n-3 polyunsaturated fatty acids and coronary thrombosis

Different frying processes stimulate lipid peroxidation and promote changes in the composition of cholesterol, free fatty acids and triglycerides in the commercial clam’s tissues Venerupis decussata

This investigation was aimed to assess and evaluate the effect of frying process with three different oils (corn, olive and margarine) on fatty acids and lipid classes’ composition of clam and their impact on the nutritional value and tissues quality. The results indicated that the contents of saturated, monounsaturated and polyunsaturated fatty acids varied significantly in fried clams and frying oil. Our data demonstrated that all lipid classes’ contents increased significantly after all frying processes. It was concluded that the frying process decreased the n-3/n-6 and DHA+EPA and increased the levels of atherogenic; thrombogenic indices. Additionally, these culinary processes promoted lipid peroxidation through the enhancement of TBARs, PV and FFA. These changes were more significant and intensive after frying with margarine and corn oils followed by virgin olive oil. These results suggest that clam fried with olive oil can be classified as highly nutritive in regard to its lipid content, major fatty acid profile; and nutritional value.

Microbial sources of polyunsaturated fatty acids (PUFAs) and the prospect of organic residues and wastes as growth media for PUFA-producing microorganisms

The discovery of non-fish sources of polyunsaturated fatty acids (PUFAs) is of great biotechnological importance. Although various oleaginous microalgae and fungi are able of accumulating storage lipids (single cell oils - SCOs) containing PUFAs, the industrial applications utilizing these organisms are rather limited due to the high-fermentation cost. However, combining SCO production with other biotechnological applications, including waste and by-product valorization, can overcome this difficulty. In the current review, we present the major sources of fungi (i.e. members of Mucoromycota, fungoid-like Thraustochytrids and genetically modified strains of Yarrowia lipolytica) and microalgae (e.g. Isochrysis, NannochloropsisandTetraselmis) that have come recently to the forefront due to their ability to produce PUFAs. Approaches adopted in order to increase PUFA productivity and the potential of using various residues, such as agro-industrial, food and aquaculture wastes as fermentation substrates for SCO production have been considered and discussed. We concluded that several organic residues can be utilized as feedstock in the SCO production increasing the competitiveness of oleaginous organisms against conventional PUFA producers.

Lifestyle, Inflammation, and Vascular Calcification in Kidney Transplant Recipients: Perspectives on Long-Term Outcomes

After decades of pioneering and improvement, kidney transplantation is now the renal replacement therapy of choice for most patients with end-stage kidney disease (ESKD). Where focus has traditionally been on surgical techniques and immunosuppressive treatment with prevention of rejection and infection in relation to short-term outcomes, nowadays, so many people are long-living with a transplanted kidney that lifestyle, including diet and exposure to toxic contaminants, also becomes of importance for the kidney transplantation field. Beyond hazards of immunological nature, a systematic assessment of potentially modifiable-yet rather overlooked-risk factors for late graft failure and excess cardiovascular risk may reveal novel targets for clinical intervention to optimize long-term health and downturn current rates of premature death of kidney transplant recipients (KTR). It should also be realized that while kidney transplantation aims to restore kidney function, it incompletely mitigates mechanisms of disease such as chronic low-grade inflammation with persistent redox imbalance and deregulated mineral and bone metabolism. While the vicious circle between inflammation and oxidative stress as common final pathway of a multitude of insults plays an established pathological role in native chronic kidney disease, its characterization post-kidney transplant remains less than satisfactory. Next to chronic inflammatory status, markedly accelerated vascular calcification persists after kidney transplantation and is likewise suggested a major independent mechanism, whose mitigation may counterbalance the excess risk of cardiovascular disease post-kidney transplant. Hereby, we first discuss modifiable dietary elements and toxic environmental contaminants that may explain increased risk of cardiovascular mortality and late graft failure in KTR. Next, we specify laboratory and clinical readouts, with a postulated role within persisting mechanisms of disease post-kidney transplantation (i.e., inflammation and redox imbalance and vascular calcification), as potential non-traditional risk factors for adverse long-term outcomes in KTR. Reflection on these current research opportunities is warranted among the research and clinical kidney transplantation community.

Dietary and Pharmacological Fatty Acids and Cardiovascular Health

CONTEXT

The effects of dietary intake of different fatty acids and pharmacological use of fatty acids, specifically long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), on cardiovascular health and atherosclerotic cardiovascular disease (ASCVD) prevention have been examined in a large number of observational studies and clinical trials. This review summarizes recent data and discusses potential mechanisms.

EVIDENCE ACQUISITION

The review is based on the authors' knowledge of the field supplemented by a PubMed search using the terms seafood, fish oil, saturated fatty acids, omega-3 fatty acids, eicosapentaenoic acid, docosahexaenoic acid, polyunsaturated fatty acids, monounsaturated fatty acids, and ASCVD.

EVIDENCE SYNTHESIS

We mainly discuss the recent clinical trials that examine the effects of different types of dietary fatty acids and pharmacological use of n-3 PUFA products on ASCVD prevention and the potential mechanisms.

CONCLUSIONS

While replacement of dietary saturated fat with unsaturated fat, polyunsaturated fat in particular, or intake of LC n-3 PUFA-rich seafood has generally shown benefit for ASCVD prevention and is recommended for cardiovascular benefits, data on effects of n-3 PUFA products on ASCVD health are inconsistent. However, recent clinical trials support benefits of prescription EPA in ASCVD prevention. n-3 PUFAs may contribute to ASCVD prevention through multiple mechanisms, including lowering plasma triglyceride levels, anti-inflammatory effects, antithrombotic effects, and effects on endothelial function.

Plasma Phospholipid Fatty Acids, FADS1 and Risk of 15 Cardiovascular Diseases: A Mendelian Randomisation Study

Whether circulating fatty acids (FAs) play a causal role in the development of cardiovascular disease (CVD) remains unclear. We conducted a Mendelian randomisation study to explore the associations between plasma phospholipid FA levels and 15 CVDs. Summary-level data from the CARDIoGRAMplusC4D, MEGASTROKE, and Atrial Fibrillation consortia and UK Biobank were used. Sixteen single-nucleotide polymorphisms (SNPs) associated with ten plasma FAs were used as instrumental variables. SNPs in or close to the FADS1 gene were associated with most FAs. We performed a secondary analysis of the association between a functional variant (rs174547) in FADS1, which encodes ?5-desaturase (a key enzyme in the endogenous FA synthesis), and CVD. Genetic predisposition to higher plasma α-linolenic, linoleic, and oleic acid levels was associated with lower odds of large-artery stroke and venous thromboembolism, whereas higher arachidonic and stearic acid levels were associated with higher odds of these two CVDs. The associations were driven by SNPs in or close to FADS1. In the secondary analysis, the minor allele of rs174547 in FADS1 was associated with significantly lower odds of any ischemic stroke, large-artery stroke, and venous thromboembolism and showed suggestive evidence of inverse association with coronary artery disease, abdominal aortic aneurysm and aortic valve stenosis. Genetically higher plasma α-linolenic, linoleic, and oleic acid levels are inversely associated with large-artery stroke and venous thromboembolism, whereas arachidonic and stearic acid levels are positively associated with these CVDs. The associations were driven by FADS1, which was also associated with other CVDs.

A Dietary Pattern Derived from Reduced Rank Regression and Fatty Acid Biomarkers Is Associated with Lower Risk of Type 2 Diabetes and Coronary Artery Disease in Chinese Adults

BACKGROUND

Combinations of circulating fatty acids may affect the risk of type 2 diabetes (T2D) and coronary artery disease (CAD). No previous studies have identified a dietary pattern predicting fatty acid profiles using reduced rank regression (RRR) and evaluated its associations with the risk of T2D and CAD.

OBJECTIVE

The aim of this study was to derive a dietary pattern to explain variation in plasma fatty acid concentrations using RRR and evaluate these in relation to risk of T2D and CAD.

METHODS

We derived a dietary pattern using fatty acid concentrations from 711 controls of a nested case-control study in the Singapore Chinese Health Study using RRR with 36 food and beverages as predictors and 19 fatty acid biomarkers as responses. Dietary pattern scores were then calculated for the full cohort of men and women (mean age: 56 y). We followed up 45,411 and 58,065 participants for incident T2D and CAD mortality, respectively. Multivariable Cox regression models were used to estimate HRs and 95% CIs.

RESULTS

We identified a dietary pattern high in soy, vegetables, fruits, tea, tomato products, bread, fish, margarine and dairy, and low in rice, red meat, coffee, alcohol, sugar-sweetened beverages, and eggs. This pattern predicted higher circulating n-3 (ω-3) PUFAs (18:3n-3, 20:3n-3, 20:5n-3), odd-chain fatty acids (15:0, 17:0), 18:2n-6 and 20:1, and lower 20:4n-6 and 16:1. During a mean follow-up of 11 y and 19 y, 5207 T2D and 3016 CAD mortality events, respectively, were identified. Higher dietary pattern scores were associated with a lower risk of T2D [multivariable-adjusted HR comparing extreme quintiles, 0.86 (95% CI: 0.79, 0.95); P-trend <0.001] and CAD mortality [HR, 0.76 (95% CI: 0.68, 0.86); P-trend <0.001].

CONCLUSIONS

Dietary patterns reflecting higher circulating n-3 PUFAs, odd-chain fatty acids, and linoleic acid may be associated with lower T2D and CAD risk in Chinese adults. This trial was registered at www.clinicaltrials.gov as NCT03356340.

Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits

Omega-3 polyunsaturated fatty acids (PUFAs) include α-linolenic acid (ALA; 18:3 ω-3), stearidonic acid (SDA; 18:4 ω-3), eicosapentaenoic acid (EPA; 20:5 ω-3), docosapentaenoic acid (DPA; 22:5 ω-3), and docosahexaenoic acid (DHA; 22:6 ω-3). In the past few decades, many epidemiological studies have been conducted on the myriad health benefits of omega-3 PUFAs. In this review, we summarized the structural features, properties, dietary sources, metabolism, and bioavailability of omega-3 PUFAs and their effects on cardiovascular disease, diabetes, cancer, Alzheimer's disease, dementia, depression, visual and neurological development, and maternal and child health. Even though many health benefits of omega-3 PUFAs have been reported in the literature, there are also some controversies about their efficacy and certain benefits to human health.

Food group consumption in an Italian population using the updated food classification system FoodEx2: Results from the Italian Nutrition & HEalth Survey (INHES) study

BACKGROUND AND AIM

Dietary habits evolve over time, being influenced by many factors and complex interactions. This work aimed at evaluating the updated information on food group consumption in Italy.

METHODS AND RESULTS

A total of 8944 (4768 women and 4176 men) participants aged >18 years from all over Italy recruited in 2010-13 (Italian Nutrition & HEalth Survey, INHES) was analyzed. The recruitment was performed using computer-assisted-telephone-interviewing and one-day 24-h dietary recall retrieved from all participants. The updated, second version, of FoodEx2 food classification system was applied to extract data on food group consumption. The participation rate was 53%; 6.2% of the participants declared to follow a special diet, the most prevalent being hypo-caloric diets (55.7% of special diets). Men compared to women presented significantly higher intakes of "grains and grain-based products", "meat and meat products", "animal and vegetable fats and oils and primary derivatives" and "alcoholic beverages" (P for all<0.001); moreover, men had lower intakes of "milk and dairy products", "water and water-based beverages" and "products for non-standard diets, food imitates and food supplements" (P for all<0.001). Differences in food group intake among age groups, geographical regions and educational level groups were also identified (P for all<0.05).

CONCLUSIONS

Data on the consumption of more than 70 food groups and sub-groups were illustrated in different strata. The present analysis could be considered as an updated source of information for future nutrition research in Italy and in the EU.

A porcine gluteus medius muscle genome-wide transcriptome analysis: dietary effects of omega-6 and omega-3 fatty acids on biological mechanisms

Background

The level of omega-6 and omega-3 polyunsaturated fatty acids can affect many cellular systems and function via nuclear receptors or the bioactive lipid regulation of gene expression. The objective of this study was to investigate changes in the muscle transcriptome and the biological functions regulated by increased consumption of omega-3 and omega-6 fatty acids in the pig gluteus medius muscle.

Results

The transcriptome of the gluteus medius muscle was studied for pigs subjected to either a control diet or a diet supplemented with linseed and rapeseed oil to increase polyunsaturated fatty acid content. Next-generation sequencing (NGS) was used to generate the muscle tissue transcriptome database pointing differentially expressed genes (DEG). Comparative expression analyses identified 749 genes significantly differing at least in the twofold of change between two groups of animals fed with divergent level of omega-3 and omega-6 fatty acids. The expression of 219 genes was upregulated, and the expression of 530 genes was downregulated in the group of pigs supplemented with omega-3 and omega-6 fatty acids in relation to control group pigs. Results of RNA-seq indicated a role of fatty acid in the regulation of the expression of genes which are essential for muscle tissue development and functioning. Functional analysis revealed that the identified genes were important for a number of biological processes including inflammatory response, signaling, lipid metabolism, and homeostasis.

Conclusions

Summarizing, obtained results provide strong evidence that omega-6 and omega-3 fatty acids regulate fundamental metabolic processes in muscle tissue development and functioning.

Electronic supplementary material

The online version of this article (doi:10.1186/s12263-017-0552-8) contains supplementary material, which is available to authorized users.

Olive Oil-Based Lipid Emulsions Do Not Influence Platelet Receptor Expression in Comparison to Medium and Long Chain Triglycerides In vitro

Lipid emulsions influence platelet aggregation and receptor expression. However, the effect on platelet function is not fully explained. Therefore, the aim of this study was to examine the influence of the lipids Lipofundin^®, Lipidem^® and ClinOleic^® on surface expressions of P-selectin, GPIb and GPIIb/IIIa on platelets in vitro. Whole blood was incubated in two different concentrations (0.06 and 0.6 mg/ml) of LCT/MCT, n-3/LCT/MCT and LCT-MUFA for 30 min, followed by activation with TRAP-6 or ADP for flow-cytometric assay. Rates of P-selectin, GPIb and GPIIb/IIIa expression were analyzed. There was a significant increase in GPIIb/IIIa- and P-selectin-expression after incubation with LCT/MCT and n-3/LCT/MCT at the concentration of 0.6 mg/ml, without and after stimulation with TRAP-6 and ADP. GPIb was significantly decreased. Accordingly, LCT-MUFA had no effect on receptor expression of platelets in vitro. We demonstrated that LCT-MUFA did not activate receptor expression of platelets whereas LCT/MCT significantly increased platelet aggregation in vitro. This finding should be noted for parenteral nutrition of intensive care patients and, in the future, might provide further insight into the pathogenic pathways of acute thromboembolic events. However, prospectively designed clinical studies are needed to support our results.

Nutraceuticals and Bioactive Components from Fish for Dyslipidemia and Cardiovascular Risk Reduction

Cardiovascular disease remains the most common health problem in developed countries, and residual risk after implementing all current therapies is still high. Permanent changes in lifestyle may be hard to achieve and people may not always be motivated enough to make the recommended modifications. Emerging research has explored the application of natural food-based strategies in disease management. In recent years, much focus has been placed on the beneficial effects of fish consumption. Many of the positive effects of fish consumption on dyslipidemia and heart diseases have been attributed to n-3 polyunsaturated fatty acids (n-3 PUFAs, i.e., EPA and DHA); however, fish is also an excellent source of protein and, recently, fish protein hydrolysates containing bioactive peptides have shown promising activities for the prevention/management of cardiovascular disease and associated health complications. The present review will focus on n-3 PUFAs and bioactive peptides effects on cardiovascular disease risk factors. Moreover, since considerable controversy exists regarding the association between n-3 PUFAs and major cardiovascular endpoints, we have also reviewed the main clinical trials supporting or not this association.

Plasma α-Linolenic and Long-Chain ω-3 Fatty Acids Are Associated with a Lower Risk of Acute Myocardial Infarction in Singapore Chinese Adults

BACKGROUND

Long-chain marine omega-3 polyunsaturated fatty acids (n-3 PUFAs) are associated with a lower risk of acute myocardial infarction (AMI), but results for plant-derived α-linolenic acid (ALA; 18:3n-3) are inconsistent.

OBJECTIVE

We aimed to examine the association between plasma n-3 PUFAs and AMI risk and to explore potential mediation by cardiovascular disease risk factors.

METHODS

A nested case-control study with 744 incident AMI cases and 744 matched controls was conducted within the Singapore Chinese Health Study for participants aged 47-83 y. Conditional logistic regression was used to calculate the multivariable ORs for AMI with and without adjustment for cardiovascular disease risk factors, including blood lipids, blood pressure, C-reactive protein, serum creatinine, and glycated hemoglobin.

RESULTS

Plasma long-chain n-3 PUFAs were associated with lower AMI risk (multivariable OR: 0.62; 95% CI: 0.41, 0.94; for the highest compared with the lowest quartile; P-trend = 0.03). This association was not substantially changed after adjustment for cardiovascular disease risk factors. Dietary intakes of fish and long-chain n-3 PUFAs were similarly inversely associated with AMI risk. Plasma ALA was marginally associated with a lower risk of AMI (multivariable OR: 0.73; 95% CI: 0.51, 1.05; P-trend = 0.07) even in persons with high plasma concentrations of long-chain n-3 PUFAs. This association became significantly weaker after adjustment for blood pressure and LDL cholesterol.

CONCLUSIONS

Plasma long-chain n-3 PUFAs are associated with a lower risk of AMI in this Asian population. Plasma ALA may be marginally associated with reduced AMI risk, even in persons with high concentrations of long-chain n-3 PUFAs, and this association may be partially mediated by lower blood pressure and LDL cholesterol.

Relation of fish oil supplementation to markers of atherothrombotic risk in patients with cardiovascular disease not receiving lipid-lowering therapy

Fish oil supplementation (FOS) is known to have cardiovascular benefits. However, the effects of FOS on thrombosis are incompletely understood. We sought to determine if the use of FOS is associated with lower indices of atherothrombotic risk in patients with suspected coronary artery disease (sCAD). This is a subgroup analysis of consecutive patients with sCAD (n=600) enrolled in the Multi-Analyte, Thrombogenic, and Genetic Markers of Atherosclerosis study. Patients on FOS were compared with patients not on FOS. Lipid profile was determined by vertical density gradient ultracentrifugation (n=520), eicosapentaenoic acid+docosahexaenoic acid was measured by gas chromatography (n=437), and AtherOx testing was performed by immunoassay (n=343). Thromboelastography (n=419), ADP- and collagen-induced platelet aggregation (n=137), and urinary 11-dehydrothromboxane B2 levels (n=259) were performed immediately before elective coronary angiography. In the total population, FOS was associated with higher eicosapentaenoic acid+docosahexaenoic acid content (p<0.001), lower triglycerides (p=0.04), total very low-density lipoprotein cholesterol (p=0.002), intermediate-density lipoprotein cholesterol (p=0.02), and AtherOx levels (p=0.02) but not in patients on lipid-lowering therapy. Patients not on lipid-lowering therapy taking FOS had lower very low-density lipoprotein cholesterol, intermediate-density lipoprotein cholesterol, remnant lipoproteins, triglycerides, low-density lipoprotein cholesterol, AtherOx levels, collagen-induced platelet aggregation, thrombin-induced platelet-fibrin clot strength, and shear elasticity (p<0.03 for all). In clopidogrel-treated patients, there was no difference in ADP-induced aggregation between FOS groups. Patients on FOS had lower urinary 11-dehydrothromboxane B2 levels regardless of lipid-lowering therapy (p<0.04). In conclusion, the findings of this study support the potential benefit of FOS for atherothrombotic risk reduction in sCAD with the greatest benefit in patients not receiving lipid-lowering therapy. Future prospective studies to compare FOS with lipid-lowering therapy and to assess the independent effects of FOS on thrombogenicity are needed.

A randomized controlled trial investigating the effects of parenteral fish oil on survival outcomes in critically ill patients with sepsis: a pilot study

INTRODUCTION

Death from sepsis in the intensive care unit (ITU) is frequently preceded by the development of multiple organ failure as a result of uncontrolled inflammation. Treatment with ω-3 has been demonstrated to attenuate the effects of uncontrolled inflammation and may be clinically beneficial.

METHOD

A randomized control trial investigating the effects of parenteral ω-3 was carried out. Consecutive patients diagnosed with sepsis were entered into the study and randomized to receive either parenteral ω-3 or standard medical care only. The primary outcome measure was a reduction in organ dysfunction using the Sequential Organ Failure Assessment (SOFA) score as a surrogate marker. The secondary outcome measures were mortality, length of stay, mean C-reactive protein (CRP), and days free of organ dysfunction/failure.

RESULTS

Sixty patients were included in the study. The baseline demographics were matched for the two cohorts. Patients treated with parenteral ω-3 were associated with a significant reduction in new organ dysfunction (Δ-SOFA 2.2 ± 2.2 vs. 1.0 ± 1.5, P = .005 and maximum-SOFA 10.1 ± 4.2 vs. 8.1 ± 3.2, P = .041) and maximum CRP (186.7 ± 78 vs. 141.5 ± 62.6, P = .019). There was no significant reduction in the length of stay between cohorts. Patients treated with ω-3 in the strata of less severe sepsis had a significant reduction in mortality (P = .042).

CONCLUSION

The treatment of critically ill septic patients with parenteral ω-3 is safe. It is associated with a significant reduction in organ dysfunction. It may be associated with a reduction in mortality in patients with less severe sepsis.

Omega-3 fatty acids and cardiovascular disease: epidemiology and effects on cardiometabolic risk factors

Clinical and epidemiological studies provide support that the polyunsaturated omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid from fish and fish oils are cardioprotective, particularly in the setting of secondary prevention.

Dietary n-3 PUFA and CVD: a review of the evidence

Many clinical and epidemiological studies have shown that the polyunsaturated n-3 fatty acids EPA and DHA from fish and fish oils, provide cardiovascular protection, particularly in the setting of secondary prevention. n-3 Fatty acids beneficially influence a number of cardiometabolic risk factors including blood pressure, cardiac function, vascular reactivity and lipids, as well as having anti-platelet, anti-inflammatory and anti-oxidative actions. They do not appear to adversely interact with other medications such as statins and other lipid-lowering drugs or antihypertensive medications. n-3 Fatty acids have gained widespread usage by general practitioners and clinicians in a number of clinical settings such as pregnancy and infant development, secondary prevention in CHD patients, treatment of dyslipidaemias and haemodialysis patients. Small doses are achievable with consumption of two to three oily fish meals per week or via purified encapsulated preparations now readily available. n-3 Fatty acids, particularly when consumed as fish, should be considered an important component of a healthy diet. The present paper reviews the effects of n-3 fatty acids on cardiometabolic risk factors, concentrating particularly on the evidence from randomised controlled studies in human subjects.

Effect of ω-3 fatty acid supplementation on endothelial function, endogenous fibrinolysis and platelet activation in patients with a previous myocardial infarction: a randomised controlled trial

OBJECTIVE

The mechanisms through which ω-3 fatty acids reduce adverse cardiac events remain uncertain. We aimed to investigate the effect of ω-3 fatty acid supplementation on endothelial vasomotor function, endogenous fibrinolysis, and platelet and monocyte activation in patients with coronary heart disease.

DESIGN

Randomised, double-blind, placebo-controlled, cross-over trial.

SETTING

Academic cardiac centre.

PARTICIPANTS

20 male patients with a previous myocardial infarction.

INTERVENTION

ω-3 Fatty acid supplementation (2 g/day for 6 weeks) versus olive oil placebo.

OUTCOME MEASURES

Peripheral blood was taken for analysis of platelet and monocyte activation, and forearm blood flow (FBF) was assessed in a subset of 12 patients during intrabrachial infusions of acetylcholine, substance P and sodium nitroprusside. Stimulated plasma tissue plasminogen activator (t-PA) concentrations were measured during substance P infusion.

RESULTS

All vasodilators caused dose-dependent increases in FBF (p<0.0001). ω-3 Fatty acid supplementation did not affect endothelium-dependent vasodilation with acetylcholine and substance P compared with placebo (p=0.5 and 0.9). Substance P caused a dose-dependent increase in plasma t-PA concentrations (p<0.0001), which was not affected by ω-3 fatty acid supplementation (p=0.9). ω-3 Fatty acids did not affect platelet-monocyte aggregation, platelet P-selectin or CD40L, or monocyte CD40.

CONCLUSIONS

We have demonstrated that dietary supplementation with ω-3 fatty acids does not affect endothelial vasomotor function, endothelial t-PA release, or platelet and monocyte activation in patients with coronary heart disease. Cardiac benefits conferred by ω-3 fatty acids in coronary heart disease are unlikely to be mediated through effects on these systems.

Fish oil administration in older adults: is there potential for adverse events? A systematic review of the literature

Background

Omega-3 (n-3) fatty acid supplementation is becoming increasingly popular. However given its antithrombotic properties the potential for severe adverse events (SAE) such as bleeding has safety implications, particularly in an older adult population. A systematic review of randomized control trials (RCT) was conducted to explore the potential for SAE and non-severe adverse events (non-SAE) associated with n-3 supplementation in older adults.

Methods

A comprehensive search strategy using Medline and a variety of other electronic sources was conducted. Studies investigating the oral administration of n-3 fish oil containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or both against a placebo were sourced. The primary outcome of interest included reported SAE associated with n-3 supplementation. Chi-square analyses were conducted on the pooled aggregate of AEs.

Results

Of the 398 citations initially retrieved, a total of 10 studies involving 994 older adults aged ≥60 years were included in the review. Daily fish oil doses ranged from 0.03 g to 1.86 g EPA and/or DHA with study durations ranging from 6 to 52 weeks. No SAE were reported and there were no significant differences in the total AE rate between groups (n-3 intervention group: 53/540; 9.8%; placebo group: 28/454; 6.2%; p = 0.07). Non-SAE relating to gastrointestinal (GI) disturbances were the most commonly reported however there was no significant increase in the proportion of GI disturbances reported in participants randomized to the n-3 intervention (n-3 intervention group: 42/540 (7.8%); placebo group: 24/454 (5.3%); p = 0.18).

Conclusions

The potential for AEs appear mild-moderate at worst and are unlikely to be of clinical significance. The use of n-3 fatty acids and the potential for SAE should however be further researched to investigate whether this evidence is consistent at higher doses and in other populations. These results also highlight that well-documented data outlining the potential for SAE following n-3 supplementation are limited nor adequately reported to draw definitive conclusions concerning the safety associated with n-3 supplementation. A more rigorous and systematic approach for monitoring and recording AE data in clinical settings that involve n-3 supplementation is required.

Omega-3 Fatty acids and vitamin d in cardiology

Dietary modification and supplementation play an increasingly important role in the conservative treatment of cardiovascular disease. Current interest has focused on n-3 polyunsaturated fatty acids (PUFA) and vitamin D. Clinical trial results on this subject are contradictory in many aspects. Several studies indicate that n-3 PUFA consumption improves vascular and cardiac hemodynamics, triglycerides, and possibly endothelial function, autonomic control, inflammation, thrombosis, and arrhythmia. Experimental studies show effects on membrane structure and associated functions, ion channel properties, genetic regulation, and production of anti-inflammatory mediators. Clinical trials evaluating a possible reduction in cardiovascular disease by n-3 PUFA have shown different results. Supplementation of vitamin D is common regarding prevention and treatment of osteoporosis. But vitamin D also seems to have several effects on the cardiovascular system. Vitamin D deficiency appears to be related to an increase in parathyroid hormone levels and can predispose to essential hypertension and left ventricular hypertrophy, increased insulin resistance, and eventually to atherosclerosis and adverse cardiovascular events. Randomized prospective clinical trials are needed to determine whether vitamin D and omega-3 FA supplementation therapy should be recommended as a routine therapy for primary or secondary prevention of cardiovascular disease.

Role of Omega-3 fatty acids in preventing metabolic disturbances in patients on olanzapine plus either sodium valproate or lithium: a randomized double-blind placebo-controlled trial

Background

Metabolic and cardiovascular side effects have been noted with the use of second generation antipsychotics (SGAs) and mood stabilizers. Since Omega-3 fatty acids have been known to prevent some cardiovascular risks, this preliminary study was designed to evaluate the cardiovascular benefits of omega-3 when added to the combinations of olanzapine with mood stabilizers.

Methods

This study was a randomized, double-blind, placebo-controlled, within-subject trial in adult psychiatric patients who were receiving olanzapine combined with lithium (Li) or valproate sodium (VPA). Omega-3 as fish oil with less than 1 g/day of EPA/DHA or its placebo was added to patients’ olanzapine and mood stabilizer regimens for 6 weeks. Metabolic parameters including anthropometric variables, lipid profile, metabolic syndrome indices, C-reactive protein, fibrinogen and lipoprotein (a) [(Lp) (a)] were assessed for participants.

Results

Forty one participants completed this study; 20 patients received omega-3 and 21 patients received placebo, added to their regimen of SGA and mood stabilizer. Omega-3 addition did not modulate anthropometric, metabolic syndrome and lipid parameter changes in 6 weeks. However, fibrinogen levels significantly decreased, Lp (a) did not increase and non-high-density lipoprotein cholesterol (non-HDL-C) did not go beyond its target level after omega-3 supplementation. Additionally, a significant inter-group effect was noted for Lp(a).

Conclusions

This study suggests that use of short-term omega-3 supplementation added to a combined regimen of olanzapine and mood stabilizer may have a small modulating effect on some cardiovascular risk factors. Trials in longer periods of time and with larger number of patients are needed to further evaluate the effects of omega-3 supplements on preventing cardiovascular risk factors.

This trial is registered at irct.ir and its Identifier is as following: IRCT138712231764N1

Long chain omega-3 fatty acids and cardiovascular disease: a systematic review

Introduction: Cardiovascular disease remains the commonest health problem in developed countries, and residual risk after implementing all current therapies is still high. The use of marine omega-3 fatty acids (DHA and EPA) has been recommended to reduce cardiovascular risk by multiple mechanisms. Objectives: To update the current evidence on the influence of omega-3 on the rate of cardiovascular events. Review Methods: We used the MEDLINE and EMBASE databases to identify clinical trials and randomized controlled trials of omega-3 fatty acids (with quantified quantities) either in capsules or in dietary intake, compared to placebo or usual diet, equal to or longer than 6 months, and written in English. The primary outcome was a cardiovascular event of any kind and secondary outcomes were all-cause mortality, cardiac death and coronary events. We used RevMan 5·1 (Mantel-Haenszel method). Heterogeneity was assessed by the I2and Chi2tests. We included 21 of the 452 pre-selected studies. Results: We found an overall decrease of risk of suffering a cardiovascular event of any kind of 10 % (OR 0·90; [0·85–0·96],p = 0·001), a 9 % decrease of risk of cardiac death (OR 0·91; [0·83–0·99];p = 0·03), a decrease of coronary events (fatal and non-fatal) of 18 % (OR 0·82; [0·75–0·90];p < 1 × 10− 4), and a trend to lower total mortality (5 % reduction of risk; OR 0·95; [0·89–1·02];p = 0·15. Most of the studies analyzed included persons with high cardiovascular risk. Conclusions: marine omega-3 fatty acids are effective in preventing cardiovascular events, cardiac death and coronary events, especially in persons with high cardiovascular risk.

Omega-3 fatty acids and cardiovascular disease: effects on risk factors, molecular pathways, and clinical events

We reviewed available evidence for cardiovascular effects of n-3 polyunsaturated fatty acid (PUFA) consumption, focusing on long chain (seafood) n-3 PUFA, including their principal dietary sources, effects on physiological risk factors, potential molecular pathways and bioactive metabolites, effects on specific clinical endpoints, and existing dietary guidelines. Major dietary sources include fatty fish and other seafood. n-3 PUFA consumption lowers plasma triglycerides, resting heart rate, and blood pressure and might also improve myocardial filling and efficiency, lower inflammation, and improve vascular function. Experimental studies demonstrate direct anti-arrhythmic effects, which have been challenging to document in humans. n-3 PUFA affect a myriad of molecular pathways, including alteration of physical and chemical properties of cellular membranes, direct interaction with and modulation of membrane channels and proteins, regulation of gene expression via nuclear receptors and transcription factors, changes in eicosanoid profiles, and conversion of n-3 PUFA to bioactive metabolites. In prospective observational studies and adequately powered randomized clinical trials, benefits of n-3 PUFA seem most consistent for coronary heart disease mortality and sudden cardiac death. Potential effects on other cardiovascular outcomes are less-well-established, including conflicting evidence from observational studies and/or randomized trials for effects on nonfatal myocardial infarction, ischemic stroke, atrial fibrillation, recurrent ventricular arrhythmias, and heart failure. Research gaps include the relative importance of different physiological and molecular mechanisms, precise dose-responses of physiological and clinical effects, whether fish oil provides all the benefits of fish consumption, and clinical effects of plant-derived n-3 PUFA. Overall, current data provide strong concordant evidence that n-3 PUFA are bioactive compounds that reduce risk of cardiac death. National and international guidelines have converged on consistent recommendations for the general population to consume at least 250 mg/day of long-chain n-3 PUFA or at least 2 servings/week of oily fish.

[Critical analysis of the American Diabetes Association dietary recommendations for cardiovascular disease in diabetes mellitus]

Cardiovascular disease (CVD) is the main cause of mortality among patients with diabetes mellitus (DM), and dietary intervention is an essential measure to prevent and treat this complication. The aim of this manuscript was to review scientific evidence that underlies the dietetic recommendations of the American Diabetes Association (ADA) for prevention and treatment of CVD in patients with DM. The ADA guidelines are mostly based on studies performed on patients with CVD and without DM. The evidence-based dietary recommendations for patients with DM are to increase the intake of fish and soluble fibers. Although DM has been considered as an equivalent of established CVD, the adoption of the same dietary recommendations for patients without DM and with CVD for all patients with DM is still questionable -- especially considering the peculiarities of CVD in DM. Randomized clinical trials including patients with DM should provide further information regarding the benefits of these dietary interventions for CVD.

Cardiovascular effects of marine omega-3 fatty acids

Much evidence shows that the marine omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid have beneficial effects in various cardiac disorders, and their use is recommended in guidelines for management of patients after myocardial infarction. However, questions have been raised about their usefulness alongside optimum medical therapies with agents proven to reduce risk of cardiac events in high-risk patients. Additionally, there is some evidence for a possible pro-arrhythmic effect in subsets of cardiac patients. Some uncertainly exists about the optimum dose needed to obtain beneficial effects and the relative merit of dietary intake of omega-3 polyunsaturated fatty acids versus supplements. We review evidence for the effects of omega-3 polyunsaturated fatty acids on various cardiac disorders and the risk factors for cardiac disease. We also assess areas of uncertainty needing further research.

Combination drug-diet therapies for dyslipidemia

Expense, high drug dose, and low compliance to strict dietary therapies are current issues surrounding modern drug- and diet-based lipid-lowering approaches. Furthermore, variable patient outcomes and suboptimal response to both drug and diet therapies are increasingly evident. Therefore, the question arises as to whether more emphasis should be placed on combination diet/drug therapies to reduce cholesterol levels in patients who respond suboptimally to diet and drug monotherapies. Although considerable research has explored multidrug combination therapies, combination drug/diet therapies receive less attention. However, combined drug/diet approaches may reduce the number of drug prescriptions, the progressive increase in "optimal" drug dosage, and costs associated with pharmaceutical disease management. Future research priorities in drug/diet therapeutic approaches should not only emphasize the discovery of novel combinations but also should address potential safety issues prior to wide-scale acceptance in clinical practice. Accordingly, this review will assess current limitations associated with both drug and diet lipid-lowering therapies and explore the potential of combination drug/diet therapies in the treatment of dyslipidemia.

Fish, mercury, selenium and cardiovascular risk: current evidence and unanswered questions

Controversy has arisen among the public and in the media regarding the health effects of fish intake in adults. Substantial evidence indicates that fish consumption reduces coronary heart disease mortality, the leading cause of death in developed and most developing nations. Conversely, concerns have grown regarding potential effects of exposure to mercury found in some fish. Seafood species are also rich in selenium, an essential trace element that may protect against both cardiovascular disease and toxic effects of mercury. Such protective effects would have direct implications for recommendations regarding optimal selenium intake and for assessing the potential impact of mercury exposure from fish intake in different populations. Because fish consumption appears to have important health benefits in adults, elucidating the relationships between fish intake, mercury and selenium exposure, and health risk is of considerable scientific and public health relevance. The evidence for health effects of fish consumption in adults is reviewed, focusing on the strength and consistency of evidence and relative magnitudes of effects of omega-3 fatty acids, mercury, and selenium. Given the preponderance of evidence, the focus is on cardiovascular effects, but other potential health effects, as well as potential effects of polychlorinated biphenyls and dioxins in fish, are also briefly reviewed. The relevant current unanswered questions and directions of further research are summarized.

Chronic effects of a high-fat diet enriched with virgin olive oil and a low-fat diet enriched with α-linolenic acid on postprandial endothelial function in healthy men

Traditional cardiovascular risk factors are associated with endothelial dysfunction. The vascular endothelium plays a key role in local vascular tone regulation and can be modulated by dietary fat. We propose to determine the chronic effect of three diets with different fat compositions on postprandial endothelial function and inflammatory biomarkers. Twenty healthy men followed three 4-week diets in a randomised cross-over design: a Western diet, rich in saturated fat (22 % SFA, 12 % MUFA and 0·4 % α-linolenic acid (ALA), all fractions are % of energy); a Mediterranean diet, rich in MUFA ( < 10 % SFA, 24 % MUFA and 0·4 % ALA); a low-fat diet enriched in ALA ( < 10 % SFA, 12 % MUFA and 2 % ALA). At the end of each dietary period all subjects underwent a postprandial study. Plasma concentrations of lipid parameters, soluble intercellular cell-adhesion molecule-1, soluble vascular cell-adhesion molecule-1 (sVCAM-1), nitrates and nitrites (NOx) and endothelial function studied by laser Doppler were examined at 0, 2, 4, 6 and 8 h. The endothelium-dependent vasodilatory response was greater 4 h after the ingestion of the MUFA-rich diet than after the SFA or ALA low-fat diets (P = 0·031). The 4 h postprandial plasma sVCAM-1 levels were lower after the MUFA meals than after the ALA low-fat diet (P = 0·043). The bioavailability of NOx was higher following the MUFA diet than after the SFA and ALA low-fat diets (P = 0·027). We found no differences in the other parameters measured. Chronic ingestion of a Mediterranean diet avoids the postprandial deterioration of endothelial function associated with Westernised diets in healthy individuals.

Dietary intervention with oil rich fish reduces platelet-monocyte aggregation in man

BACKGROUND

Dietary intake of fish rich in omega-3 fatty acids is associated with a reduction in cardiovascular events. The mechanisms for this are uncertain and previous studies investigating effects on platelet function have produced inconsistent results. Platelet-monocyte aggregation is a sensitive marker of platelet activation and may contribute to the initiation and progression of atherothrombosis. This study assessed the effect of dietary intervention with oily fish on platelet-monocyte aggregation in healthy subjects.

METHODS

Fourteen subjects had their diet supplemented with 500 g of oil-rich fish per week for 4 weeks. A control group of 14 subjects received no dietary intervention over a 4-week period. Platelet-monocyte aggregates were assessed with flow cytometry.

RESULTS

Dietary intervention with fish led to an increase in omega-3 fatty acids in plasma phospholipids (14.2+/-3.4% versus 5.8+/-1.3%, P<0.001). In contrast to the control group, platelet-monocyte aggregates were reduced by 35% following dietary intervention with oily fish (16.0+/-9.0% versus 24.8+/-10.9%, P<0.01), and returned to basal levels 4 weeks after discontinuation of supplementation. There was an inverse correlation between platelet-monocyte aggregation and plasma omega-3 fatty acid concentrations (r=-0.421, P=0.006). There were no changes in the plasma markers of platelet activation, soluble P-selectin or soluble CD40 ligand.

CONCLUSIONS

We have demonstrated, for the first time, that dietary intervention with oil-rich fish reduces platelet-monocyte aggregation in man. Our results suggest that reduced platelet activation provides a potential mechanism through which fish oils confer their cardiovascular preventative benefits.

Safety considerations with omega-3 fatty acid therapy

It has been suggested that the potential antithrombotic effect of fish oils may theoretically increase the risk for bleeding, which may be a safety concern for individual patients. However, clinical trial evidence has not supported increased bleeding with omega-3 fatty acid intake, even when combined with other agents that might also increase bleeding (such as aspirin and warfarin). Another potential safety concern is the susceptibility of omega-3 fatty acid preparations to undergo oxidation, which contributes to patient intolerance and potential toxicity. Finally, large amounts of fish consumption may result in adverse experiences due to the potential presence of environmental toxins such as mercury, polychlorinated biphenyls, dioxins, and other contaminants. The risks of exposure to environmental toxins and hypervitaminosis with fish consumption are substantially reduced through purification processes used to develop selected concentrated fish oil supplements and prescription preparations. Thus, in choosing which fish oil therapies to recommend, clinicians should be aware of available information to best assess their relative safety, which includes the US Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) advisory statement regarding fish consumption, the meaning of certain labeling (such as "verification" through the US Pharmacopeia) and the differences in FDA regulatory requirements between nonprescription fish oil supplements and prescription fish oil preparations, and how all of this is important to the optimal treatment of patients.

n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review

Studies on the relation between dietary n-3 fatty acids (FAs) and cardiovascular disease vary in quality, and the results are inconsistent. A systematic review of the literature on the effects of n-3 FAs (consumed as fish or fish oils rich in eicosapentaenoic acid and docosahexaenoic acid or as alpha-linolenic acid) on cardiovascular disease outcomes and adverse events was conducted. Studies from MEDLINE and other sources that were of > or =1 y in duration and that reported estimates of fish or n-3 FA intakes and cardiovascular disease outcomes were included. Secondary prevention was addressed in 14 randomized controlled trials (RCTs) of fish-oil supplements or of diets high in n-3 FAs and in 1 prospective cohort study. Most trials reported that fish oil significantly reduced all-cause mortality, myocardial infarction, cardiac and sudden death, or stroke. Primary prevention of cardiovascular disease was reported in 1 RCT, in 25 prospective cohort studies, and in 7 case-control studies. No significant effect on overall deaths was reported in 3 RCTs that evaluated the effects of fish oil in patients with implantable cardioverter defibrillators. Most cohort studies reported that fish consumption was associated with lower rates of all-cause mortality and adverse cardiac outcomes. The effects on stroke were inconsistent. Evidence suggests that increased consumption of n-3 FAs from fish or fish-oil supplements, but not of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. The evidence for the benefits of fish oil is stronger in secondary- than in primary-prevention settings. Adverse effects appear to be minor.

Omega-3 fatty acids: antiarrhythmic, proarrhythmic or both?

Initial epidemiological, clinical trial and animal data have suggested that a diet high in omega-3 fatty acids reduces the risk of cardiac death and that this reduction in the risk was owing to the prevention of fatal arrhythmias. More recent data, however, suggest that, in some patients with heart disease, omega-3 fatty acid supplementation may increase the risk of potentially fatal cardiac arrhythmias and the risk of sudden cardiac death. Additional research needs to be carried out to confirm and characterize the proarrhythmic properties of omega-3 fatty acids and to determine their role in the treatment of patients with heart disease who have not had a recent myocardial infarction.

Effects of omega-3 fatty acids on coronary restenosis, intima–media thickness, and exercise tolerance: A systematic review

Greater omega-3 fatty acid consumption is associated with reduced cardiovascular disease risk. Though the mechanisms of their effect are unclear, they may involve lesion formation and heart function. We conducted a systematic review of the clinical literature on the effect of omega-3 fatty acids on measures of vascular structure and function. We included studies that assessed fish and plant sources of omega-3 fatty acids on coronary artery restenosis after angioplasty, carotid IMT, and exercise capacity. Compared to placebo, the summary risk ratio of coronary artery restenosis with fish oil is 0.87 (95% CI 0.73, 1.05) across 12 randomized controlled trials. Two prospective studies reported increased carotid IMT, whereas two cross-sectional studies reported a reduction of IMT, with fish, fish oil or ALA consumption. Three randomized trials and three uncontrolled studies reported small non-significant improvements in exercise capacity with fish oil. Overall, little or no effect of fish oil was found for a variety of markers of cardiovascular disease risk. There are insufficient studies to draw conclusions about the effect of ALA. The dearth of long term data on fish consumption or omega-3 fatty acid supplementation on measures of cardiovascular disease risk severely limits our ability to draw definitive conclusions at this time.

Marine n-3 polyunsaturated fatty acids and coronary heart disease

In this paper, we will give an overview of the background for the possible effects of long-chain marine n-3 (synonymously called omega-3) polyunsaturated fatty acids (PUFA) in coronary heart disease (CHD) with focus on recent findings. In a forthcoming paper, we will focus on the clinical trial data, current recommendations and suggest trials to further study the role of marine n-3 PUFA in the prevention and treatment of CHD.

Rationale and design of a randomised controlled clinical trial on supplemental intake of n-3 fatty acids and incidence of cardiac arrhythmia: SOFA

BACKGROUND

Evidence from earlier studies indicates that intake of very long-chain n-3 polyunsaturated fatty acids (n-3 PUFA, also named omega-3 fatty acids) as present in fish oil reduces the risk of sudden death. Sudden death forms a major part of mortality from cardiovascular disease and is in most cases a direct consequence of cardiac arrhythmia. n-3 PUFA may exert their protective effect through reducing the susceptibility for cardiac arrhythmia.

OBJECTIVE

To investigate the effect of n-3 PUFA on the incidence of recurrent ventricular arrhythmia. This paper presents the rationale, design and methods of the Study on Omega-3 Fatty acids and ventricular Arrhythmia (SOFA) and discusses problems encountered in conducting a multicentre clinical trial on food.

DESIGN

A randomised, parallel, placebo-controlled, double blind intervention study, which obeys the guidelines for Good Clinical Practice.

SETTING

Multiple cardiology centres in Europe.

SUBJECTS

A total of 500 patients with an implantable cardioverter defibrillator (ICD). An ICD detects, treats and stores cardiac arrhythmic events in its memory chip.

INTERVENTIONS

Patients receive either 2 g/day of fish oil, containing approximately 450 mg eicosapentaenoic acid and 350 mg docosahexaenoic acid, or placebo for 12 months.

PRIMARY OUTCOME

Spontaneous ventricular tachyarrhythmias as recorded by the ICD or all-cause mortality.

CONCLUSION

SOFA is designed to answer the question whether intake of n-3 PUFA from fish-a regular food ingredient-can reduce the incidence of life-threatening cardiac arrhythmia. If this proves to be true, increasing the intake of n-3 PUFA could be an easy, effective and safe measure to prevent fatal arrhythmia in the general population.

Omega 3 fatty acids and cardiovascular disease--fishing for a natural treatment

Omega 3 fatty acids from fish and fish oils can protect against coronary heart disease. This article reviews the evidence regarding fish oils and coronary disease and outlines the mechanisms through which fish oils might confer cardiac benefits

Dietary docosahexaenoic acid-induced production of tissue lipid peroxides is not suppressed by higher intake of ascorbic acid in genetically scorbutic Osteogenic Disorder Shionogi/Shi-od/od rats

In previous studies, we showed that docosahexaenoic acid (DHA) ingestion enhanced the susceptibility of rat liver and kidney to lipid peroxidation, but did not increase lipid peroxide formation to the level expected from the relative peroxidizability index (P-index) of the total tissue lipids. The results suggested the existence of some suppressive mechanisms against DHA-induced tissue lipid peroxide formation, as increased tissue ascorbic acid (AsA) and glutathione levels were observed. Therefore, we focused initially on the role of AsA for the suppressive mechanisms. For this purpose, we examined the influence of different levels of dietary AsA (low, moderate, high and excessive levels were 100, 300 (control), 600 and 3000 mg/kg diet respectively) on the tissue lipid peroxide and antioxidant levels in AsA-requiring Osteogenic Disorder Shionogi/Shi-od/od (ODS) rats fed DHA (6.4 % total energy) for 32 or 33 d. Diets were pair-fed to the DHA- and 100 mg AsA/kg diet-fed group. We found that the lipid peroxide concentrations of liver and kidney in the DHA-fed group receiving 100 mg AsA/kg diet were significantly higher or tended to be higher than those of the DHA-fed groups with AsA at more than the usual control level of 300 mg/kg diet. Contrary to this, the liver alpha-tocopherol concentration was significantly lower or tended to be lower in the DHA and 100 mg AsA/kg diet-fed group than those of the other DHA-fed groups. However, tissue lipid peroxide formation and alpha-tocopherol consumption were not suppressed further, even after animals received higher doses of AsA. The present results suggest that higher than normal concentrations of tissue AsA are not necessarily associated with the suppressive mechanisms against dietary DHA-induced tissue lipid peroxide formation.