Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

Evans, Jennifer R

doi:10.1002/14651858.cd000254.pub2

Cited by 85 publications

(59 citation statements)

References 46 publications

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“…In addition, to our knowledge there is no evidence that patients with early ARMD will benefit from betacarotene supplementation. 19 Based on our findings, we believe that the public should be discouraged from taking beta-carotene supplements to improve vision without a recommendation from their ophthalmologists.…”

Section: Discussionmentioning

confidence: 78%

Beta‐carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers

Tanvetyanon

Bepler

2008

Cancer

110

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BACKGROUNDSome studies have suggested that beta‐carotene supplementation may increase the risk of lung cancer, particularly among smokers or former smokers. Beta‐carotene, a provitamin A, is available in multivitamins. In the current study, the authors investigated the risk of lung cancer associated with beta‐carotene in smokers or former smokers and surveyed the beta‐carotene content in national brand multivitamins.METHODSThe authors systemically reviewed the published literature using a search of the MEDLINE database and performed a meta‐analysis of large randomized trials that reported on the effect of beta‐carotene supplementation on the incidence of lung cancer among smokers or former smokers. A sample of multivitamins was evaluated for their beta‐carotene content and the suggested daily dosage.RESULTSFour studies contributing 109,394 subjects were available for analysis. The average daily beta‐carotene dosage in these trials ranged from 20 to 30 mg daily. Among current smokers, beta‐carotene supplementation was found to be significantly associated with an increased risk of lung cancer (odds ratio [OR], 1.24; 95% confidence interval [95% CI], 1.10–1.39). Among former smokers, there was no significant increase noted (OR, 1.10; 95% CI, 0.84–1.45). In a sample of 47 common multivitamins, beta‐carotene was present in 70% of the identified formulas. The median dosage of beta‐carotene was 0.3 mg (range, 0–17.2 mg) daily. The beta‐carotene content was found to be significantly higher among multivitamins sold to improve visual health than among other multivitamins, with a median daily dosage of 3 mg (range, 0–24 mg).CONCLUSIONSHigh‐dose beta‐carotene supplementation appears to increase the risk of lung cancer among current smokers. Although beta‐carotene was prevalent in multivitamins, high‐dose beta‐carotene was observed among multivitamin formulas sold to promote visual health. Cancer 2008. © 2008 American Cancer Society.

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Section: Discussionmentioning

confidence: 78%

Beta‐carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers

Tanvetyanon

Bepler

2008

Cancer

110

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“…3,4 In brief, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library, MEDLINE, SIGLE, EMBASE, National Research Register, AMED and PubMed, reference lists of identified reports, and the Science Citation Index. We contacted investigators and experts in the field for details of unpublished studies.…”

Section: Methodsmentioning

confidence: 99%

“…Trials were selected according to prespecified inclusion criteria. 3,4 Five parameters of trial quality were assessed: allocation concealment, method of allocation to treatment, documentation of exclusions, masking of outcome assessment, and completeness of follow-up. 7 Each parameter of trial quality was graded: A, low risk of bias; B, moderate risk of bias; or C, high risk of bias.…”

Section: Methodsmentioning

confidence: 99%

“…This article summarises the results of two comprehensive regularly updated systematic reviews published on the Cochrane Library. 3,4 Two questions are addressed: firstly, should the general population be taking routine antioxidant and vitamin mineral supplements to prevent or delay the onset of AMD in later life? Secondly, should people with AMD be taking these supplements to slow down the progression of the disease?…”

Section: Introductionmentioning

confidence: 99%

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Antioxidant supplements to prevent or slow down the progression of AMD: a systematic review and meta-analysis

Evans

2008

Eye

117

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Introduction The aim of this review was to examine the evidence as to whether antioxidant vitamin or mineral supplements prevent the development of AMD or slow down its progression. Methods Randomised trials comparing antioxidant vitamin and/or mineral supplement to control were identified by systematic electronic searches (updated August 2007) and contact with investigators. Data were pooled after investigating clinical and statistical heterogeneity. Results There was no evidence that antioxidant (vitamin E or b-carotene) supplementation prevented AMD. A total of 23 099 people were randomised in three trials with treatment duration of 4-12 years; pooled risk ratio ¼ 1.03 (95% CI, 0.74-1.43). There was evidence that antioxidant (b-carotene, vitamin C, and vitamin E) and zinc supplementation slowed down the progression to advanced AMD and visual acuity loss in people with signs of the disease (adjusted odds ratio ¼ 0.68, 95% CI, 0.53-0.87 and 0.77, 95% CI, 0.62-0.96, respectively). The majority of people were randomised in one trial (AREDS, 3640 people randomised). There were seven other small trials (total randomised 525). Conclusions Current evidence does not support the use of antioxidant vitamin supplements to prevent AMD. People with AMD, or early signs of the disease, may experience some benefit from taking supplements as used in the AREDS trial. Potential harms of high-dose antioxidant supplementation must be considered. These may include an increased risk of lung cancer

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“…Individuals with low zinc levels have shown reduced lymphocyte proliferation response to mitogens and other adverse alterations in immunity that can be corrected by zinc supplementation . Both zinc and antioxidants delay the progression of age-related macular degeneration (AMD) and vision loss, possibly by preventing cellular damage in the retina (Marshall, 2000;Evans, 2006). Cigarette smoke contains a large number of oxidative compounds.…”

Section: Introductionmentioning

confidence: 99%

Improving effect of zinc supplementation on pituitary gonadotropins secretion in smokers

Bakheet¹,

Almarshad²

2014

Afr. J. Pharm. Pharmacol.

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This study aimed to investigate the effect of zinc supplementation on testicular tissue as a feed-back mechanism of the pituitary secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on cigarette smoker subjects. Total of twenty subjects participated in this study as per the national bioethics committee guidelines. Venous blood samples were collected for determination of serum level of LH and FSH before and after zinc supplementation. LH and FSH determination were done using enzyme-linked immunosorbent assay (ELISA). A t-test was used to compare the means of two groups, P value was considered significant if ≤ 0.05. Results showed that LH serum levels were elevated in smokers as compared to the control group (p 0.05). Similar observation was found in FSH levels (p>0.05). After one month of zinc supplementation, LH levels decreased in smokers group (after: 4.14 ± 2.38 mlU/ml, before: 7.43 ± 4.32 mlU/ml; p>0.05). FSH levels also decreased after zinc supplementation in smokers group (after: 1.50 ± 1.12 mlU/ml, before: 3.88 ± 1.57 mlU/ml; p>0.05). The improving effect of zinc supplementation on LH and FSH pituitary and testicular steroid secretions for smoker subjects is obviously observed. These findings can be implemented to contribute to the outcome of zinc treatment associated with smoking.

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Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

Abstract: Effects of long-term zinc supplementation on plasma thiol metabolites and redox status in patients with age-related macular degeneration.

Cited by 85 publications

References 46 publications

Beta‐carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers

Beta‐carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers

Antioxidant supplements to prevent or slow down the progression of AMD: a systematic review and meta-analysis

Improving effect of zinc supplementation on pituitary gonadotropins secretion in smokers

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