Impact of serum estradiol on postprandial lipemia, oxidative stress, and inflammation across a single menstrual cycle.
BACKGROUND
An abrupt rise in circulating lipids, oxidative stress, and inflammatory biomarkers is a common finding after ingestion of a high-fat meal. Estradiol, typically provided via hormone replacement therapy to postmenopausal women, has been reported to possess lipidemic, antioxidant, and antiinflammatory properties, all of which may minimize postprandial oxidative stress.


OBJECTIVE
The purpose of this study was to compare the postprandial triglyceride (TG), oxidative stress, and inflammatory responses after a lipid meal in menstruating women during the early follicular (days 1-3) and preovulatory (day 14) phases of the menstrual cycle.


METHODS
Healthy normolipidemic women (fasting blood TG, <200 mg/dL) with regular menstrual cycles reported to the Cardiorespiratory/Metabolic Laboratory at the University of Memphis, Memphis, Tennessee (October-December 2008) and consumed an identical lipid meal (heavy whipping cream and water) on 2 separate days during the menstrual cycle. Blood samples were collected premeal and 1, 2, 4, and 6 hours postmeal, then assayed for TG, malondialdehyde (MDA), hydrogen peroxide, Trolox equivalent antioxidant capacity (TEAL), nitrate/nitrite, and C-reactive protein (CRP). The AUC was calculated for each variable, and a 2 (menstrual cycle phase) x 5 (time) ANOVA with Tukey post hoc testing was also conducted. Estradiol concentration was measured in premeal samples for verification of cycle phase.


RESULTS
Ten women (mean [SD] age, 29 [11] years; 8 white, 2 black; body mass index, 22 [3] kg/m(2)) participated in the study. Despite a higher serum estradiol concentration on day 14 (113 [56] pg/mL) compared with the early follicular phase (61 [34] pg/mL), the TG, oxidative stress, and inflammatory AUC responses to feeding were not significantly different. TG (P = 0.03), MDA (P = 0.02), and hydrogen peroxide (P < 0.001) were significantly increased in response to feeding (time effect), whereas nitrate/nitrite was decreased (P = 0.01). TEAC and CRP were not significantly affected.


CONCLUSIONS
These data indicate that estradiol, at the concentrations noted in the present study, had no significant effect on postprandial TG or biomarkers of oxidative stress or inflammation in a sample of young, healthy women. It is possible that a greater divergence in circulating estradiol may be needed for significant differences to be detected, as may be the case with chronic hormone replacement therapy in postmenopausal women.
Bell
Heather K
HK
University of Memphis, Tennessee 38152, USA.
Bloomer
Richard J
RJ
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000378:metabolism; D019540:Area Under Curve; D002097:C-Reactive Protein / Q000378:metabolism; D002839:Chromans / Q000097:blood; D004041:Dietary Fats / Q000009:adverse effects*; D002149:Energy Intake / Q000502:physiology; D004958:Estradiol / Q000097:blood / Q000502:physiology; D005260:Female; D005498:Follicular Phase / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D006949:Hyperlipidemias / Q000209:etiology / Q000276:immunology / Q000378:metabolism; D007249:Inflammation; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D009566:Nitrates / Q000097:blood; D009573:Nitrites / Q000097:blood; D018384:Oxidative Stress / Q000502:physiology; D019518:Postprandial Period / Q000502:physiology*; D013714:Tennessee; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D000975:Antioxidants; D002839:Chromans; D004041:Dietary Fats; D009566:Nitrates; D009573:Nitrites; D014280:Triglycerides; D004958:Estradiol; D008315:Malondialdehyde; D002097:C-Reactive Protein; D006861:Hydrogen Peroxide; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid