the outer and inner plexiform layers in the area outside 0.5°. The anatomic characteristics of Müller cells at the fovea and parafovea likely affect the MP distribution.

Concurrent validity of skin carotenoid status as a concentration biomarker of vegetable and fruit intake compared to multiple 24-h recalls and plasma carotenoid concentrations across one year: a cohort study.

BACKGROUND: Biological markers of vegetable and fruit (VF) intake are needed both for nutrition surveillance and for the evaluation of nutrition interventions. Optically assessed skin carotenoid status (SCS) has been proposed as a marker of intake but there are few published validity studies to date. Therefore, the objective of the study was to examine the concurrent validity of multiple methods of assessing VF intake cross-sectionally and seasonally over one year and to discuss the relative merits and limitations of each method. METHODS: Fifty-two 40-60 y old women completed a 1-year longitudinal study that included 1) SCS assessment using resonance Raman spectroscopy (RRS) and using pressure-mediated reflection spectroscopy (RS) at 12 timepoints, 2) thirty-six 24-h recalls using the Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA24; total 1866 recalls), and 3) plasma carotenoid concentrations measured every 3 months. Pearson correlation coefficients and mixed linear models were used to estimate pairwise correlations between RRS, RS, ASA24, and plasma carotenoids. RESULTS: RS and RRS were strongly correlated at baseline and over the year (r = 0.86 and 0.76; respectively, P < 0.001). RS was strongly correlated with plasma carotenoids at baseline (r = 0.70) and moderately across the year (r = 0.65), as was RRS (r = 0.77 and 0.69, respectively, all P < 0.001). At baseline, self-reported VF was weakly correlated with RRS (r = 0.33; P = 0.016), but not with RS or plasma carotenoids. Across the year, self-reported VF intake was weakly correlated with both RS (r = 0.37; P = 0.008), RRS (r = 0.37; P = 0.007), and with plasma carotenoids (r = 0.36; P < 0.008). CONCLUSIONS: SCS as measured by RS and RRS is moderately to strongly correlated with plasma carotenoid concentrations both cross-sectionally and longitudinally, indicating that it can be a powerful tool to assess carotenoid-rich VF intake in populations. CLINICAL TRIAL REGISTRY: This trial was registered at ClinicalTrials.gov as NCT01674296.

Skin Carotenoid Index in a large Japanese population sample.

Carotenoids are anti-oxidative agents. Human skin and eyes contain specific carotenoid species known to prevent various pathologies caused by oxidative stress. We quantified skin and eye carotenoid levels and investigated their potential correlation in a population including 985 Japanese patients and staff members of an ophthalmology clinic (577 men, 408 women, mean age of 69.7 ± 13.6 [SD]). Skin carotenoid (SC) and macular pigment (MP) levels were measured with reflection spectroscopy and autofluorescence imaging methods, respectively. The mean SC index was 343.1 ± 142.1 (SD). SC indices for women were higher than for men (382 vs 315, p < 0.001). Smokers and overweight subjects (BMI ≥ 25) had lower SC indices. Subjects taking lutein supplements had higher SC indices than non-supplementing subjects (415 vs 325, p < 0.001). SC and MP indices were significantly correlated. The obtained data set can be used for reference purposes by Japanese subjects and researchers interested in tissue responses to diets high in carotenoids and lutein supplementation.

Grade of Cataract and Its Influence on Measurement of Macular Pigment Optical Density Using Autofluorescence Imaging.

Purpose: To evaluate the influence of cataracts on measuring macular pigment optical density (MPOD) using a dual-wavelength confocal scanning autofluorescence imaging technique and to establish methods to compensate for the influence of cataracts. Methods: This prospective case series comprised 100 eyes that underwent cataract surgery. Cataracts were graded based on the World Health Organization classification. MPOD levels were measured with the MPOD module of the Spectralis MultiColor instrument (Spectralis-MP), pre- and postoperatively. We investigated the relationship between change in MPOD values and age, cataract grade, and quality of autofluorescence images. Local MPOD levels were evaluated for four strategically chosen eccentricities within the macular region, and the total MPOD volume was evaluated within 8.98° eccentricity from the center. Results: MPOD levels could be obtained in 67 eyes before surgery. Local and volume MPOD levels were higher postoperatively relative to preoperatively in all eyes. The mean ratio of local MPOD levels after and before surgery (correction factor, CF) ranged from 1.42 to 1.77, with larger CFs required for eccentricities closer to the foveal center. The CF for the MPOD volume was 1.31. Age, grade of nuclear cataract (NUC), posterior subcapsular opacity, and image quality index (IQI) significantly contributed to CFs. For example, regression equation for CF at 0.23° = 0.17 + 0.16 × IQI + 0.29 × NUC grade + 0.01 × age (P < 0.001). Conclusions: Cataracts affected MPOD measurements with the Spectralis-MP, but corrected MPOD results could be obtained via regression equations.

Optical Detection of Macular Pigment Formation in Premature Infants.

PURPOSE: To demonstrate the presence of macular pigment in the retina of premature infants, and to examine its changes with age. METHODS: The participants included 40 premature infants. Infants who had received laser photocoagulation for retinopathy of prematurity were excluded. Macular pigment optical density (MPOD) was measured by fundus reflectometry using RetCam3, a digital fundus camera. The reflection imaging was performed for ROP screening. The imaging time points were from a post menstrual age (PMA) of 29 weeks 0 days to 46 weeks 5 days. RESULTS: The MPOD levels could be obtained from 39 premature infants. The levels at the first measurement ranged from 0 to 0.18 (mean 0.076, SD 0.044). The earliest time, when a nonvanishing MPOD level was obtained, was at a PMA of 33 weeks and 2 days, and that level was 0.05. The initial examination MPOD levels showed a moderate correlation with age (R2 = 0.32, P < 0.00017). The mean MPOD levels measured each week during the follow-up period showed a very strong correlation with age (R2 = 0.91, P < 0.0001). A regression line of MPOD = 0.0069 × age - 0.1783 was derived, where age is counted in PMA days. CONCLUSIONS: The MPOD levels of premature infants were for the first time measured in living eyes. Macular pigment increased linearly with age. TRANSLATIONAL RELEVANCE: Macular pigment increased with the development of macular morphology. This result suggested the importance of nutritional management of infants and mothers during perinatal period.

Optical assessment of skin carotenoid status as a biomarker of vegetable and fruit intake.

Resonance Raman spectroscopy (RRS) and reflection spectroscopy (RS) are optical methods applicable to the non-invasive detection of carotenoids in human skin. RRS is the older, more thoroughly validated method, whereas RS is newer and has several advantages. Since collective skin carotenoid levels serve as a biomarker for vegetable and fruit intake, both methods hold promise as convenient screening tools for assessment of dietary interventions and correlations between skin carotenoids and health and disease outcomes. In this manuscript, we describe the most recent optimized device configurations and compare their use in various clinical and field settings. Both RRS and RS devices yield a wide range of skin carotenoid levels between subjects, which is a critical feature for a biomarker. Repeatability of the methods is 3-15% depending on the subject's skin carotenoid level and the uniformity of its local distribution. For 54 subjects recruited from an ophthalmology clinic, we first checked the validity of the relatively novel RS methodology via biochemical serum carotenoid measurements, the latter carried out with high performance liquid chromatography (HPLC). A high correlation between RS skin and serum HPLC carotenoid levels was established (R = 0.81; p < 0.001). Also, a high correlation was found between RS and RRS skin levels (R = 0.94 p < 0.001). Subsequent comparisons of skin carotenoid measurements in diverse age groups and ethnicities included 569 Japanese adults, 947 children with ages 2-5 screened in 24 day care centers in San Francisco, and 49 predominantly Hispanic adults screened at an outdoor health fair event. Depending on the particular subject group, correlation coefficients between the RRS and RS methods ranged between R ∼0.80 and R ∼0.96. Analysis of the Japanese screening showed that, on average, skin carotenoid levels are higher in women compared to men, skin levels do not depend on age, and tobacco smokers have reduced levels versus non-smokers. For the two most ethnically diverse groups with widely varying melanin levels, we investigated the effect of dermal melanin on RS and RRS skin carotenoid levels. The analysis revealed that large variations in skin carotenoid levels remain detectable independent of the particular melanin index. This behavior is consistent with the absence of melanin effects on the skin carotenoid levels generated with the instrument configurations. The RS method has an advantage over RRS in its relative simplicity. Due to its detection of skin reflection over a wide spectral range from the near UV to the near IR, it has the unique ability to quantify each of the major tissue chromophores and take them into account in the derivation of skin carotenoid levels.

Reliability of a two-wavelength autofluorescence technique by Heidelberg Spectralis to measure macular pigment optical density in Asian subjects.

This study evaluates the accuracy of an objective two-wavelength fundus autofluorescence technique for the purpose of measuring the macular pigment optical density (MPOD) in Asian pigmented eyes. Potential differences between MPOD values obtained via autofluorescence technique and subjective heterochromatic photometry (HFP) were examined. Inter-examiner reproducibility between three examiners and test-retest reliability over five time points were also explored. Subjects were 27 healthy Japanese volunteers aged 24 to 58 (mean ±â€¯standard deviation, 40.2 ±â€¯9.0) years. An MPOD module of the Spectralis MultiColor instrument configuration (Spectralis-MP) was used for the autofluorescence technique, and a Macular Metrics Densitometer (MM) was used for HFP. The mean MPOD values at 0.25° and 0.5° eccentricities using the Spectralis-MP were 0.51 ±â€¯0.12 and 0.48 ±â€¯0.13, respectively. In comparison, the MM based values were 0.72 ±â€¯0.23 and 0.61 ±â€¯0.25, respectively. High correlations between the Spectralis-MP and MM instrument were found (Pearson's correlation coefficients of 0.73 and 0.87 at 0.25° and 0.5° eccentricities, respectively), but there was a systematic bias: the MPOD values by MM method were significantly higher than those by Spectralis-MP at 0.25° eccentricity. High inter-examiner reproducibility and test-retest reliability were found for MM measurements at 0.5° eccentricity, but not at 0.25°. The Spectralis-MP showed less inter-examiner and test-retest variability than the MM instrument at 0.25° and 0.5° eccentricities. We conclude that the Spectralis-MP, given its high agreement with the HFP method and due to its higher reproducibility and reliability, is well suited for clinical measurements of MPOD levels in Asian pigmented eyes.

Correlations Between Macular, Skin, and Serum Carotenoids.

Purpose: Ocular and systemic measurement and imaging of the macular carotenoids lutein and zeaxanthin have been employed extensively as potential biomarkers of AMD risk. In this study, we systematically compare dual wavelength retinal autofluorescence imaging (AFI) of macular pigment with skin resonance Raman spectroscopy (RRS) and serum carotenoid levels in a clinic-based population. Methods: Eighty-eight patients were recruited from retina and general ophthalmology practices from a tertiary referral center and excluded only if they did not have all three modalities tested, had a diagnosis of macular telangiectasia (MacTel) or Stargardt disease, or had poor AFI image quality. Skin, macular, and serum carotenoid levels were measured by RRS, AFI, and HPLC, respectively. Results: Skin RRS measurements and serum zeaxanthin concentrations correlated most strongly with AFI macular pigment volume under the curve (MPVUC) measurements up to 9° eccentricity relative to MPVUC or rotationally averaged macular pigment optical density (MPOD) measurements at smaller eccentricities. These measurements were reproducible and not significantly affected by cataracts. We also found that these techniques could readily identify subjects taking oral carotenoid-containing supplements. Conclusions: Larger macular pigment volume AFI and skin RRS measurements are noninvasive, objective, and reliable methods to assess ocular and systemic carotenoid levels. They are an attractive alternative to psychophysical and optical methods that measure MPOD at a limited number of eccentricities. Consequently, skin RRS and MPVUC at 9° are both reasonable biomarkers of macular carotenoid status that could be readily adapted to research and clinical settings.

Using Skin Carotenoids to Assess Dietary Changes in Students After 1 Academic Year of Participating in the Shaping Healthy Choices Program.

OBJECTIVE: To determine whether fourth-grade students participating in the Shaping Healthy Choices Program (SHCP), a school-based nutrition intervention, would change vegetable and carotenoid intake measured by skin carotenoids and dietary intake. METHODS: Single-group pretest-posttest with a self-selected, convenience sample of students (n = 30) participating in the SHCP, which lasted 1 academic year (9 months). Dietary intake of vegetables and carotenoids as measured by Block food frequency questionnaire and skin carotenoids as measured by Raman spectroscopy were collected at the school preintervention and postintervention. RESULTS: Reported carotenoid intake decreased by 1.5 mg (P = .05) and skin carotenoids decreased by 2,247.9 RRS intensity units (P = .04). Change in reported intake correlated with change in skin carotenoids (r = .43; P = .02). CONCLUSIONS AND IMPLICATIONS: The reported decrease in vegetable and carotenoid intake was unanticipated; nevertheless, the RRS measurements confirmed this. RRS data can help evaluate changes in fruit and vegetable intake.

MACULAR PIGMENT DISTRIBUTION RESPONSES TO HIGH-DOSE ZEAXANTHIN SUPPLEMENTATION IN PATIENTS WITH MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: To analyze macular pigment (MP) amount and distribution in patients with macular telangiectasia Type 2 receiving oral zeaxanthin supplementation in a randomized, open-label, interventional trial. METHODS: Eight macular telangiectasia Type 2 patients were randomized to 10 mg or 20 mg of zeaxanthin per day. At each visit, best-corrected visual acuity, contrast sensitivity, fundus biomicroscopy, color fundus photography, autofluorescence imaging, optical coherence tomography, and serum carotenoid levels were tested. Patients were assessed at baseline and after 6, 12, 18, and 24 months of zeaxanthin supplementation. Concentration of MP was analyzed and calculated from autofluorescence imaging obtained at 488-nm excitation wavelength. Serum carotenoid levels were obtained using high-performance liquid chromatography. RESULTS: The majority of patients had definite increases in the intensity of hypofluorescent ring of MP, but none of them deposited MP centrally at the fovea. Although some patients noted subjective improvements in vision, no objective improvements could be documented, and there were no changes in foveal optical coherence tomographic features. Yellowish, hypofluorescent crystals appeared in one patient's macular region with no change in visual acuity. These inner retinal crystals disappeared several months after discontinuing her 20-mg zeaxanthin supplement. CONCLUSION: Based on the current study, zeaxanthin supplementation does not result in any visual benefit in patients with macular telangiectasia Type 2 and does not reestablish a normal peaked distribution of MP in the fovea. One patient developed a novel, reversible, crystalline maculopathy in response to zeaxanthin supplementation that was reminiscent of canthaxanthin crystalline maculopathy.

Changes in Macular Pigment Optical Density and Serum Lutein Concentration in Japanese Subjects Taking Two Different Lutein Supplements.

PURPOSE: To investigate macular pigment optical density (MPOD) and serum concentration changes of lutein in Japanese subjects participating in a clinical trial in which two formulations of lutein and zeaxanthin supplements with different physiochemical properties are used. METHODS: Thirty-six healthy volunteers were recruited into this prospective, randomized, parallel-group, double-masked comparative study at a single institute. Two products were used, FloraGLO® (Kemin Japan) and XanMax® (Katra Phytochem). The lutein particle size and zeaxanthin concentrations differed between the formulations. The subjects consumed one of the two supplements for a duration of up to 6 months. MPOD levels were measured by resonance Raman spectrometry at baseline and once a month until the end of the study. Serum lutein concentration was measured at baseline, month 3, and month 6. The subjects were also tested for contrast sensitivity, glare sensitivity, visual acuity, and in addition had a focal electroretinogram measured. RESULTS: The mean serum lutein concentrations increased significantly after the first three months, but the mean MPOD levels in either supplement group did not show any statistically significant increase. A detailed analysis, however, revealed three response patterns in both groups for the increase of MPOD levels and serum lutein concentration, i.e. "retinal responders", who had an increase of both MPOD levels and serum lutein concentrations (n = 13), "retinal non-responders", who had only increased serum concentrations and no change in MPOD levels (n = 20), and "retinal and serum non-responders", who had neither MPOD level nor plasma concentration increases (n = 3). The subjects with low MPOD levels at baseline appeared to show increased MPOD levels at the 6 month time point upon lutein supplementation (r = -0.4090, p = 0.0133). Glare sensitivity improved in retinal responders in both supplement groups, while there were no remarkable changes in contrast sensitivity. CONCLUSIONS: No statistically significant differences could be detected for MPOD levels and serum lutein concentrations between the two investigated lutein supplement formulations. Responses to lutein supplementation regarding MPOD levels and serum lutein concentrations varied between subjects. Subjects with lower MPOD levels at baseline responded well to lutein supplementation. However, since the number of subjects was low, a further study with more subjects is needed to prove that subjects with low MPOD levels will benefit from lutein supplementation. TRIAL REGISTRATION: UMIN-CTR UMIN000004593.

Evaluating the relationship between plasma and skin carotenoids and reported dietary intake in elementary school children to assess fruit and vegetable intake.

Accurate assessment of dietary intake of children can be challenging due to the limited reliability of current dietary assessment methods. Plasma carotenoid concentration has been used to assess fruit and vegetable intake, but this testing is rarely conducted in school settings in children. Resonance Raman spectroscopy (RRS) is emerging as a useful method to objectively assess fruit and vegetable intake. This methodology has been validated in adults, but limited work has been done in children, particularly in the school setting. The purpose of this research is to further validate the RRS methodology in children. Children (9-12 year) participating in a school-based intervention were recruited. Plasma carotenoids were quantified using HPLC, skin carotenoid status was measured using RRS, and dietary intake of carotenoids was measured with the Block Food Frequency Questionnaire Ages 8-17. Total plasma carotenoid concentrations and skin carotenoid intensities were strongly correlated (r=0.62, p<0.001, n=38). Reported total carotenoid intake correlated with skin carotenoids (r=0.40, p<0.0001, n=128). Skin carotenoid status as measured by RRS can be a strong predictor of plasma carotenoid status and dietary intake of carotenoids in children. RRS may be used as a valid, non-invasive, and useful method to assess fruit and vegetable intakes in this population.

Optical detection methods for carotenoids in human skin.

Resonance Raman spectroscopy and reflection spectroscopy are non-invasive optical quantitative methods for the measurement of carotenoid antioxidant levels in human skin in vivo. Since all tissue carotenoids are derived from the diet, optical monitoring in skin may serve as an objective indicator for fruit and vegetable intake, and more broadly also as an effective biomarker for integrative health. The two optical methods have already found enthusiastic application in the Nutritional Supplement Industry where they are used with large populations to measure skin carotenoid uptake upon consumption of carotenoid-containing dietary supplements. Applications in medical fields such as nutrition science and epidemiology have been awaiting rigorous correlation studies between the optical carotenoid detection methods and the established gold standard detection method of high-performance liquid chromatography, which requires excised tissue samples. In this article we review the principles of the methods along with the current status of validations so the reader can assess the merits of the optical methods in their respective fields of interest.