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Effects of Omega-3 fatty acids supplementation and resistance training on skeletal muscle.
Uchida, Y, Tsuji, K, Ochi, E
Clinical nutrition ESPEN. 2024;61:189-196
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The age-related decline in muscle strength and skeletal muscle mass can impede the daily lives of older adults and make independent living difficult. The study aimed to investigate the effects of omega-3 fatty acids supplementation and resistance training on muscle strength and mass. This study was a systematic review and meta-analysis of five studies. Results showed that: - omega-3 fatty acids supplementation, when combined with resistance training, significantly improved muscle strength compared to the placebo-controlled group. - no significant effects were observed in terms of muscle mass. Authors concluded that omega-3 fatty acids and strength training could be a potential strategy in preventing sarcopenia.
Abstract
BACKGROUND & AIMS The aim of this study was to investigate the omega-3 fatty acids supplementation, and resistance training on muscle strength and mass. METHODS A review was conducted by searching relevant randomized controlled trials investigating the effects of omega-3 fatty acids supplementation and resistance training on skeletal muscle strength and mass. Three experts independently performed a thorough examination of the literature database and conducted the systematic review and meta-analysis. RESULTS Four studies were ultimately included in the systematic review after screening. The results of the meta-analysis revealed that the supplementation of omega-3 fatty acids and resistance training significantly improved muscle strength compared to the placebo-controlled group. However, no significant effects were observed in the effect for muscle mass. CONCLUSIONS The interventions of omega-3 fatty acids supplementation and resistance training show promise as a countermeasure against muscular dysfunction. While further research is warranted to investigate its effects on skeletal muscle mass, the findings of this study hold implications for maintaining and/or improving the quality of life to elderly people.
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The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.
Santo André, HC, Esteves, GP, Barreto, GHC, Longhini, F, Dolan, E, Benatti, FB
Advances in nutrition (Bethesda, Md.). 2023;14(1):115-127
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Omega 3 polyunsaturated fatty acids (n-3PUFA) are long-chain polyunsaturated fatty acids essential to human health. They play a role in cell membrane integrity, immune and inflammation regulation, cognition and neuromuscular function. As the human body cannot make these fatty acids, they need to be obtained through diet or supplementation. Regarding skeletal muscle, recent research showed that n-3PUFAs may increase the uptake of amino acids by increasing the membrane fluidity in the muscle, and by activating pathways that inhibit protein breakdown. This led to the hypothesis that n-3PUFAs may enhance muscle mass gain and strength. This systematic review sought to gather all available evidence about the impact of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. The review included 14 studies with a total of 1443 participants. The authors found that n-3PUFA supplementation had no significant effect on muscle mass or muscle function in healthy young and older adults, however, a very small but significant positive effect was noted regarding muscle strength. In the discussion section, the authors explain the challenges of their review and how these findings integrate with the current understanding and other research findings. They concluded more research is needed to get a better insight into the effects of n-3PUFA on muscle function and the variants.
Abstract
The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.
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The effects of multi-nutrient formulas containing a combination of n-3 PUFA and B vitamins on cognition in the older adult: a systematic review and meta-analysis.
Fairbairn, P, Dyall, SC, Tsofliou, F
The British journal of nutrition. 2023;129(3):428-441
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Due to the insidious onset, cognitive impairment often goes unnoticed for several years, with clinical diagnosis being made late into the disease progression. Cognition is critical for functional independence as people age, and intact cognition is vital for humans to communicate effectively. The aims of this study were to (i) investigate whether supplementation with a combination of omega-3 polyunsaturated fatty acids (n-3 PUFA) and B vitamins alone or as part of a multi-nutrient formula can prevent cognitive decline in older adults, and (ii) determine whether the effects of a single nutrient intervention with either n-3 PUFA or B vitamins could be modified by the status of the other nutrient. This study is a systematic review and meta-analysis of fourteen studies of which eleven were randomised controlled trials and the rest were post hoc analysis of randomised controlled trials. Results show a benefit of supplementing with nutrient formulas that contain both n-3 PUFA and B vitamins on global cognition and episodic memory with small to moderate effect sizes. In fact, they can help preserve cognition in the older adults. Authors conclude that more experimental work providing a combination of nutrients including both n-3 PUFA and B vitamins, in healthy older adults or those showing early signs of cognitive decline, is clearly warranted to better explore how nutrition can impact the trajectory of cognition in older adults.
Abstract
There is now evidence to suggest that there may be an interaction between B vitamins and n-3 PUFA, with suggestions that increasing intake of both nutrients simultaneously may benefit cognition in older adults. The aim of this systematic review was to investigate whether supplementation with a combination of n-3 PUFA and B vitamins can prevent cognitive decline in older adults. Randomised controlled trials conducted in older adults that measured cognitive function were retrieved. The included trials provided a combination of n-3 PUFA and B vitamins alone, or in combination with other nutrients. Trials that provided n-3 PUFA alone and also measured B vitamin status or provided B vitamin supplementation alone and measured n-3 PUFA status were also included. The databases searched were The Cochrane Library, EMBASE, CINAHL, Scopus and MEDLINE. A total of 14 papers were included in the analysis (n 4913; age: 60-70 years; follow-up 24 weeks to 4 years). The meta-analysis results found a significant benefit of nutrient formulas, which included both n-3 PUFA and B vitamins alongside other nutrients, v. placebo on global cognition assessed using composite scores from a neuropsychological test battery (G = 0·23, P = 0·002), global cognition using single measures of cognition (G = 0·28, P = 0·004) and episodic memory (G = 0·32, P = 0·001). The results indicate that providing a combination of n-3 PUFA and B vitamins as part of a multi-nutrient formula benefits cognition in older adults v. a placebo, and the potential for an interaction between these key nutrients should be considered in future experimental work.
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Effect of omega-3 supplementation on lipid profile in children and adolescents: a systematic review and meta-analysis of randomized clinical trials.
Khorshidi, M, Hazaveh, ZS, Alimohammadi-Kamalabadi, M, Jamshidi, S, Moghaddam, OM, Olang, B, Hatefi, S, Hosseini, A, Jamilian, P, Zarezadeh, M, et al
Nutrition journal. 2023;22(1):9
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Dyslipidaemia is considered as a substantial risk factor for cardiovascular disease (CVD). It is characterised by increased levels of triglyceride and low-density lipoprotein (LDL) and decreased levels of high-density lipoprotein (HDL). Consumption of omega-3 supplements play an important role in reduction of CVD events and its associated mortality by ameliorating lipid profile via lowering triglyceride levels. The aim of this study was to evaluate the effect of omega 3 supplementation on lipid profile in children and adolescents. This study is a systematic review and meta-analysis of fourteen studies. Three trials out of 14 had cross-over design, while others were parallel randomised trials. Results show that omega-3 supplementation may exert therapeutic effects on triglyceride (TG) levels, however, there weren’t any remarkable effects on HDL, LDL, and total cholesterol status. The subgroup analysis showed an improvement in TG levels in studies conducted on participants ≤13 years old and those with hypertriglyceridemia. Furthermore, due to meta-regression results, the omega-3 supplementation improved HDL levels when administered with longer duration. Authors conclude that omega-3 supplementation may have favourable hypolipidemic effects through reduction of TG levels. Additionally, clinical trials with longer duration of intervention and appropriate designs are recommended for younger children and those with hypertriglyceridemia.
Abstract
PURPOSE Dyslipidemia is considered as a known risk factor for cardiovascular disease. Yet various trials with wide ranges of doses and durations have reported contradictory results. We undertook this meta-analysis of randomized controlled trials (RCTs) to determine whether omega-3 supplementation can affect lipid profile in children and adolescents. METHODS Cochrane Library, Embase, PubMed, and Scopus databases were searched up to March 2021. Meta-analysis was performed using random-effect method. Effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI). Heterogeneity was assessed using the I2 index. In order to identification of potential sources of heterogeneity, predefined subgroup and meta-regression analysis was conducted. RESULTS A total of 14 RCTs with 15 data sets were included. Based on the combination of effect sizes, there was a significant reduction in TG levels (WMD: -15.71 mg/dl, 95% CI: -25.76 to -5.65, P=0.002), with remarkable heterogeneity (I2=88.3%, P<0.001). However, subgroup analysis revealed that omega-3 supplementation significantly decreased TG only in studies conducted on participants ≤13 years old (WMD=-25.09, 95% CI: -43.29 to -6.90, P=0.007), (I2=84.6%, P<0.001) and those with hypertriglyceridemia (WMD=-28.26, 95% CI: -39.12 to -17.41, P<0.001), (I2=0.0%, P=0.934). Omega-3 supplementation had no significant effect on total cholesterol, HDL, and LDL levels. Also, results of nonlinear analysis showed significant effect of treatment duration on HDL status (Pnon-linearity=0.047). CONCLUSION Omega-3 supplementation may significantly reduce TG levels in younger children and those with hypertriglyceridemia. Also, based on the HDL-related results, clinical trials with longer duration of intervention are recommended in this population.
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The Effect of Walnut Intake on Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Alshahrani, SM, Mashat, RM, Almutairi, D, Mathkour, A, Alqahtani, SS, Alasmari, A, Alzahrani, AH, Ayed, R, Asiri, MY, Elsherif, A, et al
Nutrients. 2022;14(21)
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The prevalence of cardiovascular disease increases as the modifiable risk factors increase, such as metabolic syndrome, obesity, type 2 diabetes, dyslipidaemia, and high blood pressure. Walnuts are a rich source of anti-inflammatory polyunsaturated fatty acids and omega-3 fatty acids. Walnuts are also known for their antioxidant properties and have been found to improve dyslipidaemia by reducing total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c). This systematic review and meta-analysis of thirteen randomised controlled trials evaluated the effects of walnut intake on lipid profile. Most of the included studies used walnut dosage ranging from 15 g to 99 g/day for six to sixteen weeks of intervention. The results of this systematic review and meta-analysis showed significant improvements in TC, LDL-c, and triglyceride (TG) levels. Subgroup analysis revealed greater improvement in TC, LDL-c, and TG in overweight and other comorbidities but had normal levels of TC and LDL-C. Additionally, female participants showed greater improvements in TG levels, followed by the walnut intervention. Intervention duration also affected the beneficial effect of the walnut intervention. Further robust studies are required to determine the effects of walnut intake on cardiovascular disease risk reduction due to the high heterogeneity between the included studies. However, healthcare professionals can use the results of this research to understand the benefits of including walnuts as part of a healthy diet and their impact on reducing dyslipidaemia.
Abstract
Cardiovascular diseases (CVD) are the leading causes of death worldwide. Dyslipidemia is a cardiometabolic risk factor of CVD, yet it can be modifiable. Walnuts have been suggested as a dietary intervention to improve the lipid profile. Therefore, we reviewed the literature to assess the evidence linking walnut intake to the improvement of blood lipids, including total cholesterol (TC), low-density lipoprotein (LDL-C) cholesterol, high-density lipoprotein (HDL-C) cholesterol, and triglycerides (TG). PubMed and Embase databases were searched from 2010 up to March 2022. We limited our search to randomized controlled trials conducted on humans and published in English during the specified period. Cochrane's risk of bias tool for interventional studies was used. A random-effects model was used for the meta-analysis, and weighted mean differences were obtained (WMD) Thirteen trials from the U.S., Europe, and Asia were included. Walnut intake was associated with significant reductions in TC (WMD: -8.58 mg/dL), LDL-C (WMD: -5.68 mg/dL), and TG (WMD: -10.94 mg/dL). Walnut consumption was not associated with HDL-C. Subgroup analysis showed that overweight/obese and those with comorbidities had more lipid improvement. A longer trial duration did result in further improvements. However, our results may be prone to bias due to extraneous confounding factors. Additionally, levels of heterogeneity were considerable for some outcomes of interest. Results from this meta-analysis provide evidence for the health benefits of walnuts on blood lipids. Walnuts possibly reduce the risk of CVD; thus, they can be successfully added to a dietary pattern to enhance health benefits.
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Effects of camelina oil supplementation on lipid profile and glycemic control: a systematic review and dose‒response meta-analysis of randomized clinical trials.
Jalili, C, Talebi, S, Mehrabani, S, Bagheri, R, Wong, A, Amirian, P, Zarpoosh, M, Ghoreishy, SM, Kermani, MAH, Moradi, S
Lipids in health and disease. 2022;21(1):132
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Research indicates that alpha-linolenic acid (ALA) can reduce the risk of cardiovascular disease by improving blood lipids, blood pressure, and haemostatic factors, among others. Camelina oil, considered a good source of ALA compared to other edible oils, is one of the richest dietary sources of omega-3 fatty acids, with a polyunsaturated fatty acid content over 50%. The aim of this study was to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycaemic control in human studies. This study is a systematic review and meta-analysis of seven randomised controlled trials with a total of 428 individuals (202 participants in the COS group and 226 in the control group). Results did not show any affects of COS on lipid profile and glycaemic indices compared with placebo intake. However, subgroup analysis showed that COS for more than 8 weeks and at a dose lower than 30g/d could decrease total cholesterol. Authors conclude that COS may be a beneficial nonpharmacological strategy for the improvement of this lipid marker. However, further studies are required to confirm the findings of this study.
Abstract
BACKGROUND This systematic review and dose-response meta-analysis of published randomized controlled trials (RCTs) was conducted to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycemic indices. METHODS Relevant RCTs were selected by searching the ISI Web of Science, PubMed, and Scopus databases up to July 1, 2022. RTCs with an intervention duration of less than 2 weeks, without a placebo group, and those that used COS in combination with another supplement were excluded. Weighted mean differences and 95% confidence intervals were pooled by applying a random-effects model, while validated methods examined sensitivity analyses, heterogeneity, and publication bias. RESULTS Seven eligible RCTs, including 428 individuals, were selected. The pooled analysis revealed that COS significantly improved total cholesterol in studies lasting more than 8 weeks and utilizing dosages lower than 30 g/d compared to the placebo group. The results of fractional polynomial modeling indicated that there were nonlinear dose-response relations between the dose of COS and absolute mean differences in low-density cholesterol, high-density cholesterol, and total cholesterol, but not triglycerides. It appears that the greatest effect of COS oil occurs at the dosage of 20 g/day. CONCLUSION The present meta-analysis indicates that COS may reduce cardiovascular disease risk by improving lipid profile markers. Based on the results of this study, COS at dosages lower than 30 g/d may be a beneficial nonpharmacological strategy for lipid control. Further RCTs with longer COS durations are warranted to expand on these results.
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Impact of α-Linolenic Acid, the Vegetable ω-3 Fatty Acid, on Cardiovascular Disease and Cognition.
Sala-Vila, A, Fleming, J, Kris-Etherton, P, Ros, E
Advances in nutrition (Bethesda, Md.). 2022;13(5):1584-1602
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α-Linolenic acid (ALA) is an omega-3 fatty acid found in seeds and nuts such as flaxseeds, chia seeds, and walnuts and in oils such as canola oil, soybean oil, flaxseed oil and walnut oil. It has been shown to reduce the risk of coronary heart disease and cardiovascular disease. This meta-analysis examined the results of various studies, including epidemiologic studies, randomized controlled trials, and systematic reviews, to evaluate the beneficial effects of ALA in improving cognitive function and reducing the risk of cardiovascular disease and coronary heart disease. The included studies showed a correlation between ALA intake and a decreased risk of cardiovascular disease and coronary heart disease, possibly due to ALA's anti-inflammatory properties, as well as its ability to reduce total cholesterol, LDL cholesterol, triglycerides, and blood pressure. The analysis also found that ALA intake may reduce the risk of type 2 diabetes and cognitive impairment. Healthcare professionals can leverage the findings of this analysis to educate individuals about the benefits of dietary ALA in improving cardiovascular and cognitive outcomes. However, further studies are necessary to establish definitive conclusions and determine therapeutic dosage.
Abstract
Given the evidence of the health benefits of plant-based diets and long-chain n-3 (ω-3) fatty acids, there is keen interest in better understanding the role of α-linolenic acid (ALA), a plant-derived n-3 fatty acid, on cardiometabolic diseases and cognition. There is increasing evidence for ALA largely based on its major food sources (i.e., walnuts and flaxseed); however, this lags behind our understanding of long-chain n-3 fatty acids. Meta-analyses of observational studies have shown that increasing dietary ALA is associated with a 10% lower risk of total cardiovascular disease and a 20% reduced risk of fatal coronary heart disease. Three randomized controlled trials (RCTs) [AlphaOmega trial, Prevención con Dieta Mediterránea (PREDIMED) trial, and Lyon Diet Heart Study] all showed benefits of diets high in ALA on cardiovascular-related outcomes, but the AlphaOmega trial, designed to specifically evaluate ALA effects, only showed a trend for benefit. RCTs have shown that dietary ALA reduced total cholesterol, LDL cholesterol, triglycerides, and blood pressure, and epidemiologic studies and some trials also have shown an anti-inflammatory effect of ALA, which collectively account for, in part, the cardiovascular benefits of ALA. A meta-analysis reported a trend toward diabetes risk reduction with both dietary and biomarker ALA. For metabolic syndrome and obesity, the evidence for ALA benefits is inconclusive. The role of ALA in cognition is in the early stages but shows promising evidence of counteracting cognitive impairment. Much has been learned about the health benefits of ALA and with additional research we will be better positioned to make strong evidence-based dietary recommendations for the reduction of many chronic diseases.
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Effects of Omega-3 Fatty Acids on Muscle Mass, Muscle Strength and Muscle Performance among the Elderly: A Meta-Analysis.
Huang, YH, Chiu, WC, Hsu, YP, Lo, YL, Wang, YH
Nutrients. 2020;12(12)
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Age-related musculoskeletal decline presents a significant risk for falls in the elderly. Sarcopenia (a loss of skeletal muscle mass and function) is common with advancing age. Physical exercise and nutritional supplementation are currently recommended as preventive measures against the loss of muscle mass, muscle strength, or physical performance. The aim of this study was to assess the probable effects of increasing n-3 PUFAs (through supplementation or dietary ingestion) on key skeletal muscle outcomes in adults aged 60 years or older. This study is a systematic review of twelve randomised controlled trials (692 participants) and meta-analysis of ten out of the twelve studies (552 participants). Results show that omega 3 polyunsaturated fatty acids (n-3 PUFAs) supplementation: - was associated with an increase in muscle mass by ~0.33 kg for the elderly, especially when more than 2 g/day of n-3 PUFAs was given. - did not elicit greater handgrip strength or one-repetition maximum strength of the leg. - slightly enhanced performance in the timed up and go test compared to that for the controls and facilitated a faster walking speed when administered for more than 24 weeks. Authors conclude that the appropriate supplementation of n-3 PUFAs may have benefits on muscle mass and performances among the elderly.
Abstract
There is increasing evidence showing the role of fatty acids and their derived lipid intermediates in the regulation of skeletal muscle mass synthesis and function. However, the role of omega-3 fatty acids remains unclear. Therefore, we conducted a meta-analysis to evaluate the potential effects of omega-3 fatty acids on sarcopenia-related performances among the elderly. Eligible literature and reports of randomized controlled trials were comprehensively searched from the PubMed, Cochrane Library, ClinicalTrials.gov, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases until July 2018. A total of 10 articles were available for the meta-analysis. There were minor benefits for muscle mass gain (0.33 kg; 95% CI: 0.05, 0.62) and timed up and go performance (-0.30 s; 95% CI: -0.43, -0.17). Subgroup analyses regarding muscle mass and walk speed indicated that omega-3 fatty acid supplements at more than 2 g/day may contribute to muscle mass gain (0.67 kg; 95% CI: 0.16, 1.18) and improve walking speed, especially for those receiving more than 6 months of intervention (1.78 m/sec; 95% CI: 1.38, 2.17). Our findings provide some insight into the effects of omega-3 fatty acids on muscle mass, especially for those taking supplements at more than 2 g/day. We also observed that a long period of omega-3 fatty acids supplementation may improve walking speed.
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Effects of fish oil supplement on psoriasis: a meta-analysis of randomized controlled trials.
Yang, SJ, Chi, CC
BMC complementary and alternative medicine. 2019;19(1):354
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Psoriasis is a chronic inflammatory dermatosis which has substantial negative impact on affected patient’s quality of life. The aim of this study was to systemically assess the evidence on the effects of fish oil supplement in treating psoriasis. This study is a systematic review and meta-analysis of thirteen randomized controlled trials with 625 participants. Results demonstrate that fish oil supplement did not significantly reduce the severity of psoriasis. Authors conclude that there is no consistent evidence supporting the use of fish oil supplement in treating psoriasis.
Abstract
BACKGROUND Fish oils, which contain omega-3 polyunsaturated fatty acids as the active ingredients, possess anti-inflammatory activities and may have therapeutic potential in diseases with an inflammatory etiology. Fish oil supplement has been advocated for treating psoriasis which is a chronic inflammatory dermatosis. OBJECTIVE We aimed to investigate the effects of fish oil supplement on psoriasis. METHODS We searched CENTRAL, Embase and MEDLINE on 24 January 2018 for randomized control trials (RCTs) on the effects of fish oil supplement in treating psoriasis. The Cochrane Collaboration's tool was used to assess the risk of bias of included RCTs. We performed a random-effects model meta-analysis to obtain the pooled treatment effect estimates. RESULTS We included 13 RCTs with 625 participants. Three RCTs involving 337 participants provided usable data for meta-analysis. Fish oil supplement did not significantly reduce the severity of psoriasis when assessed by Psoriasis Area and Severity Index score (mean difference - 0.28; 95% confidence interval - 1.74 to 1.19). CONCLUSION The current evidence does not support the use of fish oil supplement in treating psoriasis.
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Immunonutrition for acute respiratory distress syndrome (ARDS) in adults.
Dushianthan, A, Cusack, R, Burgess, VA, Grocott, MP, Calder, PC
The Cochrane database of systematic reviews. 2019;1:CD012041
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Acute respiratory distress syndrome (ARDS) is a life-threatening condition wherein the lungs are inflamed (irritated) and damaged. The aim of this study was to systematically review and critically appraise available evidence on the effects of immunonutrition compared to standard non-immunonutrition formula feeding on mechanically ventilated adults (aged 18 years or older) with acute respiratory distress syndrome (ARDS). This meta-analysis included a total of 13 publications reporting 10 randomised controlled trials. Results indicate that no clinical trials were identified with any other specific immunonutrition intervention for this patient population. Furthermore, evidence is inconclusive to whether this type of nutrition improves the primary outcome of all-cause mortality at the longest period reported. Authors conclude that no mortality benefit is derived from the use of omega-3 fatty acids and/or antioxidants in ARDS.
Abstract
BACKGROUND Acute respiratory distress syndrome (ARDS) is an overwhelming systemic inflammatory process associated with significant morbidity and mortality. Pharmacotherapies that moderate inflammation in ARDS are lacking. Several trials have evaluated the effects of pharmaconutrients, given as part of a feeding formula or as a nutritional supplement, on clinical outcomes in critical illness and ARDS. OBJECTIVES To systematically review and critically appraise available evidence on the effects of immunonutrition compared to standard non-immunonutrition formula feeding on mechanically ventilated adults (aged 18 years or older) with acute respiratory distress syndrome (ARDS). SEARCH METHODS We searched MEDLINE, Embase, CENTRAL, conference proceedings, and trial registries for appropriate studies up to 25 April 2018. We checked the references from published studies and reviews on this topic for potentially eligible studies. SELECTION CRITERIA We included all randomized controlled trials (RCTs) and quasi-randomized controlled trials comparing immunonutrition versus a control or placebo nutritional formula in adults (aged 18 years or older) with ARDS, as defined by the Berlin definition of ARDS or, for older studies, by the American-European Consensus Criteria for both ARDS and acute lung injury. DATA COLLECTION AND ANALYSIS Two review authors independently assessed the quality of studies and extracted data from the included trials. We sought additional information from study authors. We performed statistical analysis according to Cochrane methodological standards. Our primary outcome was all-cause mortality. Secondary outcomes included intensive care unit (ICU) length of stay, ventilator days, indices of oxygenation, cardiac adverse events, gastrointestinal adverse events, and total number of adverse events. We used GRADE to assess the quality of evidence for each outcome. MAIN RESULTS We identified 10 randomized controlled trials with 1015 participants. All studies compared an enteral formula or additional supplemental omega-3 fatty acids (i.e. eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)), gamma-linolenic acid (GLA), and antioxidants. We assessed some of the included studies as having high risk of bias due to methodological shortcomings. Studies were heterogenous in nature and varied in several ways, including type and duration of interventions given, calorific targets, and reported outcomes. All studies reported mortality. For the primary outcome, study authors reported no differences in all-cause mortality (longest period reported) with the use of an immunonutrition enteral formula or additional supplements of omega-3 fatty acids and antioxidants (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.59 to 1.07; participants = 1015; studies = 10; low-quality evidence).For secondary outcomes, we are uncertain whether immunonutrition with omega-3 fatty acids and antioxidants reduces ICU length of stay (mean difference (MD) -3.09 days. 95% CI -5.19 to -0.99; participants = 639; studies = 8; very low-quality evidence) and ventilator days (MD -2.24 days, 95% CI -3.77 to -0.71; participants = 581; studies = 7; very low-quality evidence). We are also uncertain whether omega-3 fatty acids and antioxidants improve oxygenation, defined as ratio of partial pressure of arterial oxygen (PaO₂) to fraction of inspired oxygen (FiO₂), at day 4 (MD 39 mmHg, 95% CI 10.75 to 67.02; participants = 676; studies = 8), or whether they increase adverse events such as cardiac events (RR 0.87, 95% CI 0.09 to 8.46; participants = 339; studies = 3; very low-quality evidence), gastrointestinal events (RR 1.11, 95% CI 0.71 to 1.75; participants = 427; studies = 4; very low-quality evidence), or total adverse events (RR 0.91, 95% CI 0.67 to 1.23; participants = 517; studies = 5; very low-quality evidence). AUTHORS' CONCLUSIONS This meta-analysis of 10 studies of varying quality examined effects of omega-3 fatty acids and/or antioxidants in adults with ARDS. This intervention may produce little or no difference in all-cause mortality between groups. We are uncertain whether immunonutrition with omega-3 fatty acids and antioxidants improves the duration of ventilator days and ICU length of stay or oxygenation at day 4 due to the very low quality of evidence. Adverse events associated with immunonutrition are also uncertain, as confidence intervals include the potential for increased cardiac, gastrointestinal, and total adverse events.