The effect of α-tocopherol supplementation on LDL oxidation: A dose-response study

Ishwarlal Jialal, Cindy J. Fuller, Beverley A. Huet

Research output: Contribution to journalArticle

321 Citations (Scopus)

Abstract

Because much data have accrued to support the concept that oxidatively modified LDL (Ox-LDL) can promote atherogenesis, the role of antioxidants in decreasing LDL oxidation has assumed great importance. High-dose α-tocopherol supplementation in humans decreases the susceptibility of LDL to oxidation. Hence, the aim of the present study was to ascertain the minimum dose of α-tocopherol that would decrease the susceptibility of LDL to oxidation. The effect of α-tocopherol in doses of 60, 200, 400, 800, and 1200 IU/d on copper-catalyzed LDL oxidation was tested in a randomized placebo-controlled study over 8 weeks. There were eight subjects in each group. Oxidation of LDL was monitored by measuring the formation of conjugated dienes and lipid peroxides by the thiobarbituric acid-reacting substances (TBARS) assay over an 8-hour time course at baseline and after 8 weeks of supplementation. Neither placebo nor any of the doses of α-tocopherol resulted in any side effects or exerted an adverse effect on the plasma lipoprotein profile. However, there was a dose-dependent increase in plasma and lipid-standardized α-tocopherol levels with increasing doses of α-tocopherol supplementation. LDL α-tocopherol appeared to follow a similar trend. When the time-course curves of LDL oxidation and the kinetics of LDL oxidation were examined, there was no significant effect at 8 weeks compared with baseline in the groups that received placebo or α-tocopherol 60 or 200 IU/d. However, in the groups that received at least 400 IU/d α-tocopherol, there was a decreased susceptibility of LDL to oxidation, as shown by the mean levels in the time-course curves, prolongation in the lag phase, and a decrease in the oxidation rate. Furthermore, both plasma and LDL α-tocopherol correlated significantly with the lag phase of oxidation and inversely with the oxidation rate. The results of the present study show that the minimum dose of α-tocopherol needed to significantly decrease the susceptibility of LDL to oxidation is 400 IU/d.

Original languageEnglish (US)
Pages (from-to)190-198
Number of pages9
JournalArteriosclerosis, Thrombosis, and Vascular Biology
Volume15
Issue number2
StatePublished - Feb 1995
Externally publishedYes

Fingerprint

Tocopherols
Placebos
oxidized low density lipoprotein
Lipid Peroxides
Lipoproteins
Copper
Atherosclerosis
Antioxidants
Lipids

Keywords

  • α-tocopherol
  • Antioxidants
  • Atherosclerosis
  • LDL oxidation
  • Lipid peroxidation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

The effect of α-tocopherol supplementation on LDL oxidation : A dose-response study. / Jialal, Ishwarlal; Fuller, Cindy J.; Huet, Beverley A.

In: Arteriosclerosis, Thrombosis, and Vascular Biology, Vol. 15, No. 2, 02.1995, p. 190-198.

Research output: Contribution to journalArticle

Jialal, Ishwarlal ; Fuller, Cindy J. ; Huet, Beverley A. / The effect of α-tocopherol supplementation on LDL oxidation : A dose-response study. In: Arteriosclerosis, Thrombosis, and Vascular Biology. 1995 ; Vol. 15, No. 2. pp. 190-198.
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