Lutein for Cataract Sufferers
Supplementing with lutein improves visual function in cataract sufferers and may slow the progression of the cataracts, according to a study published in Nutrition (2003;19:21–4). Cataracts are among the most common causes of visual impairment in the elderly. They are caused by progressive degeneration of the proteins that make up the lens of the eye, which eventually results in clouding of the lens. The cause of age-related cataracts is unknown.
In the new study, 15 individuals with age-related cataracts were randomly assigned to receive either 15 mg of lutein, 100 IU of vitamin E, or a placebo three times per week for up to two years. Visual acuity improved significantly in the lutein group, whereas no change was seen in the vitamin E and placebo groups. In addition, sensitivity to glare improved in those taking lutein, but not in the other groups. During the study, the cataracts did not progress in four of the five people in the lutein group, three of five in the vitamin E group, and one of five in the placebo group. No significant side effects were seen in those taking lutein.
Although the number of participants in the study was small, the results suggest that taking lutein improves visual acuity and reduces glare sensitivity in people with age-related cataracts, and may also help delay the progression of the cataracts. Vitamin E was ineffective in this study, possibly because a relatively small amount was used.
Lutein is a carotenoid (a compound similar in structure to beta-carotene) that is present in high concentrations in spinach, other dark green leafy vegetables, egg yolk, and corn, and in smaller amounts in kiwi, grapes, oranges, zucchini, and certain kinds of squash. Lutein from the diet accumulates in the portion of the retina known as the macula. Previous research has suggested that lutein protects the macula against the damaging effects of sunlight, and may therefore help prevent the development of age-related macular degeneration, the most common cause of blindness. In one study, a higher intake of spinach or collard greens was associated with a substantially lower risk of age-related macular degeneration.
In the new study, the improvements in visual acuity were probably due to a direct effect of lutein on the retina, rather than a reduction in the severity of the cataracts. Nevertheless, the results suggest that lutein may also be capable of inhibiting the process of cataract formation. Larger studies are needed to confirm that possibility.
Other nutrients that show promise for cataract prevention include riboflavin, vitamin C, selenium, and quercetin.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
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