Antioxidant vitamins may reduce cataract risk

NEW YORK (Reuters Health) – People who eat lots of yellow or dark leafy vegetables, as well as foods rich in vitamin E, may be reducing their risk of developing cataracts, according to new research published in the 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, Christen and colleagues note in their report.

Lutein and zeaxanthin are the only carotenoids detected in the human lens and the oxidation products of lutein and zeaxanthin further support a role for these nutrients in preserving lens clarity, they also note.

Christen and colleagues studied the relationship between carotenoids and vitamin C and E in the diet and the risk of cataracts 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 with the diets of 33,520 women who did not, the researchers observed “significant inverse trends” in the risk of cataracts and dietary quantities of lutein, zeaxanthin and vitamin E.

Further analysis suggested women with the highest amounts of lutein and zeaxanthin in their diet (about 6,716 micrograms per day) had an 18 percent lower risk of cataract compared with those with the lowest amounts (about 1,177 micrograms per day).

Similarly, women with the highest dietary levels of vitamin E from foods and supplements (about 262.2 milligrams per day) were 14 percent less likely than women with the lowest levels (about 4.4 milligrams per day).

In this study, higher levels of vitamin C were associated with a “weak, and statistically nonsignificant, inverse association with risk of cataract,” the investigators also report.

These data, Christen and colleagues note, indicate a decreased risk of cataract with higher dietary levels of lutein, zeaxanthin and vitamin E.

Although reliable data from other studies are accumulating that confirm the value of vitamin E and other antioxidant vitamins, studies in which the subjects are randomly assigned to different levels of lutein and zeaxanthin are lacking, they note.

“Such information will help to clarify the benefits of supplemental use of lutein/zeaxanthin,” they add, “and provide the most reliable evidence on which to base public health recommendations for cataract prevention by vitamin supplementation.”

SOURCE: Archives of Ophthalmology, January 2008.