Research

Long-term vitamin E supplementation fails to reduce lipid peroxidation in people at cardiovascular risk: analysis of underlying factors

Chiara Chiabrando¹ , Fausto Avanzini² , Claudia Rivalta¹ , Fabio Colombo² , Roberto Fanelli¹ , Gaetana Palumbo³ and Maria Carla Roncaglioni² for PPP Collaborative Group on the antioxidant effect of vitamin E

¹  Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche 'Mario Negri', via Eritrea 62, 20157 Milano, Italy

²  Department of Cardiovascular Research, Istituto di Ricerche Farmacologiche 'Mario Negri', via Eritrea 62, 20157 Milano, Italy

³  Divisione di Medicina V piano, Azienda Ospedaliera Ospedale San Carlo Borromeo, Via Pio II 3, 20153 Milano, Italy

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Current Controlled Trials in Cardiovascular Medicine 2002, 3:5doi:10.1186/1468-6708-3-5

Published:	19 March 2002

Abstract

Background

Antioxidant supplementation with vitamin E had no effect in the prevention of cardiovascular diseases (CVD) in three recent large, randomized clinical trials. In order to reassess critically the role of vitamin E in CVD prevention, it is important to establish whether these results are related to a lack of antioxidant action.

Methods

We examined the in vivo antioxidant effect of vitamin E (300 mg/day for about three years) in 144 participants in the Primary Prevention Project (females and males, aged ≥ 50 y, with at least one major CV risk factor, but no history of CVD). Urinary 8-epi-PGF_2α (isoprostane F_2α-III or 15-F_2t-isoP), a validated biomarker of lipid peroxidation, was measured by mass spectrometry.

Results

Urinary excretion of 8-epi-PGF_2α [pg/mg creatinine, median (range)] was 141 (67–498) in treated and 148 (76–561) in untreated subjects (p = 0.10). Taking into account possible confounding variables, multiple regression analysis confirmed that vitamin E had no significant effect on this biomarker. Levels of 8-epi-PGF_2α were in the normal range for most subjects, except smokers and those with uncontrolled blood pressure or hyperglycemia.

Conclusions

Prolonged vitamin E supplementation did not reduce lipid peroxidation in subjects with major cardiovascular risk factors. The observation that the rate of lipid peroxidation was near normal in a large proportion of subjects may help explain why vitamin E was not effective as an antioxidant in the PPP study and was ineffective for CVD prevention in large scale trials.