Impact of serum estradiol on postprandial lipemia, oxidative stress, and inflammation across a single menstrual cycle

Are there sex differences in the variability of fasting metabolism?

There is evidence across species and across many traits that males display greater between-individual variance. In contrast, (premenopausal) females display large within-individual variance in sex hormone concentrations, which can increase within-individual variance in many other parameters. The latter may contribute to the lower representation of females in metabolic research. This study is a pooled secondary analysis of data from seven crossover studies to investigate the between-individual and the within-individual variance in fasting plasma metabolites, resting metabolic rate (RMR), and body mass. Females demonstrated higher within-individual variability of plasma 17β-estradiol [coefficient of variation (CV): 15 ± 15% for males vs. 38 ± 34% for females, P < 0.001] and progesterone concentrations (CV: 13 ± 11% for males vs. 52 ± 51% for females, P < 0.001) but there were no meaningful differences in the variability of plasma glucose (CV: 4 ± 3% for males vs. 5 ± 5% for females), insulin, lactate, triglycerides (CV: 15 ± 9% for males vs. 15 ± 10% for females), and esterified fatty acid concentrations or in RMR and body mass (CV: 0.43 ± 0.34% for males vs. for 0.42 ± 0.33% females; P > 0.05 for all outcomes). Males displayed higher between-individual variance in RMR compared with females (SD: 224 kcal·day-1 for males vs. 151 kcal·day-1 for females). In conclusion, these data do not provide evidence that females show greater within-individual variability in many fasting metabolic variables, RMR, or body mass compared with males. We conclude that including females in metabolic research is unlikely to introduce greater within-individual variance when using the recruitment and control procedures described in these studies.NEW & NOTEWORTHY To investigate the within-individual variability in metabolic parameters in males and females, we performed a pooled secondary analysis of fasting blood samples, resting metabolic rate, and body mass from seven crossover studies. We found a greater day-to-day variation in 17β-estradiol and progesterone in females compared with males but no meaningful difference in within-individual variability of fasting plasma glucose, insulin, lactate, triglycerides, NEFA, resting metabolic rate, or body mass between females and males.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

Variations of Ghrelin and Obestatin Hormones During the Menstrual Cycle of Women of Different BMIs

Introduction

The cyclical changes of hormones during the menstrual cycle are responsible not only for reproductive function but also have other effects on dietary intake and appetite. The current study aimed to investigate the variations of appetite-related hormones (ghrelin and obestatin) during the menstrual cycle and their association with adipokines, estrogen, and BMI.

Methods

Fifty-six regularly menstruating female students were grouped into normal weight (BMI ≤24.9; n = 26), and overweight/obese subjects (BMI ≥25; n = 30). Serum ghrelin, obestatin, leptin, adiponectin, and estrogen levels were measured during the early follicular, preovulatory, and luteal phases of the menstrual cycle using the ELISA technique.

Results

There were insignificant differences in the levels of serum ghrelin, obestatin, and ghrelin/obestatin ratio across menstrual cycle phases in the whole cohort as well as in each group separately (p > 0.05). Serum ghrelin was significantly less in OW-OB as compared to the NW group (p = 0.005), whereas the average serum obestatin did not show any significant differences between the two groups. No significant correlation was seen between ghrelin and obestatin with the adipokines and estradiol.

Conclusion

Significant low level of ghrelin was observed in obese group during the follicular phase. This finding may provide new insights into the altered ghrelin patterns in OW-OB individuals, as a cause or a consequence of obesity and related menstrual disorders.

Depression and obesity among females, are sex specificities considered?

This study aimed to systematically review the relationship of obesity-depression in the female sex. We carried out a systematic search (PubMed, MEDLINE, Embase) to quantify the articles (controlled trials and randomized controlled trials) regarding obesity and depression on a female population or a mixed sample. Successively, we established whether the sex specificities were studied by the authors and if they reported on collecting data regarding factors that may contribute to the evolution of obesity and depression and that could be responsible for the greater susceptibility of females to those conditions. After applying the inclusion and exclusion criteria, we found a total of 20 articles with a female sample and 54 articles with a mixed sample. More than half of all articles (51.35%, n = 38) evaluated the relationship between depression and obesity, but only 20 (27.03%) evaluated this relationship among females; still, 80% of those (n = 16) presented supporting results. However, few articles considered confounding factors related to female hormones (12.16%, n = 9) and none of the articles focused on factors responsible for the binomial obesity-depression in the female sex. The resulting articles also supported that depression (and related impairments) influencing obesity (and related impairments) is a two-way road. This systematic review supports the concurrency of obesity-depression in females but also shows how sex specificities are ultimately under-investigated. Female sex specificity is not being actively considered when studying the binomial obesity-depression, even within a female sample. Future studies should focus on trying to understand how the female sex and normal hormonal variations influence these conditions.

Temporal changes in blood oxidative stress biomarkers across the menstrual cycle and with oral contraceptive use in active women

PURPOSE

To examine the temporal changes in blood oxidative stress biomarkers in recreationally-trained women that were naturally-cycling (WomenNC) or using oral contraceptives (WomenOC) across one month.

METHODS

Blood samples were acquired at three timepoints of the menstrual cycle (1: early-follicular, 2: late-follicular and 3: mid-luteal) and oral contraceptive packet (1: InactiveOC, 2: Mid-activeOC and 3: Late-activeOC) for determination of estradiol, progesterone, oxidative stress, C-reactive protein (CRP) and other cardiometabolic biomarkers in plasma and serum.

RESULTS

There was a Group by Time effect on estradiol (p < 0.001, partial η² = 0.64) and progesterone (p < 0.001, partial η² = 0.77). Malondialdehyde, lipid hydroperoxides and CRP concentrations were higher in WomenOC during Late-activeOC compared to InactiveOC (+ 96%, + 23% and + 104%, respectively, p < 0.05). However, there were no changes in these biomarkers across the menstrual cycle in WomenNC (p > 0.05). At all timepoints (i.e., 1, 2 and 3), WomenOC had elevated lipid hydroperoxides (+ 28, + 48% and + 50%) and CRP (+ 71%, + 117% and + 130%) compared to WomenNC (p < 0.05, partial η² > 0.25). There was no Group by Time effect on non-enzymatic antioxidants or glutathione peroxidase; however, glutathione peroxidase was lower in WomenOC, i.e., main effect of group (p < 0.05, partial η² > 0.20).

CONCLUSION

These findings demonstrate that WomenOC not only have higher oxidative stress and CRP than WomenNC, but also a transient increase across one month of habitual oral contraceptive use. Since changes in oxidative stress and CRP often relate to training stress and recovery, these outcomes may have implications to workload monitoring practices in female athletes.

Gender differences on oxidative stress markers and complement component C3 plasma values after an oral unsaturated fat load test

OBJECTIVE

Post-prandial lipaemia (PL), oxidative stress (OS), and complement component C3 (C3) values are related to the atherosclerosis process. The post-prandial response of C3 after an oral fat load test (OFLT) using unsaturated fat is poorly addressed. The aim of this study was to analyze and compare the post-prandial response of OS markers and C3 values in men and women after an OFLT using unsaturated fat.

METHODS

The study included a total of 22 healthy subjects with normal lipids and normal blood glucose (11 men and 11 pre-menopausal women). An oral unsaturated fat load test (OFLT: 50g fat per m² body surface) was performed using a commercial liquid preparation of long chain triglycerides (Supracal®). OS markers and C3 were measured using standardized methods at fasting state and every 2h up to 8h after the OFLT.

RESULTS

Men showed statistically significant higher C3, oxidized glutathione (GSSG), and oxidized-reduced glutathione (GSSG/GSH) ratio values at fasting state compared to that obtained in women. In addition, post-prandial C3 values and GSSG/GSH ratios were significantly higher in men compared to women. The GSSG value and GSSG/GSH ratio significantly decreased in men after the OFLT compared to fasting values. In contrast, the post-prandial OS markers decrease observed in women was not statistically significant.

CONCLUSIONS

In fasting state, men showed higher statistically significant C3 values and OS markers than women. The post-prandial OS markers (GSSG and GSSG/GSH ratio) significantly decrease after the OFLT with unsaturated fat in men compared to women.

Serum leptin level across different phases of menstrual cycle in normal weight and overweight/obese females

We compared serum leptin levels during various phases of menstrual cycle and its correlation with serum estradiol between normal weight and overweight/obese young females. Fifty-six young females with normal menstrual cycle were grouped into 26 normal weight and 30 overweight/obese subjects. Serum leptin and estradiol levels were measured during early follicular, pre-ovulatory and luteal phases of menstrual cycle in both groups using ELISA technique. Serum leptin levels were significantly different across different phases of menstrual cycle with a steady increment from follicular phase (9.97 ± 5.48 ng/dl) through pre-ovulatory phase (11.58 ± 6.49 ng/dl) with their peaks in luteal phase (12.52 ± 6.39 ng/dl, p < .001). Same pattern of change during menstrual phases was observed when the normal weight and overweight/obese group were analyzed separately. Serum leptin levels were significantly higher in overweight/obese group compared to normal weight subjects. In any of the study groups, leptin levels were not found to be correlated with estradiol level during different phases of menstrual cycle.

The effect of hydroalcoholic extract of Teucrium polium L. on the inflammatory markers and lipid profile in hypercholesterolemic rats

Background

Cardiovascular diseases are among the most common causes of mortality worldwide. Therefore, it is necessary to control the risk factors of these patients. Since the level of inflammatory markers and lipid profiles has increased in cardiovascular diseases and due to the increasing role of plants in the treatment of diseases, the current study aimed to investigate the effect of hydroalcoholic extract of Teucrium polium on inflammatory markers and lipid profile in hypercholesterolemic rats.

Materials and methods

A total of 24 adult male Wistar rats were randomly divided into four groups of six each and treated with oral administration for 8 weeks. The control group received normal diet, the sham group received high-cholesterol diet and experimental groups 1 and 2 received high-cholesterol diet in the 8 weeks and doses of 85 and 170 mg/kg, respectively, of the T. polium hydroalcoholic extract (TPHAE) in the second 4 weeks. At the beginning and the end of the study, rats were examined for biochemical parameters. The mean level of variables for each group was presented as mean ± standard error of mean.

Results

The results of this study showed that, after administration of TPHAE, there was a significant decrease in the mean of inflammatory markers in all groups compared to sham group (P<0.001). Also, administration of the extract significantly reduced the serum levels of triglyceride, cholesterol and LDL-cholesterol and significantly increased the serum HDL-cholesterol levels. In addition, the 170 mg/kg dose of TPHAE was the most effective in reducing serum levels of inflammatory and lipid markers.

Conclusion

Treatment with TPHAE caused dose-dependent decrease in serum levels of inflammatory markers and lipid profile in hypercholesterolemic rats. Therefore, it can be applied as a natural product for the management of cardiovascular diseases.

Dietary Total Antioxidant Capacity and Cardiovascular Disease Risk Factors: A Systematic Review of Observational Studies

OBJECTIVE

Measurement of dietary total antioxidant capacity (DTAC) is considered a new holistic dietary approach and assesses total antioxidants present in the overall diet. Our aim was to perform a comprehensive review of the literature on the association between DTAC and cardiovascular disease (CVD) risk factors.

METHODS

PubMed, Web of Science, and Scopus were used to conduct a comprehensive search for articles published on this topic through September 2017. There was no limit on earliest year of publication. The search was based on the following keywords: dietary total antioxidant capacity, nonenzymatic antioxidant capacity, total radical-trapping antioxidant parameter, ferric reducing ability of plasma, oxygen radical absorbance capacity, Trolox equivalent antioxidant capacity, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), total cholesterol (TC), waist circumference (WC), insulin resistance, homeostatic model assessment of insulin resistance (HOMA-IR), insulin, obesity, glucose, C-reactive protein (CRP), blood pressure (BP), and body mass index. In total, 16 papers were identified for inclusion in the present systematic review.

RESULTS

Most well-designed studies that evaluated associations between DTAC and CVD risk factors showed inverse associations for fasting blood glucose, CRP, BP, and WC and positive associations for HDL-C. However, there was no association between DTAC and LDL-C or TC in any of the studies. Results regarding the association of DTAC with insulin, HOMA-IR, high-sensitivity CRP, and TG in the published literature were inconsistent.

CONCLUSIONS

Findings indicated a substantial association between high DTAC and most CVD-related risk factors.

A randomized, crossover, head-to-head comparison of eicosapentaenoic acid and docosahexaenoic acid supplementation to reduce inflammation markers in men and women: the Comparing EPA to DHA (ComparED) Study

BACKGROUND

To date, most studies on the anti-inflammatory effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in humans have used a mixture of the 2 fatty acids in various forms and proportions.

OBJECTIVES

We compared the effects of EPA supplementation with those of DHA supplementation (re-esterified triacylglycerol; 90% pure) on inflammation markers (primary outcome) and blood lipids (secondary outcome) in men and women at risk of cardiovascular disease.

DESIGN

In a double-blind, randomized, crossover, controlled study, healthy men (n = 48) and women (n = 106) with abdominal obesity and low-grade systemic inflammation consumed 3 g/d of the following supplements for periods of 10 wk: 1) EPA (2.7 g/d), 2) DHA (2.7 g/d), and 3) corn oil as a control with each supplementation separated by a 9-wk washout period. Primary analyses assessed the difference in cardiometabolic outcomes between EPA and DHA.

RESULTS

Supplementation with DHA compared with supplementation with EPA led to a greater reduction in interleukin-18 (IL-18) (-7.0% ± 2.8% compared with -0.5% ± 3.0%, respectively; P = 0.01) and a greater increase in adiponectin (3.1% ± 1.6% compared with -1.2% ± 1.7%, respectively; P < 0.001). Between DHA and EPA, changes in CRP (-7.9% ± 5.0% compared with -1.8% ± 6.5%, respectively; P = 0.25), IL-6 (-12.0% ± 7.0% compared with -13.4% ± 7.0%, respectively; P = 0.86), and tumor necrosis factor-α (-14.8% ± 5.1% compared with -7.6% ± 10.2%, respectively; P = 0.63) were NS. DHA compared with EPA led to more pronounced reductions in triglycerides (-13.3% ± 2.3% compared with -11.9% ± 2.2%, respectively; P = 0.005) and the cholesterol:HDL-cholesterol ratio (-2.5% ± 1.3% compared with 0.3% ± 1.1%, respectively; P = 0.006) and greater increases in HDL cholesterol (7.6% ± 1.4% compared with -0.7% ± 1.1%, respectively; P < 0.0001) and LDL cholesterol (6.9% ± 1.8% compared with 2.2% ± 1.6%, respectively; P = 0.04). The increase in LDL-cholesterol concentrations for DHA compared with EPA was significant in men but not in women (P-treatment × sex interaction = 0.046).

CONCLUSIONS

DHA is more effective than EPA in modulating specific markers of inflammation as well as blood lipids. Additional studies are needed to determine the effect of a long-term DHA supplementation per se on cardiovascular disease risk. This trial was registered at clinicaltrials.gov as NCT01810003.

Consumption of a high-fat meal containing cheese compared with a vegan alternative lowers postprandial C-reactive protein in overweight and obese individuals with metabolic abnormalities: a randomised controlled cross-over study

Dietary recommendations suggest decreased consumption of SFA to minimise CVD risk; however, not all foods rich in SFA are equivalent. To evaluate the effects of SFA in a dairy food matrix, as Cheddar cheese, v. SFA from a vegan-alternative test meal on postprandial inflammatory markers, a randomised controlled cross-over trial was conducted in twenty overweight or obese adults with metabolic abnormalities. Individuals consumed two isoenergetic high-fat mixed meals separated by a 1- to 2-week washout period. Serum was collected at baseline, and at 1, 3 and 6 h postprandially and analysed for inflammatory markers (IL-6, IL-8, IL-10, IL-17, IL-18, TNFα, monocyte chemotactic protein-1 (MCP-1)), acute-phase proteins C-reactive protein (CRP) and serum amyloid-A (SAA), cellular adhesion molecules and blood lipids, glucose and insulin. Following both high-fat test meals, postprandial TAG concentrations rose steadily (P < 0·05) without a decrease by 6 h. The incremental AUC (iAUC) for CRP was significantly lower (P < 0·05) in response to the cheese compared with the vegan-alternative test meal. A treatment effect was not observed for any other inflammatory markers; however, for both test meals, multiple markers significantly changed from baseline over the 6 h postprandial period (IL-6, IL-8, IL-18, TNFα, MCP-1, SAA). Saturated fat in the form of a cheese matrix reduced the iAUC for CRP compared with a vegan-alternative test meal during the postprandial 6 h period. The study is registered at clinicaltrials.gov under NCT01803633.

CRP at early follicular phase of menstrual cycle can cause misinterpretation for cardiovascular risk assessment

OBJECTIVE

C-reactive protein (CRP) is a well-known marker of inflammation and infection in clinical practice. This study is designed to evaluate CRP levels in different phases of menstrual cycle, which might end up with misleading conclusions especially when used for cardiovascular risk assessment.

METHODS

Twenty-seven women were eligible for the cross-sectional study. Venous blood samples from each participant were collected twice during the menstrual cycle. The first sampling was held at 2nd to 5th days of the menstrual cycle for FSH, estradiol, CRP, and sedimentation, and the second was done at 21st to 24th days of the menstrual cycle for measurement of progesterone, CRP, and sedimentation values.

RESULTS

CRP values were significantly higher in the early follicular phase compared to luteal phase (1.8 mg/L [0.3-7.67] vs. 0.7 mg/L [0.1-8.3], p < 0.001, respectively). In both phases of the menstrual cycle, sedimentation rate was similar (12.1 ± 6.7 vs. 12.3 ± 7.7; p = 0.717, respectively).

CONCLUSIONS

CRP levels in early follicular phase of the menstrual cycle (menstruation) are significantly higher than CRP levels in luteal phase of the same cycle. In reproductive age women, detection of CRP for cardiovascular risk assessment during menstruation might not be appropriate.

Serum kisspeptin levels in normal and overweight Saudi females and its relation with anthropometric indices

BACKGROUND AND OBJECTIVES

Animal studies suggest that undernutrition and low body weight are associated with low kisspeptin expression and vice versa. This led us to hypothesize that obese and overweight individuals might have significant differences in kisspeptin levels compared with normal-weight individuals.

DESIGN AND SETTINGS

A prospective cohort study of 1-year duration involving young Saudi female students in the University of Dammam.

SUBJECTS AND METHODS

Young Saudi females studying in a Saudi university were divided into 2 groups: normal weight with a body mass index (BMI)=18.5-24.99 and overweight/obese with a BMI >=25. Serum kisspeptin levels were measured by enzyme-linked immunosorbent assay in early follicular, pre-ovulatory, and luteal phases, and anthropometric parameters were recorded.

RESULTS

Mean serum kisspeptin levels in the overweight/obese group (follicular phase: 266.88 [45.53], pre.ovulatory phase: 477.12 [21.18], and luteal phase: 735.13 [52.59]) did not differ significantly compared with the normal-weight group (follicular phase: 259.82 [20.50], pre-ovulatory phase: 448.36 [24.58], and luteal phase 708.18 [49.47]) in any of the menstrual phase. In any of the menstrual phase, kisspeptin levels were not found to be correlated with any of the anthropometric variable in any group.

CONCLUSION

Serum kisspeptin levels in overweight and obese young females may not differ significantly compared with normal-weight females, and there may not be any correlation between serum kisspeptin and anthropometric indices.

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 μmol·L^-1·4 hr^-1; p = 0.009; effect size = 0.47), H₂O₂ (29.9 ± 2.4 vs. 22.5 ± 1.6 μmol·L^-1·4 hr^-1; p = 0.001; effect size = 0.55), AOPP (92.8 ± 6.9 vs. 56.4 ± 3.7 μmol·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 μmol·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.

Premenopausal women exhibit an inherent protection of endothelial function following a high-fat meal

Endogenous estrogens likely increase blood flow and subsequently shear stress but have also been associated with improved endothelial function and cardiovascular protection. In contrast, a high-fat meal is thought to reduce endothelial function and increase cardiovascular risk. Therefore, we tested the hypotheses that fluctuating hormones across the menstrual cycle (1) facilitate an increase in shear rate and explain phase-specific differences in flow-mediated dilation (FMD) and (2) provide vascular protection against the insult of a high-fat meal. Flow-mediated dilation was determined at baseline and 4 hours following a high-fat meal in young women during the menses (M), follicular (F), and luteal (L) phases of the menstrual cycle. Male control participants were studied once. 17β-Estradiol was elevated (P < .05) during the F (5.3 ± 0.7 pg/mL) and L (5.2 ± 0.6 pg/mL) phases when compared to the M (3.9 ± 0.5 pg/mL) phase, and this was accompanied by an elevated FMD in the F and L phases (12.4 ± 1.4% and 11.2 ± 0.9%, respectively) compared to M (8.0 ± 0.9) with no change in shear rate. Female postprandial FMD was similar throughout the menstrual cycle, while men exhibited a 50% reduction (6.4 ± 1 to 3.3 ± 1%; P < .05). Interestingly, the postprandial FMD response was not associated with concentrations of either 17β-estradiol or progesterone. Despite acutely changing ovarian hormones across the menstrual cycle, shear stress is invariant and therefore does not account for the changes in FMD. Additionally, young women appear to have an inherent vascular protection from the insult of a high-fat meal, perhaps helping to explain sex-specific differences in cardiovascular risk.

Dietary total antioxidant capacity is inversely related to central adiposity as well as to metabolic and oxidative stress markers in healthy young adults

Background

Dietary total antioxidant capacity (TAC) has been assumed as a useful tool to assess the relationship between the cumulative antioxidant food capacity and several chronic disorders. The aim of this cross-sectional study was to investigate the potential relationships of dietary TAC with adiposity, metabolic and oxidative stress markers in healthy young adults.

Methods

This study enrolled 266 healthy subjects (105 men/ 161 women; 22 ± 3 years-old; 22.0 ± 2.7 kg/m²). Dietary intake, anthropometry, blood pressure, lifestyle features, and biochemical data were assessed with validated procedures.

Results

In linear regression analyses, dietary TAC values were inversely associated with glycemia, total cholesterol:HDL-c ratio, triglycerides and oxidized-LDL concentrations, and positively associated with HDL-c concentrations, independently of gender, age, smoking status, physical activity, vitamin use supplement, waist circumference, energy intake, fatty acid intake. In addition, plasma TAC was negatively correlated with ox-LDL concentrations (r= -0.20, P = 0.003), independently of the assessed confounding variables. Finally, dietary TAC values were inversely related to waist circumference values (r= -0.17, P = 0.005) as well as to lower mild central obesity occurrence (waist circumference ≥ 80/ 94 cm for women/ men, respectively).

Conclusion

Dietary TAC values are inversely associated with glucose and lipid biomarkers as well as with central adiposity measurements in healthy young adults, indicating dietary TAC as a useful tool to assess the health benefits of cumulative antioxidant capacity from food intake. In addition, the independent and inverse relationships of ox-LDL concentrations with dietary and plasma TAC respectively suggest a putative role of antioxidant rich-diet in the link between redox state and atherogenesis at early stage.

Postprandial lipid responses to an alpha-linolenic acid-rich oil, olive oil and butter in women: a randomized crossover trial

Background

Postprandial lipaemia varies with gender and the composition of dietary fat due to the partitioning of fatty acids between beta-oxidation and incorporation into triacylglycerols (TAGs). Increasing evidence highlights the importance of postprandial measurements to evaluate atherogenic risk. Postprandial effects of alpha-linolenic acid (ALA) in women are poorly characterized. We therefore studied the postprandial lipid response of women to an ALA-rich oil in comparison with olive oil and butter, and characterized the fatty acid composition of total lipids, TAGs, and non-esterified fatty acids (NEFAs) in plasma.

Methods

A randomized crossover design (n = 19) was used to compare the postprandial effects of 3 meals containing 35 g fat. Blood samples were collected at regular intervals for 7 h. Statistical analysis was carried out with ANOVA (significant difference = P < 0.05).

Results

No significant difference was seen in incremental area under the curve (iAUC) plasma-TAG between the meals. ALA and oleic acid levels were significantly increased in plasma after ALA-rich oil and olive oil meals, respectively. Palmitic acid was significantly increased in plasma-TAG after the butter meal. The ratios of 18:2 n-6 to18:3 n-3 in plasma-TAGs, three and seven hours after the ALA-rich oil meal, were 1.5 and 2.4, respectively. The corresponding values after the olive oil meal were: 13.8 and 16.9; and after the butter meal: 9.0 and 11.6.

Conclusions

The postprandial p-TAG and NEFA response in healthy pre-menopausal women was not significantly different after the intake of an ALA-rich oil, olive oil and butter. The ALA-rich oil significantly affected different plasma lipid fractions and improved the ratio of n-6 to n-3 fatty acids several hours postprandially.

17β-estradiol attenuates exercise-induced neutrophil infiltration in men

17β-estradiol (E2) attenuates exercise-induced muscle damage and inflammation in some models. Eighteen men completed 150 eccentric contractions after random assignment to placebo (Control group) or E2 supplementation (Experimental group). Muscle biopsies and blood samples were collected at baseline, following 8-day supplementation and 3 h and 48 h after exercise. Blood samples were analyzed for sex hormone concentration, creatine kinase (CK) activity and total antioxidant capacity. The mRNA content of genes involved in lipid and cholesterol homeostasis [forkhead box O1 (FOXO1), caveolin 1, and sterol regulatory element binding protein-2 (SREBP2)] and antioxidant defense (SOD1 and -2) were measured by RT-PCR. Immunohistochemistry was used to quantify muscle neutrophil (myeloperoxidase) and macrophage (CD68) content. Serum E2 concentration increased 2.5-fold with supplementation ( P < 0.001), attenuating neutrophil infiltration at 3 h ( P < 0.05) and 48 h ( P < 0.001), and the induction of SOD1 at 48 h ( P = 0.02). Macrophage density at 48 h ( P < 0.05) and SOD2 mRNA at 3 h ( P = 0.01) increased but were not affected by E2. Serum CK activity was higher at 48 h for both groups ( P < 0.05). FOXO1, caveolin 1 and SREBP2 expression were 2.8-fold ( P < 0.05), 1.4-fold ( P < 0.05), and 1.5-fold ( P < 0.001) and higher at 3 h after exercise with no effect of E2. This suggests that E2 attenuates neutrophil infiltration; however, the mechanism does not appear to be lesser oxidative stress or membrane damage and may indicate lesser neutrophil/endothelial interaction.

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.

Postprandial oxidative stress in response to dextrose and lipid meals of differing size

We have recently noted that ingestion of dietary lipid (in the form of heavy whipping cream) leads to greater oxidative stress than dietary carbohydrate (in the form of dextrose), when consumed in isocaloric amounts.

Objective

In the present investigation we attempted to replicate our work and also to determine the oxidative stress response to dextrose and lipid meals of two different kilocalorie (kcal) amounts.

Design

Nine young (22 ± 2 years), healthy men consumed in a random order, cross-over design one of four meals/drinks: dextrose at 75 g (300 kcals), dextrose at 150 g (600 kcals), lipid at 33 g (300 kcals), lipid at 66 g (600 kcals). Blood samples were collected Pre meal, and at 30 min, 60 min, 120 min, and 180 min post meal. Samples were assayed for glucose, triglycerides (TAG), malondialdehyde (MDA), and hydrogen peroxide (H₂O₂). Area under the curve (AUC) was calculated for each variable, and a 4 × 5 ANOVA was utilized to further analyze data.

Results

A meal × time effect (p = 0.0002) and a time effect was noted for glucose (p < 0.0001; 30 min > Pre, 1 hr, 2 hr, and 3 hr). The dextrose meals primarily contributed to this time effect. No other effects were noted for glucose (p > 0.05). A meal effect was noted for TAG (p = 0.01; 66 g lipid meal > 75 g and 150 g dextrose meals). No other effects were noted for TAG (p > 0.05). An AUC effect was noted for MDA (p = 0.04; 66 g lipid meal > 75 g and 150 g dextrose meals). A meal × time effect (p = 0.02) and a meal effect was noted for MDA (p = 0.004; 66 g lipid meal > 75 g and 150 g dextrose meals). No time effect was noted for MDA (p = 0.72). An AUC effect was noted for H₂O₂ (p = 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals). A meal × time effect (p = 0.0002), a meal effect (p < 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals), and a time effect was noted for H₂O₂ (p < 0.0001; 2 hr > Pre, 30 min, and 1 hr; 3 hr > Pre). The time effect for H₂O₂ was primarily influenced by the 66 g lipid meal.

Conclusions

These data indicate that 1) minimal oxidative stress is observed following ingestion of dextrose loads of either 75 g or 150 g, or a lipid load of 33 g and 2) lipid ingestion at 66 g leads to greater oxidative stress than lipid at 33 g or dextrose at either 75 g or 150 g. Hence, in a sample of young and healthy men, only 66 g of lipid (taken in the form of heavy whipping cream) leads to a significant increase in blood oxidative stress, as measured by MDA and H₂O₂.