Circulating triacylglycerol and apoE levels in response to EPA and docosahexaenoic acid supplementation in adult human subjects

Efficacy and safety of n-3 fatty acids supplementation on depression: a systematic review and dose-response meta-analysis of randomised controlled trials

We aimed to investigate the effectiveness of n-3 fatty acids supplementation on the risk of developing depression, depressive symptoms and remission of depression. We searched PubMed, Scopus and Web of Science from inception to December 2022 to find randomised trials of n-3 fatty acids supplementation in adults. We conducted random-effects meta-analyses to estimate standardised mean differences (SMD) and 95 % CI for continuous outcomes and risk difference and 95 % CI for binary outcomes. A total of sixty-seven trials were included. Each 1 g/d n-3 fatty acids supplementation significantly improved depressive symptoms in adults with and without depression (moderate-certainty evidence), with a larger improvement in patients with existing depression. Dose-response analyses indicated a U-shaped effect in patients with existing depression, with the greatest improvement at 1·5 g/d. The analysis showed that n-3 fatty acid supplementation significantly increased depression remission by 19 more per 100 in patients with depression (low-certainty evidence). Supplementation with n-3 fatty acids did not reduce the risk of developing depression among the general population, but it did improve the severity of depression among patients with existing depression.

Variability in the Clinical Effects of the Omega-3 Polyunsaturated Fatty Acids DHA and EPA in Cardiovascular Disease-Possible Causes and Future Considerations

Cardiovascular disease (CVD) that includes myocardial infarction and stroke, is the leading cause of mortality worldwide. Atherosclerosis, the primary underlying cause of CVD, can be controlled by pharmacological and dietary interventions, including n-3 polyunsaturated fatty acid (PUFA) supplementation. n-3 PUFA supplementation, primarily consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has shown promise in reducing atherosclerosis by modulating risk factors, including triglyceride levels and vascular inflammation. n-3 PUFAs act by replacing pro-inflammatory fatty acid types in cell membranes and plasma lipids, by regulating transcription factor activity, and by inducing epigenetic changes. EPA and DHA regulate cellular function through shared and differential molecular mechanisms. Large clinical studies on n-3 PUFAs have reported conflicting findings, causing confusion among the public and health professionals. In this review, we discuss important factors leading to these inconsistencies, in the context of atherosclerosis, including clinical study design and the differential effects of EPA and DHA on cell function. We propose steps to improve clinical and basic experimental study design in order to improve supplement composition optimization. Finally, we propose that understanding the factors underlying the poor response to n-3 PUFAs, and the development of molecular biomarkers for predicting response may help towards a more personalized treatment.

Higher docosahexaenoic acid levels lower the protective impact of eicosapentaenoic acid on long-term major cardiovascular events

Introduction

Long-chain omega-3 polyunsaturated fatty acids (OM3 PUFA) are commonly used for cardiovascular disease prevention. High-dose eicosapentaenoic acid (EPA) is reported to reduce major adverse cardiovascular events (MACE); however, a combined EPA and docosahexaenoic acid (DHA) supplementation has not been proven to do so. This study aimed to evaluate the potential interaction between EPA and DHA levels on long-term MACE.

Methods

We studied a cohort of 987 randomly selected subjects enrolled in the INSPIRE biobank registry who underwent coronary angiography. We used rapid throughput liquid chromatography-mass spectrometry to quantify the EPA and DHA plasma levels and examined their impact unadjusted, adjusted for one another, and fully adjusted for comorbidities, EPA + DHA, and the EPA/DHA ratio on long-term (10-year) MACE (all-cause death, myocardial infarction, stroke, heart failure hospitalization).

Results

The average subject age was 61.5 ± 12.2 years, 57% were male, 41% were obese, 42% had severe coronary artery disease (CAD), and 311 (31.5%) had a MACE. The 10-year MACE unadjusted hazard ratio (HR) for the highest (fourth) vs. lowest (first) quartile (Q) of EPA was HR = 0.48 (95% CI: 0.35, 0.67). The adjustment for DHA changed the HR to 0.30 (CI: 0.19, 0.49), and an additional adjustment for baseline differences changed the HR to 0.36 (CI: 0.22, 0.58). Conversely, unadjusted DHA did not significantly predict MACE, but adjustment for EPA resulted in a 1.81-fold higher risk of MACE (CI: 1.14, 2.90) for Q4 vs. Q1. However, after the adjustment for baseline differences, the risk of MACE was not significant for DHA (HR = 1.37; CI: 0.85, 2.20). An EPA/DHA ratio ≥1 resulted in a lower rate of 10-year MACE outcomes (27% vs. 37%, adjusted p-value = 0.013).

Conclusions

Higher levels of EPA, but not DHA, are associated with a lower risk of MACE. When combined with EPA, higher DHA blunts the benefit of EPA and is associated with a higher risk of MACE in the presence of low EPA. These findings can help explain the discrepant results of EPA-only and EPA/DHA mixed clinical supplementation trials.

Comparing the effects of docosahexaenoic and eicosapentaenoic acids on cardiovascular risk factors: Pairwise and network meta-analyses of randomized controlled trials

BACKGROUND

Evidence from clinical trial studies suggests that docosahexaenoic acids (DHA) may have greater potential effects on improving cardiovascular risk factors than eicosapentaenoic acid (EPA). However, this evidence has not yet been meta-analyzed and quantified. The aim of this study was to evaluate and compare the effect of DHA and EPA monotherapy on cardiovascular risk factors based on paired and network meta-analysis.

METHODS

Relevant articles published up to January 2022 were systematically retrieved from relevant databases. We included all Randomized Controlled Trials (RCTs) on adults that directly compared the effects of DHA with EPA and RCTs of indirect comparisons (DHA and EPA monotherapy compared to control groups). Data were pooled by pairwise and network meta-analysis and expressed as mean differences (MDs) with 95% CIs. The study protocol was registered with PROSPERO (Registration ID: CRD42022328630).

RESULTS

Network meta-analysis of comparisons of DHA and EPA suggested significant comparable effects only on LDL-C (MD EPA versus DHA = -8.51 mg/L; 95% CI: -16.67; -0.35). However, the Network meta-analysis not show a significant effect for other risk factors. Furthermore, pairwise meta-analysis of direct comparisons of DHA and EPA showed significant difference in their effects on plasma glucose (MD _{EPA versus DHA} = -0.31 mg/L; 95% CI: -0.60, -0.02), Insulin (MD _{EPA versus DHA} = -2.14 mg/L; 95% CI: -3.26, -1.02), but the results were not significant for risk factors.

CONCLUSION

Our findings suggest that both EPA and DHA act similarly on the markers under study, with slight changes in plasma glucose, insulin, and LDL-C.

The genetic interactions between non-alcoholic fatty liver disease and cardiovascular diseases

The ongoing debate on whether non-alcoholic fatty liver disease (NAFLD) is an active contributor or an innocent bystander in the development of cardiovascular disease (CVD) has sparked interests in understanding the common mediators between the two biologically distinct entities. This comprehensive review identifies and curates genetic studies of NAFLD overlapping with CVD, and describes the colinear as well as opposing correlations between genetic associations for the two diseases. Here, CVD described in relation to NAFLD are coronary artery disease, cardiomyopathy and atrial fibrillation. Unique findings of this review included certain NAFLD susceptibility genes that possessed cardioprotective properties. Moreover, the complex interactions of genetic and environmental risk factors shed light on the disparity in genetic influence on NAFLD and its incident CVD. This serves to unravel NAFLD-mediated pathways in order to reduce CVD events, and helps identify targeted treatment strategies, develop polygenic risk scores to improve risk prediction and personalise disease prevention.

Effects of dietary eicosapentaenoic acid and docosahexaenoic acid supplementation on metabolic syndrome: A systematic review and meta-analysis of data from 33 randomized controlled trials

BACKGROUND & AIMS

Previous randomized controlled trials (RCTs) have compared the effects of pure preparations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in reducing metabolic syndrome (MetS) risk factors, but the results were inconsistent. The present study aimed to clarify whether EPA and DHA have differential effects on MetS features in humans.

METHODS

A systematic literature search was conducted in CNKI, PubMed, Embase and Scopus updated to February 2021. The mean changes in the characteristics of MetS were calculated as weighted mean differences by using a random-effects model. Thirty-three RCTs were included.

RESULTS

The results showed that both EPA and DHA were effective at lowering serum triglycerides (TG) levels. EPA supplementation decreased the serum levels of total cholesterol (TC) (WMD = -0.24 mmol/L; 95% CI, -0.43, -0.05 mmol/L), TG (WMD = -0.77 mmol/L; 95% CI, -1.54, -0.00 mmol/L) and low density lipoprotein-cholesterol (LDL-C) (WMD = -0.13 mmol/L; 95% CI, -0.25, -0.01 mmol/L), while DHA increased the serum levels of TC (WMD = 0.14 mmol/L; 95% CI, 0.03, 0.25 mmol/L), LDL-C (WMD = 0.26 mmol/L; 95% CI, 0.15, 0.38 mmol/L) and high density lipoprotein-cholesterol (HDL-C) (WMD = 0.07 mmol/L; 95% CI, 0.04, 0.09 mmol/L). Moreover, DHA increased the serum levels of insulin compared with EPA, especially in subgroups whose mean age was <60 years (0.43 mU/L; 95% CI: 0.04, 0.81 mU/L) and duration of DHA supplementation < 3 months (0.39 mU/L; 95% CI: 0.01, 0.77 mU/L).

CONCLUSIONS

The present meta-analysis provides evidence that EPA and DHA have different effects on risk factors of MetS.

Fish Oil Increases Diet-Induced Thermogenesis in Mice

Increasing energy expenditure (EE) is beneficial for preventing obesity. Diet-induced thermogenesis (DIT) is one of the components of total EE. Therefore, increasing DIT is effective against obesity. We examined how much fish oil (FO) increased DIT by measuring absolute values of DIT in mice. C57BL/6J male mice were given diets of 30 energy% fat consisting of FO or safflower oil plus butter as control oil (Con). After administration for 9 days, respiration in mice was monitored, and then the data were used to calculate DIT and EE. DIT increased significantly by 1.2-fold in the FO-fed mice compared with the Con-fed mice. Body weight gain was significantly lower in the FO-fed mice. FO increased the levels of uncoupling protein 1 (Ucp1) mRNA and UCP1 protein in brown adipose tissue (BAT) by 1.5- and 1.2-fold, respectively. In subcutaneous white adipose tissue (subWAT), the levels of Ucp1 mRNA and UCP1 protein were increased by 6.3- and 2.7-fold, respectively, by FO administration. FO also significantly increased the expression of markers of browning in subWAT such as fibroblast growth factor 21 and cell death-inducing DNA fragmentation factor α-like effector a. Thus, dietary FO seems to increase DIT in mice via the increased expressions of Ucp1 in BAT and induced browning of subWAT. FO might be a promising dietary fat in the prevention of obesity by upregulation of energy metabolism.

Cardiovascular effects of omega-3 fatty acids: Hope or hype?

Omega-3 fatty acids have emerged as a new option for controlling the residual risk for cardiovascular disease (CVD) in the statin era after a clinical trial (REDUCE-IT) reported positive results with icosapent ethyl (IPE) in patients receiving maximally tolerated statin therapy. However, another trial which used high dose eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) combination (STRENGTH) has failed. Together, these results raise clinically important questions. Are effects of omega-3 fatty acids neutral or beneficial in patients on statin therapy, or perhaps even harmful? The current contradictory results could be attributed to different types of omega-3 fatty acids (only EPA or combination of EPA + DHA), doses (higher vs. lower dose) of omega-3 fatty acids or different comparators (corn oil or mineral oil), as well as the underlying severity of the CVD risk or use of statins. Together with these issues, we will discuss different biological and clinical effects of various types of omega-3 fatty acids and then interpret different results of past and current clinical studies and propose practical suggestions, which could be applied in patient management.

The ratio of eicosapentaenoic acid to docosahexaenoic acid as a modulator for the cardio-metabolic effects of omega-3 supplements: A meta-regression of randomized clinical trials

BACKGROUND

A large number of studies have demonstrated the effects of omega- 3 supplements containing mixtures of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), known to favorably affect many modifiable risk factors of coronary heart disease (CHD). These studies have used diverse ratios and doses of EPA and DHA. However, it is not known whether the ratio of EPA to DHA in omega-3 supplements affect their efficacy as modulators for cardiovascular risk factors. This meta-regression aimed to investigate the effect of different ratios of EPA to DHA on risk factors associated with CHD including lipid profile, blood pressure, heart rate, and inflammation.

METHOD

A regression analysis was carried out on 92 clinical trials with acceptable quality (Jadad score ≥ 3) that were previously identified from two databases (PubMed and Cochrane Library).

RESULTS

Data from studies that met the inclusion criteria for this analysis showed that the ratio of EPA to DHA was not associated with lipid profile, diastolic blood pressure, or heart rate. With all studies, the ratio of EPA to DHA was associated with C-reactive protein (CRP) (β = -1.3121 (95 % CI: -1.6610 to -0.9543), that is, the higher the EPA to DHA ratio, the greater the reduction. Using only studies that supplied EPA and DHA in the range of 2 g-6 g, the ratio of EPA to DHA was also associated with CRP (β = -2.10429 and 95 % CI: -3.89963 to -0.30895); that is, an even more pronounced reduction in CRP with a higher EPA to DHA ratio. Systolic blood pressure was only associated with an increasing EPA to DHA ratio in the 2 g-6 g range (β = 5.47129 and 95 % CI: 0.40677-10.53580), that is, a higher EPA to DHA ratio within this dose range, the greater the increase in SBP.

CONCLUSION

Current data suggest that the EPA to DHA ratio only correlates to the modulation of CRP by omega-3 supplementation of EPA and DHA, and SBP in studies that supplemented EPA and DHA in the range of 2 g-6 g, shedding light on potential differential effects of EPA vs. DHA on inflammation and systolic blood pressure.

Development of omega-3 rich eggs through dietary flaxseed and bio-evaluation in metabolic syndrome

An egg is a nutrient-dense food that contains protein, fats, vitamins, and minerals. It is proven that the consumption of eggs influences serum lipid concentration. Therefore, a study was conducted to investigate the effect of normal and omega-3 eggs on serum lipids profiles. Lipids were extracted from egg yolks and analyzed for fatty acids content. The present research is a crossover study design in which 20 participants were recruited randomly, and all subjects received three treatments: no eggs, omega-3 eggs, and normal eggs. However, fasting blood was drawn at baseline and the end of each diet period and analyzed for serum lipids, blood glucose, and insulin level. Omega-3 egg treatment showed reduction in the serum total cholesterol by 16.57 mg/dl (p < .001), triglyceride by 17.48 mg/dl, and increase in HDL cholesterol concentration by 0.48 mg/dl (p < .001) as compared to no-egg. A significant (p < .05) reduction in blood pressure by 8.34/8.67 mm/Hg and insulin level was observed due to omega-3 egg consumption which indicates that omega-3 fatty acids improve insulin sensitivity. On the other hand, regular egg intake elevates serum total cholesterol and triglycerides concentration but decreases blood pressure. It was concluded that omega-3-enriched egg consumption had a positive effect on the serum lipid profile and blood pressure of patients with metabolic syndrome as compared to normal eggs.

High-dose omega-3 polyunsaturated fatty acid supplementation might be more superior than low-dose for major depressive disorder in early therapy period: a network meta-analysis

BACKGROUND

The application of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) supplementation for major depressive disorder (MDD) has been widely discussed in recent years, but its efficacy and application are still controversial. This network meta-analysis was conducted to compare the efficacy of different dosages of n-3 PUFAs on MDD patients in the early period of treatment.

METHODS

Randomized controlled trials (RCTs) exploring the efficacy of n-3 PUFA supplementation for patients with MDD were retrieved from the databases of Pubmed, Embase and the Cochrane Library. RCTs comparing the efficacy of n-3 PUFA for adult (≥18 years) MDD patients without comorbidity were eligible for our study. The score of depressive symptoms in early therapy period of the treatment (≤9 weeks) was extracted. Standardized mean deviations (SMDs) of all the sores from the eligible RCTs were synthesized in a pairwise meta-analysis in frequentist framework and a random-effects network meta-analysis in Bayesian framework for the overall and subgroups (high- and low-dose) efficacy of n-3 PUFAs.

RESULTS

A total of 910 MDD patients in 10 trials with 3 adjuvant therapy strategies (high-dose n-3 PUFAs, low-dose n-3 PUFAs and placebo) were included. Results of pairwise meta-analysis showed that n-3 PUFAs were superior to placebo (SMD: 1.243 ± 0.596; 95% CI: 0.060 ~ 2.414). Results of the network meta-analysis showed that both the high (SMD: 0.908 ± 0.331; 95% CI: 0.262 ~ 1.581) and the low-dose (SMD: 0.601 ± 0.286; 95% CI: 0.034 ~ 1.18) n-3 PUFAs were superior to placebo, and the efficacy of high-dose n-3 PUFAs is superior to that of low-dose.

CONCLUSIONS

High-dose n-3 PUFAs supplementation might be more superior than low-dose in the early therapy period for MDD. More head-to-head clinical trials need to be carried out to provide more direct comparison and enhance the evidence of the efficacy of n-3PUFAs for MDD.

Inflammation and cardiovascular disease: are marine phospholipids the answer?

This review presents the latest research on the cardioprotective effects of n-3 fatty acids (FA) and n-3 FA bound to polar lipids (PL). Overall, n-3 PL may have enhanced bioavailability and potentially bioactivityversusfree FA and ester forms of n-3 FA.

Efficacy of DHA and EPA on Serum Triglyceride Levels of Healthy Participants: Systematic Review

Background Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are categorized as omega-3 poly unsaturated fatty acids (PUFAs) that are present in fish oil, etc. DHA and EPA omega-3 PUFAs have a well-established fasting serum triglycerides (TG) lowering effect that may result in normal lipidemia in hyperlipidemic patients. In general, omega-3 PUFAs, such as DHA and EPA, can be ingested easily, and because they are highly safe, they are assumed to be suitable for controlling fasting serum TG in the serum of those who do not require drug treatment. To the best of our knowledge, however, almost all systematic reviews on the effects of omega-3 PUFAs on lowering fasting serum TG are directed at patients fulfilling the diagnostic criteria of dyslipidemia. Objectives To review and confirm the preventive effect of omega-3 PUFAs against hypertriglyceridemia or the effect on nondrug treatment in patients with a mild disease, a systematic review was conducted to determine whether there was a fasting serum TG-lowering effect in subjects without disease and those with a slightly higher triglyceride level who consumed DHA and/or EPA orally compared to those with placebo or no intake of DHA and/or EPA. Search Methods We evaluated articles from searches of PubMed (1946-February 2016), Ichushi-Web (1977-February 2016), and J Dream III (JST Plus, 1981-February 2016; JMED Plus, 1981-February 2016). The keywords were set as follows: “DHA” or “docosahexaenoic acid” or “EPA” or “eicosapentaenoic acid” and “TG” or “triglyceride” or “triglycerol” or “triacylglycerol” or “neutral lipid.”. In addition to the literature group obtained by the database search, we included participants not suffering from any disease (i.e., excluding mild hypertriglyceridemia). Eligibility Criteria Before the test selection process, the following inclusion criteria were defined. Participants were healthy men and women including those with mild hypertriglyceridemia (fasting serum TG level, 150-199 mg/dL [1.69-2.25 mmol/L)). Intervention was defined as orally ingested DHA and/or EPA. Comparison was made to placebo intake or no intake of DHA and/or EPA. Results were measured for the fasting serum TG level. The test design was RCT, and quasi-RCT. Data Abstraction Various characteristics were extracted from original reports using a standardized data extraction form, including the author of the study, research year, research design, subject characteristics (sex, age, sample size), period, dose of DHA and/or EPA (mg/day), and comparison group. Main Results We identified 37 documents for review. Among the 37 reports used to integrate literature results, 25 revealed a decrease in fasting serum TG level ​​due to the oral ingestion of DHA and/or EPA. Sixteen studies on subjects without disease and 21 on subjects with slightly higher fasting serum TG levels were separated and stratified analysis was conducted. Ten of the 16 (normal TG participant) and 15 of the 21 studies (slightly higher TG participant) respectively, indicated that at least 133 mg/day of DHA and/or EPA intervention provided a statistically significant decrease in the fasting serum TG level between an intervention group versus a placebo group.

Apolipoprotein E in lipoprotein metabolism, health and cardiovascular disease

Apolipoprotein E (apoE), a 34 kDa circulating glycoprotein of 299 amino acids, predominantly synthesised in the liver, associates with triglyceride-rich lipoproteins to mediate the clearance of their remnants after enzymatic lipolysis in the circulation. Its synthesis in macrophages initiates the formation of high density-like lipoproteins to effect reverse cholesterol transport to the liver. In the nervous system apoE forms similar lipoproteins which perform the function of distributing lipids amongst cells. ApoE accounts for much of the variation in plasma lipoproteins by three common variants (isoforms) that influence low-density lipoprotein concentration and the risk of atherosclerosis. ApoE2 generally is most favourable and apoE4 least favourable for cardiovascular and neurological health. The apoE variants relate to different amino acids at positions 112 and 158: cysteine in both for apoE2, arginine at both sites for apoE4, and respectively cysteine and arginine for apoE3 that is viewed as the wild type. Paradoxically, under metabolic stress, homozygosity for apoE2 may result in dysbetalipoproteinaemia in adults owing to impaired binding of remnant lipoproteins to the LDL receptor and related proteins as well as heparan sulphate proteoglycans. This highly atherogenic condition is also seen with other mutations in apoE, but with autosomal dominant inheritance. Mutations in apoE may also cause lipoprotein glomerulopathy. In the central nervous system apoE binds amyloid β-protein and tau protein and fragments may incur cellular damage. ApoE4 is a strong risk factor for the development of Alzheimer's disease. ApoE has several other physiological effects that may influence health and disease, including supply of docosahexaenoic acid for the brain and modulating immune and inflammatory responses. Genotyping of apoE may have application in disorders of lipoprotein metabolism as well as glomerulopathy and may be relevant to personalised medicine in understanding cardiovascular risk, and the outcome of nutritional and therapeutic interventions. Quantitation of apoE will probably not be clinically useful. ApoE is also of interest as it may generate peptides with biological function and could be employed in nanoparticles that may allow crossing of the blood-brain barrier. Therapeutic options may emerge from these newer insights.

Effect of omega-3 supplements on plasma apolipoprotein C-III concentrations: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Apolipoprotein C-III (apo C-III) is a key regulator of triglycerides metabolism. The aim of this meta-analysis was to assess the effect of fish omega-3 polyunsaturated fatty acids (PUFAs) on apo C-III levels.

METHODS

Randomized placebo-controlled trials investigating the impact of omega-3 on apo C-III levels were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on glycemic parameters.

RESULTS

This meta-analysis comprising 2062 subjects showed a significant reduction of apo C-III concentrations following treatment with omega-3 (WMD: -22.18 mg/L, 95% confidence interval: -31.61, -12.75, p < .001; I²: 88.24%). Subgroup analysis showed a significant reduction of plasma apo C-III concentrations by eicosapentaenoic acid (EPA) ethyl esters but not omega-3 carboxylic acids or omega-3 ethyl esters. There was a greater apo C-III reduction with only EPA as compared with supplements containing EPA and docosahexaenoic acid (DHA) or only DHA. A positive association between the apo C-III-lowering effect of omega-3 with baseline apo C-III concentrations and treatment duration was found.

CONCLUSIONS

This meta-analysis has shown that omega-3 PUFAs might significantly decrease apo C-III. Key messages Omega-3 PUFA supplements significantly reduce apo C-III plasma levels, particularly in hypertriglyceridemic patients when applied in appropriate dose (more than 2 g/day) Triglyceride (TG)-lowering effect is achieved via peroxisome proliferator-activated receptors α Further studies should address the effect of omega-3 PUFAs alone or with other lipid-lowering drugs in order to provide a final answer whether apo C-III could be an important target for prevention of cardiovascular disease New apo C-III antisense oligonucleotide drug (Volanesorsen) showed to be promising in decreasing elevated TGs by reducing levels of apo C-III mRNA.

High-Dose DHA Has More Profound Effects on LDL-Related Features Than High-Dose EPA: The ComparED Study

CONTEXT

Supplementation with high-dose docosahexaenoic acid (DHA) increases serum low-density lipoprotein (LDL) cholesterol (LDL-C) concentrations more than high-dose eicosapentaenoic acid (EPA). The mechanisms underlying this difference are unknown.

OBJECTIVE

To examine the phenotypic change in LDL and mechanisms responsible for the differential LDL-C response to EPA and DHA supplementation in men and women at risk of cardiovascular disease.

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTION

In a double-blind, controlled, crossover study, 48 men and 106 women with abdominal obesity and subclinical inflammation were randomized to a sequence of three treatment phases: phase 1, 2.7 g/d of EPA; phase 2, 2.7 g/d of DHA; and phase 3, 3 g/d of corn oil. All supplements were provided as three 1-g capsules for a total of 3 g/d. The 10-week treatment phases were separated by a 9-week washout period.

MAIN OUTCOME MEASURE

In vivo kinetics of apolipoprotein (apo)B100-containing lipoproteins were assessed using primed-constant infusion of deuterated leucine at the end of each treatment in a subset of participants (n = 19).

RESULTS

Compared with EPA, DHA increased LDL-C concentrations (+3.3%; P = 0.038) and mean LDL particle size (+0.7 Å; P < 0.001) and reduced the proportion of small LDL (-3.2%; P < 0.01). Both EPA and DHA decreased proprotein convertase subtilisin/kexin type 9 concentrations similarly (-18.2% vs -25.0%; P < 0.0001 vs control). Compared with EPA, DHA supplementation increased both the LDL apoB100 fractional catabolic rate (+11.4%; P = 0.008) and the production rate (+9.4%; P = 0.03).

CONCLUSIONS

The results of the present study have shown that supplementation with high-dose DHA increases LDL turnover and contributes to larger LDL particles compared with EPA.

How does high DHA fish oil affect health? A systematic review of evidence

The health benefits of fish oil, and its omega-3 long chain polyunsaturated fatty acid content, have attracted much scientific attention in the last four decades. Fish oils that contain higher amounts of eicosapentaenoic acid (EPA; 20:5n-3) than docosahexaenoic acid (DHA; 22:6n-3), in a distinctive ratio of 18/12, are typically the most abundantly available and are commonly studied. Although the two fatty acids have traditionally been considered together, as though they were one entity, different physiological effects of EPA and DHA have recently been reported. New oils containing a higher quantity of DHA compared with EPA, such as fractionated and concentrated fish oil, tuna oil, calamari oil and microalgae oil, are increasingly becoming available on the market, and other oils, including those extracted from genetically modified oilseed crops, soon to come. This systematic review focuses on the effects of high DHA fish oils on various human health conditions, such as the heart and cardiovascular system, the brain and visual function, inflammation and immune function and growth/Body Mass Index. Although inconclusive results were reported in several instances, and inconsistent outcomes observed in others, current data provides substantiated evidence in support of DHA being a beneficial bioactive compound for heart, cardiovascular and brain function, with different, and at times complementary, effects compared with EPA. DHA has also been reported to be effective in slowing the rate of cognitive decline, while its possible effects on depression disorders are still unclear. Interestingly, gender- and age- specific divergent roles for DHA have also been reported. This review provides a comprehensive collection of evidence and a critical summary of the documented physiological effects of high DHA fish oils for human health.

An Improvement of Cardiovascular Risk Factors by Omega-3 Polyunsaturated Fatty Acids

An epidemiological survey in the Northwest Greenland reported that the Greenlanders have a lower frequency of acute myocardial infarction and diabetes mellitus. The very low incidence of ischemic heart disease in the Greenlanders was explained by consumption of a diet rich in omega-3 polyunsaturated fatty acids (PUFAs). Possible anti-atherothrombotic effects of omega-3 PUFA include an improvement of lipid metabolism such as a reduction of triglyceride and an increase of high-density lipoprotein-cholesterol (HDL-C), and glucose metabolism, anti-platelet activity, anti-inflammatory effects, an improvement of endothelial function and stabilization of atherosclerotic plaque. The present study reviews an improvement of cardiovascular risk factors such as dyslipidemia and diabetes due to consumption of omega-3 PUFA. A sufficient number of studies suggest that omega-3 PUFA supplementation reduces serum triglyceride and increases HDL-cholesterol. The mechanisms for omega-3 PUFA-mediated improvements of lipid metabolism have been partially elucidated. The studies using experimental animals, part of trials in humans, have shown the beneficial effects of omega-3 PUFA on glucose metabolism and insulin sensitivity. The meta-analysis showed that omega-3 PUFA might prevent development of diabetes in part of population. Further studies should be performed to elucidate the association of omega-3 PUFA supplementation with diabetes, in the future.

The Differential Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid on Cardiometabolic Risk Factors: A Systematic Review

A large body of evidence supports the cardioprotective effects of the long-chain omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). There is increasing interest in the independent effects of EPA and DHA in the modulation of cardiometabolic risk factors. This systematic review aims to appraise the latest available evidence of the differential effects of EPA and DHA on such risk factors. A systematic literature review was conducted up to May 2017. Randomised controlled trials were included if they met strict eligibility criteria, including EPA or DHA > 2 g/day and purity ≥ 90%. Eighteen identified articles were included, corresponding to six unique studies involving 527 participants. Both EPA and DHA lowered triglyceride concentration, with DHA having a greater triglyceride-lowering effect. Whilst total cholesterol levels were largely unchanged by EPA and DHA, DHA increased high-density lipoprotein (HDL) cholesterol concentration, particularly HDL₂, and increased low-density lipoprotein (LDL) cholesterol concentration and LDL particle size. Both EPA and DHA inhibited platelet activity, whilst DHA improved vascular function and lowered heart rate and blood pressure to a greater extent than EPA. The effects of EPA and DHA on inflammatory markers and glycaemic control were inconclusive; however both lowered oxidative stress. Thus, EPA and DHA appear to have differential effects on cardiometabolic risk factors, but these need to be confirmed by larger clinical studies.

Omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and their mechanisms of action on apolipoprotein B-containing lipoproteins in humans: a review

Background

Epidemiological and genetic studies suggest that elevated triglyceride (TG)-rich lipoprotein levels in the circulation increase the risk of cardiovascular disease. Prescription formulations of omega-3 fatty acids (OM3FAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), reduce plasma TG levels and are approved for the treatment of patients with severe hypertriglyceridemia. Many preclinical studies have investigated the TG-lowering mechanisms of action of OM3FAs, but less is known from clinical studies.

Methods

We conducted a review, using systematic methodology, of studies in humans assessing the mechanisms of action of EPA and DHA on apolipoprotein B-containing lipoproteins, including TG-rich lipoproteins and low-density lipoproteins (LDLs). A systematic search of PubMed retrieved 55 articles, of which 30 were used in the review; 35 additional arrticles were also included.

Results

In humans, dietary DHA is retroconverted to EPA, while production of DHA from EPA is not observed. Dietary DHA is preferentially esterified into TGs, while EPA is more evenly esterified into TGs, cholesterol esters and phospholipids. The preferential esterification of DHA into TGs likely explains the higher turnover of DHA than EPA in plasma. The main effects of both EPA and DHA are decreased fasting and postprandial serum TG levels, through reduction of hepatic very-low-density lipoprotein (VLDL)-TG production. The exact mechanism for reduced VLDL production is not clear but does not include retention of lipids in the liver; rather, increased hepatic fatty acid oxidation is likely. The postprandial reduction in TG levels is caused by increased lipoprotein lipase activity and reduced serum VLDL-TG concentrations, resulting in enhanced chylomicron clearance. Overall, no clear differences between the effects of EPA and DHA on TG levels, or on turnover of TG-rich lipoproteins, have been observed. Effects on LDL are complex and may be influenced by genetics, such as APOE genotype.

Conclusions

EPA and DHA diminish fasting circulating TG levels via reduced production of VLDL. The mechanism of reduced VLDL production does not involve hepatic retention of lipids. Lowered postprandial TG levels are also explained by increased chylomicron clearance. Little is known about the specific cellular and biochemical mechanisms underlying the TG-lowering effects of EPA and DHA in humans.

Eicosapentaenoic acid and docosahexaenoic acid containing supplements modulate risk factors for cardiovascular disease: a meta-analysis of randomised placebo-control human clinical trials

BACKGROUND

Over 200 clinical trials have examined the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplements on risk factors associated with cardiovascular disease. However, an updated analysis of the evidence is lacking. The aim of the present meta-analysis was to quantify the effect of supplements containing EPA and DHA on risk factors for cardiovascular disease.

METHODS

An analysis was carried on 171 clinical trials with acceptable quality (Jadad score ≥3) that were identified from a comprehensive electronic search strategy of two databases (Pubmed and Cochrane Library). A random effect model was used to obtain an overall estimate on outcomes of interest. Heterogeneity between trial results was tested for using a standard chi-squared test.

RESULTS

Compared with control, EPA and DHA supplements produced significant reductions of triglycerides of 0.368 mmol L^-1 [95% confidence interval (CI) = -0.427 to -0.309], systolic blood pressure of 2.195 mmHg (95% CI = -3.172 to -1.217), diastolic blood pressure of 1.08 mmHg (95% CI = -1.716 to -0.444), heart rate of 1.37 bpm (95% CI = -2.41 to -0.325) and C-reactive protein of 0.343 mg L^-1 (95% CI = -0.454 to -0.232). This analysis indicates an increase in both low-density lipoprotein cholesterol (mean difference = 0.150 mmol L^-1 ; 95% CI = 0.058-0.243) and high-density lipoprotein cholesterol (mean difference = 0.039 mmol L^-1 ; 95% CI = 0.024-0.054). The triglyceride-lowering effect was dose-dependent.

CONCLUSIONS

The lipid-lowering, hypotensive, anti-arrhythmic and anti-inflammatory actions of EPA and DHA supplements were confirmed in this analysis of randomised placebo-control blinded clinical trials.

Dietary Strategies and Novel Pharmaceutical Approaches Targeting Serum ApoA-I Metabolism: A Systematic Overview

The incidence of CHD is still increasing, which underscores the need for new preventive and therapeutic approaches to decrease CHD risk. In this respect, increasing apoA-I concentrations may be a promising approach, especially through increasing apoA-I synthesis. This review first provides insight into current knowledge on apoA-I production, clearance, and degradation, followed by a systematic review of dietary and novel pharmacological approaches to target apoA-I metabolism. For this, a systematic search was performed to identify randomized controlled intervention studies that examined effects of whole foods and (non)nutrients on apoA-I metabolism. In addition, novel pharmacological approaches were searched for, which were specifically developed to target apoA-I metabolism. We conclude that both dietary components and pharmacological approaches can be used to increase apoA-I concentrations or functionality. For the dietary components in particular, more knowledge about the underlying mechanisms is necessary, as increasing apoA-I per se does not necessarily translate into a reduced CHD risk.

Association between the docosahexaenoic acid to arachidonic acid ratio and acute coronary syndrome: a multicenter observational study

Background

A low eicosapentaenoic acid (EPA) to arachidonic acid (AA) ratio is a known risk for acute coronary syndrome (ACS). However, the association between the docosahexaenoic acid (DHA) to AA ratio and ACS remains unclear. This study aimed to assess the association between the DHA/AA ratio and ACS by patient characteristics.

Methods

We enrolled 1733 patients and evaluated the serum levels of polyunsaturated fatty acids in 5 cardiology departments in a metropolitan area of Japan. We assessed the relationship between the DHA/AA ratio (median cut-off value: 0.903) and ACS according to the following 10 subgroups: sex, age, diabetes mellitus, hypertension, dyslipidemia, smoking history, family history of ischemic heart disease, chronic kidney disease, obesity, and history of coronary revascularization.

Results

Interaction tests in the 10 subgroup analyses revealed a significant difference for adjusted log odds ratios between male and females (p = 0.01), and those with and without hypertension (p = 0.06). Especially in the subgroup based on sex difference, a high DHA/AA ratio was significantly associated with a low risk of ACS among men (adjusted odds ratio = 0.389; 95 % confidence interval: 0.211–0.716). In contrast, a reverse association was found among women, although this was not statistically significant (adjusted odds ratio = 3.820; 95 % confidence interval: 0.718–20.325).

Conclusions

The association between the DHA/AA ratio and ACS differed by clinical characteristic. Notably, patients with a low DHA/AA ratio had a higher risk of ACS than those with a high DHA/AA ratio, and this was significant for men in particular.

Icosapent ethyl (eicosapentaenoic acid ethyl ester): Effects on plasma apolipoprotein C-III levels in patients from the MARINE and ANCHOR studies

BACKGROUND

Apolipoprotein C-III (ApoC-III) regulates lipoprotein and triglyceride (TG) metabolism and may have a causal role in cardiovascular disease. In the Multi-Center, Placebo-Controlled, Randomized, Double-Blind, 12-Week Study With an Open-Label Extension (MARINE) and ANCHOR studies, icosapent ethyl, a high-purity prescription eicosapentaenoic acid ethyl ester, reduced TG, and other atherogenic lipid parameters without increasing low-density lipoprotein cholesterol (LDL-C) compared with placebo.

OBJECTIVE

To evaluate the effects of icosapent ethyl on plasma ApoC-III levels in patients from 2 phase 3 studies.

METHODS

MARINE and ANCHOR were 12-week double-blind studies of icosapent ethyl in adult patients. Patients in MARINE had very high TG levels (≥500 and ≤2000 mg/dL) and patients in ANCHOR had high TG levels (≥200 and <500 mg/dL) despite statin control of LDL-C. This post hoc analysis of MARINE and ANCHOR assessed the median percent change from baseline in plasma ApoC-III levels vs placebo and includes subgroup analyses by statin use/efficacy and median ApoC-III levels.

RESULTS

We assessed ApoC-III levels in 148 and 612 patients in the MARINE and ANCHOR studies, respectively. In MARINE, the approved prescription dose of icosapent ethyl (4 g/day) significantly reduced ApoC-III levels by 25.1% (P < .0001) vs placebo. In ANCHOR, icosapent ethyl 4 g/day significantly reduced ApoC-III levels by 19.2% (P < .0001) vs placebo; subanalysis by statin efficacy revealed significant reductions vs placebo in the higher-efficacy and medium-efficacy groups (24.6% and 17.2%, respectively; both P < .0001).

CONCLUSION

Icosapent ethyl 4 g/day significantly reduced plasma ApoC-III levels in patients with elevated TGs from the MARINE and ANCHOR studies.

A review of the effect of omega-3 polyunsaturated fatty acids on blood triacylglycerol levels in normolipidemic and borderline hyperlipidemic individuals

Circulating levels of triacylglycerol (TG) is a recognized risk factor for developing cardiovascular disease, a leading cause of death worldwide. The Institute of Medicine and the American Heart Association both recommend the consumption of n-3 polyunsaturated fatty acids (PUFA), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), to reduce serum TG in hyperlipidemic individuals. Additionally, a number of systematic reviews have shown that individuals with any degree of dyslipidemia, elevated serum TG and/or cholesterol, may benefit from a 20-30 % reduction in serum TG after consuming n-3 PUFA derived from marine sources. Given that individuals with serum lipid levels ranging from healthy to borderline dyslipidemic constitute a large portion of the population, the focus of this review was to assess the potential for n-3 PUFA consumption to reduce serum TG in such individuals. A total of 1341 studies were retrieved and 38 clinical intervention studies, assessing 2270 individuals, were identified for inclusion in the current review. In summary, a 9-26 % reduction in circulating TG was demonstrated in studies where ≥ 4 g/day of n-3 PUFA were consumed from either marine or EPA/DHA-enriched food sources, while a 4-51 % reduction was found in studies where 1–5 g/day of EPA and/or DHA was consumed through supplements. Overall, this review summarizes the current evidence with regards to the beneficial effect of n-3 PUFA on circulating TG levels in normolipidemic to borderline hyperlipidemic, otherwise healthy, individuals. Thus demonstrating that n-3 PUFA may play an important role in the maintenance of cardiovascular health and disease prevention.

Comparison of the Effects of Eicosapentaenoic Acid With Docosahexaenoic Acid on the Level of Serum Lipoproteins in Helicobacter pylori: A Randomized Clinical Trial

Background:

Helicobacter pylori infection is the most common chronic bacterial infection around the world and an important cause of gastrointestinal disorders, which might be involved in the pathogenesis of some extragastrointestinal disturbances as well as changes in serum lipid profile. Hypolipemic properties of omega-3 fatty acids have been studied in several studies.

Objectives:

The present study aimed to compare the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on the level of serum lipoproteins in H. pylori.

Patients and Methods:

In a randomized, double-blinded, placebo-controlled clinical trial in Iran, 105 Helicobacter pylori were randomly allocated to receive 2 g of daily EPA (35 patients), DHA (35 patients), or medium-chain triglyceride (MCT) oil as placebo (33 patients) along with conventional tetra-drug H. pylori eradication regimen for 12 weeks.

Results:

From 105 included patients, 97 (31 in EPA, 33 in DHA, and 33 in control groups) completed the study and were included in final analysis. The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and the ratios of TG/HDL-C, TC/HDL-C, and LDL-C/HDL-C were not significantly different among the three groups, while the level of triglyceride (TG) was statistically different. DHA (-16.6 ± 30.34) and control (+ 15.32 ± 56.47) groups were statistically different with regard to changes in TG levels (P = 0.000).

Conclusions:

There was no difference between the effects of 2 g of EPA or DHA supplementation for 12 weeks on the levels of total cholesterol, LDL-C, HDL-C, TC/HDL-C, TG/HDL-C, and LDL-C/HDL-C; however, it had a desirable effect on the level of TG in a way that the effect of DHA was clearer.

Omega-3 polyunsaturated fatty acids and cardiovascular disease: an emphasis on omega-3-acid ethyl esters 90 for the treatment of hypertriglyceridemia

A number of epidemiological/observational studies, as well as large-scale randomized intervention studies, have been conducted to provide evidence for the efficacy of ω-3 fatty acids against atherosclerotic diseases. Currently, ω-3 fatty acids are commercially available in many parts of the world containing the same active ingredients as Lotriga(®) (ω-3-acid ethyl esters 90 [O3AE highly concentrated ω-3 fatty acid ethyl esters, consisting of eicosapentaenoic acid-ethyl ester and docosahexaenoic acid-ethyl ester [EPA-E/DHA-E]). A recent head-to-head comparative study of O3AEE90 versus EPA-E demonstrated that O3AEE90 4g/day led to a significantly greater reduction in triglycerides (TG) than EPA-E 1.8g/day and that O3AEE90 2g/day produced comparable effects on TG to those with EPA-E 1.8g/day. While both agents were shown to be useful in lowering TG, the hallmark feature of O3AEE90, that is, the presence of the DHA-E component versus its absence in EPA-E, needs to be further examined for its clinical implications.

Differential effects of eicosapentaenoic acid and docosahexaenoic acid in promoting the differentiation of 3T3-L1 preadipocytes

The objective of this study was to determine the effects of enrichment with n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the differentiation of 3T3-L1 preadipocytes. Enrichment with DHA but not EPA significantly increased the differentiation markers compared to control differentiated cells. DHA compared to EPA treatment led to a greater increase in adiponectin secretion and, conditioned media collected from DHA treated cells inhibited monocyte migration. Moreover, DHA treatment resulted in inhibition of pro-inflammatory signaling pathways. DHA treated cells predominantly accumulated DHA in phospholipids whereas EPA treatment led to accumulation of both EPA and its elongation product docosapentaenoic acid (DPA), an n-3 fatty acid. Of note, adding DPA to DHA inhibited DHA-induced differentiation. The differential effects of EPA and DHA on preadipocyte differentiation may be due, in part, to differences in their intracellular modification which could impact the type of n-3 fatty acids incorporated into the cells.

Omega-3 fatty acids: new insights into the pharmacology and biology of docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid

PURPOSE OF REVIEW

Fish oil contains a complex mixture of omega-3 fatty acids, which are predominantly eicosapentaenoic acid (EPA), docosapentaenoic acid, and docosahexaenoic acid (DHA). Each of these omega-3 fatty acids has distinct biological effects that may have variable clinical effects. In addition, plasma levels of omega-3 fatty acids are affected not only by dietary intake, but also by the polymorphisms of coding genes fatty acid desaturase 1-3 for the desaturase enzymes that convert short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. The clinical significance of this new understanding regarding the complexity of omega-3 fatty acid biology is the purpose of this review.

RECENT FINDINGS

FADS polymorphisms that result in either lower levels of long-chain omega-3 fatty acids or higher levels of long-chain omega-6 polyunsaturated fatty acids, such as arachidonic acid, are associated with dyslipidemia and other cardiovascular risk factors. EPA and DHA have differences in their effects on lipoprotein metabolism, in which EPA, with a more potent peroxisome proliferator-activated receptor-alpha effect, decreases hepatic lipogenesis, whereas DHA not only enhances VLDL lipolysis, resulting in greater conversion to LDL, but also increases HDL cholesterol and larger, more buoyant LDL particles.

SUMMARY

Overall, these results emphasize that blood concentrations of individual long-chain polyunsaturated fatty acids, which reflect both dietary intake and metabolic influences, may have independent, but also complementary- biological effects and reinforce the need to potentially provide a complex mixture of omega-3 fatty acids to maximize cardiovascular risk reduction.

Atherosclerosis, dyslipidemia, and inflammation: the significant role of polyunsaturated Fatty acids

Phospholipids play an essential role in cell membrane structure and function. The length and number of double bonds of fatty acids in membrane phospholipids are main determinants of fluidity, transport systems, activity of membrane-bound enzymes, and susceptibility to lipid peroxidation. The fatty acid profile of serum lipids, especially the phospholipids, reflects the fatty acid composition of cell membranes. Moreover, long-chain n-3 polyunsatured fatty acids decrease very-low-density lipoprotein assembly and secretion reducing triacylglycerol production. N-6 and n-3 polyunsatured fatty acids are the precursors of signalling molecules, termed "eicosanoids," which play an important role in the regulation of inflammation. Eicosanoids derived from n-6 polyunsatured fatty acids have proinflammatory actions, while eicosanoids derived from n-3 polyunsatured fatty acids have anti-inflammatory ones. Previous studies showed that inflammation contributes to both the onset and progression of atherosclerosis: actually, atherosclerosis is predominantly a chronic low-grade inflammatory disease of the vessel wall. Several studies suggested the relationship between long-chain n-3 polyunsaturated fatty acids and inflammation, showing that fatty acids may decrease endothelial activation and affect eicosanoid metabolism.

The effect of EPA and DHA on metabolic syndrome patients: a systematic review of randomised controlled trials

Metabolic syndrome (MS) is characterised by accumulation of CVD risk factors. The use of very long chain n-3 polyunsaturated fatty acids (VLC n3 PUFA) could potentially benefit MS by reducing risk factors. To better understand the possible VLC n3 PUFA benefits, the literature was systematically reviewed for randomised controlled trials (RCT) that published effects of VLC n3 PUFA on MS patients. 17 RCT fulfilled the inclusion criteria and were analysed for relevance to the research question. The available RCT convincingly show that the administration of VLC n3 PUFA doses > 1 g for at least 3 months produces a significant reduction of triglycerides ranging from 7 % to 25 %. These results confirm the hypotriglyceridemic effect of VLC n3 PUFA in MS patients. The triglyceride lowering may produce further benefits by reducing the % of pro-atherogenic small dense LDL particles (sdLDL) and also perhaps by ameliorating the inflammatory process associated with MS. High doses of VLC n3 PUFA ( ≥ 3 g/day) may produce further TAG reductions but could raise other risk factors such as LDL-C. No clear effects were found on other MS markers. The combination of VLC n3 PUFA plus a statin may be useful to prevent the occurrence of coronary events. More studies are needed using different amounts of VLC n3 PUFA, time lengths, dietary backgrounds and different profiles of MS patients before clear recommendations can be made.

(n-3) fatty acids and cardiovascular health: are effects of EPA and DHA shared or complementary?

Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil. Whether individual long-chain (n-3) PUFA have shared or complementary effects is not well established. We reviewed evidence for dietary and endogenous sources and cardiovascular effects on biologic pathways, physiologic risk factors, and clinical endpoints of EPA [20:5(n-3)], docosapentaenoic acid [DPA, 22:5(n-3)], and DHA [22:6(n-3)]. DHA requires direct dietary consumption, with little synthesis from or retroconversion to DPA or EPA. Whereas EPA is also largely derived from direct consumption, EPA can also be synthesized in small amounts from plant (n-3) precursors, especially stearidonic acid. In contrast, DPA appears principally derived from endogenous elongation from EPA, and DPA can also undergo retroconversion back to EPA. In experimental and animal models, both EPA and DHA modulate several relevant biologic pathways, with evidence for some differential benefits. In humans, both fatty acids lower TG levels and, based on more limited studies, favorably affect cardiac diastolic filling, arterial compliance, and some metrics of inflammation and oxidative stress. All three (n-3) PUFA reduce ex vivo platelet aggregation and DHA also modestly increases LDL and HDL particle size; the clinical relevance of such findings is uncertain. Combined EPA+DHA or DPA+DHA levels are associated with lower risk of fatal cardiac events and DHA with lower risk of atrial fibrillation, suggesting direct or indirect benefits of DHA for cardiac arrhythmias (although not excluding similar benefits of EPA or DPA). Conversely, EPA and DPA, but not DHA, are associated with lower risk of nonfatal cardiovascular endpoints in some studies, and purified EPA reduced risk of nonfatal coronary syndromes in one large clinical trial. Overall, for many cardiovascular pathways and outcomes, identified studies of individual (n-3) PUFA were relatively limited, especially for DPA. Nonetheless, the present evidence suggests that EPA and DHA have both shared and complementary benefits. Based on current evidence, increasing consumption of either would be advantageous compared to little or no consumption. Focusing on their combined consumption remains most prudent given the potential for complementary effects and the existing more robust literature on cardiovascular benefits of their combined consumption as fish or fish oil for cardiovascular benefits.

Similarities and differences between the effects of EPA and DHA on markers of atherosclerosis in human subjects

We have reviewed effects of long chain (LC) n-3 PUFA on markers of atherosclerosis in human subjects with a focus on individual effects of EPA and DHA. Initial results from epidemiological studies suggested that LC n-3 PUFA from fish oils (FO) reduced incidence of CVD; those results have been confirmed in interventional studies. Dietary intervention with n-3 PUFA decreased fasting and postprandial TAG, number of remnant-like chylomicron particles, large VLDL, and total and small dense LDL particles. It increased mean size of LDL particles by increasing number of large and decreasing those of small dense particles. With some exceptions, n-3 PUFA decreased blood pressure (BP) and heart rate (HR), flow-mediated dilation (FMD) and plasma concentrations of inflammatory markers. n-3 PUFA also decreased circulating adhesion molecules and intima-media thickness (IMT) in some but not other studies. For IMT, results varied with the sex and artery being examined. EPA effects on FMD are endothelial cell dependent, while those of DHA seem to be endothelial cell independent. Individually, both EPA and DHA decreased TAG and inflammatory markers, but only DHA decreased HR, BP and number of small dense LDL particles. Results varied because of dose and duration of n-3 PUFA, EPA:DHA, health status of subjects and other reasons. Future studies are needed to determine optimal doses of EPA and DHA individually, their synergistic, additive or antagonistic effects, and to understand underlying mechanisms. In conclusion, n-3 PUFA decreased several risk factors for atherosclerosis without any serious adverse effects.

Increasing dietary linoleic acid does not increase tissue arachidonic acid content in adults consuming Western-type diets: a systematic review

Background

Linoleic acid, with a DRI of 12-17 g/d, is the most highly consumed polyunsaturated fatty acid in the Western diet and is found in virtually all commonly consumed foods. The concern with dietary linoleic acid, being the metabolic precursor of arachidonic acid, is its consumption may enrich tissues with arachidonic acid and contribute to chronic and overproduction of bioactive eicosanoids. However, no systematic review of human trials regarding linoleic acid consumption and subsequent changes in tissue levels of arachidonic acid has been undertaken.

Objective

In this study, we reviewed the human literature that reported changes in dietary linoleic acid and its subsequent impact on changing tissue arachidonic acid in erythrocytes and plasma/serum phospholipids.

Design

We identified, reviewed, and evaluated all peer-reviewed published literature presenting data outlining changes in dietary linoleic acid in adult human clinical trials that reported changes in phospholipid fatty acid composition (specifically arachidonic acid) in plasma/serum and erythrocytes within the parameters of our inclusion/exclusion criteria.

Results

Decreasing dietary linoleic acid by up to 90% was not significantly correlated with changes in arachidonic acid levels in the phospholipid pool of plasma/serum (p = 0.39). Similarly, when dietary linoleic acid levels were increased up to six fold, no significant correlations with arachidonic acid levels were observed (p = 0.72). However, there was a positive relationship between dietary gamma-linolenic acid and dietary arachidonic acid on changes in arachidonic levels in plasma/serum phospholipids.

Conclusions

Our results do not support the concept that modifying current intakes of dietary linoleic acid has an effect on changing levels of arachidonic acid in plasma/serum or erythrocytes in adults consuming Western-type diets.

The differential effects of EPA and DHA on cardiovascular risk factors

Compelling evidence exists for the cardioprotective benefits resulting from consumption of fatty acids from fish oils, EPA (20:5n-3) and DHA (22:6n-3). EPA and DHA alter membrane fluidity, interact with transcription factors such as PPAR and sterol regulatory element binding protein, and are substrates for enzymes including cyclooxygenase, lipoxygenase and cytochrome P450. As a result, fish oils may improve cardiovascular health by altering lipid metabolism, inducing haemodynamic changes, decreasing arrhythmias, modulating platelet function, improving endothelial function and inhibiting inflammatory pathways. The independent effects of EPA and DHA are poorly understood. While both EPA and DHA decrease TAG levels, only DHA appears to increase HDL and LDL particle size. Evidence to date suggests that DHA is more efficient in decreasing blood pressure, heart rate and platelet aggregation compared to EPA. Fish oil consumption appears to improve arterial compliance and endothelial function; it is not yet clear as to whether differences exist between EPA and DHA in their vascular effects. In contrast, the beneficial effect of fish oils on inflammation and insulin sensitivity observed in vitro and in animal studies has not been confirmed in human subjects. Further investigation to clarify the relative effects of consuming EPA and DHA at a range of doses would enable elaboration of current understanding regarding cardioprotective effects of consuming oily fish and algal sources of long chain n-3 PUFA, and provide clearer evidence for the clinical therapeutic potential of consuming either EPA or DHA-rich oils.

Nutritional compounds influence tissue factor expression and inflammation of chronic kidney disease patients in vitro

OBJECTIVE

Nutritional compounds that potentially limit inflammation and tissue factor expression may decrease the progression of chronic kidney disease (CKD) and associated cardiovascular disease. This project aimed to determine the effect of curcumin, bovine colostrum, and fish oil on inflammatory cytokine and tissue factor procoagulant activity of peripheral blood mononuclear cells (PBMCs) from patients with CKD before dialysis.

METHODS

Peripheral blood mononuclear cells from patients with CKD before dialysis (n = 13) and age- and sex-matched healthy controls (n = 12) were cultured alone and with low and high doses of the nutritional compounds for 24 h. Cells were cultured with and without lipopolysaccharide. Supernatants were analyzed for tumor necrosis factor-α, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1, IL-1β, C-reactive protein, and tissue factor procoagulant activity.

RESULTS

The production of C-reactive protein, monocyte chemoattractant protein-1, IL-6, and IL-1β by PBMCs was inhibited by low- and high-dose fish oil in the CKD group (P < 0.05). Curcumin decreased secretion of IL-6 (P = 0.015) and IL-1 β (P = 0.016). Curcumin was more effective than colostrum at decreasing the procoagulant activity of PBMCs in the CKD and control groups (P < 0.019).

CONCLUSION

Fish oil decreased inflammatory cytokine secretion from CKD PBMCs. In addition, the beneficial effects of curcumin were demonstrated in decreasing inflammation in vitro, often to a similar magnitude as fish oil.

Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid dose-dependently reduce fasting serum triglycerides

The objectives of this review were to determine whether the long-chain omega-3 fatty acids eicosapentaenoic acid and/or docosahexaenoic acid dose-dependently reduce fasting serum triglycerides (TG) and, if so, to create a mathematical model that may be used to predict potential percent reductions in fasting serum TG levels at the recommended intakes of 200-500 mg/day. The assessment included 15 randomized controlled trials that met pre-defined inclusion and exclusion criteria. Across these 15 studies, the dose-response was modeled using a first-order elimination curve. The response variable was defined as percent change from baseline in fasting serum TG, adjusted for the placebo effect. A weighting factor equal to the product of each study's sample size and quality score was used. Using the equation of the dose-response curve, predicted reductions in fasting serum TG levels at the recommended long-chain omega-3 fatty acid intakes of 200-500 mg/day are 3.1 to 7.2%.

Comparison of seal oil to tuna oil on plasma lipid levels and blood pressure in hypertriglyceridaemic subjects

As meat is a rich source of the omega-3 fatty acid docosapentaenoic acid (DPA) and Australians consume six times more meat than fish, investigation of the potential health benefit of DPA is warranted. The aims were to compare the effects of seal oil supplementation with fish oil, on measures of plasma lipids and blood pressure in hypertriglyceridaemic subjects. Forty-eight volunteers were recruited from the Wollongong community and were randomly allocated to one of three groups either receiving 1 g/day of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) using one of three oils: seal oil capsules (340 mg eicosapentaenoic acid (EPA), 230 mg DPA, 450 mg DHA), fish oil capsules (210 mg EPA, 30 mg DPA, 810 mg DHA) or placebo capsules (containing sunola oil) for 6 weeks. Plasma triglycerides remained unchanged in the placebo group, whilst reductions of 7 and 14% (P < 0.05) were seen in the fish oil and seal oil groups respectively. Systolic blood pressure improved by 8 and 5 mmHg with seal oil and fish oil respectively (P < 0.05). The mean arterial pressure was significantly lower after seal oil supplementation (P < 0.005) compared with the placebo group. These results indicate that seal oil is as effective as fish oil in lowering plasma triglycerides and blood pressure.

Effects of moderate-dose omega-3 fish oil on cardiovascular risk factors and mood after ischemic stroke: a randomized, controlled trial

BACKGROUND AND PURPOSE

Fish-derived omega-3 fatty acids have long been associated with cardiovascular protection. In this trial, we assessed whether treatment with a guideline-recommended moderate-dose fish oil supplement could improve cardiovascular biomarkers, mood- and health-related quality of life in patients with ischemic stroke.

METHODS

Patients with CT-confirmed stroke were randomized to 3 g/day encapsulated fish oil containing approximately 1.2 g total omega-3 (0.7 g docosahexaenoic acid; 0.3 g eicosapentaenoic acid) or placebo oil (combination palm and soy) taken daily over 12 weeks. Serum triglycerides, total cholesterol and associated lipoproteins, selected inflammatory and hemostatic markers, mood, and health-related quality of life were assessed at baseline and follow-up. The primary outcome was change in triglycerides. Compliance was assessed by capsule count and serum phospholipid omega-3 levels (Australian Clinical Trials Registration: ACTRN12605000207617).

RESULTS

One hundred two patients were randomized to fish oil or placebo. Intention-to-treat and per-protocol (>85% compliance) analyses showed no significant effect of fish oil treatment on any lipid, inflammatory, hemostatic, or composite mood parameters measured. Adherence to treatment based on pill count was good (89%) reflected by increased serum docosahexanoic acid (P<0.001) and eicosapentaenoic acid (P=0.0006) in the fish oil group. Analysis of oil composition, however, showed some degradation and potentially adverse oxidation products at the end of the study.

CONCLUSIONS

There was no effect of 12 weeks of treatment with moderate-dose fish oil supplements on cardiovascular biomarkers or mood in patients with ischemic stroke. It is possible that insufficient dose, short duration of treatment, and/or oxidation of the fish oils may have influenced these outcomes.

Contribution of apolipoprotein E genotype and docosahexaenoic acid to the LDL-cholesterol response to fish oil

OBJECTIVES

To investigate the impact of apolipoprotein E (apoE) genotype on the response of the plasma lipoprotein profile to eicosapentaenoic acid (EPA) versus docosahexaenoic acid (DHA) intervention in humans.

METHODS AND RESULTS

38 healthy normolipidaemic males, prospectively recruited on the basis of apoE genotype (n=20 E3/E3 and n=18 E3/E4), completed a double-blind placebo-controlled cross-over trial, consisting of 3 x 4 week intervention arms of either control oil, EPA-rich oil (ERO, 3.3g EPA/day) or DHA-rich oil (DRO, 3.7g DHA/day) in random order, separated by 10 week wash-out periods. A significant genotype-independent 28% and 19% reduction in plasma triglycerides in response to ERO and DRO was observed. For total cholesterol (TC), no significant treatment effects were evident; however a significant genotype by treatment interaction emerged (P=0.045), with a differential response to ERO and DRO in E4 carriers. Although the genotype x treatment interaction for LDL-cholesterol (P=0.089) did not reach significance, within DRO treatment analysis indicated a 10% increase in LDL (P=0.029) in E4 carriers with a non-significant 4% reduction in E3/E3 individuals. A genotype-independent increase in LDL mass was observed following DRO intervention (P=0.018). Competitive uptake studies in HepG2 cells using plasma very low density lipoproteins (VLDL) from the human trial, indicated that following DRO treatment, VLDL(2) fractions obtained from E3/E4 individuals resulted in a significant 32% (P=0.002) reduction in LDL uptake relative to the control.

CONCLUSIONS

High dose DHA supplementation is associated with increases in total cholesterol in E4 carriers, which appears to be due to an increase in LDL-C and may in part negate the cardioprotective action of DHA in this population subgroup.

Intervention with fish oil, but not with docosahexaenoic acid, results in lower levels of hepatic soluble epoxide hydrolase with time in apoE knockout mice

Long-chain n-3 PUFA from fish oil protect against death from CHD but mechanisms are not well understood. Preliminary results indicate that fish oil may affect the enzyme soluble epoxide hydrolase (sEH) and influence inflammatory pathways in a time-dependent manner. In the present study male apoE knockout (Apoe-/-) mice were randomised to three dietary groups receiving a high-fat high-cholesterol diet supplemented with 2 % (w/w) high-oleic acid sunflower-seed (HOSF) oil, DHA oil or fish oil. Livers and proximal aortas were collected on day 2 and on weeks 1, 2, 4 and 10 to determine hepatic sEH levels, hepatic fatty acid composition, hepatic proteome and atherosclerotic plaque size in the aortic root. Intervention with fish oil, but not with DHA, resulted in significantly lower levels of hepatic sEH levels with time compared with HOSF oil. DHA and fish oil caused differential regulation of thirty-five hepatic proteins which were mainly involved in lipoprotein metabolism and oxidative stress. All mice developed atherosclerosis without differences in plaque size between the three groups. Thus EPA may be responsible for lowering levels of hepatic sEH and both fish oil and DHA could beneficially affect lipoprotein metabolism and oxidative stress.