A possible role for vitamins C and E in cataract prevention

Article Abstract:

Cataracts develop over the lens of the eye and interfere with vision. Inside the eye, oxygen from the air can be converted to active oxygen radicals (highly reactive atoms with unpaired electrons) that cause tissue damage and may be involved in cataract formation. The eye has protective enzymes, such as superoxide dismutase, that destroy oxygen radicals. Antioxidant vitamins, such as vitamins C and E, also act as oxygen radical scavengers (inactivators of oxygen radicals). Therefore, antioxidant vitamins may be of clinical use in preventing cataracts. Studies in patients with cataracts indicated that these patients had blood levels of vitamins C and E and beta-carotene that were lower than those of patients without cataracts. Results of a self-administered questionnaire (given to 152 cataract patients age 55 and older and 152 matched subjects without cataracts) indicated that individuals with cataracts consumed less supplementary vitamin C and E than did individuals without cataracts. These findings indicated a 50 percent reduction in the risk of developing cataracts when vitamins C and E were consumed as supplements; subjects were not asked about the dose of the vitamins in the supplements. These data based upon questionnaires are only preliminary, and a placebo-controlled, double-blind study should be performed to better assess the possible effectiveness of these vitamins in reducing the risk of cataracts. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Epidemiological evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention

Article Abstract:

Cataracts represent the most common visual impairment in the elderly; the cataract forms over the lens of the eye, clouding the vision. Oxidation of proteins in the lens of the eye is thought to play an important role in the development of cataracts. Certain vitamins (C, E and carotene, a form of vitamin A) have antioxidant properties that may be useful in preventing cataracts. Plasma levels of vitamin C, vitamin E and carotene were determined in 77 subjects with cataracts and 35 subjects without cataracts to investigate whether vitamin status might be related to cataract development. An increased risk of cataract development was associated with low dietary intake of vitamin C. Subjects who consumed less than three to four servings of vegetables and fruits per day were at greater risk for developing cataracts. An increase in fruit and vegetable consumption is recommended to protect against cataract development. (Consumer Summary produced by Reliance Medical Information, Inc.)

Carotenes

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Assessment of the roles of vitamin C, vitamin E, and beta-carotene in the modulation of oxidant stress mediated by cigarette smoke-activated phagocytes

Article Abstract:

Phagocytes are cells of the immune system that engulf and destroy foreign or invading infectious agents and microorganisms. During the process of phagocytosis, free radicals, also known as reactive oxidants (highly reactive atoms with unpaired electrons) are released. These free radicals cause damage to the surrounding tissue. Antioxidant vitamins such as vitamin C and beta-carotene (a form of vitamin A) can inactivate the free radicals and prevent tissue damage. Cigarette smoking is associated with reduced plasma levels of beta-carotene and vitamin C, and also with activation of phagocytes. This puts cigarette smokers at greater risk for developing pulmonary (lung) damage caused by free radicals. Cigarette smoking leads to an imbalance of oxidants and antioxidants (favoring the oxidants) and thereby increases the risk of tissue damage and disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

Smoking, Free radicals (Chemistry), Free radicals, Beta carotene

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