title: Vitamins E and C are safe across a broad range of intakes.
abstract: A robust database shows that dietary supplements of vitamins E and C are safe for the general population. Because these nutrients supply antioxidant and other functions for homeostasis and protection against free radical damage, supplementation has been intensively studied. Because of perceived benefits, many persons consume quantities of vitamins E and C well above the recommended dietary allowances. As safety guidance, tolerable upper intake levels have been established by the Food and Nutrition Board, Institute of Medicine, at 1000 mg for vitamin E and 2000 mg for vitamin C in adults. Many clinical trials with these vitamins have involved subjects with various diseases, and no consistent pattern of adverse effects has occurred at any intake. Numerous studies of vitamin C supplementation have provided no pattern of evidence to support concerns about safety other than occasional gastrointestinal upset or mild diarrhea resulting from the osmotic effects of unabsorbed quantities of vitamin C. Evidence of bleeding effects and other potential adverse effects of high vitamin E intakes in humans is not convincing. Evidence of adverse effects of vitamin C that result from its effects on iron absorption and metabolism has not been confirmed in clinical trials. Thus, we conclude from clinical trial evidence that vitamin E supplements appear safe for most adults in amounts </=1600 IU (1073 mg RRR-alpha-tocopherol or the molar equivalent of its esters) and that vitamin C supplements of </=2000 mg/d are safe for most adults.
authors.affiliation: Council for Responsible Nutrition, Washington, DC, USA. jhathcock@crnusa.org
authors.forename: John N
authors.initials: JN
authors.lastname: Hathcock
authors.forename: Angelo
authors.initials: A
authors.lastname: Azzi
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Blumberg
authors.forename: Tammy
authors.initials: T
authors.lastname: Bray
authors.forename: Annette
authors.initials: A
authors.lastname: Dickinson
authors.forename: Balz
authors.initials: B
authors.lastname: Frei
authors.forename: Ishwarlal
authors.initials: I
authors.lastname: Jialal
authors.forename: Carol S
authors.initials: CS
authors.lastname: Johnston
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Kelly
authors.forename: Klaus
authors.initials: K
authors.lastname: Kraemer
authors.forename: Lester
authors.initials: L
authors.lastname: Packer
authors.forename: Sampath
authors.initials: S
authors.lastname: Parthasarathy
authors.forename: Helmut
authors.initials: H
authors.lastname: Sies
authors.forename: Maret G
authors.initials: MG
authors.lastname: Traber
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D018673:Nutrition Policy; D016032:Randomized Controlled Trials as Topic; D014810:Vitamin E / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D001205:Ascorbic Acid