Blood and lens lipid peroxidation and antioxidant status in normal individuals, senile and diabetic cataractous patients.
PURPOSE: Oxidative mechanisms are believed to play an important role in the pathogenesis of cataract, the most important cause of visual impairment at advanced age. To determine the body’s antioxidant status as well as its lipid peroxidation levels, both blood and lens parameters were evaluated. METHODS: This study was performed on the blood samples and lenses obtained from 46 patients diagnosed as having cataract and 20 control subjects. The control group was composed of 10 women and 10 men who do not smoke. Control subjects without any lens opacity or vacuoles when observed with a slit lamp were recruited on the same exclusion criteria as far as disease and treatment were concerned. No antioxidant medicines were used. They were all healthy individuals without any systemic diseases. Superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GSSG-Red) activities in red blood cell (RBC) lysates as well as whole blood glutathione (GSH) and plasma thiobarbituric acid reactive substances (TBARS), the indicator of lipid peroxidation concentrations, were determined quantitatively both in the blood samples and the lenses of the patients with senile and diabetic cataracts. RESULTS: Whole blood GSH values, and erythrocyte SOD activities were significantly lower in the cataractous patients than those in the control group. The values in the diabetic cataractous group were also less than those in the senile cataractous group. Significantly decreased erythrocyte GSSG-Red and G6PD activities were detected in the diabetic cataractous group. Plasma TBARS values were higher both in the senile and diabetic groups when compared to those in the control group. Significantly decreased values were observed for GSSG-Red activities and TBARS values in the lenses of the senile cataractous patients in comparison with those in the diabetic cataractous patients. The lens GSH values were found to be higher in the senile cataractous group than the values obtained in the diabetic cataractous group. CONCLUSIONS: A strong correlation was found between lens GSH and lens TBARS concentrations in the diabetic group. This emphasized the vital role of GSH as an antioxidant in the lens over the other antioxidant parameters, e.g., enzymes, and the oxidative stress is at the highest level in lens.
Curr Eye Res. 2002 Jul;25(1):9-16
Long-term intake of vitamins and carotenoids and odds of early age-related cortical and posterior subcapsular lens opacities.
BACKGROUND: Proper nutrition appears to protect against cataracts. Few studies have related nutrition to the odds of developing cortical or posterior subcapsular (PSC) cataracts. OBJECTIVE: We assessed the relation between usual nutrient intakes and age-related cortical and PSC lens opacities. DESIGN: We studied 492 nondiabetic women aged 53-73 yeas from the Nurses’ Health Study cohort who were without previously diagnosed cataracts. Usual nutrient intake was calculated as the average intake from 5
food-frequency questionnaires collected over a 13-15-year period before the eye examination. Duration of vitamin supplement use was determined from 7 questionnaires collected during this same period. We defined cortical opacities as grade > or = 0.5 and subcapsular opacities as grade > or =0.3 of the Lens Opacities Classification System III. RESULTS: Some lenses had more than one opacity. No nutrient measure was related to prevalence of opacities in the full sample, but significant interactions were seen between age and vitamin C intake (P = 0.02) for odds of cortical opacities and between smoking status and folate (P = 0.02), alpha-carotene (P = 0.02), beta-carotene (P = 0.005), and total carotenoids (P = 0.02) for odds of PSC opacities. For women aged <60 years old, a vitamin C intake > or = 362 mg/d was associated with a 57% lower odds ratio (0.43; 95% CI: 0.2, 0.93) of developing a cortical cataract than was an intake <140 mg/d, and use of vitamin C supplements for > or = 10 y was associated with a 60% lower odds ratio (0.40; 0.18, 0.87) than was no vitamin C supplement use. Prevalence of PSC opacities was related to total carotenoid intake in women who never smoked (P = 0.02). CONCLUSIONS: Our results support a role for vitamin C in diminishing the risk of cortical cataracts in women aged <60 years old and for carotenoids in diminishing the risk of PSC cataracts in women who have never smoked.
Am J Clin Nutr. 2002 Mar;75 (3):540-9
Vitamin C is associated with reduced risk of cataract in a Mediterranean population.
Cataract is an important visual problem of older people and a substantial health care cost in many countries. Most studies investigating risk factors for cataract have been conducted in the United States, and there is less information on the possible role of dietary factors in European populations. We conducted a case-control study to investigate the association of antioxidant vitamins (vitamin C, vitamin E, vitamin A, beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, zeaxanthin andlutein) and minerals (zinc and selenium) and risk of cataract in a Mediterranean population. Cases with cataract (343) and 334 age/sex frequency-matched controls aged 55 to 74 years old were selected from an ophthalmic outreach clinic in Valencia, Spain. Participants were interviewed about their diet using a Food Frequency Questionnaire, and other information on potential confounders, such as smoking, alcohol, and education. Blood samples were
analyzed by a colorimetric method for vitamin C and by reversed-phase HLPC for other blood antioxidants. Blood levels of vitamin C above 49 micromol/L were associated with a 64% reduced odds for cataract (P < 0.0001). Dietary intake of vitamins C, E and selenium were marginally associated with decreased odds (P = 0.09, P = 0.09, P = 0.07, respectively), whereas moderately high levels of blood lycopene (>0.30 micromol/L) were associated with a 46% increased odds of cataract (P = 0.04). Our results strengthen the evidence for a protective role for vitamin C on the aging lens as this effect was seen in a population characterized by high vitamin C intakes.
J Nutr. 2002 Jun;132(6):1299-306