The highest average levels of lutein and zeaxanthin were associated with a 42 and 41% reduction in the risk of cataract, respectively, compared with the lowest average levels, according to results published in the British Journal of Nutrition.
The study adds to an ever-growing body of science supporting the role of lutein and zeaxanthin for eye health, with the majority supporting their role against age-related macular degeneration, the leading cause of legal blindness for people over 55 years of age in the Western world, according to AMD Alliance International.
Study details
Researchers from the University of Eastern Finland and Lapland Central Hospital base their conclusions of data from 1,689 elderly people aged between 61 and 80 participating in the Kuopio Ischaemic Heart Disease Risk Factor Study.
The data revealed 113 cases of incident age-related cataracts, of which 108 were nuclear cataracts, said the researchers.
The highest versus lowest average levels of lutein and zeaxanthin were associated with significant reductions in the risk of cataract, wrote the researchers.
Lens ratio
The researchers note that both compounds appeared to provide similar levels of protection from cataracts, an observation they said challenges the hypothesis that zeaxanthin is more important for lens health.
“The ratio of zeaxanthin:lutein is much higher in the lens than in the plasma, suggesting that the lens of the eye mainly accumulates zeaxanthin,” they explained. “Both lutein and zeaxanthin protect liposomal membranes from light-induced oxidative stress.
“Zeaxanthin appears to be a more effective protector against UV light exposure, because lutein and zeaxanthin may be oriented differently in biological membranes.
“In addition, zeaxanthin is also especially very effective in protecting lipid membranes against peroxyl radical oxidation.”
Source: British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S0007114511005332
“Plasma lutein and zeaxanthin and the risk of age-related nuclear cataract among the elderly Finnish population”
Authors: Jouni Karppi, Jari A. Laukkanen and Sudhir Kurl