Oral vitamin C administration increases lipid peroxidation in hemodialysis patients.
BACKGROUND
Since vitamin C (ascorbic acid, AA) deficiency is common in hemodialysis patients, systematic supplementation has been recommended. Further, vitamin C has been advocated as a potential adjuvant to erythropoietin by virtue of its capacity to improve iron utilization. However, vitamin C may have a paradoxical pro-oxidant effect in the presence of iron.


METHODS
In 109 hemodialysis patients, oral vitamin C was administered at 360 and 1,500 mg/week during 3 months each, followed by a wash-out period of 3 months.


RESULTS
Serum AA increased from 0.22 to 0.33 and 0.63 mg/dl after 360 and 1,500 mg/week, respectively. However, a commensurate increase of plasma malondialdehyde (MDA), a parameter of lipid peroxidation, with 9 and 26% was observed. Serum AA and plasma MDA returned to baseline after withdrawal of vitamin C. Parameters of iron status, nutrition, inflammation, dialysis efficiency and plasma lipids remained unaltered. In a stepwise multiple regression analysis, serum AA and ferritin were strong and independent predictors of MDA.


CONCLUSIONS
Oral vitamin C supplementation in hemodialysis patients increases lipid peroxidation, especially in patients with increased serum ferritin. The potential benefits of restored vitamin C status and improved erythropoiesis may be entirely overruled by the adverse consequences of oxidative tissue injury.
De Vriese
An S
AS
Renal Unit, AZ Sint-Jan AV, Brugge, Belgium. an.devriese@azbrugge.be
Borrey
Daniëlle
D
Mahieu
Els
E
Claeys
Ilse
I
Stevens
Lut
L
Vanhaeverbeke
Ann
A
Roelens
Mieke
M
Langlois
Michel R
MR
D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D006435:Renal Dialysis / Q000379:methods / Q000639:trends*
D001205:Ascorbic Acid