Safety of Antioxidant Vitamins

Meyers, David G.; Maloley, Pierre A.; Weeks, David M.

doi:10.1001/archinte.1996.00440090015002

Cited by 116 publications

(37 citation statements)

References 159 publications

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“…Because vitamin A is fat soluble and stored in the liver, deficiencies of this vitamin are seldom encountered in the industrialized world (8)(9)(10)(11)(12). Because excessive intake is potentially toxic to the liver and other tissues (5,6,13,14), vitamin A supplementation is of concern to public health officials as well as to physicians who prescribe this vitamin.…”

Section: Introductionmentioning

confidence: 99%

Safety of <7500 RE (<25000 IU) vitamin A daily in adults with retinitis pigmentosa

Sibulesky

Hayes

Prończuk

et al. 1999

The American Journal of Clinical Nutrition

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Background: Vitamin A supplementation is being used successfully to treat some forms of cancer and the degenerative eye disease retinitis pigmentosa. The daily biological need for vitamin A is estimated to be 800 retinol equivalents ( Results: Patients in group A showed an 8% increase in mean serum retinol concentration at 5 y and an 18% increase at 12 y (P < 0.001); no retinol value exceeded the upper normal limit (3.49 mol/L, or 100 g/dL). Mean serum retinyl esters were elevated Ϸ1.7-fold at 5 y and remained relatively stable thereafter. No clinical symptoms or signs of liver toxicity attributable to vitamin A excess were detected. Conclusions: Prolonged daily consumption of < 7500 RE (< 25 000 IU) vitamin A/d can be considered safe in this age group.

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Section: Introductionmentioning

confidence: 99%

Safety of <7500 RE (<25000 IU) vitamin A daily in adults with retinitis pigmentosa

Sibulesky

Hayes

Prończuk

et al. 1999

The American Journal of Clinical Nutrition

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“…Aside from crystalluria and rare stones that may occur in patients with renal dysfunction, ascorbate is without important adverse effects at doses Ϸ2 to 10 g/d. 33 Ascorbate was selected not only for its strong scavenging H 2 O 2 activity within plasma and PMNs but also for its effect in improving endothelial function and vasodilatation and preventing the formation of oxLDL-induced leukocyte-platelet aggregates in the blood stream. 34 Ascorbate can protect vascular smooth muscle cells against apoptosis induced by oxLDL/lipid hydroperoxides (eg, PCOOH).…”

Section: Discussionmentioning

confidence: 99%

Ascorbate Supplement Reduces Oxidative Stress in Dyslipidemic Patients Undergoing Apheresis

Chien

Chang

Chen

et al. 2004

ATVB

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Objective-The effect of ascorbate treatment on apheresis-induced oxidative stress in uremic and dyslipidemic patients was evaluated. Methods and Results-We developed a chemiluminescence-emission spectrum and high-performance liquid chromatography analysis to assess the effect of ascorbate supplement on plasma reactive oxygen species (ROS) scavenging activity and oxidized lipid/protein production in hyperlipidemic and uremic patients undergoing apheresis. Apheresis was efficient in reduction of atherogenic lipoproteins, complement, fibrinogen, soluble intercellular adhesion molecule-1, and oxidative parameters including phosphatidylcholine hydroperoxide (PCOOH), malonaldehyde, methylguanidine, and diotyrosine. Apheresis itself, however, activated leukocytes to increase ROS activity and reduced the plasma ROS scavenging activity. Ascorbate administration selectively diminished apheresis-enhanced H 2 O 2 and inflammatory mediators such as tumor necrosis factor alpha (TNF-␣) and monocyte chemoattractant protein-1. Chronically dyslipidemic and uremic patients undergoing biweekly apheresis plus ascorbate treatment had lower levels of C-reactive protein and PCOOH than did those without ascorbate treatment during a 6-month follow-up study period. Conclusions-We

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“…1) The percentage of the United States population that take antioxidant/mineral supplements has grown since the mid-1950's from probably less than a fraction of one percent to forty to fifty per cent today (13)(14)(15)(16)(17). Most individuals who take antioxidant supplements (13)(14)(15)(16)(17) do so on an irregular basis; around 4 percent take vitamin E daily (usually 100 IU or more) and 8 percent take vitamin C (frequently 500mg).…”

Section: Resultsmentioning

confidence: 99%

Antioxidant supplements: Effects on disease and aging in the United States population

Harman

2000

AGE

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Ingestion of antioxidant supplements by the United States (US) population has increased steadily since the mid-1950's. This review tried to determine if the supplements have contributed significantly to beneficial changes in the US during this period. Experimental animal studies have demonstrated that anti-oxidant supplements lower the incidence of a wide variety of diseases and increase life span. Anti-oxidants are associated with similar changes in man. Changes since the mid-1950's in the US population include: 1) ingestion of antioxidant supplements has increased from one percent, or less, to 40-50 percent today. Cost: now 4-5 billion dollars per year, 2) disproportionate increases in the percentage of older individuals as average life expectancy at birth (ALE-B) rose, 3) declining chronic disability in the elderly since 1982, 4) declining cancer mortality since 1991, and 5) the decline in the rate of reported cardiovascular disease beginning in the 1950's which significantly increased further in 1965. The last four changes suggest that the rate of increase in physiological age with time has been slowed. This can be attributed to decreases in the rate of accumulation of free radical-induced aging changes by the joint action of antioxidant supplements/dietary measures, and improvements in conventional measures (CM) which increase ALE-B, e.g., better medical care, nutrition, housing, accident prevention. The contribution by antioxidants to decreases in physiological age is seemingly small compared to that of CM. However, it will grow relative to CM as the amount and duration of supplement use increases and improvements in CM raise ALE-B closer to 85 years, the age associated with optimal living conditions.

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Safety of Antioxidant Vitamins

Cited by 116 publications

References 159 publications

Safety of <7500 RE (<25000 IU) vitamin A daily in adults with retinitis pigmentosa

Safety of <7500 RE (<25000 IU) vitamin A daily in adults with retinitis pigmentosa

Ascorbate Supplement Reduces Oxidative Stress in Dyslipidemic Patients Undergoing Apheresis

Antioxidant supplements: Effects on disease and aging in the United States population

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