Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract

Mathew, Milan C; Ervin, Ann Margret; Tao, Jeremiah; Davis, Richard M.

doi:10.1002/14651858.cd004567.pub2

Cited by 85 publications

(73 citation statements)

References 72 publications

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“…Furthermore, suboptimal intake of vitamins with antioxidant function (vitamin E, but also vitamin C and provitamin A) have been associated with oxidative stressrelated degenerative diseases such as atherosclerosis, cardiovascular and neurodegenerative disease, chronic inflammation and some cancers (Bjelakovic et al 2012;Mathew et al 2012). Diets rich in plant foods (especially fruit and vegetables) have been associated with moderately lower overall mortality rates and lower death rates from cardiovascular disease and some types of cancer (Stanner et al 2004).…”

Section: Functions Of Plant Amino Acid-based Vitamins In Humansmentioning

confidence: 99%

“…Diets rich in plant foods (especially fruit and vegetables) have been associated with moderately lower overall mortality rates and lower death rates from cardiovascular disease and some types of cancer (Stanner et al 2004). The major meta-analyses of randomized trials of antioxidant supplements for primary and secondary mortality, degenerative illness or cancer prevention fail, however, to confirm a protective role for a single or combined group of antioxidants (Bjelakovic 2007;Fortes and Boffetta 2011;Bjelakovic et al 2012Bjelakovic et al , 2013Mathew et al 2012). Indeed, some studies even suggest that treatment with vitamin E may increase mortality (Bjelakovic 2007;Bjelakovic et al 2013).…”

Section: Functions Of Plant Amino Acid-based Vitamins In Humansmentioning

confidence: 99%

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Plant amino acid-derived vitamins: biosynthesis and function

Miret

Munné‐Bosch

2013

Amino Acids

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Vitamins are essential organic compounds for humans, having lost the ability to de novo synthesize them. Hence, they represent dietary requirements, which are covered by plants as the main dietary source of most vitamins (through food or livestock's feed). Most vitamins synthesized by plants present amino acids as precursors (B1, B2, B3, B5, B7, B9 and E) and are therefore linked to plant nitrogen metabolism. Amino acids play different roles in their biosynthesis and metabolism, either incorporated into the backbone of the vitamin or as amino, sulfur or one-carbon group donors. There is a high natural variation in vitamin contents in crops and its exploitation through breeding, metabolic engineering and agronomic practices can enhance their nutritional quality. While the underlying biochemical roles of vitamins as cosubstrates or cofactors are usually common for most eukaryotes, the impact of vitamins B and E in metabolism and physiology can be quite different on plants and animals. Here, we first aim at giving an overview of the biosynthesis of amino acid-derived vitamins in plants, with a particular focus on how this knowledge can be exploited to increase vitamin contents in crops. Second, we will focus on the functions of these vitamins in both plants and animals (and humans in particular), to unravel common and specific roles for vitamins in evolutionary distant organisms, in which these amino acid-derived vitamins play, however, an essential role.

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Section: Functions Of Plant Amino Acid-based Vitamins In Humansmentioning

confidence: 99%

Section: Functions Of Plant Amino Acid-based Vitamins In Humansmentioning

confidence: 99%

Plant amino acid-derived vitamins: biosynthesis and function

Miret

Munné‐Bosch

2013

Amino Acids

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“…Cochrane reviews of randomised controlled studies on supplementation of vitamin C alone or in combination with other antioxidants conclude that there are no effects on the prevention or course of eye diseases [74][75][76] .…”

Section: Preventive Aspectsmentioning

confidence: 99%

New Reference Values for Vitamin C Intake

Society¹

2015

Ann Nutr Metab

101

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The German, Austrian, and Swiss nutrition societies are the editors of the ‘reference values for nutrient intake'. They have revised the reference values for the intake of vitamin C and published them in February 2015. The average vitamin C requirement in healthy adults is considered to be the vitamin C amount that compensates for the metabolic losses of vitamin C, and ensures a fasting ascorbate plasma level of 50 µmol/l. Based on the present data from studies with non-smoking men, metabolic losses of 50 mg/day are assumed, as well as an absorption rate of 80% and an urinary excretion of 25% of the vitamin C intake. Taking this into account, the calculated average requirement in men is 91 mg/day. Considering a coefficient of variation of 10%, a reference value (recommended intake) of 110 mg/day for men is derived. The vitamin C requirement in women as well as in children and adolescents is extrapolated from the requirement in men and in relation to their body weight. This results in a recommended intake of about 95 mg/day for adult women. Because the requirement in pregnant and lactating women is increased, higher recommended intakes are derived for them, 105 mg/day for pregnant women from the fourth month on and 125 mg/day for lactating women, respectively. For boys and girls at the age of 1 to under 15 years, there are increasing recommended intake values from 20 to 85 mg/day. For male and female adolescents, at the age of 15 to under 19 years, the recommended intake is 105 and 90 mg, respectively. As smokers have higher metabolic losses and lower plasma levels of vitamin C than non-smokers (turnover is 40% higher), the reference value for vitamin C intake is set to 135 mg/day for female smokers and 155 mg/day for male smokers. For infants in their first year of life, the reference value (estimated value) is set to 20 mg vitamin C/ day, based upon the lowest observed vitamin C intake for infants in the United Kingdom and the United States, that obviously meets the requirement in infants and that is 3 times higher than the amount necessary to prevent scurvy (7 mg/day).

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“…However, not all of these data are consistent and there is a risk that the reported outcomes may be subject to bias Published in Current Pharmaceutical Design http://www.ncbi.nlm.nih.gov/pubmed/26350529 and confounding. A Cochrane Systematic Review 'Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract' was published in 2012 [41] and included data from 9 trials of generally high methodological quality, in which 117,272 individuals over the age of 35 had been randomised to receive antioxidant vitamins (β-carotene, vitamin C and vitamin E, used alone or in combination) or placebo. In the pooled analysis, there was no evidence of effect for β-carotene in reducing risk of cataract (2 trials) (RR 0.99, 95% CI 0.91 to 1.08) or reducing rates of cataract extraction (3 trials) (RR 1.00 95% CI 0.91 to 1.10), vitamin E in reducing risk of cataract (3 trials) (RR 0.97, 95% CI 0.9 to 1.04) or cataract extraction (5 trials) (RR 0.98 95% CI 0.91to 1.04).…”

Section: Cataractmentioning

confidence: 99%

Controversies in the Use of Nutritional Supplements in Ophthalmology

Lawrenson

Grzybowski²

2015

CPD

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KeywordsAge-related macular degeneration, cataract, dry eye, nutritional supplements, antioxidants, essential fatty acids Running title Nutritional supplements in ophthalmology Word Count 39977 Conflicts of interest NonePublished in Current Pharmaceutical Design http://www.ncbi.nlm.nih.gov/pubmed/26350529 Abstract Nutritional supplements are widely taken by the general population and several of these products are marketed specifically to improve eye health. The aim of this review is to summarise the evidence for the benefit of supplementation with antioxidant vitamins and other micronutrients for three of the most common eye diseases of the elderly: age-related macular degeneration (AMD), cataract and dry eye syndrome (DES). Although the potential importance of diet and nutrition in these conditions is strongly supported by data from observational studies, evidence from randomised controlled trials (RCTs) on the benefit of nutritional supplementation is generally lacking. However, there is high quality evidence to support the use of an Age-Related Eye-Disease Study (AREDS) supplement containing antioxidants (β-carotene, vitamin C and vitamin E) and zinc to slow progression in those at moderate to high risk of developing advanced AMD. Recent data from the AREDS2 trial provided data to suggest that β-carotene could be replaced with lutein and zeaxanthin on the based on improved safety without compromising efficacy. Although there is currently insufficient evidence to recommend the routine use of any of the commercially available supplements in cataract and DES, given the public health importance of these conditions further research into the benefit of dietary modification or nutritional supplementation should be a priority.

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Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract

Cited by 85 publications

References 72 publications

Plant amino acid-derived vitamins: biosynthesis and function

Plant amino acid-derived vitamins: biosynthesis and function

New Reference Values for Vitamin C Intake

Controversies in the Use of Nutritional Supplements in Ophthalmology

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