Cataracts in the elderly are an important health problem worldwide. Cataracts (clouding over of the lens of the eye) are thought to be caused by oxidative stress. Increasing the antioxidant defenses of the lens prevents or delays the formation of cataracts. Anti-oxidants are chemicals that reduce free radicals. Because free radicals cause chain reactions that damage cells, anti-oxidants are thought to help in a number of illnesses. These scientists tested whether curcumin, an antioxidant, present in the spice turmeric, prevented cataract formation in rats. Rats were maintained on a standard diet for 2 weeks. Then they were divided into two groups. One was given a dose of corn oil alone for 14 days. The other group was fed 75 milligrams of curcumin in corn oil per kilogram of weight for 14 days. Their lenses were removed and grown for 72 hours in test tubes. The test tubes contained either no or 100 micromoles of 4-hydroxy-2-nonenal (4-HNE). 4-HNE was used to artificially produce cataracts through a process called lipid peroxidation. As expected, 4-HNE caused clouding of the lenses. The lenses from curcumin fed rats were much more resistant to 4-HNE-induced clouding than were lenses from rats fed oil alone. The lenses from the curcumin fed rats contained significantly more glutathione S-transferase isozyme rGST8-8. By increasing this enzyme curcumin may have reduced the amount of 4-HNE, thereby reducing the cataracts. These studies suggest that curcumin protects against cataracts caused by lipid peroxidation.