Postprandial Oxidative Stress Research Articles

The effects of a single bolus of Capsosiphon fulvescenssupplement on a postprandial oxidative stress induced by a challenge of high‐fat formula in healthy subjects

The postprandial state is a dynamic period of metabolic trafficking, biosynthesis, and oxidative metabolism of absorbed nutrients. Considering the fact that most people eat several times a day, postprandial period‐induced chronic disease can be attributed to an exaggerated metabolic and oxidative imbalance. This study was investigated to test whether Capsosiphon fulvescens supplement can attenuate the oxidative stress and imbalance in lipid metabolism which was induced by feeding a bolus of high‐fat, high‐carbohydrate meal in healthy subjects. In a double‐blinded, randomized, and crossover design, thirty six subjects (18 females and 18 males) were enrolled in the trial and underwent three 6‐h oral lipid tolerance tests: control, low dose Capsosiphon fulvescens supplement, and high dose Capsosiphon fulvescens supplement. Treatment visits were scheduled approximately 1 week apart. Ethics approved for the trial was obtained from the institution review board of Ewha Womans University. The Capsosiphon fulvescens supplement was standardized with pheophorbide A. Plasma and urine samples were collected at 0, 30, 60, 120, and 360 min after the consumption of oral lipid tolerance test formula with Capsosiphon fulvescenssupplement or placebo. In plasma, glucose, insulin, triglycerides, oxidized low‐density lipoprotein, malondialdehyde, and reactive oxygen species were measured and area under the curve (AUC), Cmax, and Tmas of each parameter were calculated. Homeostatic model assessment insulin resistance (HOMA‐IR) was also calculated. Together, these data suggest that Capsosiphon fulvescens is an excellent antioxidant and may exert beneficial effects on postprandial metabolic overload.

The impact of beef steak thermal processing on lipid oxidation and postprandial inflammation related responses

Oxidised lipid species, their bioavailability and impact on inflammatory responses from cooked beef steak are poorly characterised. Oxidised lipid species from pan-fried (PF) and sous-vide (SV) thermally processed beef were determined with UHPLC-ESI/MS. Twenty-three lipid oxidation products increased with thermal processing and differences between the PF and SV steaks were measured. Fifteen oxidised lipids were measured in post-meal plasma after a cross-over randomised clinical study. Postprandial plasma inflammatory markers tended to remain lower following the SV meal than the PF meal. High levels of conjugated dienes were measured in the HDL fraction, suggesting that the protective effect of HDL may extend to the reverse-transport of oxidised lipid species. Oxidised lipids in a single meal may influence postprandial oxidative stress and inflammation. Further studies are required to examine the lipid oxidative responses to increased dietary oxidative lipid load, including the reverse transport activity of HDL.

Predicting Postprandial Oxidative Stress Using Serum Triglycerides Following Oral Fat Tolerance Testing

Background: The topic of postprandial oxidative stress continues to receive considerable attention, with elevations in oxidative stress biomarkers associated with human disease (e.g., insulin resistance, atherosclerosis). The predictable rise in serum triglyceride (TAG) following high fat meal ingestion is strongly correlated to the increase in circulating oxidative stress biomarkers. Our intent with the present study was two-fold: 1) To further characterize the postprandial response to high fat feeding and 2) to develop regression models that could be used to predict the oxidative stress response to high fat feeding. Methods: 154 men and women reported to the lab in the morning hours following an overnight fast and consumed a high fat liquid meal. Blood samples were collected before meal ingestion and at 2 and 4 hours following meal ingestion. Samples were analyzed for TAG and oxidative stress biomarkers (hydrogen peroxide [H2O2], malondialdehyde [MDA], advanced oxidation protein Original Research Article Bloomer et al; BJMMR, 5(12): 1514-1526, 2015; Article no.BJMMR.2015.171 1515 products [AOPP]). Simple linear regression analyses were used for model development to predict the oxidative stress response to feeding. In addition, biochemical variables were analyzed using an analysis of variance (ANOVA) to present response to feeding data across time. Results: In all of the regression models, TAG explained a significant portion of the outcome variables (H2O2, MDA, and AOPP) and predictor models were created for each variable. In addition, values for TAG and all oxidative stress biomarkers increased following meal ingestion. A time effect was noted where all values were higher post meal ingestion as compared to pre meal for all biochemical variables (p<0.05). Conclusion: Obtaining serum TAG values in response to a high fat meal challenge may provide investigators with the ability to predict postprandial oxidative stress using regression equations.

Changes in LDL Oxidative Status and Oxidative and Inflammatory Gene Expression after Red Wine Intake in Healthy People: A Randomized Trial.

Postprandial oxidative stress is characterized by an increased susceptibility of the organism towards oxidative damage after consumption of a meal rich in lipids and/or carbohydrates. Micronutrients modulate immune system and exert a protective action by reducing low density lipoproteins (LDL) oxidation via induction of antioxidant enzymes. We evaluated the gene expression of oxidative stress (HOSp), inflammasome (HIp), and human drug metabolism pathways (HDM) and ox-LDL level at baseline and after the intake of red wine naturally enriched with resveratrol (NPVRW), in association with or without a McDonald's meal (McDM). The ox-LDL levels significantly increase comparing baseline (B) versus McDM and decreased comparing McDM versus McDM + NPVRW (P ≤ 0.05). Percentages of significant genes expressed after each nutritional intervention were the following: (1) B versus McDM, 2.88% HOSp, 2.40% of HIp, and 3.37% of HDMp; (2) B versus McDM + NPVRW, 1.44% of HOSp, 4.81% of HIp, and 0.96% of HDMp; (3) McDM versus McDM + NPVRW, 2.40% of HOSp, 2.40% of HIp, and 5.77% of HDMp; (4) B versus NPVRW, 4.80% HOSp, 3.85% HIp, and 3.85% HDMp. NPVRW intake reduced postprandial ox-LDL and the expression of inflammation and oxidative stress related genes. Chronic studies on larger population are necessary before definitive conclusions.

Costus afer Possesses Carbohydrate Hydrolyzing Enzymes Inhibitory Activity and Antioxidant Capacity In Vitro.

Diabetes mellitus is a metabolic disorder of glucose metabolism which correlates with postprandial hyperglycemia and oxidative stress. Control of blood glucose level is imperative in the management of diabetes. The present study tested the hypothesis that Costus afer, an antihyperglycemic medicinal plant, possesses inhibitory activity against carbohydrate hydrolyzing enzymes. Hexane, ethyl acetate, methanol, and water extracts were prepared from the leaf, stem, and rhizome of C. afer and subjected to phytochemical screening, assayed for α-amylase and α-glucosidase inhibitory activities and antioxidant capacity (determined by total phenolic and total flavonoids contents, ferric reducing antioxidant power (FRAP), and DPPH radical scavenging activity). All extracts inhibited α-amylase and α-glucosidase activities. Ethyl acetate rhizome and methanol leaf extracts exhibited the best inhibitory activity against α-amylase and α-glucosidase (IC50: 0.10 and 5.99 mg/mL), respectively. Kinetic analysis revealed two modes of enzyme inhibition (competitive and mixed). All extracts showed antioxidant capacity, with hexane extracts exhibiting the best activity. DPPH assay revealed that methanol leaf, rhizome, and ethyl acetate stem extracts (IC50 < 5 mg/mL) were the best antioxidants. The presence of bioactive compounds such as flavonoids, alkaloids, phenols, and tannins may account for the antioxidant capacity and carbohydrate hydrolyzing enzyme inhibitory activity of C. afer.

Chemically synthesized glycosides of hydroxylated flavylium ions as suitable models of anthocyanins: binding to iron ions and human serum albumin, antioxidant activity in model gastric conditions.

Polyhydroxylated flavylium ions, such as 3',4',7-trihydroxyflavylium chloride (P1) and its more water-soluble 7-O-β-d-glucopyranoside (P2), are readily accessible by chemical synthesis and suitable models of natural anthocyanins in terms of color and species distribution in aqueous solution. Owing to their catechol B-ring, they rapidly bind FeIII, weakly interact with FeII and promote its autoxidation to FeIII. Both pigments inhibit heme-induced lipid peroxidation in mildly acidic conditions (a model of postprandial oxidative stress in the stomach), the colorless (chalcone) forms being more potent than the colored forms. Finally, P1 and P2 are moderate ligands of human serum albumin (HSA), their likely carrier in the blood circulation, with chalcones having a higher affinity for HSA than the corresponding colored forms.

High density lipoprotein level is negatively associated with the increase of oxidized low density lipoprotein lipids after a fatty meal.

Recent reports show that a fatty meal can substantially increase the concentration of oxidized lipids in low density lipoprotein (LDL). Knowing the LDL-specific antioxidant effects of high density lipoprotein (HDL), we aimed to investigate whether HDL can modify the postprandial oxidative stress after a fatty meal. Subjects of the study (n = 71) consumed a test meal (a standard hamburger meal) rich in lipid peroxides, and blood samples were taken before, 120, 240, and 360 min after the meal. The study subjects were divided into four subgroups according to the pre-meal HDL cholesterol value (HDL subgroup 1, 0.66-0.91; subgroup 2, 0.93-1.13; subgroup 3, 1.16-1.35; subgroup 4, 1.40-2.65 mmol/L). The test meal induced a marked postprandial increase in the concentration of oxidized LDL lipids in all four subgroups. The pre-meal HDL level was associated with the extent of the postprandial rise in oxidized LDL lipids. From baseline to 6 h after the meal, the concentration of ox-LDL increased by 48, 31, 24, and 16% in the HDL subgroup 1, 2, 3, and 4, respectively, and the increase was higher in subgroup 1 compared to subgroup 3 (p = 0.028) and subgroup 4 (p = 0.0081), respectively. The pre-meal HDL correlated with both the amount and the rate of increase of oxidized LDL lipids. Results of the present study show that HDL is associated with the postprandial appearance of lipid peroxides in LDL. It is therefore likely that the sequestration and transport of atherogenic lipid peroxides is another significant mechanism contributing to cardioprotection by HDL.

Effect of frying oils on the postprandial endoplasmic reticulum stress in obese people.

The addition of antioxidants to frying oil reduces postprandial oxidative stress and the inflammatory response. ER stress may trigger both inflammation and oxidative stress processes. We aimed to determine the biological effects of the intake of four models of frying oils on postprandial ER stress in peripheral blood mononuclear cells. Twenty obese people received four breakfasts following a randomized crossover design, consisting of muffins made with different oils (virgin olive oil (VOO), sunflower oil (SFO), and a mixture of seed oils (SFO/canola oil) with either dimethylpolysiloxane (SOD) or natural antioxidants from olives (SOP) added), which were previously subjected to 20 heating cycles. ER stress was assessed by measuring the mRNA levels of sXBP1, BiP, CRT, and CNX in peripheral blood mononuclear cells. Our study showed that the intake of the muffins made with SFO induced the postprandial increase of the mRNA levels of the ER stress-sensor sXBP1, and the ER stress related chaperones BiP and CRT (all p-values <0.05). The harmful effects associated with the use of SFO as frying oil, in terms of inflammatory response and postprandial oxidative stress, may be partially mediated by the induction of postprandial ER stress.

Enhanced reduction in oxidative stress and altered glutathione and thioredoxin system response to unsaturated fatty acid load in familial hypercholesterolemia

ObjectivesFamilial hypercholesterolemia (FH) is characterized by increased oxidative stress (OS) levels. In the postprandial state, lipids and lipoproteins modulate OS status through their impact on pro-oxidant and antioxidant mechanisms. The objective of this study was to evaluate in patients with FH the response to an unsaturated oral fat load test (OFLT) by analyzing the mRNA levels of genes involved in the glutathione and thioredoxin antioxidant systems. Design and MethodsWe analyzed 14 FH patients and 20 normolipidemic and normoglycemic controls. In both groups, mRNA values of antioxidant enzyme genes (glutathione and thioredoxin systems) were determined at baseline and at 2, 4, 6, and 8h after OFLT by real time PCR. ResultsIn the fasting state the mRNA levels of antioxidant enzymes GPX4 and the GSR, GSS, and GCLC enzymes (involved in glutathione regeneration and synthesis) and thioredoxin (TXN), were significantly increased in the FH group compared to the healthy controls. Some genes (GPX1 and GPX4) were increased at 4h in both groups, but values for the rest of the antioxidant enzyme mRNAs were decreased in FH patients after 4h from unsaturated OFLT and were increased in controls. ConclusionsWe concluded that an OFLT with predominantly unsaturated fat has a different effect on postprandial antioxidant enzyme mRNA levels in controls than in FH patients. Increased antioxidant enzyme mRNA is not the main way to reduce postprandial oxidative stress in FH. This difference could determine the influence of dietary patterns in these patients.

Peripheral blood mononuclear cells as in vivo model for dietary intervention induced systemic oxidative stress

Our aim was to assess the use of peripheral blood mononuclear cells (PBMC) as an in vivo cellular model to evaluate diet-induced changes in the oxidative stress status by analyzing the gene expression pattern of NADPH-oxidase subunits and antioxidant genes. A randomized, controlled trial assigned metabolic syndrome patients to 4 diets for 12weeks each: (i) high-saturated fatty acid (HSFA), (ii) high-monounsaturated fatty acid, and (iii), (iv) two low-fat, high-complex carbohydrate diets supplemented with n-3 polyunsaturated fatty acids or placebo. A fat challenge reflecting the fatty acid composition as the original diets was conducted post-intervention. The mRNA levels of gp91phox (P<0.001), p22phox (P=0.005), p47phox (P=0.001) and p40phox (P<0.001) increased at 2h after the intake of the HSFA meal. The expression of SOD1, SOD2, GSR, GPx1, GPX4, TXN, TXNRD1 and Nrf2 increased after the HSFA meal (p<0.05). In contrast, the expression of these genes remained unaltered in response to the other dietary interventions. Our results suggest that the increased expression of antioxidant genes in PBMC seems to be due to the response to the postprandial oxidative stress generated mainly in adipose tissue after the consumption of an HSFA diet.

Extra virgin olive oil blunt post-prandial oxidative stress via NOX2 down-regulation

ObjectiveOlive oil protects against cardiovascular disease but the underlying mechanism is still unclear. We speculated that olive oil could inhibit oxidative stress, which is believed to be implicated in the atherosclerotic process. Methods and resultsPost-prandial oxidative stress and endothelial dysfunction were investigated in twenty-five healthy subjects who were randomly allocated in a cross-over design to a Mediterranean diet added with or without extra virgin olive oil (EVOO, 10 g) (first study, n = 25) or Mediterranean diet with EVOO (10 g) or corn oil (10 g) (second study, n = 25). Oxidative stress biomarkers including platelet reactive oxidant species (ROS) and 8-iso-PGF2α-III, activity of NOX2, the catalytic sub-unit of NADPH oxidase, as assessed in platelets and serum, serum vitamin E and endothelial dysfunction, were measured before and 2 h after lunch.In the first study a significant increase of platelet ROS, 8-iso-PGF2α-III, NOX2 activity, sE-selectin, sVCAM1 and a decrease of serum vitamin E were detected in controls but not when EVOO was included in the Mediterranean diet; oxidative stress and endothelial dysfunction increase were also observed in the second study in subjects given corn oil. A significant correlation was found between NOX2 activity and platelet oxidative stress. In vitro study demonstrated that EVOO but not corn oil significantly decreased platelet and PMNs oxidative stress and NOX2 activity. ConclusionThe study provides the first evidence that post-prandial oxidative stress may be triggered by NOX2 up-regulation. EVOO but not corn oil, is able to counteract such phenomenon suggesting that addition of EVOO to a Mediterranean diet protects against post-prandial oxidative stress.

Influence of acute exercise of varying intensity and duration on postprandial oxidative stress.

Aerobic exercise can reduce postprandial lipemia, and possibly oxidative stress, when performed prior to a lipid-rich meal. To compare the impact of acute exercise on postprandial oxidative stress. We compared aerobic and anaerobic exercise bouts of different intensities and durations on postprandial blood triglycerides (TAG), oxidative stress biomarkers (malondialdehyde, hydrogen peroxide, advanced oxidation protein products), and antioxidant status (trolox equivalent antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase). Twelve trained men (21-35 years) underwent four conditions: (1) No exercise rest; (2) 60-min aerobic exercise at 70% heart rate reserve; (3) five 60-s sprints at 100% max capacity; and (4) ten 15-s sprints at 200% max capacity. All exercise bouts were performed on a cycle ergometer. A high-fat meal was consumed 1 h after exercise cessation. Blood samples were collected pre-meal and 2 and 4 h post-meal and analyzed for TAG, oxidative stress biomarkers, and antioxidant status. No significant interaction or condition effects were noted for any variable (p > 0.05), with acute exercise having little to no effect on the magnitude of postprandial oxidative stress. In a sample of healthy, well-trained men, neither aerobic nor anaerobic exercise attenuates postprandial oxidative stress in response to a high-fat meal.

Combination of grape seed proanthocyanidin extract and docosahexaenoic acid-rich oil increases the hepatic detoxification by GST mediated GSH conjugation in a lipidic postprandial state

The ingestion of dietary lipids leads to oxidative stress. This postprandial oxidative stress may potentiate the adverse effects of postprandial hyperlipidaemia. Proanthocyanidins have been shown to alleviate oxidative stress and hypertriglyceridaemia associated with the postprandial state. Additionally, omega-3 polyunsaturated fatty acids (PUFAs) also have beneficial effects on lipoprotein metabolism and oxidative stress. The present study was designed to investigate the possible additive effects in liver of an acute dose of grape seed proanthocyanidins extract (GSPE) and oil rich in docosahexaenoic acid (DHA-OR) on lipidic postprandial oxidative stress in Wistar rats. GSPE+DHA-OR modifies the hepatic antioxidant enzymatic activities (GST and GPx), clearly showing that this combination increases the detoxification of postprandial xenobiotics via the GST action mediated hepatic GSH conjugation. In conclusion, this study provides evidence that the combination of GSPE and DHA-OR ameliorate the transient imbalance between the lipid hydroperoxide level and antioxidant status related to a lipidic postprandial state.

Postprandial oxidative stress is increased after a phytonutrient-poor food but not after a kilojoule-matched phytonutrient-rich food

Research indicates that energy-dense foods increase inflammation and oxidative activity, thereby contributing to the development of vascular disease. However, it is not clear whether the high kilojoule load alone, irrespective of the nutritional content of the ingested food, produces the postprandial oxidative and inflammatory activity. This study investigated the hypothesis that ingestion of a high-fat, high-sugar, phytonutrient-reduced food (ice cream) would increase oxidative and inflammatory activity greater than a kilojoule-equivalent meal of a phytonutrient-rich whole food (avocado). The individual contributions of the fat/protein and sugar components of the ice cream meal to postprandial inflammation and oxidative stress were also quantified. Using a randomized, crossover design, 11 healthy participants ingested 4 test meals: ice cream, avocado, the fat/protein component in ice cream, and the sugar equivalent component in ice cream. Plasma glucose, cholesterol, triglycerides, and inflammatory and oxidative stress markers were measured at baseline and 1, 2, and 4 hours (t1, t2, t4) after ingestion. Lipid peroxidation was increased at 2 hours after eating fat/protein (t0-t2, P < .05) and sugar (t1-t2, P < .05; t1-t4, P < .05). Antioxidant capacity was decreased at 4 hours after eating ice cream (t0-t4, P < .01) and sugar (t0-t4, P < .01). Ingestion of a kilojoule-equivalent avocado meal did not produce any changes in either inflammatory or oxidative stress markers. These data indicate that the ingestion of a phytonutrient-poor food and its individual fat/protein or sugar components increase plasma oxidative activity. This is not observed after ingestion of a kilojoule-equivalent phytonutrient-rich food.

Effect of a walnut meal on postprandial oxidative stress and antioxidants in healthy individuals

BackgroundIn vitro studies rank walnuts (Juglans regia) among the plant foods high in antioxidant capacity, but whether the active constituents of walnuts are bioavailable to humans remains to be determined. The intention of this study was to examine the acute effects of consuming walnuts compared to refined fat on meal induced oxidative stress. At issue is whether the ellagitannins and tocopherols in walnuts are bioavailable and provide postprandial antioxidant protection.MethodsA randomized, crossover, and controlled-feeding study was conducted to evaluate a walnut test meal compared to one composed of refined ingredients on postprandial serum antioxidants and biomarkers of oxidative status in healthy adults (n = 16) with at least 1 week between testing sessions. Following consumption of a low phenolic diet for one day and an overnight fast, blood was sampled prior to the test meals and at intervals up to 24 hours post ingestion and analyzed for total phenols, malondiadehyde (MDA), oxidized LDL, ferric reducing antioxidant power (FRAP), hydrophilic and lipophilic oxygen radical absorbance capacity (ORAC), uric acid, catechins and urinary excretion of phenylacetate metabolites and of urolithin A.ResultsMixed linear models demonstrated a diet effect (P < 0.001) for plasma γ-tocopherol but not for α-tocopherol with the walnut meal. Following the walnut test meal, the incremental 5 hour area under the curve (AUC0-5h) was reduced 7.4% for MDA, increased 7.5% for hydrophilic and 8.5% for lipophilic ORAC and comparable for total phenols, FRAP and uric acid. Oxidized LDL was reduced at 2 hours after the walnut meal. Plasma concentrations of gallocatechin gallate (GCG), epicatechin gallate (ECG) and epicallocatechin gallate (EGCG) increased significantly at 1 hour after the walnut test meal. Quantities of urolithin-A excreted in the urine were significantly higher following the walnut meal.ConclusionsCompared to the refined control meal, the walnut meal acutely increased postprandial γ-tocopherol and catechins and attenuated some measures of oxidative stress.

Absence of attenuation in oxidative stress response with repeated lipid-rich feedings

Background: The study of postprandial oxidative stress has received considerable attention in recent years. Excess production of reactive oxygen and nitrogen species (RONS) in response to high fat feeding can lead to oxidative stress. However, repeated exposure to the same stressor may lead to attenuation in the oxidative stress response, possibly via an up-regulation in antioxidant enzyme activity. Objective: To determine if repeated exposure to lipid-rich meal ingestion leads to a lower oxidative stress response over time, possibly due to an increase in antioxidant enzyme activity. Methods: Sixteen healthy men consumed 10 high fat milkshakes over a 3+ week period. Blood was taken from subjects on the first day of each week (before and for 4 hours after milkshake ingestion) and analyzed for oxidative stress and antioxidant biomarkers. Results: The oxidative stress response to repeated lipid-rich feeding was not different over time, as indicated by similar changes in plasma malondialdehyde and hydrogen peroxide, as well as superoxide dismutase, catalase and glutathione peroxidase activity. Conclusion: These data indicate that RONS production is likely similar with repeated exposure to lipid-rich meals and does not induce an adaptive response within the blood antioxidant defense system in a way that is protective to cells.

Diet antioxidant capacity: Relationship to oxidative stress and health.

This review will discuss some of the antioxidant assays and biomarkers/measurements used to assess the effect of dietary components on ameliorating in vivo oxidative stress. Although the development of dietary antioxidants has become a major component of the dietary supplement market, this review will focus on foods (primarily fruits and vegetables) and their impact on biomarkers of oxidative stress and the ultimate appearance of disease states. Data is reviewed demonstrating the importance of consumption of dietary antioxidants along with meals to prevent postprandial oxidative stress. Epidemiology studies have demonstrated the relationships between dietary antioxidant intake in the form of polyphenolic type compounds and health outcomes. However, additional research is needed in order to clearly define the mechanism(s) of action of the polyphenolics and whether their effects are direct or indirect in nature.

Effect of grape seed extract on postprandial oxidative status and metabolic responses in men and women with the metabolic syndrome - randomized, cross-over, placebo-controlled study

Objective: This investigation was undertaken to determine whether a grape seed extract (GSE) that is rich in mono-, oligo- and poly- meric polyphenols would modify postprandial oxidative stress and inflammation in individuals with the metabolic syndrome (MetS).Background: MetS is known to be associated with impaired glucose tolerance and poor glycemic control. Consumption of a meal high in readily available carbohydrates and fat causes postprandial increases in glycemia and lipidemia and markers of oxidative stress, inflammation and insulin resistance.Materials/methods: After an overnight fast, twelve subjects with MetS (5 men and 7 women) consumed a breakfast meal high in fat and carbohydrate in a cross-over design. A GSE (300 mg) or placebo capsule was administrated 1 hr before the meal (-1 hr). Changes in plasma insulin, glucose, oxidative stress and inflammatory markers were measured hourly for 6 hr. Results: Plasma hydrophilic oxygen radical absorbance capacity (ORAC) measured as the positive incremental area under the curve (-1 to 5 hr) was significantly increased when the meal was preceded by GSE compared with placebo (P&lt;0.05). Meal-induced increases in oxidized LDL were attenuated with GSE (P&lt;0.05). Plasma glucose concentrations (area under the curve from -1 to 5 hr) were also significantly lower when the meal was preceded by GSE (P&lt;0.05) while the insulin concentrations remained unchanged (P&gt;0.05). No changes in inflammatory markers were evident. Conclusion: These data suggest that GSE enhances postprandial plasma antioxidant status and reduces the glycemic response to a meal, high in fat and carbohydrate in subjects with the MetS. Key words: Polyphenols, Oxidative stress, Inflammation, ORAC, Oxidized LDL

Strawberry As a Functional Food: An Evidence-Based Review

Emerging research provides substantial evidence to classify strawberries as a functional food with several preventive and therapeutic health benefits. Strawberries, a rich source of phytochemicals (ellagic acid, anthocyanins, quercetin, and catechin) and vitamins (ascorbic acid and folic acid), have been highly ranked among dietary sources of polyphenols and antioxidant capacity. It should however be noted that these bioactive factors can be significantly affected by differences in strawberry cultivars, agricultural practices, storage, and processing methods: freezing versus dry heat has been associated with maximum retention of strawberry bioactives in several studies. Nutritional epidemiology shows inverse association between strawberry consumption and incidence of hypertension or serum C-reactive protein; controlled feeding studies have identified the ability of strawberries to attenuate high-fat diet induced postprandial oxidative stress and inflammation, or postprandial hyperglycemia, or hyperlipidemia in subjects with cardiovascular risk factors. Mechanistic studies have elucidated specific biochemical pathways that might confer these protective effects of strawberries: upregulation of endothelial nitric oxide synthase (eNOS) activity, downregulation of NF-kB activity and subsequent inflammation, or inhibitions of carbohydrate digestive enzymes. These health effects may be attributed to the synergistic effects of nutrients and phytochemicals in strawberries. Further studies are needed to define the optimal dose and duration of strawberry intake in affecting levels of biomarkers or pathways related to chronic diseases.

Short-Term Effect of Pitavastatin Treatment on Glucose and Lipid Metabolism and Oxidative Stress in Fasting and Postprandial State Using a Test Meal in Japanese Men

Introduction. The objective of this study was to clarify how pitavastatin affects glucose and lipid metabolism, renal function, and oxidative stress. Methods. Ten Japanese men (average age of 33.9 years) were orally administered 2 mg of pitavastatin for 4 weeks. Postprandial glucose, lipoprotein metabolism, and oxidative stress markers were evaluated at 0 and 4 weeks of pitavastatin treatment (2 mg once daily) with a test meal consisting of total calories: 460 kcal, carbohydrates: 56.5 g (226 kcal), protein: 18 g (72 kcal), lipids: 18 g (162 kcal), and NaCl: 1.6 g. Metabolic parameters were measured at 0, 60, and 120 minutes after test meal ingestion. Results. After administration of pitavastatin, serum total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, arachidonic acid, insulin, and adjusted urinary excretion of uric acid decreased, whereas creatinine clearance (C Cr) and uric acid clearance (C UA) increased. And postprandial versus fasting urine 8-hydroxydeoxyguanosine remained unchanged, while postprandial versus fasting isoprostane decreased after pitavastatin treatment. Next, we compared postprandial glucose and lipid metabolism after test meal ingestion before and after pitavastatin administration. Incremental areas under the curve significantly decreased for triglycerides (P < 0.05) and remnant-like particle cholesterol (P < 0.01), while those for apolipoprotein E (apoE), glucose, insulin, and high-sensitivity C-reactive protein remained unchanged. Conclusion. Pitavastatin improves postprandial oxidative stress along with hyperlipidemia.