Effects of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants

ObjectiveThe purpose of this study was to examine the influence of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants.Study designIn this cross-section study, nonfasting blood samples were collected twice from 10 healthy premenopausal women during the follicular phase (between days 8 and 11) and the luteal phase (between days 18 and 22) of their same menstrual cycle. In addition, blood samples from 15 premenopausal women who used oral contraceptive for at least 6 months and 40 women who did not use oral contraceptive were collected randomly at any day of the menstrual cycle. Serum levels of coenzyme Q10, α-tocopherol, γ-tocopherol, β-carotene, α-carotene, and lycopene were determined using high pressure liquid chromatography.ResultsSerum coenzyme Q10 and α-tocopherol levels were significantly lower during the follicular phase compared with the luteal phase of the same menstrual cycle (P < .05). Oral contraceptive use also significantly decreased coenzyme Q10 and α-tocopherol (P < .001). Other antioxidant levels were comparable.ConclusionAlterations in coenzyme Q10 and α-tocopherol levels during the menstrual cycle and in oral contraceptive users should be taken into consideration, concerning the future antioxidant research in premenopausal women. Further studies are needed to investigate the potential role of endogenous and exogenous ovarian hormones on oxidative stress in women.