Women experience lower postprandial oxidative stress compared to men

Background: Women have enhanced triglyceride (TAG) removal from the circulation following consumption of high-fat loads, potentially leading to decreased reactive oxygen and nitrogen species (RONS) generation. This may have implications related to long-term health outcomes. We examined the oxidative stress response to high-fat feeding between men and women to determine if women are less prone to postprandial oxidative stress as compared to men. Methods: A total of 49 women (mean age: 31 +/- 12 yrs) and 49 men (mean age: 27 +/- 9 yrs) consumed a high-fat meal in the morning hours following a 10-12 hour overnight fast. Blood samples were collected before and at 2 and 4 hours after the meal. Samples were analyzed for TAG, various markers of oxidative stress (malondialdehyde [MDA], hydrogen peroxide [H2O2], Advanced Oxidation Protein Products [AOPP], nitrate/nitrite [NOx]), and Trolox-Equivalent Antioxidant Capacity (TEAC). Area under the curve (AUC) was calculated for each variable. Effect size calculations were performed using Cohen's d. Data from the total sample of 98 subjects were collected as a part of six previously conducted studies in our lab focused on postprandial oxidative stress, between 2007 and 2012. Results: AUC was higher for men compared to women for TAG (249.0 +/- 21.5 vs. 145.0 +/- 9.8 mg.dL(-1).4 hr(-1); p < 0.0001; effect size = 0.89), MDA (2.7 +/- 0.2 vs. 2.2 +/- 0.1 mu mol.L-1.4 hr(-1); p = 0.009; effect size = 0.47), H2O2 (29.9 +/- 2.4 vs. 22.5 +/- 1.6 mu mol.L-1. 4 hr(-1); p = 0.001; effect size = 0.55), AOPP (92.8 +/- 6.9 vs. 56.4 +/- 3.7 mu mol.L-1.4 hr(-1); p < 0.0001; effect size = 1.38), and TEAC (1.7 +/- 0.1 vs. 1.3 +/- 0.0 mmol.L-1.4 hr(-1); p = 0.002; effect size = 0.91). No significant difference was noted for NOx (42.2 +/- 4.6 vs. 38.3 +/- 3.5 mu mol.L-1.4 hr(-1) for men and women, respectively; p = 0.09; effect size = 0.17). Conclusion: In the context of the current design, women experienced lower postprandial oxidative stress compared to men. Future work is needed to determine the potential health implications of lower postprandial oxidative stress in women.