Jahreszeitliche Schwankungen und Einfluss der Ernährung auf die makuläre Pigmentdichte

Age-related macular degeneration: Effects of a short-term intervention with an oleaginous kale extract--a pilot study

OBJECTIVE

Age-related macular degeneration (AMD) is a multifactorial degenerative disease of the retina, which accounts for slowly progressive visual impairment in the elderly. An increased dietary intake of xanthophylls is suggested to be inversely related to the risk of macular disease.

METHODS

The present study was designed as a randomized, double-blind, placebo-controlled, parallel trial examining the influence of a short-term intervention with an oleaginous extract of Brassica oleracea var. sabellica L. (kale) on plasma xanthophyll concentrations and the optical density of the macular pigment xanthophylls (MPOD). Twenty patients with non-exudative AMD were recruited for a 10-wk study period (2-wk run-in, 4-wk intervention, 4-wk washout). All participants received 50 mL of a beverage containing either an oleaginous extract of kale (kale) or refined rapeseed oil (placebo). The verum product provides 10 mg lutein and 3 mg zeaxanthin per day.

RESULTS

The concentrations of the xanthophylls in plasma and the MPOD increased significantly in the kale group after 4 wk of intervention. The successive washout period resulted in a significant decline of the values in plasma and macula. The values at the end of the study were still significantly higher than the initial values. Nevertheless, the improvements did not persist over 4 wk of washout.

CONCLUSION

The distribution of the xanthophylls in the macula seems to be more dynamic than originally assumed.

Repeated measures of macular pigment optical density to test reproducibility of heterochromatic flicker photometry

PURPOSE

To report the reproducibility of macular pigment optical density (MPOD) values assessed with heterochromatic flicker photometry (HFP) in healthy individuals.

METHODS

Twenty-four volunteers from our department underwent MPOD testing of both eyes by flicker photometry on three separate occasions. To test reproducibility of MPOD, the coefficient of variance was calculated separately for right and left eyes. In addition, we investigated MPOD averages of right and left eyes and interocular correlations (Pearson's r) at every visit.

RESULTS

The mean MPODs at the first visit were 0.61 +/- 0.24 and 0.72 +/- 0.27 in right and left eyes, respectively. Mean values of 0.58 +/- 0.29 and 0.60 +/- 0.21 (second visit) and 0.62 +/- 0.27 and 0.63 +/- 0.24 (third visit) were assessed for right and left eyes, respectively. Differences of the mean values between eyes were not significant. Correlations were weak at visits one and two (r = 0.49, p < 0.014 and r = 0.43, p < 0.038, respectively) and moderate at visit three (r = 0.58, p < 0.003). The coefficients of variance were 36.1% and 23% for right and left eyes, respectively.

CONCLUSION

Our mean MPODs are higher and the interocular correlations weaker compared to the literature. The coefficient of variance in both eyes is high and does not imply good reproducibility of obtained MPOD values.

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

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION

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

[Lutein and antioxidants in the prevention of age-related macular degeneration]

Demographic developments in Europe and North America are causing an increase of age-related diseases. Age-related macular degeneration (AMD) is one of the leading causes of severe central visual acuity loss in elderly people and seems to be an economic problem, too. There is evidence that oxidative damage is an important factor for exacerbation of AMD. Macular pigment with its antioxidative effect may serve as"natural sunglasses" filtering the blue light acting as a possible source of photooxidative damage to the neurosensory retina. The macular pigment consists mostly of lutein and zeaxanthin. These micronutrients from the group of carotenoids, as is the case for vitamins (vitamins C, E, and beta-carotene), cannot be synthesized in mammals and that is the reason why the role of micronutrition or its supplementation and its correlation to AMD progression has been discussed for years. The results of currently published studies are often contradictory. At present there are no results from randomized controlled studies confirming that supplementation of lutein and zeaxanthin can reduce the risk for AMD. Several epidemiological studies investigating the impact of antioxidants and omega-3 fatty acids on the incidence of AMD provided conflicting results.Up to now, AREDS is the largest randomized controlled study investigating the effect of supplementation of antioxidants, zinc, and copper on the progression of AMD. AREDS showed a significant effect of this supplementation in some particular groups of patients with AMD. The supplementation of lutein and omega-3 fatty acids is not toxic but a positive effect has not been proven by randomized studies.

Changes in macular pigment optical density and serum concentrations of its constituent carotenoids following supplemental lutein and zeaxanthin: The LUNA study

Macular pigment (MP), consisting of lutein (L) and zeaxanthin (Z), is believed to protect the retina from photo-oxidative damage. The current study investigates, in terms of MP optical density (MPOD) and serum concentrations of its constituent carotenoids, response to supplemental L and Z, and co-antioxidants. An intervention (I) group, consisting of 108 subjects (mean [+/-SD] age: 71.5 [+/-7.1] years), of which 92.6% exhibited features of age-related macular degeneration (AMD), received a daily supplement consisting of 12 mg L and 1 mg Z, both provided as ester 120 mg vitamin C, 17.6 mg vitamin E, 10 mg zinc, 40 microg selenium (Ocuvite Luteintrade mark) for a period of 6 months. MPOD was measured, by 2-wavelength autofluorescence (AF), on five occasions during the period of supplementation, and once again 3 months following discontinuation of the supplement. A control (C) group of 28 subjects (mean [+/-SD] age: 71.0 [+/-8.1] years), who received no dietary supplementation or modification, was examined at baseline and once again after a mean of 29.4 (+/-9.3) weeks. At baseline, mean (+/-SD) MPOD (at 0.5 degrees) was 0.504 (+/-0.197) and 0.525 (+/-0.189) in the I and C groups, respectively. There was a statistically significant increase in MPOD (at 0.5 degrees) for the I group (0.1 [+/-0.009]; p<0.0008), whereas no significant increase was seen in the C group (0.03 [+/-0.02]; p>0.05), over the period of supplementation. In order to classify supplemented subjects into quartiles, in terms of MPOD response, we calculated the difference between MPOD (at 0.5 degrees) at visit 6 and at baseline (visit 1). Quartile 1 (the "non-responder" quartile) displayed no increase in MPOD (at 0.5 degrees), in spite of rises seen in serum concentrations of L and Z. The three "responder" quartiles reached similar final plateaus of MPOD (at 0.5 degrees), reflected in final mean (+/-SEM) values of 0.59 (+/-0.04) optical density unit (ODU), 0.64 (+/-0.03) ODU and 0.64 (+/-0.03) ODU for quartiles 2, 3 and 4, respectively. Subjects with low baseline MPOD were more likely to exhibit a dramatic rise in MPOD, or to exhibit no rise in MPOD, in response to supplements than subjects with medium to high baseline MPOD values. Supplementation with 12 mg L and 1 mg Z, combined with co-antioxidants, resulted in an increase of MPOD at 0.5 degrees eccentricity in a majority of subjects, including those afflicted with AMD. However, there remains a substantial proportion of subjects for whom, in spite of rises in serum concentrations of L and Z in these subjects, MPOD augmentation in response to supplemental L, Z and co-antioxidants could not be detected over the study period, thus indicating that intestinal malabsorption of these carotenoids is not responsible for the lack of a macular response to such supplements. Further, our results suggest that saturable mechanisms play a role in the retinal capture and/or stabilisation of the macular carotenoids.