Lower postprandial oxidative stress in women compared with men.
BACKGROUND
Previous studies indicate that oxidative stress is increased following intake of a high-fat meal, mediated in large part by the triglyceride (TG) response to feeding as well as fasting oxidative stress values. It has been suggested that women may process TG more efficiently after high-fat meals, based on the antilipidemic properties of estrogen. It has also been reported that women present with lower fasting oxidative stress values than do men. It is possible that women experience attenuated postprandial oxidative stress compared with men.


OBJECTIVE
The purpose of this study was to compare the postprandial TG and oxidative stress response after a lipid meal in healthy men and women.


METHODS
This study was conducted at The University of Memphis in Memphis, Tennessee, from October to December 2008. Blood samples were collected before (in a 10-hour fasted state), and at 1, 2, 4, and 6 hours after ingestion of a lipid load (heavy whipping cream at 1 g · kg(-1)). Blood samples were analyzed for TG, malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), and nitrate/nitrite (NOx). The AUC was calculated for each variable and results were compared using a t test. Effect-size calculations were performed using Cohen's d.


RESULTS
Samples from 10 men and 10 women, aged 18 to 47 years (17 subjects aged <37 years), were compared. AUC data were not significantly different for TG (mean [SEM] 330 [48] vs 354 [34] mg · dL(-1) · 6h(-1) for men and women, respectively; effect size = 0.09) or NOx (165 [25] vs 152 [17] μmol · L(-1) · 6h(-1) for men and women; effect size = 0.09). However, significant differences were noted for MDA (10.7 [1.3] vs 6.1 [0.5] μmol · L(-1) · 6h(-1) for men and women, respectively; P = 0.002; effect size = 0.61) and H(2)O(2) (154 [23] vs 86 [8] μmol · L(-1) · 6h(-1) for men and women; P = 0.013; effect size = 0.53).


CONCLUSIONS
These data indicate that women experience lower oxidative stress than do men, with regard to MDA and H(2)O(2), after ingestion of a lipid load in the form of heavy whipping cream. Considering the strong association between oxidative stress and cardiovascular disease, lower postprandial oxidative stress may be one mechanism associated with decreased risk of cardiovascular disease in women compared with men. Further research is needed to confirm this hypothesis.
Bloomer
Richard J
RJ
The University of Memphis, Tennessee 38152, USA. rbloomer@memphis.edu
Fisher-Wellman
Kelsey H
KH
D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D004041:Dietary Fats / Q000008:administration & dosage; D005215:Fasting; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D008055:Lipids / Q000008:administration & dosage; D008297:Male; 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*; D012727:Sex Characteristics; D014280:Triglycerides / Q000097:blood*; D055815:Young Adult
D004041:Dietary Fats; D008055:Lipids; D009566:Nitrates; D009573:Nitrites; D014280:Triglycerides; D008315:Malondialdehyde; D006861:Hydrogen Peroxide