Long term Lutein Supplementation Improves Eyesight in People with Age-related Cataract

The Lutein-Cataract Connection

Previous issues of Staying Healthy have reported on studies that suggest when you consistently eat more lutein from spinach, kale, and other leafy vegetables you may lower your risk of developing age-related macular degeneration. But boosting lutein intake may also be of benefit to people with cataract, or clouding of the eye's lens. Cataract reduces vision, and is responsible for about 30-50 million cases of blindness worldwide, according to the authors of a study published last month (1).

Oxidative damage plays a role in the formation of cataracts, and antioxidant nutrients are believed to slow the process by reducing oxidative stress in the lens. Population studies have linked higher intake of vitamin E and lutein, as well as long-term vitamin C supplementation, with lower risk of cataracts (2-4).

Intervention trials combining high-doses of the carotenoid beta-carotene with vitamins C and E have produced mixed results (5,6). However lutein and its related compound zeaxanthin, are the only carotenoids that are present in the lens. So it's not surprising that studies examining the effects of high-dose beta-carotene in cataract have not found consistent benefit. In this double-blind study, researchers wanted to see whether supplements of lutein or vitamin E could improve eyesight in people with age-related cataract.

Better Visual Performance

Volunteers with the same types of cataract received either lutein supplements (15 mg lutein in compound form, equivalent to about 7 mg free lutein), or 100 IU vitamin E, or a placebo. The supplements were taken three times weekly, over about a two-year period. Visual acuity and the ability of people to see under bright light conditions (called glare sensitivity) were measured by a number of different tests throughout the study.

Visual performance was significantly improved in the group getting lutein, while it decreased in placebo takers. Performance remained about the same in the vitamin E group, suggesting that this antioxidant may be of some help too. When the researchers clinically examined participants, they found that cataracts did not progress in four of five patients in the lutein group, three of five in the vitamin E group, and one of five among placebo subjects.

Findings Should Spur More Research

According to the researchers, this study suggests that increasing lutein intake though lutein-rich foods or supplements improves the visual performance of patients with age-related cataract over the long-term. These results call for other investigators to conduct trials which include greater numbers of people, to confirm the cataract-slowing benefits of lutein.

References

1. Olmedilla B et al. Lutein, but not alpha tocopherol, supplementation improves visual function in patients with age-related cataracts: A 2 year double-blind, placebo controlled pilot study. Nutrition 19:21-24, 2003
2. Taylor A et al. Long-term intake of vitamins and carotenoids and odds of early age-relate cortical and posterior subcapsular lens opacities. Am J Clin Nutr; 75:540-49, 2002
3. Lyle BJ et al. Serum carotenoids and tocopherols and incidence of age-related cataract. Am J Clin Nutr; 69:272-7, 1999
4. Chasan-Taber et al. A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women. Am J Clin Nutr; 70:431-2, 1999
5. The REACT Group. The Roche European American Cataract Trial (REACT): A randomized clinical trial to investigate the efficacy of an oral antioxidant micronutrient mixture to slow progression of age-related cataract. Ophthalmic Epidemiology; 9:49-80, Feb. 2002
6. AREDS report no. 9. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E and beta carotene for age-related cataract and vision loss. Arch Ophthalmol 119(10):1439-52, 2001.