Verification of Meso-Zeaxanthin in Fish.

BACKGROUND/OBJECTIVES: The carotenoids lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) accumulate in the central retina (the macula), where they are collectively known as macular pigment (MP). MP has been shown to enhance visual function in both diseased and non-diseased retinae, and therefore an understanding and confirmation of, the origins of these carotenoids is needed. Studies have shown that L and Z are present in many foodstuffs found in a typical Western diet (e.g. spinach, kale, peppers, yellow corn and eggs). It has been shown that MZ is generated from L in the primate retina and earlier reports suggested that MZ was present in some fish species. Recently, however, one research group reported that MZ is not present in fish and suggested that the earlier reports showing MZ in these marine species were a methodological artefact. The current study was designed to investigate the reason for the contradiction, and test for the presence of MZ in fish and some other foods. METHODS: Raw fruits, vegetables and fish were extracted for carotenoid analysis by high performance liquid chromatography. RESULTS: MZ was not detected in any of the fruits or vegetables tested in our study. However, using retention time matching, absorption spectrum comparison, and sample spiking, we verified the presence of MZ in salmon skin, sardine skin, trout skin and trout flesh. CONCLUSION: This study confirmed the presence MZ in nature, and in the human food chain.

Education is positively associated with macular pigment: the Irish Longitudinal Study on Ageing (TILDA).

PURPOSE: The three carotenoids lutein, zeaxanthin, and meso-zeaxanthin, are found at the macula and referred to as macular pigment (MP). This study was undertaken to investigate determinants of MP in a large randomly selected sample from the Republic of Ireland (as part of The Irish Longitudinal Study on Ageing [TILDA]). METHODS: MP optical density (MPOD) was measured using customized heterochromatic flicker photometry in 4373 participants. Sociodemographic and self reported health data was obtained using computer assisted personal interview (CAPI). RESULTS: Mean (SD) MPOD for the study group was 0.203 (0.156) with a range of 0 to 1.01. MPOD was higher for participants with secondary education (mean [SD] = 0.205 [0.148]) than for those with only primary education or no education (mean [SD] = 0.183 [0.113]; P < 0.001). MPOD was also higher for those with tertiary education (mean [SD] = 0.232 [0.231]) compared with primary/no education or secondary education (P < 0.001 for both comparisons). CONCLUSIONS: We report that MP is lower amongst those participants of a population-representative study who did not have secondary or third level education when compared with participants who had such education. Given the emerging evidence that MP is important for visual performance and comfort, and given the putative protection that this pigment confers against AMD (especially important in the context of increased risk of AMD in this social group), public health measures aimed at improving diet for this at-risk population need to be considered.

The impact of macular pigment augmentation on visual performance using different carotenoid formulations.

PURPOSE: To investigate changes in macular pigment optical density (MPOD) and visual performance following supplementation with different macular carotenoid formulations. METHODS: Thirty-six subjects (19 male, 17 female; mean SD, age 51 13 years) were recruited into this single-masked placebo-controlled study, and were randomly assigned to one of the following three intervention (supplementation) groups: (1) group 1 (20 mg lutein [L] and 2 mg zeaxanthin [Z]); (2) group 2 (10 mg L, 2 mg Z, and 10 mg meso-zeaxanthin [MZ]); and group 3 (placebo). Outcomes measures included visual performance and MPOD response. Data were collected at baseline, at 3 months, and at 6 months. RESULTS: At 3 and 6 months, a statistically significant increase in MPOD was found at all eccentricities (other than the most peripheral 3° location) in group 2 (P < 0.05 for all), whereas no significant increase in MPOD was demonstrable at any eccentricity for subjects in groups 1 and 3. Statistically significant improvements in visual performance measures including visual acuity and contrast sensitivity with and without glare were observed for group 2 only. Only mesopic contrast sensitivity at one spatial frequency improved significantly by 6 months (P < 0.05) for group 1. No improvements in any parameters of visual performance were observed for subjects supplemented with placebo (P > 0.05 for all). CONCLUSIONS: These results suggest that supplementation with all three macular carotenoids potentially offered advantages over preparations lacking MZ, both in terms of MPOD response and visual performance enhancement.