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Ánh sáng mặt trời, quy trình môi trường độc hại, và ngay cả các hoạt động trao đổi chất bình thường có thể tạo ra các phân tử phản ứng được gọi là các gốc tự do. Những gốc tự do có thể gây tổn hại tế bào và các mô xung quanh. Vitamin và khoáng chất chống oxy hóa bảo vệ chống lại thiệt hại gây ra bởi các gốc tự do. | Vitamins 119 Sunlight toxic environmental processes and even normal metabolic activities can generate highly reactive molecules known as free radicals. These free radicals can damage surrounding cells and tissues. Antioxidant vitamins and minerals protect against injury caused by free radicals. There are over 200 antioxidants including vitamins A C and E beta-carotene and minerals such as selenium and zinc. Free radical formation has been implicated in a number of conditions including cataracts dry eye and macular degeneration. The retina seems to be more susceptible to this damage than other tissues. Some studies suggest that the intake of antioxidant vitamins may help to delay the formation or slow the progress of these conditions. These relationships were extensively studied in a major multicenter clinical trial known as the Age-Related Eye Disease Study AREDS . It was sponsored by the National Eye Institute one of the federal government s National Institutes of Health. The AREDS set out to determine the natural history and risk factors of age-related macular degeneration AMD and cataract and to evaluate the effect of high doses of antioxidants and zinc on the progression of AMD and cataract. Results from the AREDS showed that high levels of antioxidants and zinc significantly reduce the risk of advanced age-related macular degeneration AMD and its associated vision loss. These same nutrients had no significant effect on the development or progression of cataract. Supplements Who should take the AREDS formulation Those individuals who are at high risk for developing advanced AMD with either intermediate AMD the presence of either many mediumsized drusen or 1 or more large drusen in 1 or both eyes or advanced AMD in 1 eye but not the other eye should take the formulation a combination of antioxidants plus zinc. Advanced AMD is defined as either a breakdown of light-sensitive cells and supporting tissue in the central retinal area advanced dry form or the .
