More support for carotenoids for eye health
rare isomer of zeaxanthin, may offer protection against age-related
macular degeneration.
"We have shown for the first time that meso-zeaxanthin is absorbed into the serum following ingestion," wrote lead author Richard Bone from Florida International University. "The data indicate that a supplement containing predominantly meso-zeaxanthin is generally effective at raising macular pigment density, and may turn out to be a useful addition to the defenses against AMD," he added. AMD affects the central part of the retina called the macula, which controls fine vision, leaving sufferers with only limited sight. AMD affects over 30m people worldwide, and is the leading cause of blindness in people over 50. Previous studies have reported a link between AMD and lutein and zeaxanthin, found in leafy green vegetables, corn, egg yolks, squash, broccoli and peas. The carotenoids are proposed to reduce the risk of AMD by absorbing blue light that could damage the macula, by preventing free radicals from damaging eye cells and by strengthening eye cell membranes. The new study supports and adds to these previous studies by reporting that supplementation with meso-zeaxanthin, an unusual and consequently rare zeaxanthin isomer, may also offer protection from AMD. Writing in the journal Nutrition & Metabolism, Bone and collaborators from the University of Cambridge, report that supplementation of 10 subjects with gelcaps providing 20 mg/day of predominantly meso-zeaxanthin, with smaller amounts of lutein and zeaxanthin, increased macular pigment optical density after 120 days of supplementation. Nine other subjects received gelcaps containing placebo. The researchers report that macular pigment optical density increased as a result of carotenoid supplementation by an average rate of 0.59 milli-absorbance unit/day in the 10 supplemented subjects. The placebo group experienced reductions with an average decreasing rate of 0.17 milliabsorbance units/day. "Our study shows that a supplement containing the macular carotenoids, lutein, zeaxanthin and meso-zeaxanthin but principally meso-zeaxanthin, is effective at raising macular pigment optical density (MPOD) in the majority of subjects. Increased MPOD may be an effective means of protecting the aging population from AMD," concluded the researchers. Lutein remains the most widely-known carotenoid most associated with eye health. A survey by Frost & Sullivan, commissioned by Kemin Health, maker of FloraGLO branded lutein, found that awareness of the antioxidant carotenoid lutein has never been so high in Europe: in Portugal it had doubled compared to last year, to 39 per cent, and surpassed the previous leaders, Germany, in the process. Germans again showed a great awareness, with 37 per cent of respondents aware of lutein, up from 33.3 per cent last year. Similar increases were observed in the UK (up to 27 per cent from 20 per cent in 2006), and Spain (up to 13 per cent from 9.8 per cent last year). Source: Nutrition & Metabolism 2007, 4:12 doi:10.1186/1743-7075-4-12 "Macular pigment response to a supplement containing meso-zeaxanthin, lutein and zeaxanthin" Authors: Richard A Bone, J.T. Landrum, Y. Cao, A.N. Howard and F. Alvarez-Calderon
