Omega-3 Fatty Acid Supplementation is Associated With Oxidative Stress and Dyslipidemia, but Does not Contribute to Better Lipid and Oxidative Status on Hemodialysis Patients

The In Vitro, Ex Vivo, and In Vivo Effect of Edible Oils: A Review on Cell Interactions

Consumption of edible oils is a significant part of the dietary pattern in the developed and developing world. Marine and vegetable oils are assumed to be part of a healthy food pattern, especially if one takes into account their potential role in protecting against inflammation, cardiovascular disease, and metabolic syndrome due to the presence of polyunsaturated fatty acids and minor bioactive compounds. Exploring the potential effect of edible fats and oils on health and chronic diseases is an emerging field worldwide. This study reviews the current knowledge of the in vitro, ex vivo, and in vivo effect of edible oils in contact with various cell types and aims to demonstrate which nutritional and bioactive components of a variety of edible oils present biocompatibility, antimicrobial properties, antitumor activity, anti-angiogenic activity, and antioxidant activity. Through this review, a wide variety of cell interactions with edible oils and their potential to counteract oxidative stress in pathological conditions are presented as well. Moreover, the gaps in current knowledge are also highlighted, and future perspectives on edible oils and their health benefits and potential to counteract a wide variety of diseases through possible molecular mechanisms are also discussed.

A Consistency Model for Identifying the Effects of n-3 and n-6 Fatty Acids on Lipoproteins in Dialysis Patients

Numerous randomized controlled trials (RCTs) and meta-analyses have assessed the effects of supplemental dietary polyunsaturated fatty acids (PUFAs) on levels of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) and the LDL/HDL ratio in patients receiving renal replacement therapy (RRT). However, results are ambiguous due to mixed reports of various nutrients used in the intervention group. We performed a network meta-analysis of RCTs to assess the effects of PUFAs on lipid profiles in patients undergoing RRT. RCTs performed before November 2021 were gathered from three databases. The means, standard deviations and the number of cases for each arm were independently extracted by two authors to form a network meta-analysis of LDL and HDL levels and the LDL/HDL ratio in a random effects model. Twenty-eight RCTs (n = 2017 subjects) were included in this study. The pooled results revealed that the combination of omega-3 fatty acids (n-3) and omega-6 fatty acids (n-6) produced significantly lower LDL (standardized mean difference (SMD) = −1.43, 95% confidence interval: −2.28 to −0.57) than the placebo. Both n-3 fatty acids (SMD = 0.78) and the combination of n-3 + n-6 (SMD = 1.09) benefited HDL significantly compared with placebo. Moreover, n-3 alone also exhibited a significantly lower LDL/HDL ratio than placebo. Collectively, PUFAs seem to be adequate nutrients for controlling lipoproteins in patients undergoing RRT. Specifically, n-3 + n-6 supplementation improved LDL levels, while n-3 improved HDL levels and the LDL/HDL ratio. However, our data provide limited information on specific dosages of PUFAs to form a concrete recommendation.

Effects of Omega-3 Fatty Acid Intake in Patients Undergoing Dialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective: Fish oil supplementation has been shown to be beneficial for hemodialysis (HD) patients. The aim of this study was to evaluate the efficacy and safety of omega-3 fatty acid supplementation or dietary adjustment in dialysis patients.Methods: A systematic literature search was performed to identify relevant randomized controlled trials (RCTs) to study the effects of omega-3 supplementation on dialysis patients. The variables of interest included the levels of blood lipids, inflammatory indicators, proteins, parathyroid hormone (PTH), gastrointestinal adverse reactions, and all-cause mortality. The mean differences (MDs) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed with the I² test. Subgroup and sensitivity analyses were performed to identify potential sources.Results: The systematic review included 49 RCTs and evaluated the efficacy and safety of omega-3 fatty acid supplementation in dialysis patients. Data synthesis showed that compared with the control group, the group receivingomega-3 supplementation exhibited significantly decreased serum triglyceride (TG) levels, decreased C-reactive protein (CRP) and TNF-alpha levels, increased hemoglobin levels, reduced serum phosphorus levels, increased PTH levels, and increased gastrointestinal adverse reactions to a certain extent. Furthermore, there was no effect on the blood total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), albumin or calcium levels and all-cause mortality.Conclusion: Omega-3 fatty acid supplementation is related to a reduction in serum TG, LDL and inflammation index levels and has few adverse reactions. Therefore, omega-3 fatty acid supplementation may be a useful nutrition therapy for dialysis patients.

Dietary Lipids and Dyslipidemia in Chronic Kidney Disease

The progression of chronic kidney disease (CKD) leads to altered lipid metabolism. CKD patients exhibit high blood triglyceride (TG) levels, reduced concentrations and functionality of high-density lipoproteins (HDL), and elevated levels of atherogenic small, dense, low-density lipoproteins (sdLDL). Disorders of lipid metabolism and other metabolic disturbances place CKD patients at high risk for cardiovascular disease (CVD). Extensive evidence supports the cardioprotective effects of unsaturated fatty acids, including their beneficial effect on serum cholesterol and TG levels. Dietary lipids might therefore be especially important in the nutritional management of CKD. We review current dietary recommendations for fat intake by CKD patients and suggest potential nutritional interventions by emphasizing dietary lipids that might improve the blood lipid profile and reduce cardiovascular risk in CKD.

Omega-3 fatty acids supplementation and oxidative stress parameters: A systematic review and meta-analysis of clinical trials

Omega-3 fatty acids (omega-3 FAs) supplementation effects on oxidants and antioxidants are always controversial. Oxidative stress (OS) is one of the major mechanisms that contribute to the pathogenesis of several chronic diseases. The present systematic review and meta-analysis aimed to summarize the finding of randomized clinical trials (RCTs) examining the effects of omega-3 FAs on OS markers. Five databases including PubMed, Embase, Scopus, Web of science, and Cochrane were searched up to May 5th, 2019 with no language restriction. RCTs included if they compared OS indices among subjects who received omega-3 FAs supplements and subjects who supplemented with placebo. To estimate the effects of omega-3 FAs supplementation, standardized mean difference (SMD) with 95% confidence intervals (95% CI) were pooled using random effects model. Of 5,887 publications, 39 trials involving 2,875 participants were included for the meta-analysis. The pooled analysis of data indicated that omega-3 FAs significantly increased serum total antioxidant capacity (TAC) (SMD: 0.48, 95% CI: 0.23, 0.72, P< 0.001; I²= 60%), glutathione peroxidase (GPx) (SMD: 0.73, 95% CI: 0.30, 1.16, P= 0.001; I²= 83%) activity and decreased malondialdehyde (MDA) (SMD= -0.42, 95% CI: -0.62, -0.21; P < 0.001; I²= 74%) compared to the placebo group. However, the effects of omega-3 FAs on nitric oxide (NO) (SMD: -0.17 , 95% CI: -0.77, 0.43, P = 0.57; I²= 91%), reduced glutathione (GSH) (SMD= 0.23, 95% CI= -0.17, 0.64, P= 0.25; I²= 75%), superoxide dismutase (SOD) (0.12 , 95% CI: -0.40, 0.65, P= 0.64; I²= 89%) and catalase (CAT) (0.16, 95% CI: -0.33, 0.65, P= 0.52; I²= 75%,) activities was not significant. Supplementation with omega-3 FAs significantly improves MDA, TAC levels, and GPx activity. Thus, omega-3 FAs can be mentioned as enhancer factors in antioxidant defense against reactive oxygen species (ROS).

The Effect of Omega-3 Supplementation on Serum Levels of Inflammatory Biomarkers and Albumin in Hemodialysis Patients: A Systematic Review and Meta-analysis

This systematic review and meta-analysis were performed to evaluate the effect of omega-3 supplementation on serum levels of inflammatory biomarkers (C-reactive protein [CRP], high-sensitivity CRP [hs-CRP], tumor necrosis factor-alpha, interleukin-6) and albumin in patients on hemodialysis. A literature search was performed in MEDLINE, Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Web of Science, and Google Scholar. Randomized controlled trials that evaluated the effect of omega-3 supplementation versus placebo were selected. Eight randomized controlled trials comprising 371 patients on hemodialysis were included. According to our results, omega-3 supplementation significantly decreased serum levels of CRP (standardized mean difference [SMD]: -1.95 mg/Dl; 95% confidence interval [CI]: -3.09, -0.80) and hs-CRP (SMD: -2.09; 95% CI: -3.62, -0.56) but did not significantly improve albumin (SMD: 0.91; 95% CI: -0.78, 2.59), tumor necrosis factor-alpha (SMD: -1.51; 95% CI: -3.24, 0.22), and interleukin-6 (SMD: 0.72, 95% CI: -0.56, 1.99). We concluded that omega-3 supplementation leads to a significant decrease in serum levels of CRP and hs-CRP.

Efficacy of Polyunsaturated Fatty Acids on Inflammatory Markers in Patients Undergoing Dialysis: A Systematic Review with Network Meta-Analysis of Randomized Clinical Trials

The effects of polyunsaturated fatty acids (PUFAs) on inflammatory markers among patients receiving dialysis have been discussed for a long time, but previous syntheses made controversial conclusion because of highly conceptual heterogeneity in their synthesis. Thus, to further understanding of this topic, we comprehensively gathered relevant randomized clinical trials (RCTs) before April 2019, and two authors independently extracted data of C-reactive protein (CRP), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) for conducting network meta-analysis. Eighteen eligible RCTs with 962 patients undergoing dialysis were included in our study. The result showed that with placebo as the reference, PUFAs was the only treatment showing significantly lower CRP (weighted mean difference (WMD): −0.37, 95% confidence interval (CI): −0.07 to −0.68), but the CRP in PUFAs group was not significantly lower than vitamin E, PUFAs plus vitamin E, or medium-chain triglyceride. Although no significant changes were noted for hs-CRP and IL-6 levels, PUFAs showed the best ranking among treatments according to surface under the cumulative ranking. Therefore, PUFAs could be a protective option for patients receiving dialysis in clinical practice.

Effects of Flaxseed Oil Omega-3 Fatty Acids Supplementation on Regression and Metabolic Status in Endometrial Hyperplasia: A randomized, Double-Blind, Placebo-Controlled Trial

Background:

Data on the effects of omega-3 fatty acid supplementation on clinical symptoms and metabolic profiles in patients with endometrial hyperplasia (EH) are limited. This intervention was performed to assess the effects of omega-3 fatty acid supplementation on clinical symptoms and metabolic profiles in patients with endometrial hyperplasia (EH).

Methods:

This randomized, double-blind, placebo-controlled trial was conducted among 40 women diagnosed with simple endometrial hyperplasia (EH). EH diagnosis was performed based on specific diagnostic procedures of biopsy. Participants were randomised into two groups to intake 1,000 mg omega-3 fatty acid supplements from flaxseed oil (n = 20) or placebo (n = 20), twice a day for 12 weeks. Fasting blood samples were taken at baseline and after the 12-week intervention to determine related markers.

Results:

Compared with the placebo, omega-3 fatty acid supplementation significantly decreased fasting plasma glucose (FPG) (-7.1 ± 9.6 vs. +2.0 ± 4.9 mg/dL, P = 0.001), serum insulin levels (-1.5 ± 4.6 vs. +1.6 ± 3.9 μIU/mL, P = 0.02) and homeostasis model of assessment-insulin resistance (HOMA-IR) (-0.4 ± 1.1 vs. +0.4 ± 1.0, P = 0.02). In addition, a significant increase in plasma total antioxidant capacity (TAC) (+102.6 ± 69.6 vs. +5.0 ± 37.1 mmol/L, P < 0.001) and total glutathione (GSH) levels (+63.6 ± 84.9 vs. -3.0 ± 69.4 μmol/L, P = 0.01) were seen following the supplementation of omega-3 fatty acid compared with the placebo. Omega-3 fatty acid supplementation had no significant effect on regression, lipid profiles, and other biomarkers of inflammation and oxidative.

Conclusions:

In conclusion, we found that omega-3 fatty acid administration for 12 weeks to subjects with EH significantly improved FPG, insulin, HOMA-IR, TAC and GSH levels, but did not influence regression, lipid profiles, and other biomarkers of inflammatory and oxidative stress.

Antioxidant Supplementation in Renal Replacement Therapy Patients: Is There Evidence?

The disruption of balance between production of reactive oxygen species and antioxidant systems in favor of the oxidants is termed oxidative stress (OS). To counteract the damaging effects of prooxidant free radicals, all aerobic organisms have antioxidant defense mechanisms that are aimed at neutralizing the circulating oxidants and repair the resulting injuries. Antioxidants are either endogenous (the natural defense mechanisms produced by the human body) or exogenous, found in supplements and foods. OS is present at the early stages of chronic kidney disease, augments progressively with renal function deterioration, and is further exacerbated by renal replacement therapy. End-stage renal disease patients, on hemodialysis (HD) or peritoneal dialysis (PD), suffer from accelerated OS, which has been associated with increased risk for mortality and cardiovascular disease. During HD sessions, the bioincompatibility of dialyzers and dialysate trigger activation of white blood cells and formation of free radicals, while a significant loss of antioxidants is also present. In PD, the bioincompatibility of solutions, including high osmolality, elevated lactate levels, low pH, and accumulation of advanced glycation end-products trigger formation of prooxidants, while there is significant loss of vitamins in the ultrafiltrate. A number of exogenous antioxidants have been suggested to ameliorate OS in dialysis patients. Vitamins B, C, D, and E, coenzyme Q10, L-carnitine, a-lipoic acid, curcumin, green tea, flavonoids, polyphenols, omega-3 polyunsaturated fatty acids, statins, trace elements, and N-acetylcysteine have been studied as exogenous antioxidant supplements in both PD and HD patients.

Oxidative stress in hemodialysis: Causative mechanisms, clinical implications, and possible therapeutic interventions

Oxidative stress (OS) is the result of prooxidant molecules overwhelming the antioxidant defense mechanisms. Hemodialysis (HD) constitutes a state of elevated inflammation and OS, due to loss of antioxidants during dialysis and activation of white blood cells triggering production of reactive oxygen species. Dialysis vintage, dialysis methods, and type and condition of vascular access, biocompatibility of dialyzer membrane and dialysate, iron administration, and anemia all can play a role in aggravating OS, which in turn has been associated with increased morbidity and mortality. Oral or intravenous administration of antioxidants may detoxify the oxidative molecules and at least in part repair OS-mediated tissue damage. Lifestyle interventions and optimization of a highly biocompatible HD procedure might ameliorate OS development in dialysis.

Blood Fatty Acid Status and Clinical Outcomes in Dialysis Patients: A Systematic Review

Blood fatty acids (FAs) are derived from endogenous and dietary routes. Metabolic abnormalities from kidney dysfunction, as well as cross-cultural dietary habits, may alter the FA profile of dialysis patients (DP), leading to detrimental clinical outcomes. Therefore, we aimed to (i) summarize FA status of DP from different countries, (ii) compare blood FA composition between healthy controls and DP, and (iii) evaluate FA profile and clinical endpoints in DP. Fifty-three articles from 1980 onwards, reporting FA profile in hemodialysis and peritoneal DP, were identified from PubMed, Embase, and the Cochrane library. Studies on pediatric, predialysis chronic kidney disease, acute kidney injury, and transplant patients were excluded. Moderate to high levels of n-3 polyunsaturated fatty acids (PUFA) were reported in Japan, Korea, Denmark, and Sweden. Compared to healthy adults, DP had lower proportions of n-3 and n-6 PUFA, but higher proportion of monounsaturated fatty acids. Two studies reported inverse associations between n-3 PUFAs and risks of sudden cardiac death, while one reported eicosapentaenoic acid + docosahexaenoic acid)/arachidonic acid ratio was inversely associated with cardiovascular events. The relationship between all-cause mortality and blood FA composition in DP remained inconclusive. The current evidence highlights a critical role for essential FA in nutritional management of DP.

Fatty Acids Consumption: The Role Metabolic Aspects Involved in Obesity and Its Associated Disorders

Obesity and its associated disorders, such as insulin resistance, dyslipidemia, metabolic inflammation, dysbiosis, and non-alcoholic hepatic steatosis, are involved in several molecular and inflammatory mechanisms that alter the metabolism. Food habit changes, such as the quality of fatty acids in the diet, are proposed to treat and prevent these disorders. Some studies demonstrated that saturated fatty acids (SFA) are considered detrimental for treating these disorders. A high fat diet rich in palmitic acid, a SFA, is associated with lower insulin sensitivity and it may also increase atherosclerosis parameters. On the other hand, a high intake of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids may promote positive effects, especially on triglyceride levels and increased high-density lipoprotein (HDL) levels. Moreover, polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs) are effective at limiting the hepatic steatosis process through a series of biochemical events, such as reducing the markers of non-alcoholic hepatic steatosis, increasing the gene expression of lipid metabolism, decreasing lipogenic activity, and releasing adiponectin. This current review shows that the consumption of unsaturated fatty acids, MUFA, and PUFA, and especially EPA and DHA, which can be applied as food supplements, may promote effects on glucose and lipid metabolism, as well as on metabolic inflammation, gut microbiota, and hepatic metabolism.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

Use of anabolic androgenic steroids produces greater oxidative stress responses to resistance exercise in strength-trained men

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Single session of high-intensity RE on trained bodybuilder men had effect on DNA damage and oxidative stress.

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The AAS users showed greater response than NAAS users. At pre-RE, the levels of oxidant were greater for the AAS group.

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The study has reported a range of negative redox status consequence of AAS use in conjunction with resistance training.

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The alteration of oxidative stress status with AAS use likely increase the injury risks in some organs in athletes.

The aim of this study was to determine the effect of anabolic androgenic steroids (AAS) use on oxidative stress responses to a single session of resistance exercise in strength-trained men. Twenty-three strength trained men, with 11 self-reporting regular AAS use and 12 self-reporting never taking AAS (NAAS) volunteered to participate in this study. Blood draws were obtained pre and post resistance exercise in order to evaluate changes in oxidative stress biomarkers levels (i.e., 8-hydroxy-2-deoxyguanosine [8-OHdG], malondialdehyde [MDA], and nitric oxide [NO]), antioxidant defense systems (i.e., glutathione peroxidase [GPx] and catalase [CAT]), and glucose (GLU) levels. The AAS users had higher level of 8-OHdG (77.3 ± 17 vs. 57.7 ± 18.2 ng/mg), MDA (85.6 ± 17.8 vs. 52.3 ± 15.1 ng/mL), and GPx (9.1 ± 2.3 vs. 7.1 ± 1.3 mu/mL) compared to NAAS at pre exercise (p < 0.05). Both the experimental groups showed increases in 8-OHdG (p = 0.001), MDA (p = 0.001), GPx (p = 0.001), NO (p = 0.04), CAT (p = 0.02) and GLU (p = 0.001) concentrations after resistance exercise, and the AAS group indicated significant differences in 8-OHdG (p = 0.02) and MDA (p = 0.05) concentrations compared with NAAS users at post exercise. In conclusion, use of AAS is associated with alterations in immune function resulting in oxidative stress, and cell damage; however, high-intensity resistance exercise could increase greater oxidative stress biomarkers in strength-trained men.