NEW YORK (Reuters Health) – Maintaining a diet high in lutein and zeaxanthin — found in yellow or dark leafy vegetables — as well as vitamin E may help protect against the development of cataracts, according to research published in the January issue of Archives of Ophthalmology.
“Although definitive data to guide public health recommendations regarding these and other nutrients in the prevention of cataract will come from randomized trials, a continued recommendation to increase total intake of fruits and vegetables seems warranted,” Dr. William G. Christen, from Brigham and Women’s Hospital and Harvard Medical School, Boston, told Reuters Health.
Researchers have hypothesized that oxidative damage can lead to cataract formation and that nutrients with antioxidant capabilities, such as vitamin E, lutein and zeaxanthin, can protect against these changes, Dr. Christen and colleagues note in their report. Lutein and zeaxanthin are the only carotenoids detected in the human lens and the presence of oxidation products of lutein and zeaxanthin in the lens further supports a functional role for these nutrients in maintaining lens clarity, they also note.
Dr. Christen and colleagues studied the relation between dietary intake of carotenoids and vitamin C and E and the risk of cataract in 35,551 women who enrolled in the Women’s Health Study in 1993 and who were followed for an average of 10 years. In detailed comparisons of the diets of 2,031 women who developed cataracts during the study and 33,520 who did not, the research team observed “significant inverse trends” with risk of cataract for dietary intake of lutein/zeaxanthin and vitamin E.
In multivariate analysis, women in the highest quintile of dietary lutein/zeaxanthin intake (about 6,716 µg/day) had an 18% lower risk of cataract relative to those in the lowest quintile (about 1,177 µg/day). Women in the highest quintile of vitamin E intake from food and supplements (about 262.2 mg/day) were 14% less likely than women in the lowest quintile (about 4.4 mg/day).
In this study, higher intake of vitamin C was associated with a “weak, and statistically nonsignificant, inverse association with risk of cataract,” the investigators also report.
These prospective data, Dr. Christen and colleagues note, indicate a decreased risk of cataract with higher intakes of lutein/zeaxanthin and vitamin E.
“Although reliable data from randomized trials are accumulating for vitamin E and other antioxidant vitamins, randomized trial data for lutein/zeaxanthin are lacking,” they note. “Such information will help to clarify the benefits of supplemental use of lutein/zeaxanthin and provide the most reliable evidence on which to base public health recommendations for cataract prevention by vitamin supplementation.”
Arch Ophthalmol 2008;126:102-109.