Cataracts are a leading cause of blindness in the elderly, and this is more true in developing nations where surgery for cataracts is less common. Cell culture experiments suggest that oxidative stress plays a role in the formation of cataracts and animals models support this view. In diseases that show a causative role for free radicals and oxidative stress, antioxidants nutrients in the diet are often shown to be beneficial and preventing the disease, and cataracts might be no exception. Certain dietary antioxidants can accumulate in the eye, and these antioxidants may lessen the rate of cataract formation thus preventing their development in those with a high quality diet. Studies have assessed the role of antioxidants in the prevention of cataracts by measuring blood levels of various antioxidants and using this data to find associations with cataract formation. A recent meta-analysis1 used data from such previously published studies to determine if this effect was significant when the data from all the studies was combined.
The results of the study showed that blood levels of certain antioxidants were associated with a reduction in the risk of developing cataracts. In particular, vitamin E, α-carotene, lutein and zeaxanthin were inversely associated with age-related cataracts in all ethnicities, and vitamin C and vitamin A were also inversely associated with age-related cataracts in Asians. Therefore antioxidants may be beneficial at preventing the development of age-related cataracts. The protective effect of the carotenoids is interesting as it supports previous findings that show protection for the eye from dietary carotenoids such as lutein. These carotenoids may accumulate in the eye because of their similarity in structure to the vitamin A molecule, and here they may confer protection against singlet oxygen formation, a role they play in plants. In plants carotenoids are particularly protective of excessive ultraviolet light, which is a known generator of oxidative stress.
Dr Robert Barrington’s Nutritional Recommendation: Certain antioxidant nutrients are protective of disease because they inhibit oxidative stress. In the eye, the carotenoids may be particularly beneficial. Of the carotenoids, lutein has been shown in numerous studies to have a protective effect against oxidative stress in the eye and therefore diets high in lutein may help retain optimal vision and eye health. Lutein is found in certain green leafy vegetables such as spinach as well as yellow vegetables such as peppers and corn. Lutein is also found in high concentrations in egg yolks. Spinach is also a source of zeaxanthin, another carotenoid with eye protecting effects. Consuming a high quality diet containing vegetables such as spinach may confer protection from eye diseases including age-related cataracts.
RdB
