Supplements of vitamins C and E may protect against the increase in markers of oxidative stress in women receiving oral contraceptives, says a new study.
Daily doses of vitamin C and E of 150 mg and 200 IU, respectively, were associated with significant decreases in levels of malondialdehyde (MDA - a reactive carbonyl compound and a well-established marker of oxidative stress), while levels increased in the placebo group, according to findings published in the peer-review journal Contraception .
“These data suggest that low-dose oral contraceptives, by enhancing the stress oxidative and lipid peroxidation, may represent a potential cardiovascular risk factor, and the use of vitamins E and C may be beneficial in ameliorating this side effect of oral contraceptives,” wrote researchers from the Shiraz University of Medical Sciences in Iran.
The researchers cautioned, however, that their findings are pilot study-level observations and “further research is worthwhile and can define an expected effect size that can be used in power calculations preliminary to a fully powered intervention study”.
The researchers recruited 120 health women and randomly divided them into three groups: The first group received no intervention and acted as controls, the second group received oral contraceptives only (0.03 mg ethinylestradiol and 0.15 mg levonorgestrel), and the third group received the contraceptives plus the vitamin supplements.
At the end of four weeks of study, the contraceptive-only group experienced increases in MDA levels, while activities of the antioxidant enzymes glutathione peroxidase and glutathione reductase were decreased.
However, “supplementation with vitamin C and E significantly increased the activity [glutathione peroxidase and glutathione reductase], and reduced plasma MDA levels in [the vitamin group]”, said the researchers.
“With the data from the present study, we can now consider a longitudinal trial in which women intending to use oral contraceptives are evaluated for antioxidant status either before or after commencing oral contraceptives, and also while still taking oral contraceptives and after commencing vitamin supplementation,” they concluded.
July 2012, Volume 86, Issue 1, Pages 62–66
“Effect of vitamin E and C supplements on lipid peroxidation and GSH-dependent antioxidant enzyme status in the blood of women consuming oral contraceptives”
Authors: F. Zala, Z Mostafavi-Pour, F. Amini, A. Heidari