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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 |