Abstracts
Aging & Cataracts
Age-related
Cataracts, the world's leading cause of blindness, are an enormous public health problem in both developing and industrialized countries.
The evidence is overwhelming that age, trauma, and intraocular inflammation are important cataract risks.
Work still needs to be done in two areas related to this risk.
First, regarding individuals in developing nations, the question must be asked about which nutrients (or lack thereof) are the culprits. The epidemiologic evidence that antioxidants are the missing nutrients is far from overwhelming.
Ultraviolet radiation, especially ultraviolet B radiation, is an important risk for cortical cataracts, and one study (27) has even demonstrated a dose-response relation. However, the public health implication of this finding is not clear. Isolating the risk of ultraviolet B radiation exposure as a cause of cortical cataracts (and, in general, not of other types) indicates that the risk is small on a public health scale.
Both systemic and topical steroids are significant risk factors for the formation of posterior subcapsular cataracts.
The evidence is accumulating that cataracts can be added to the list of illnesses that are at least partially attributed to smoking. At this point, nuclear sclerosis is the most important cataract type associated with smoking.
Hodge-WG et al: Risk factors for age-related cataracts. Epidemiol-Rev. 1995; 17(2): 336-46.
Antioxidants & Cataracts
Antioxidants (1)
Low serum concentrations of the antioxidant vitamins predicted the development of senile cataract patients.
There was no association found between serum concentrations of selenium, retinol, and retinol binding protein and the risk of cataracts.
Low serum concentrations of antioxidants vitamin E and beta-carotene predict the development of end stage senile cataracts.
"Serum Antioxidant Vitamins and Risk of Cataract", Knekt, Paul, et al, British Medical Journal, December 5, 1992;305:1392-1394.
Antioxidants (2)
Nutritional risk factors for cataract in the Baltimore Longitudinal Study on Aging.
Plasma beta-carotene and vitamin C levels were not associated with a risk of nuclear or cortical lens opacities when levels were assessed up to 4 years before lens photographs were taken.
High levels of vitamin E were associated with a reduced risk of nuclear opacity for the highest quartile versus the lowest quartile.
Middle levels of vitamin E were associated with a reduced risk of cortical opacities, but were not seen in the higher levels of vitamin E.
When an overall index of antioxidant status was developed, higher levels of plasma antioxidants had no association with the risk of nuclear or cortical cataracts.
It is noted this group was healthy, well nourished and highly educated.
"Plasma Antioxidants and Risk of Cortical and Nuclear Cataract", Vitale, Susan, et al, Epidemiology, May 1993;4(3):195-203.
Antioxidants (3)
Editorial on research regarding cataracts and antioxidants. The antioxidants were beta-carotene and vitamins A, C and E. The evidence is contradictory. There are studies showing some benefits of vitamins C, E and beta-caroteneand others that do not.
Presently, there is not enough data to make a public health recommendation. This is neededed, since cataract surgery is the most frequently performed surgical procedure reimbursed by Medicare; accounting for 12% of the Medicare budget. If cataracts were delayed by 10 years, this figure could be cut in half.
Approximately 20% of Americans 65 to 74 years of age, and 45% of those age 75 years or older have age-related cataracts with visual impairment.
"Antioxidants and Cataracts", Jacques, P. Epidemiology, May 1993;4(3):191-3.
Antioxidants (4)
Although numerous studies have been published about theprobable causes of age-related macular degeneration, arresting or preventing the disease continues to be an elusive goal.
The literature is reviewed to provide an overview of the relationship of the antioxidants to disorders such as heart disease,cancer, diabetes, arthritis, cataracts and macular degeneration.
Diseases associated with aging appear to have a common denominator: oxidative damage. Antioxidants have been extensively studied to determine if they can prevent or successfully treat these diseases.
Larger-than-recommended amounts of antioxidants need to be used earlier in life, for longer periods of time, to determine their effectiveness in arresting or preventing diseases of aging.
Cheraskin E: Antioxidants in health and disease. J Am Optom Assoc, 67(1):50-7 1996 Jan.
Case Report - supplements
This is a case report of a 35-year-old male who had cataract, eczema and asthma. He was treated with 600 ug of selenium from selenomethionine, 1,200 mg of vitamin E, 80 mg of pyridoxine (vitamin B6), 15 mg of vitamin B2 and 2 gms of ascorbic acid.
It is interesting to note that in less than 2 months of treatment, all signs of severe atopic dermatitis had vanished and there were no signs of asthma.
It is reasonable to try selenium and vitamin E treatment in other kinds of cataracts such as senile and diabetic cataract. The authors feel that the treatment using sodium selenite or selenomethionine can be done safely if patients have normal kidney function.
"Cataracts, Vitamin E and Selenomethionine", Ahlrot-Westerlund, Britt, MD and Norrby, Ake, ACTA Ophthalm., April, 1988;237-238.
Glutathione & Cataracts
Studied patients operated on for cataract (32 men/75 women, aged 50-93 years) with respect to antioxidative agents in aqueous humor and serum.
Extracellular glutathione peroxidase (eGSHPx) was demonstrated in aqueous humor for the first time by a radioimmunoassay, the concentration of eGSHPx being 0.66(0.18) mg/l). The concentration of eGSHPx in serum was 3.81(0.84) mg/l, and its level in aqueous humor was 18% of that level.
Serum selenium had positive correlations with both serum eGSHPx and aqueous humor eGSHPx . However, there was no relation between the concentrations of eGSHPx in aqueous humor and in serum, suggesting that the maintenance of eGSHPx levels in the two fluids is controlled by different mechanisms beside selenium status.
Concentration of ascorbic acid in aqueous humor was 2.04(0.58) mmol/l, and it was closely correlated to the level of ascorbic acid in serum (0.052(0.032) mmol/l). Since serum ascorbic acid is related to ascorbic acid intake, its association to aqueous humor ascorbic acid indicates that dietary habits are important for maintaining that level which could play an important role in protecting ocular tissue against oxidative damage.
The role of eGSHPx secreted into aqueous humor in the oxidant defence system needs further study.
Haung W et al., Extracellular glutathione peroxidase and ascorbic acid in aqueous humor and serum of patients operated on for cataract. Clin Chim Acta, 1997 May 28, 261:2, 117-30.
Leukotriene & Cataracts
Leukotriene B4
Leukotriene B4 is not associated with the development of senile cataract.
"Leukotriene B4 Levels in the Aqueous Humor of Patients With Senile Cataract", Shindo, Kunihiko and Tanaka, Makiko, Curr. Ther. Res. Sept. 1993;54(3):325-327.
Lutein & Cataracts
Characterized all the major and minor carotenoids and their metabolites in human retina and probed for the presence of the oxidative metabolites of lutein and zeaxanthin.
In addition to lutein and zeaxanthin, several oxidation products of these compounds were present in the extracts from human retina.
Lutein, zeaxanthin, 3'-epilutein, and 3-hydroxy-beta,epsilon-caroten-3'-one in human retina may be interconverted through a series of oxidation-reduction reactions.
The presence of the direct oxidation product of lutein and 3'-epilutein (metabolite of lutein and zeaxanthin) in human retina suggests that lutein and zeaxanthin may act as antioxidants to protect the macula against short-wavelength visible light. The proposed oxidative-reductive pathways for lutein and zeaxanthin in human retina, may therefore play an important role in prevention of age-related macular degeneration and cataracts.
Khachik F et al., Identification of lutein and zeaxanthin oxidation products in human and monkey retinas. Invest Ophthalmol Vis Sci, 1997 Aug, 38:9, 1802-11.
Nutritional factors & Cataracts
Contents:
Nutrition and Oxidation
Nutritional Factors
Nutrition and Oxidation
Cataracts are an opacification of the lens, which are generally caused by the precipitation of proteins or other components associated with aging. Proteins in the lens are susceptible to photo-oxidation. The accumulation of these damaged proteins is due, in part, to the reduced activity of proteolytic pathways which in younger tissues may be removed by such byproducts. Removal of cataracts and physician visits regarding this problem consumes the largest portion of the Medicare budget. Approximately $3.2 billion is spent annually on cataracts in the United States.
Reviews research showing that elevated levels of the antioxidants vitamins C and E and carotenoids are associated with the delayed development of certain forms of cataract.
Fruit and vegetable intake also benefit vision. Assuring optimal antioxidant status may help extend lens function and reduce cataract formation.
If cataracts could be delayed by 10 years in the United States, half the cataract extractions and associated costs could be eliminated. Just consuming 300 mgs or more of vitamin C a day has been shown in one study to reduce the risk of developing cataracts by one-third. Consuming 400 I.U. of vitamin E per day, also has about one-third the risk of cataract development.
It is clear, it will not be possible to surgically remove most cataracts. Devising strategies to delay cataracts should be a high priority in both, the developed and non-industrialized parts of the world.
"Cataract: Relationships Between Nutrition and Oxidation", Taylor, A. Journal of the American College of Nutrition, 1993;12(2):138-146.
Nutritional Factors
Reviews the role of specific nutrients in cataract and macular degeneration formation. It is noted that these are major causes of blindness in the United States.
Nutrients that may have value in these conditions include zinc, taurine, vitamins A, B2, C and E, selenium, beta-carotene, N-acetylcysteine, ginkgo biloba and flavonoids. The authors have treated approximately 60 patients with macular degeneration utilizing intravenous zinc, selenium and other trace minerals.
"Nutritional Factors in Degenerative Eye Disorders: Cataract and Macular Degeneration", Gaby, AR & Wright, JV. J of The Advancement of Medicine, Spring, 1993;6(1):27- 40.
Minerals/Metals
Minerals/Metals
Accumulation of several minerals -- including copper, cadmium, lead, and calcium -- may increase risk of senile cataracts. In comparing 9 normal and 37 cataractous human lenses, it was found in the cataractous group that males had higher levels of cadmium compared to females. No lead was detected in normal lenses. The calcium content was significantly higher in the cortical cataract whereas other elements were not correlated with the types of cataract
Cekic, Osman: Copper, Lead, Cadmium and Calcium in Cataractous Lenses, Ophthalmic Research, 1998;30:49-53.
Use of asthma inhalers
Use of asthma inhalers
This article, based on two studies in the New England Journal of Medicine, suggests that use of inhaled corticosteroids for asthma treatment could increase the risk of developing cataracts and/or glaucoma. However, asthmatics should continue to use inhalers despite this risk, as failing to use an inhaler could be more dangerous than the risk of glaucoma. Dr. Leo Chylack, professor of ophthalmology at Harvard Medical School, suggests that primary care doctors give their asthmatic patients a basic eye examination every 6 months. These asthmatic patients should reduce the risk of developing cataracts by wearing sunglasses, taking multivitamins, and eating plenty of fresh fruits and leafy green vegetables.
Inhaler Alert, Hippocrates, November, 1997;11.
Sodium and Cataracts
Sodium and cataracts
A diet high in salt may contribute to an increased risk for posterior subcapsular cataract, according to this population-based study conducted over 2 years. About 2,800 subjects near Sydney, Australia completed a food-frequency questionnaire, and patient lens photographs were graded for corticol, nuclear, and posterior subcapsular cataracts. Subjects with a high sodium intake demonstrated an increased incidence of posterior subcapsular cataracts.
Cumming RG, Mitchell P, Smith W: Dietary sodium intake and cataract: the Blue Mountains Eye Study, Am J Epidemiol 2000 Mar 15;151(6):624-6
Vitamins & Cataracts
Vitamins
Vitamin supplements may protect against the development of nuclear and cortical cataracts, according to this study of 2,873 subjects participating in the cross-sectional Blue Mountains Eye Study. The participants, who ranged in ages from 49 to 97, completed detailed questionnaires concerning their diet and vitamin supplement use - their cortical opacities were then graded from lens photographs using the Wisconsin method. Less prevalence of nuclear cataract was found to be associated with the regular use of thiamin, vitamin A, and folate. Protection from cortical cataract may be offered by thiamin, riboflavin, niacin, folate, and vitamin B12. Long-term use of multivitamins was also associated with reduced incidence of both nuclear and cortical cataract.
Kuzniarz M, Mitchell P, Cumming RG, Flood VM: Use of vitamin supplements and cataract: the Blue Mountains Eye Study, Am J Opthamol 2001 Jul;132(1):19-26
Vitamin Intake
Vitamin Intake
According to this study on 487 non-diabetic women aged 53 to 73, regular, life-long antioxidant intake may prevent the formation of nuclear lens opacities. The average nutrient intake and vitamin use of each woman was determined before their lens opacities were measured from questionnaires they completed during a previous 13 to 15 year period. When judging their prevalence among the participants, nuclear opacities were defined as a nuclear opalescence grade of 2.5 or higher using the Lens Opacification Classification System III. Nuclear opacities were least common in the highest vitamin C, vitamin E, riboflavin, folate, beta-carotene, and lutein/zeaxanthin intake groups. However, after adjustment for other nutrients, vitamin C intake was the only factor still significantly related to a reduction in lens opacities. Longer duration of vitamin use was also found to affect the prevalence of nuclear opacities, with ingestion of vitamin C, vitamin E, and multivitamin supplements related to decreased occurrence of nuclear opacities. Vitamin C was again the only vitamin significantly associated with reduction after adjustment for vitamin E or multivitamin supplements. Women who ingested vitamin C supplements for ten or more years had significantly less nuclear opacities than women who never did. Also, an inverse association between vitamin C and E plasma levels and prevalence of nuclear opacities was also found at the eye examination.
Jacques PF, et al: Long-term nutrient intake and early age-related nuclear lens opacities, Arch Opthalmol 2001 Jul;119(7):1009-19
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