Effects of trans- and n-3 unsaturated fatty acids on cardiovascular risk markers in healthy males. An 8 weeks dietary intervention study

Euphausia pacifica emulsified oil powder improves sleep quality in partially sleep-restricted healthy volunteers

Although it is known that adequate sleep is crucial for maintaining a healthy lifestyle, approximately 30% of the general population has experienced insomnia. Thus, a better understanding of the relationship between food components and sleep quality is needed. North Pacific krill, Euphausia pacifica, is rich in marine n-3 polyunsaturated fatty acids in phospholipid form as well as 8R-hydroxy-eicosapentanoic acid. Here, emulsified oil powder derived from this krill was used in a trial involving 64 participants to assess its potential to enhance sleep quality. Consumption of the powdered emulsified oil was found to reduce drowsiness upon waking and enhance fatigue recovery, and for participants aged 40 and above, an improvement in sleep cycle was observed. In conclusion, consumption of krill emulsified oil powder was effective in enhancing sleep quality for individuals with partial sleep restrictions.

Omega-3 fatty acids and endothelial function: A GRADE-assessed systematic review and meta-analysis

INTRODUCTION

N-3 polyunsaturated fatty acids (PUFAs) supplementation has been reported to have an impact on flow-mediated dilatation (FMD), a conventionally used clinical technique for estimating endothelial dysfunction. However, its proven effects on endothelial function are unclear. This systematic review and meta-analysis were conducted to evaluate the effects of n-3 PUFAs supplementation on FMD of the brachial artery.

METHOD

This study was performed following the PRISMA guidelines. To identify eligible RCTs, a systematic search was completed in PubMed/Medline, Scopus and Web of Science using relevant keywords. A fixed- or random-effects model was utilized to estimate the weighted mean difference (WMD) and 95% confidence interval (95% CI).

RESULTS

Thirty-two studies (with 35 arms) were included in this meta-analysis, involving 2385 subjects with intervention duration ranging from 4 to 48 weeks. The pooled meta-analysis demonstrated a significant effect of omega-3 on FMD (WMD = 0.8%, 95% CI = 0.3-1.3, p = .001) and heterogeneity was significant (I2  = 82.5%, p < .001).

CONCLUSION

We found that n-3 PUFA supplementation improves endothelial function as estimated by flow-mediated dilatation of the brachial artery.

Association Between Omega-3 Fatty Acid Intake and Dyslipidemia: A Continuous Dose-Response Meta-Analysis of Randomized Controlled Trials

Background Previous results provide supportive but not conclusive evidence for the use of omega-3 fatty acids to reduce blood lipids and prevent events of atherosclerotic cardiovascular disease, but the strength and shape of dose-response relationships remain elusive. Methods and Results This study included 90 randomized controlled trials, reported an overall sample size of 72 598 participants, and examined the association between omega-3 fatty acid (docosahexaenoic acid, eicosapentaenoic acid, or both) intake and blood lipid changes. Random-effects 1-stage cubic spline regression models were used to study the mean dose-response association between daily omega-3 fatty acid intake and changes in blood lipids. Nonlinear associations were found in general and in most subgroups, depicted as J-shaped dose-response curves for low-/high-density lipoprotein cholesterol. However, we found evidence of an approximately linear dose-response relationship for triglyceride and non-high-density lipoprotein cholesterol among the general population and more evidently in populations with hyperlipidemia and overweight/obesity who were given medium to high doses (>2 g/d). Conclusions This dose-response meta-analysis demonstrates that combined intake of omega-3 fatty acids near linearly lowers triglyceride and non-high-density lipoprotein cholesterol. Triglyceride-lowering effects might provide supportive evidence for omega-3 fatty acid intake to prevent cardiovascular events.

Omega-3 Polyunsaturated Fatty Acids Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials

Background

Current evidence might support the use of omega‐3 fatty acids (preferably docosahexaenoic acid and eicosapentaenoic acid) for lowering blood pressure (BP), but the strength and shape of the dose‐response relationship remains unclear.

Methods and Results

This study included randomized controlled trials published before May 7, 2021, that involved participants aged ≥18 years, and examined an association between omega‐3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid, or both) and BP. A random‐effects 1‐stage cubic spline regression model was used to predict the average dose‐response association between daily omega‐3 fatty acid intake and changes in BP. We also conducted stratified analyses to examine differences by prespecified subgroups. Seventy‐one trials were included, involving 4973 individuals with a combined docosahexaenoic acid+eicosapentaenoic acid dose of 2.8 g/d (interquartile range, 1.3 g/d to 3.6 g/d). A nonlinear association was found overall or in most subgroups, depicted as J‐shaped dose‐response curves. The optimal intake in both systolic BP and diastolic BP reductions (mm Hg) were obtained by moderate doses between 2 g/d (systolic BP, −2.61 [95% CI, −3.57 to −1.65]; diastolic BP, −1.64 [95% CI, −2.29 to −0.99]) and 3 g/d (systolic BP, −2.61 [95% CI, −3.52 to −1.69]; diastolic BP, −1.80 [95% CI, −2.38 to −1.23]). Subgroup studies revealed stronger and approximately linear dose‐response relations among hypertensive, hyperlipidemic, and older populations.

Conclusions

This dose‐response meta‐analysis demonstrates that the optimal combined intake of omega‐3 fatty acids for BP lowering is likely between 2 g/d and 3 g/d. Doses of omega‐3 fatty acid intake above the recommended 3 g/d may be associated with additional benefits in lowering BP among groups at high risk for cardiovascular diseases.

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.

Modulation of endothelial cell responses and vascular function by dietary fatty acids

Healthy and functional endothelial cells play important roles in maintaining vascular homeostasis, whereas endothelial dysfunction initiates and exacerbates vascular disease progression. Interventional studies with dietary fatty acids have shown that these molecules have varying effects on vascular function. It is hypothesized that the actions of dietary fatty acids on vascular function may be mediated in part through endothelial cells. This review summarizes the results of studies that have examined the acute and chronic effects of dietary fatty acids on endothelial function and vascular properties in humans, as well as the potential mechanisms by which n-3 polyunsaturated fatty acids regulate endothelial function. Altogether, this article provides an extensive review of how fatty acids contribute to vascular function through their ability to modulate endothelial cells and discusses relationships between dietary fatty acids and endothelial cells in the context of vascular dysfunction.

Heart-rate variability: a biomarker to study the influence of nutrition on physiological and psychological health?

As the influence of diet on health may take place over a period of decades, there is a need for biomarkers that help to identify those aspects of nutrition that have either a positive or a negative influence. The evidence is considered that heart-rate variability (HRV) (the time differences between one beat and the next) can be used to indicate the potential health benefits of food items. Reduced HRV is associated with the development of numerous conditions for example, diabetes, cardiovascular disease, inflammation, obesity and psychiatric disorders. Although more systematic research is required, various aspects of diet have been shown to benefit HRV acutely and in the longer term. Examples include a Mediterranean diet, omega-3 fatty acids, B-vitamins, probiotics, polyphenols and weight loss. Aspects of diet that are viewed as undesirable, for example high intakes of saturated or trans-fat and high glycaemic carbohydrates, have been found to reduce HRV. It is argued that the consistent relationship between HRV, health and morbidity supports the view that HRV has the potential to become a widely used biomarker when considering the influence of diet on mental and physical health.

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.

Dietary fat composition: replacement of saturated fatty acids with PUFA as a public health strategy, with an emphasis on α-linolenic acid

SFA intakes have decreased in recent years, both in Ireland and across other European countries; however a large proportion of the population are still not meeting the SFA recommendation of &lt;10% of total energy (TE). High SFA intakes have been associated with increased CVD and type-2 diabetes (T2D) risk, due to alterations in cholesterol homoeostasis and adipose tissue inflammation. PUFA, in particular EPA and DHA, have been associated with health benefits, including anti-inflammatory effects. It is well established that dietary fat composition plays an important role in biological processes. A recent review of evidence suggests that replacement of SFA with PUFA has potential to reduce risk of CVD and T2D. The public health and molecular impact of EPA and DHA have been well-characterised, while less is known of effects of α-linolenic acid (ALA). The current dietary guideline for ALA is 0·5% TE; however evidence from supplementation trials suggests that benefit is observed at levels greater than 2 g/d (0·6-1% TE). This review highlights the gap in the evidence base relating to effects of the replacement of SFA with ALA, identifying the need for randomised controlled trials to determine the optimal dose of ALA substitution to define the efficacy of dietary fat modification with ALA.

Replacement of pork fat in frankfurter-type sausages by soybean oil oleogels structured with rice bran wax

The objective of this study was to assess the impact of replacing pork backfat with rice bran wax oleogels on the organoleptic properties of frankfurter-type finely-comminuted sausages. Frankfurters were formulated using the following treatments as lipid replacement: 1) pork fat (PF); 2) soybean oil (SBO); 3) 2.5% rice bran wax oleogel (2.5 RBW); 4) 10% rice bran wax oleogel (10 RBW); and 5) 2.5% rice bran wax oleogel sheared less during frankfurter production (RBW/LS). In general, control PF was darker and redder than other treatments. TPA revealed oleogel treatments to be similar (P > .05) to pork fat treatment for firmness, chewiness, and springiness. Additionally, sensory evaluation revealed that replacing pork fat did not influence cured frankfurter aroma, but cured frankfurter flavor was significantly reduced (P < .05). Furthermore, lipid oxidation significantly (P < .05) differed between PF and 10 RBW. The results show that rice bran wax oleogels have the potential to successfully replace pork fat in comminuted products.

Functional Food and Cardiovascular Disease Prevention and Treatment: A Review

Cardiovascular disease (CVD) is now the leading cause of death globally and is a growing health concern. Lifestyle factors, including nutrition, play an important role in the etiology and treatment of CVD. Functional foods based on their basic nutritional functions can decrease the risk of many chronic diseases and have some physiological benefits. They contain physiologically active components either from plant or animal sources, marketed with the claim of their ability to reduce heart disease risk, focusing primarily on established risk factors, which are hyperlipidemia, diabetes, metabolic syndrome, obesity/overweight, elevated lipoprotein A level, small dense low-density lipoprotein cholesterol (LDL-C), and elevated inflammatory marker levels. Functional foods are suspected to exert their cardioprotective effects mainly through blood lipid profile level and improve hypertension control, endothelial function, platelet aggregation, and antioxidant actions. Clinical and epidemiological observations indicate that vegetable and fruit fiber, nuts and seeds, sea foods, coffee, tea, and dark chocolate have cardioprotective potential in humans, as well whole-grain products containing intact grain kernels rich in fiber and trace nutrients. They are nutritionally more important because they contain phytoprotective substances that might work synergistically to reduce cardiovascular risk. This review will focus on the reciprocal interaction between functional foods and the potential link to cardiovascular health and the possible mechanisms of action.

Effect of omega-3 long-chain polyunsaturated fatty acid supplementation on heart rate: a meta-analysis of randomized controlled trials

Background

Elevated resting heart rate (HR) has emerged as a new risk factor for all-cause and cardiovascular mortality. The effect of marine-derived omega-3 long-chain polyunsaturated fatty acid (n−3 LCPUFAs) supplementation on HR was investigated as an outcome in many clinical trials. The present study was to provide an updated meta-analysis on the HR-slowing effect of n−3 LCPUFAs, and to differentiate the chronotropic effect between eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Methods

PubMed and Cochrane databases were searched for relevant articles examining the effects of n−3 PUFAs on HR through May 2017. A random-effects model was used to generate the pooled effect sizes and 95% confidence intervals (CIs). The pooled effect sizes were presented as weighted mean differences (WMDs).

Results

A total of 51 randomized controlled trials (RCTs) with approximately 3000 participants were included in this meta-analysis. Compared to placebo, n−3 PUFA supplementation mildly but significantly reduced HR (−2.23 bpm; 95% CI: −3.07, −1.40 bpm). Moderate evidence of heterogeneity was observed among included trials (I² = 49.1%, P heterogeneity < 0.001). When DHA and EPA were separately administered, modest HR reduction was observed in trials that supplemented with DHA (−2.47 bpm; 95% CI: −3.47, −1.46 bpm), but not in trials with EPA.

Conclusions

The present meta-analysis provides strong clinical evidence demonstrating the effect of heart rate reduction by n−3 LCPUFA supplementation. When DHA or EPA administered alone, heart rate was slowed by DHA rather than by EPA.

Egg consumption, cardiovascular diseases and type 2 diabetes

Eggs are rich in nutrients and a source of essential fatty- and amino acids, and the food item with highest cholesterol content. Since the 1970s dietary recommendations have advised limiting egg intake to 2-4 a week for the healthy population, and in those diagnosed with cardiovascular disease (CVD) and type 2 diabetes (T2D) an even more restricted consumption. The aim of the present paper was to assess the recommendation to lower the dietary intake of cholesterol and especially the intake of egg to reduce the risk of CVD and T2D. We performed three web-based literature searches on human studies (observational and interventional) published within the past 10 years during spring 2015. High-quality intervention studies have found nonsignificant effects of increasing the consumption of eggs on risk markers for CVD and T2D in healthy subjects and subjects with T2D. The risk associations found in the observational studies are more likely to be attributed to a dietary pattern often accompanying high egg intake and/or the cluster of other risk factors in people with high egg consumption. Dietary patterns, physical activity and genetics affect the predisposition of CVD and T2D more than a single food item as eggs. In conclusion, up to seven eggs per week can safely be consumed, but in patients with established CVD or T2D only with special emphasis on a healthy lifestyle.

Modulation of heart rate and heart rate variability by n-3 long chain polyunsaturated fatty acids: Speculation on mechanism(s)

Heart rate (HR) and heart rate variability (HRV) are valuable markers of health. Although the underlying mechanism(s) are controversial, it is well documented that n-3 long chain polyunsaturated fatty acid (LCPUFA) intake improves HR and HRV in various populations. Autonomic modulation and/or alterations in cardiac electrophysiology are commonly cited as potential mechanisms responsible for these effects. This article reviews existing evidence for each and explores a separate mechanism which has not received much attention but has scientific merit. Based on presented evidence, it is proposed that n-3 LCPUFAs affect HR and HRV directly by autonomic modulation and indirectly by altering circulating factors, both dependently and independently of the autonomic nervous system. The evidence for changes in cardiac electrophysiology as the mechanism by which n-3 LCPUFAs affect HR and HRV needs strengthening.

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.

Effect of soy lecithin on total cholesterol content, fatty acid composition and carcass characteristics in the Longissimus dorsi of Hanwoo steers (Korean native cattle)

This study aims to investigate the effect of soy lecithin on the total cholesterol content, the fatty acid composition and carcass characteristics in the Longissimus dorsi in Hanwoo steers. Hanwoo steers (24 head) were fed two diets: Control (CON) (concentrate + alcohol-fermented feed (AFF)) and soy lecithin treatment (CON + soy lecithin at 0.5% of the AFF). Soy lecithin treatment increased average daily gain, serum concentrations of triglyceride, total cholesterol and high-density lipoprotein-cholesterol in the blood. A lower cholesterol concentration was found in the Longissimus dorsi for the soy lecithin diet compared to the CON diet. With respect to the marbling score and quality grade of Longissimus dorsi, soy lecithin supplementation significantly increased the C20:5n3, C22:4 and polyunsaturated fatty acids contents compared to the CON diet. Soy lecithin supplementation would alter the total cholesterol content, polyunsaturated fatty acid profile and meat quality of Longissimus dorsi.

Plasma trans-fatty acid concentrations continue to be associated with metabolic syndrome among US adults after reductions in trans-fatty acid intake

No study examined and compared the association between intake of trans-fatty acids (TFAs) and risk of metabolic syndrome before and after significant reduction of TFA intakes in the US population. We hypothesized that the relationship might remain significant after substantial reduction of TFA intakes in the population. We used data on 1442 and 2233 adults aged ≥20 years from the National Health and Nutrition Examination Survey 1999-2000 and 2009-2010, respectively. Multivariable logistic regression analysis was used to assess the association between plasma TFA concentrations and metabolic syndrome, including each of its 5 components. The median plasma TFA concentrations were reduced from 79.8 μmol/L in 1999-2000 to 36.9 μmol/L in 2009-2010. The fully adjusted prevalence ratios comparing the highest vs the lowest quintile of plasma TFA concentrations in 1999-2000 were 3.43 (95% confidence interval, 2.39-4.92) for metabolic syndrome, 1.72 (1.38-2.14) for large waistline, 8.25 (6.34-10.74) for high triglycerides, 1.96 (1.46-2.62) for low high-density lipoprotein cholesterol, 1.14 (0.85-1.55) for high blood pressure, and 1.48 (1.19-1.85) for high fasting glucose, respectively. The corresponding prevalence ratios in 2009-2010 were 2.93 (2.41-3.54), 1.62 (1.39-1.89), 14.93 (9.28-24.02), 3.09 (2.18-4.37), 1.27 (1.11-1.46), and 1.24 (1.06-1.46), respectively. The pattern of association between TFAs and metabolic syndrome and its components did not differ by cycles. The observed associations were consistent across the subgroups examined. Despite a 54% decline in plasma TFA concentrations from 1999-2000 to 2009-2010, it was positively associated with risk of metabolic syndrome and its individual components except for blood pressure in 1999-2000. Our findings support Food and Drug Administration initiatives to remove TFAs from the industrially-produced foods.

The future for long chain n-3 PUFA in the prevention of coronary heart disease: do we need to target non-fish-eaters?

Dietary guidelines in many countries include a recommendation to consume oily fish, mainly on the basis of evidence from prospective cohort studies that fish consumption is cardioprotective. However, average intakes are very low in a large proportion of the UK population. Some groups, such as vegans and vegetarians, purposely omit fish (along with meat) from their diet resulting in zero or trace intakes of long chain (LC) n-3 PUFA. Although the efficacy of dietary fish oil supplementation in the prevention of CVD has been questioned in recent years, the balance of evidence indicates that LC n-3 PUFA exert systemic pleiotropic effects through their influence on gene expression, cell signalling, membrane fluidity and by conversion to specialised proresolving mediators; autacoid lipid mediators that resolve inflammatory events. The long-term impact of reduced tissue LC n-3 PUFA content on cardiovascular health is surprisingly poorly understood, particularly with regard to how low proportions of LC n-3 PUFA in cell membranes may affect cardiac electrophysiology and chronic inflammation. Randomised controlled trials investigating effects of supplementation on prevention of CHD in populations with low basal LC n-3 PUFA tissue status are lacking, and so the clinical benefits of supplementing non-fish-eating groups with vegetarian sources of LC n-3 PUFA remain to be determined. Refocusing dietary LC n-3 PUFA intervention studies towards those individuals with a low LC n-3 PUFA tissue status may go some way towards reconciling results from randomised controlled trials with the epidemiological evidence.

Effects of Long-Chain Omega-3 Polyunsaturated Fatty Acids on Endothelial Vasodilator Function and Cognition-Are They Interrelated?

Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) may improve brain functions by acting on endothelial cells in the cerebrovasculature to facilitate vasodilatation and perfusion. The aim of this review is to explore this hypothesis by analyzing the effect of LCn-3 PUFA supplementation on systemic vasodilator and cognitive function and finding evidence to link LCn-3 PUFA intake, vasodilator function and cognition. Forty randomized controlled trials examining the effect of LCn-3 PUFA supplementation in humans on either endothelial vasodilator function or cognition were identified and pooled effects measured with a weighted analysis. Compared to placebo, LCn-3 PUFA tended to increase flow-mediated dilatation and significantly improved cognitive function. Emerging evidence links vasodilator dysfunction to cognitive impairment, but evidence that LCn-3 PUFA can improve cognition through enhancements of vasodilator function is still lacking. Further research is needed to determine: (1) whether LCn-3 PUFA can enhance dilatation of cerebral vessels; (2) if improvements in cerebrovascular responsiveness by LCn-3 PUFA are accompanied by cognitive benefits; and (3) the target population groups.

Fish Consumption, Omega-3 Fatty Acids, and Risk of Cardiovascular Disease

INTRODUCTION

Data on omega-3 polyunsaturated fatty acids in relation to cardiovascular disease are limited in women. The aim of this study was to examine longitudinal relations of tuna and dark fish, α-linolenic acid, and marine omega-3 fatty acid intake with incident major cardiovascular disease in women.

METHODS

This was a prospective cohort study of U.S. women participating in the Women's Health Study from 1993 to 2014, during which the data were collected and analyzed. A total of 39,876 women who were aged ≥45 years and free of cardiovascular disease at baseline provided dietary data on food frequency questionnaires. Analyses used Cox proportional hazards models to evaluate the association between fish and energy-adjusted omega-3 polyunsaturated fatty acid intake and the risk of major cardiovascular disease, defined as a composite outcome of myocardial infarction, stroke, and cardiovascular death, in 38,392 women in the final analytic sample (96%).

RESULTS

During 713,559 person years of follow-up, 1,941 cases of incident major cardiovascular disease were confirmed. Tuna and dark fish intake was not associated with the risk of incident major cardiovascular disease (p-trend >0.05). Neither α-linolenic acid nor marine omega-3 fatty acid intake was associated with major cardiovascular disease or with individual cardiovascular outcomes (all p-trend >0.05). There was no effect modification by age, BMI, or baseline history of hypertension.

CONCLUSIONS

In this cohort of women without history of cardiovascular disease, intakes of tuna and dark fish, α-linolenic acid, and marine omega-3 fatty acids were not associated with risk of major cardiovascular disease.

Marine omega-3 highly unsaturated fatty acids: From mechanisms to clinical implications in heart failure and arrhythmias

Therapeutic implications of marine omega-3 highly unsaturated fatty acids (HUFA) in cardiovascular disease are still discussed controversially. Several clinical trials report divergent findings and thus leave ambiguity on the meaning of oral omega-3 therapy. Potential prognostic indications of HUFA treatment have been predominantly studied in coronary artery disease, sudden cardiac death, ventricular arrhythmias, atrial fibrillation and heart failure of various origin. It is suspected that increased ventricular wall stress is crucially involved in the prognosis of heart failure. Increased wall stress and an unfavorable myocardial remodeling is associated with an increased risk of arrhythmias by stretch-activated membrane ion channels. Integration of HUFA into the microenvironment of cardiomyocyte ion channels lead to allosteric changes and increase the electrical stability. Increased ventricular wall stress appears to be involved in the local myocardial as well as in the hepatic fatty acid metabolism, i.e. a cardio-hepatic syndrome. Influences of an altered endogenous HUFA metabolism and an inverse shift of the fatty acid profile was underrated in the past. A better understanding of these interacting endogenous mechanisms appears to be required for interpreting the findings of recent experimental and clinical studies. The present article critically reviews major studies on basic pathophysiological mechanisms and treatment effects in clinical trials.

Trans fat and cardiovascular disease mortality: Evidence from bans in restaurants in New York

This paper analyzes the impact of trans fat bans on cardiovascular disease (CVD) mortality rates. Several New York State jurisdictions have restricted the use of ingredients containing artificial trans fat in food service establishments. The resulting within-county variation over time and the differential timing of the policy's rollout is used in estimation. The results indicate that the policy caused a 4.5% reduction in CVD mortality rates, or 13 fewer CVD deaths per 100,000 persons per year. The averted deaths can be valued at about $3.9 million per 100,000 persons annually.

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.

The autonomic nervous system and cardiovascular disease: role of n-3 PUFAs

In the last decades, a large body of experimental and clinical evidence has been accumulated showing that cardiovascular diseases are often accompanied by an imbalance in the sympathetic-vagal outflow to the heart, resulting in a chronic adrenergic activation. The arterial baroreceptor system is a key component of mechanisms contributing to the neural regulation of the cardiovascular system. Several methods have been proposed to assess autonomic activity by analyzing heart rate and blood pressure changes either spontaneously occurring or following provocations. The autonomic nervous system has been regarded as one of the putative mechanisms involved into the beneficial effects of exposure to n-3 fatty acids observed in epidemiological studies. The aim of the present review is to provide an update on the clinical evidence proposed so far linking exposure to n-3 fatty acids to autonomic nervous system modulation.

A select review reporting the quality of studies measuring endothelial dysfunction in randomised diet intervention trials

A quality assessment of the primary studies reported in the literature carried out using select dietary ingredients (DI) purported to affect vascular endothelial function was conducted through a systematic PubMed search from January 2000 to August 2012. A total of seventy randomised controlled trials with defined DI (folic acid (fifteen), n-3 fatty acids (twenty), cocoa (fifteen) and isoflavones (twenty)) and standardised measures of vascular endothelial function were evaluated. Jadad scores, quality scoring parameters for DI and flow-mediated dilation (FMD) methodology used were ascertained. A total of 3959 randomised subjects, mean age 51 (se 0·21) years (range 9-79 years), were represented in the dataset. The mean Jadad scores did not differ statistically among the DI studies, with the majority of the studies being of good quality. Higher DI quality scores were achieved by studies using the botanical ingredients cocoa and isoflavones than by those using the nutrient ingredients folic acid and n-3 fatty acids. The mean DI quality scores were 4·13 (se 0·34), 5·20 (se 0·47), 6·13 (se 0·41) and 6·00 (se 0·59) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (and significantly different). The mean Corretti FMD scores were 7·27 (se 0·56), 7·46 (se 0·79), 6·29 (se 0·61) and 7·11 (se 0·56) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (NS). FMD studies failed to adequately describe the equipment used and more than half failed to provide an adequate description of the procedures used for vascular image acquisition and measurement. DI can be utilised for dietary intervention studies; however, the methodology should be clearly reported using the guidelines for assessment for both DI and FMD.

Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review

The effects of both the amount and quality of dietary fat have been studied intensively during the past decades. Previously, low-fat diets were recommended without much attention to the quality of fat, whereas there is general emphasis on the quality of fat in current guidelines. The objective of this systematic review (SR) was to assess the evidence of an effect of the amount and type of dietary fat on body weight (BW), risk factors, and risk of non-communicable diseases, that is, type 2 diabetes (T2DM), cardiovascular diseases (CVD), and cancer in healthy subjects or subjects at risk for these diseases. This work was performed in the process of updating the fourth edition of the Nordic Nutrition Recommendations from 2004. The literature search was performed in October 2010 covering articles published since January 2000. A complementary search was done in February 2012 covering literature until December 2011. Two authors independently selected articles for inclusion from a total of about 16,000 abstracts according to predefined criteria. Randomized controlled trials (RCT) and prospective cohort studies (PCS) were included as well as nested case-control studies. A few retrospective case-control studies were also included when limited or no data were available from other study types. Altogether 607 articles were quality graded and the observed effects in these papers were summarized. Convincing evidence was found that partial replacement of saturated fat (SFA) with polyunsaturated fat (PUFA) or monounsaturated fat (MUFA) lowers fasting serum/plasma total and LDL cholesterol concentrations. The evidence was probable for a decreasing effect of fish oil on concentration of serum/plasma total triglycerides as compared with MUFA. Beneficial effect of MUFA both on insulin sensitivity and fasting plasma/serum insulin concentration was considered as probable in comparisons of MUFA and carbohydrates versus SFA, whereas no effect was found on fasting glucose concentration in these comparisons. There was probable evidence for a moderate direct association between total fat intake and BW. Furthermore, there was convincing evidence that partial replacement of SFA with PUFA decreases the risk of CVD, especially in men. This finding was supported by an association with biomarkers of PUFA intake; the evidence of a beneficial effect of dietary total PUFA, n-6 PUFA, and linoleic acid (LA) on CVD mortality was limited suggestive. Evidence for a direct association between total fat intake and risk of T2DM was inconclusive, whereas there was limited-suggestive evidence from biomarker studies that LA is inversely associated with the risk of T2DM. However, there was limited-suggestive evidence in biomarker studies that odd-chain SFA found in milk fat and fish may be inversely related to T2DM, but these associations have not been supported by controlled studies. The evidence for an association between dietary n-3 PUFA and T2DM was inconclusive. Evidence for effects of fat on major types of cancer was inconclusive regarding both the amount and quality of dietary fat, except for prostate cancer where there was limited-suggestive evidence for an inverse association with intake of ALA and for ovarian cancer for which there was limited-suggestive evidence for a positive association with intake of SFA. This SR reviewed a large number of studies focusing on several different health outcomes. The time period covered by the search may not have allowed obtaining the full picture of the evidence in all areas covered by this SR. However, several SRs and meta-analyses that covered studies published before year 2000 were evaluated, which adds confidence to the results. Many of the investigated questions remain unresolved, mainly because of few studies on certain outcomes, conflicting results from studies, and lack of high quality-controlled studies. There is thus an evident need of highly controlled RCT and PCS with sufficient number of subjects and long enough duration, specifically regarding the effects of the amount and quality of dietary fat on insulin sensitivity, T2DM, low-grade inflammation, and blood pressure. New metabolic and other potential risk markers and utilization of new methodology in the area of lipid metabolism may provide new insight.

Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and blood pressure: a meta-analysis of randomized controlled trials

BACKGROUND

Although a large body of literature has been devoted to examining the relationship between eicosapentaenoic and docosahexaenoic acids (EPA+DHA) and blood pressure, past systematic reviews have been hampered by narrow inclusion criteria and a limited scope of analytical subgroups. In addition, no meta-analysis to date has captured the substantial volume of randomized controlled trials (RCTs) published in the past 2 years. The objective of this meta-analysis was to examine the effect of EPA+DHA, without upper dose limits and including food sources, on blood pressure in RCTs.

METHODS

Random-effects meta-analyses were used to generate weighted group mean differences and 95% confidence intervals (CIs) between the EPA+DHA group and the placebo group. Analyses were conducted for subgroups defined by key subject or study characteristics.

RESULTS

Seventy RCTs were included. Compared with placebo, EPA+DHA provision reduced systolic blood pressure (−1.52mm Hg; 95% confidence interval (CI) = −2.25 to −0.79) and diastolic blood pressure (−0.99mm Hg; 95% CI = −1.54 to −0.44) in the meta-analyses of all studies combined. The strongest effects of EPA+DHA were observed among untreated hypertensive subjects (systolic blood pressure = −4.51mm Hg, 95% CI = −6.12 to −2.83; diastolic blood pressure = −3.05mm Hg, 95% CI = −4.35 to −1.74), although blood pressure also was lowered among normotensive subjects (systolic blood pressure = −1.25mm Hg, 95% CI = −2.05 to −0.46; diastolic blood pressure = −0.62mm Hg, 95% CI = −1.22 to −0.02).

CONCLUSIONS

Overall, available evidence from RCTs indicates that provision of EPA+DHA reduces systolic blood pressure, while provision of ≥2 grams reduces diastolic blood pressure.

Fortification of foods with omega-3 polyunsaturated fatty acids

A $600 million nutritional supplements market growing at 30% every year attests to consumer awareness of, and interests in, health benefits attributed to these supplements. For over 80 years the importance of polyunsaturated fatty acid (PUFA) consumption for human health has been established. The FDA recently approved the use of ω-3 PUFAs in supplements. Additionally, the market for ω-3 PUFA ingredients grew by 24.3% last year, which affirms their popularity and public awareness of their benefits. PUFAs are essential for normal human growth; however, only minor quantities of the beneficial ω-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are synthesized by human metabolism. Rather PUFAs are obtained via dietary or nutritional supplementation and modified into other beneficial metabolites. A vast literature base is available on the health benefits and biological roles of ω-3 PUFAs and their metabolism; however, information on their dietary sources and palatability of foods incorporated with ω-3 PUFAs is limited. DHA and EPA are added to many foods that are commercially available, such as infant and pet formulae, and they are also supplemented in animal feed to incorporate them in consumer dairy, meat, and poultry products. The chief sources of EPA and DHA are fish oils or purified preparations from microalgae, which when added to foods, impart a fishy flavor that is considered unacceptable. This fishy flavor is completely eliminated by extensively purifying preparations of n-3 PUFA sources. While n-3 PUFA lipid autoxidation is considered the main cause of fishy flavor, the individual oxidation products identified thus far, such as unsaturated carbonyls, do not appear to contribute to fishy flavor or odor. Alternatively, various compound classes such as free fatty acids and volatile sulfur compounds are known to impart fishy flavor to foods. Identification of the causative compounds to reduce and eventually eliminate fishy flavor is important for consumer acceptance of PUFA-fortified foods.

Do omega-3 polyunsaturated fatty acids reduce risk of sudden cardiac death and ventricular arrhythmias? A meta-analysis of randomized trials

INTRODUCTION

Omega-3 polyunsaturated fatty acids (PUFA) have demonstrated to have antiarrhythmic properties. However, randomized studies have shown inconsistent results.

OBJECTIVE

We aimed to analyze the effect of omega-3 PUFA on preventing potentially fatal ventricular arrhythmias and sudden cardiac death.

METHODS

Randomized trials comparing omega-3 PUFA to placebo and reporting sudden cardiac death (SCD) or first implanted cardioverter-defibrillator (ICD) event for ventricular tachycardia or fibrillation were included in this study. A meta-analysis using a random effects model was performed and results were expressed in terms of Odds Ratio (OR) and 95% Confidence Interval (CI) after evaluating for interstudy heterogeneity using I(2). The reported data were extracted on the basis of the intention-to-treat principle.

RESULTS

A total of 32,919 patients were included in nine trials; 16,465 patients received omega-3 PUFA and 16,454 received placebo. When comparing omega-3 PUFA to placebo, there was nonsignificant risk reduction of SCD or ventricular arrhythmias (OR = 0.82 [95% CI: 0.60-1.21], p = 0.21 I(2) = 49.7%).

CONCLUSION

Dietary supplementation with omega-3 PUFA does not affect the risk of SCD or ventricular arrhythmias.

Effects of omega-3 fatty acid supplementation on heart rate variability at rest and during acute stress in adults with moderate hypertriglyceridemia

OBJECTIVE

This study examined the dose-dependent effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on heart rate variability (HRV) at rest and during standard laboratory stress tasks. We also investigated whether EPA + DHA supplementation was associated with changes in mood state.

METHODS

This placebo-controlled, double-blind, randomized, three-period crossover trial (8-week treatment, 6-week washout) compared two doses of EPA + DHA supplementation (0.85 and 3.4 g/d) in 26 adults with elevated triglycerides. After each treatment period, HRV was assessed during an acute stress protocol that included a resting baseline, standard laboratory stress tasks (speech task and cold pressor), and recovery periods. In addition, mood state was assessed.

RESULTS

Root mean square of successive differences in interbeat interval and total power increased 9.9% and 20.6%, respectively, after the high dose relative to placebo (Tukey p = .016 and .012, respectively). The low dose was not significantly different from the high dose or placebo dose. There was a trend for a treatment effect on high-frequency HRV (p = .058), with 21.0% greater power observed after the high dose compared with placebo (Tukey p = .052). Mood did not differ between treatments, and there was no association between mood state and HRV.

CONCLUSIONS

In healthy adults with elevated triglycerides, supplementation of 3.4 g/d EPA + DHA resulted in greater HRV, whereas 0.85 g/d EPA + DHA had no effect. These results indicate that EPA + DHA supplementation may improve autonomic tone in adults at increased risk for cardiovascular disease within 8 weeks.

TRIAL REGISTRATION

NCT00504309 (ClinicalTrials.gov).

Short-term effects of fish-oil supplementation on heart rate variability in humans: a meta-analysis of randomized controlled trials

BACKGROUND

The effects of fish oil on heart rate variability in humans remain unclear.

OBJECTIVE

A meta-analysis of randomized controlled trials was performed to investigate the influence of fish oil on heart rate variability.

DESIGN

Human intervention studies were identified by systematic search of PubMed, Embase, The Cochrane Library, and references of related reviews and studies. A random-effects model was applied to estimate the pooled results.

RESULTS

Fifteen studies were included. Results of the meta-analysis showed that the SD of normal-to-normal interval [standardized mean difference (SMD) = 0.10, P = 0.35] and square of successive differences (SMD = 0.05, P = 0.35), 2 of the time-domain parameters of heart rate variability, were not significantly influenced by fish-oil supplementation. For the frequency-domain parameters, the high-frequency power (HF), a surrogate of vagal function, was significantly increased by fish-oil supplementation (SMD = 0.30, P = 0.005), the low-frequency power (LF) was not significantly affected (SMD = 0.03, P = 0.79), and the ratio of LF to HF (LF/HF) showed a trend of reduction (SMD = -0.22, P = 0.08). The trend for a treatment effect on LF/HF became significant at P = 0.01 when the 2 studies with a dose <1000 mg/d were omitted. Subgroup analyses according to predefined study characteristics showed no significant results.

CONCLUSION

Short-term fish-oil supplementation may favorably influence the frequency domain of heart rate variability, as indicated by an enhanced vagal tone, which may be an important mechanism underlying the antiarrhythmic and other clinical effects of fish oil.

Effect of fish oil supplementation on fasting vascular endothelial function in humans: a meta-analysis of randomized controlled trials

Background

Effect of fish oil supplementation on flow-mediated dilation, an index of endothelial function in humans, remains controversial. We performed a meta-analysis to determine whether fish oil supplementation could improve endothelial function.

Methods

Human intervention studies were identified by systematic searches of Medline, Embase, Cochrane's library and references of related reviews and studies. A random-effect model was applied to estimate the pooled results. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of fish oil supplementation on flow-mediated dilation.

Results

A total of sixteen records with 1,385 subjects were reviewed. The results of the pooled analysis showed that fish oil supplementation significantly improved flow-mediated dilation (weighed mean difference: 1.49%, 95% confidence interval 0.48% to 2.50%, p = 0.004). Meta-regression and subgroup analysis suggested that the quality of included studies were inversely related to the overall effect (regression coefficient  = −1.60, p = 0.04), and the significance of the effect was mainly driven by the studies with relatively poor quality. Sensitivity analysis including only double-blind, placebo-controlled studies indicated fish oil supplementation has no significant effect on endothelial function (weighed mean difference: 0.54%, 95% confidence interval −0.25% to 1.33%, p = 0.18). Besides, normoglycemic subjects or participants with lower diastolic blood pressure seemed to be associated with remarkable improvement of endothelial function after fish oil supplementation.

Conclusions

Although current evidence suggested a possible role of fish oil in improving endothelial function, large-scale and high-quality clinical trials are needed to evaluate these effects before we can come to a definite conclusion.

Trans-fatty acid consumption and heart rate variability in 2 separate cohorts of older and younger adults

BACKGROUND

Trans-fatty acid (TFA) consumption is associated with risk of coronary heart disease, and trans-18:2, but not trans-18:1, in red blood cell membranes has been associated with sudden cardiac arrest. Abnormal heart rate variability (HRV) reflects autonomic dysfunction and predicts cardiac death. Relationships between TFA consumption and HRV remain understudied. We determined whether total TFA consumption, as well as trans-18:1 and trans-18:2 TFA consumption, was independently associated with HRV in 2 independent cohorts in the United States and Portugal.

METHODS AND RESULTS

In 2 independent cohorts of older US adults (Cardiovascular Health Study [CHS], age 72±5 years, 1989/1995) and young Portuguese adults (Porto, age 19±2 years, 2008/2010), we assessed habitual TFA intake by food frequency questionnaires in CHS (separately estimating trans-18:1 and trans-18:2) and multiple 24-hour recalls in Porto (estimating total TFA only, which in a subset correlated with circulating trans-18:2 but not trans-18:1, suggesting that we captured the former). HRV was assessed using 24-hour Holters in CHS (n=1076) and repeated short-term (5-minute) ECGs in Porto (n=160). We used multivariate-adjusted linear regression to relate TFA consumption to HRV cross-sectionally (CHS, Porto) and longitudinally (CHS). In CHS, higher trans-18:2 consumption was associated with lower 24-hour SD of all normal-to-normal intervals both cross-sectionally (-12%; 95% CI, -19% to -6%; P=0.001) and longitudinally (-15%; 95% CI, -25% to -4%; P= 0.009) and lower 24-hour SD of 5-minute average N-N intervals and mean of the 5-minute SD of N-N intervals calculated over 24 hours (P<0.05 each). Higher trans-18:1 consumption in CHS was associated with more favorable 24-hour HRV in particular time-domain indices (24-hour SD of all normal-to-normal intervals, SD of 5-minute average N-N intervals, mean of the 5-minute SD of N-N intervals calculated over 24 hours; P<0.05 each). In Porto, each higher SD TFA consumption was associated with 4% lower 5-minute 24-hour SD of all normal-to-normal intervals (95% CI, -8% to -1%; P=0.04) and 7% lower 5-minute square root of the mean of the squares of successive N-N differences (95% CI, -13% to -1%; P=0.04).

CONCLUSIONS

Trans-18:2 consumption is associated with specific, less favorable indices of HRV in both older and young adults. Trans-18:1 consumption is associated with more favorable HRV indices in older adults. Our results support the need to investigate potential HRV-related mechanisms, whereby trans-18:2 may increase arrhythmic risk.

Long-chain, n-3 fatty acids and physical activity--independent and interactive associations with cardiac autonomic control

BACKGROUND/OBJECTIVES

Intake of the marine-based, n-3 fatty acids and engagement in physical activity are inversely related to cardiac morbidity and mortality. Among putative mechanisms, both n-3 fatty acids and physical activity may act through modulation of autonomic control of the cardiovascular system. This investigation examined the independent and interactive associations of n-3 fatty acids (eicosapentaenoic and docosahexanenoic acid; EPA, DHA) and physical activity with heart rate variability (HRV).

METHODS

Subjects were 259 healthy 30-54 year-old adults. Serum phospholipid fatty acid composition was employed as a biomarker of dietary n-3 fatty acid exposure. Physical activity based on the Paffenbarger questionnaire was coded as < or ≥ 2000 kcal/week. Standard time-domain (standard deviation of normal-to-normal intervals and root-mean squared of successive differences; SDNN, RMSSD) and frequency domain (high frequency and low frequency power) measures of HRV were derived from resting electrocardiographic recordings.

RESULTS

In linear regression models with covariate adjustment for age, gender and race, greater n-3 fatty acid exposure was associated with greater SDNN and RMSSD, and high physical activity was associated with greater RMSSD. n-3 fatty acid exposure also predicted variation in SDNN, RMSSD, and high-frequency power in interaction with physical activity. Specifically, n-3 fatty acid exposure covaried positively with these three HRV indices only among participants expending 2000 kcal per week or more in physical activity. These latter findings were noted for DHA but not EPA.

CONCLUSIONS

These results suggest that the cardiovascular benefits of n-3 fatty acid consumption may be mediated, in part, by effects on cardiac autonomic control and may be dependent upon concomitant habitual exercise.

Dietary methods and biomarkers of omega 3 fatty acids: a systematic review

The aims of the present study were to review the validity of dietary methods used to measure the usual long chain (LC) omega-3 polyunsaturated fatty acid (n-3 PUFA) intake of a population and to assess the usefulness of different biomarkers of n-3 PUFA in healthy humans. Two systematic literature searches were conducted until May 2011 to update previous systematic reviews. The first literature search aimed to find studies validating the methodology used for measuring the dietary intake of n-3 PUFA. The second search aimed to find human intervention studies in which n-3 PUFA status changed after 2 weeks of n-3 PUFA supplementation. Sixteen studies were identified for inclusion in the first review. Correlation coefficients between fatty acids in subcutaneous fat or blood lipids and dietary intake of n-3 PUFA from different questionnaires were similar. Subcutaneous fat has been reported as the best reference method for some authors, and these studies showed moderate correlation coefficients with no dietary intake method being superior to any other. As for the evaluation of biomarkers of docosahexaenoic acid (DHA, 22 : 6 n-3) and eicosapentaenoic acid (EPA, 20 : 5n-3) status in response to supplementation, the new search reaffirmed and reinforced the evidence supporting that plasma phospholipid DHA, erythrocyte DHA, and platelet DHA were all effective and robust biomarkers of DHA status. Our findings only confirmed earlier studies and did not provide evidence for reaching new conclusions.

Functional foods and nutraceuticals in the primary prevention of cardiovascular diseases

Cardiovascular disease (CVD) is now the leading cause of death globally and is a growing health concern. Dietary factors are important in the pathogenesis of CVD and may to a large degree determine CVD risk, but have been less extensively investigated. Functional foods are those that are thought to have physiological benefits and/or reduce the risk of chronic disease beyond their basic nutritional functions. The food industry has started to market products labelled as “functional foods.” Although many review articles have focused on individual dietary variables as determinants of CVD that can be modified to reduce the risk of CVD, the aim of this current paper was to examine the impact of functional foods in relation to the development and progression of CVD. Epidemiologic studies have demonstrated the association between certain dietary patterns and cardiovascular health. Research into the cardio-protective potential of their dietary components might support the development of functional foods and nutraceuticals. This paper will also compare the effect of individual bioactive dietary compounds with the effect of some dietary patterns in terms of their cardiovascular protection.

Effect of omega-3 fatty acids supplementation on endothelial function: a meta-analysis of randomized controlled trials

OBJECTIVE

Inverse association was reported between omega-3 fatty acids (FAs) supplementation and the risk of cardiovascular disease. Identifying the effect of omega-3 FAs on endothelial function may contribute to explain the association. We conducted a meta-analysis to assess the effect of omega-3 FAs supplementation on endothelial function, as measured by flow-mediated dilation (FMD) and endothelium-independent vasodilation (EIV).

METHODS

Randomized placebo-controlled trials (RCTs) were identified from the databases of PubMed, EMBASE and Cochrane library by two investigators and the pooled effects were measured by weighted mean difference (WMD), together with 95% confidence intervals (CIs). Subgroup and meta-regression analyses were used to explore the source of between-study heterogeneity.

RESULTS

Totally 16 eligible studies involving 901 participants were finally included in meta-analysis. Compared with placebo, omega-3 FAs supplementation significantly increased FMD by 2.30% (95% CI: 0.89-3.72%, P = 0.001), at a dose ranging from 0.45 to 4.5 g/d over a median of 56 days. Subgroup analyses suggested that the effect of omega-3 FAs on FMD might be modified by the health status of the participants or the dose of supplementation. Sensitivity analyses indicated that the protective effect of omega-3 on endothelial function was robust. No significant change in EIV was observed after omega-3 FAs supplementation (WMD: 0.57%; 95% CI: -0.88 to 2.01%; P = 0.442).

CONCLUSION

Supplementation of omega-3 fatty acids significantly improves the endothelial function without affecting endothelium-independent dilation.

Fatty acids as biocompounds: their role in human metabolism, health and disease--a review. Part 1: classification, dietary sources and biological functions

BACKGROUND

Fatty acids are substantial components of lipids and cell membranes in the form of phospholipids. This review consists of two parts. The present part aims at describing fatty acid classification, dietary sources and biological functions. The second part will focus on fatty acid physiological roles and applications in human health and disease.

RESULTS

In humans, not all fatty acids can be produced endogenously due to the absence of certain desaturases. Thus, specific fatty acids termed essential (linoleic, alpha-linolenic) need to be taken from the diet. Other fatty acids whose synthesis depends on essential fatty acid intake include eicosapentaenoic acid and docosahexaenoic acid, found in oily fish. Dietary sources of saturated fatty acids are animal products (butter, lard) and tropical plant oils (coconut, palm), whereas sources of unsaturated fatty acids are vegetable oils (such as olive, sunflower, and soybean oils) and marine products (algae and fish oils). Saturated fatty acids have been related to adverse health effects, whereas unsaturated fatty acids, especially monounsaturated and n-3 polyunsaturated, are thought to be protective. In addition, trans fatty acids have been shown to have negative effects on health, whereas conjugated fatty acids might be beneficial. Lastly, fatty acids are the main components of lipid classes (triacylglycerols, phospholipids, cholesteryl esters, non-esterified fatty acids).

CONCLUSION

Fatty acids are important biocompounds which take part in complex metabolic pathways, thus having major biological roles. They are obtained from various dietary sources which determine the type of fat consumed and consequently health outcome.

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.

Omega-3 polyunsaturated Fatty acids and heart rate variability

Omega-3 polyunsaturated fatty acids (PUFA) may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD). The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV) can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed.

Effect of industrially produced trans fat on markers of systemic inflammation: evidence from a randomized trial in women

Consumption of industrially produced trans fatty acids (IP-TFA) has been positively associated with systemic markers of low-grade inflammation and endothelial dysfunction in cross-sectional studies, but results from intervention studies are inconclusive. Therefore, we conducted a 16 week double-blind parallel intervention study with the objective to examine the effect of IP-TFA intake on biomarkers of inflammation, oxidative stress, and endothelial dysfunction. Fifty-two healthy overweight postmenopausal women (49 completers) were randomly assigned to receive either partially hydrogenated soybean oil (15.7 g/day IP-TFA) or control oil without IP-TFA. After 16 weeks, IP-TFA intake increased baseline-adjusted serum tumor necrosis factor (TNF) α by 12% [95% confidence interval (CI): 5-20; P = 0.002] more in the IP-TFA group compared with controls. Plasma soluble TNF receptors 1 and 2 were also increased by IP-TFA [155 pg/ml (CI: 63-247); P < 0.001 and 480 pg/ml (CI: 72-887); P = 0.02, respectively]. Serum C-reactive protein, interleukin (IL) 6 and adiponectin and subcutaneous abdominal adipose tissue mRNA expression of IL6, IL8, TNFα, and adiponectin as well as ceramide content were not affected by IP-TFA, nor was urinary 8-iso-prostaglandin-F(2α). In conclusion, this dietary trial indicates that the mechanisms linking dietary IP-TFA to cardiovascular disease may involve activation of the TNFα system.

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.

Dose-response effects of omega-3 fatty acids on triglycerides, inflammation, and endothelial function in healthy persons with moderate hypertriglyceridemia

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to reduce cardiovascular mortality at a dose of ≈1 g/d. Studies using higher doses have shown evidence of reduced inflammation and improved endothelial function. Few studies have compared these doses.

OBJECTIVE

The objective of this study was to compare the effects of a nutritional dose of EPA+DHA (0.85 g/d) with those of a pharmaceutical dose (3.4 g/d) on serum triglycerides, inflammatory markers, and endothelial function in healthy subjects with moderately elevated triglycerides.

DESIGN

This was a placebo-controlled, double-blind, randomized, 3-period crossover trial (8 wk of treatment, 6 wk of washout) that compared the effects of 0.85 and 3.4 g EPA+DHA/d in 23 men and 3 postmenopausal women with moderate hypertriglyceridemia (150-500 mg/dL).

RESULTS

The higher dose of EPA+DHA lowered triglycerides by 27% compared with placebo (mean ± SEM: 173 ± 17.5 compared with 237 ± 17.5 mg/dL; P = 0.002), whereas no effect of the lower dose was observed on lipids. No effects on cholesterol (total, LDL, and HDL), endothelial function [as assessed by flow-mediated dilation, peripheral arterial tonometry/EndoPAT (Itamar Medical Ltd, Caesarea, Israel), or Doppler measures of hyperemia], inflammatory markers (interleukin-1β, interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein), or the expression of inflammatory cytokine genes in isolated lymphocytes were observed.

CONCLUSION

The higher dose (3.4 g/d) of EPA+DHA significantly lowered triglycerides, but neither dose improved endothelial function or inflammatory status over 8 wk in healthy adults with moderate hypertriglyceridemia. The trial was registered at clinicaltrials.gov as NCT00504309.

Effect of trans fatty acid intake on abdominal and liver fat deposition and blood lipids: a randomized trial in overweight postmenopausal women

Background:

Intake of industrially produced trans fatty acids (TFAs) is, according to observational studies, associated with an increased risk of cardiovascular disease, but the causal mechanisms have not been fully elucidated. Besides inducing dyslipidemia, TFA intake is suspected to promote abdominal and liver fat deposition.

Objective:

We examined the effect of a high intake of TFA as part of an isocaloric diet on whole-body, abdominal and hepatic fat deposition, and blood lipids in postmenopausal women.

Methods:

In a 16-week double-blind parallel intervention study, 52 healthy overweight postmenopausal women were randomized to receive either partially hydrogenated soybean oil providing 15.7 g day⁻¹ of TFA or a control oil with mainly oleic and palmitic acid. Before and after the intervention, body composition was assessed by dual-energy X-ray absorptiometry, abdominal fat by magnetic resonance (MR) imaging, and liver fat by ¹H MR spectroscopy.

Results:

Compared with the control fat, TFA intake decreased plasma high-density lipoprotein (HDL)-cholesterol by 10%, increased low-density lipoprotein (LDL)-cholesterol by 18% and resulted in an increased LDL/HDL-cholesterol ratio (baseline adjusted mean (95% CI) difference between diet groups 0.41 (0.22; 0.60); P<0.001). TFA tended to increase the body fat (0.46 (−0.20; 1.17) kg; P=0.16) and waist circumference (1.1 (−0.1; 2.4) cm; P=0.08) more than the control fat, whereas neither abdominal nor liver fat deposition was affected by TFA.

Conclusion:

The adverse effect of dietary TFA on cardiovascular disease risk involves induction of dyslipidemia, and perhaps body fat, whereas weight gain-independent accumulation of ectopic fat could not be identified as a contributory factor during short-term intake.

Association of health behaviour with heart rate variability: a population-based study

Background

Reduced heart rate variability (HRV), a non-invasive marker of autonomic dysfunction, and an unhealthy lifestyle are associated with an increased morbidity and mortality of cardiovascular diseases (CVD). The autonomic dysfunction is a potential mediator of the association of behavioural risk factors with adverse health outcomes. We studied the association of HRV with behavioural risk factors in an elderly population.

Methods

This analysis was based on the cross-sectional data of 1671 participants (age range, 45-83 years) of the prospective, population-based Cardiovascular Disease, Living and Ageing in Halle (CARLA) Study. Physical activity, smoking habits, alcohol consumption and dietary patterns were assessed in standardized interviews. Time and frequency domain measures of HRV were computed from 5-min segments of highly standardized 20-min electrocardiograms. Their association with behavioural risk factors was determined by linear and non-parametric regression modelling.

Results

There were only weak and inconsistent associations of higher physical activity, moderate consumption of alcohol, and non-smoking with higher time and frequency domain HRV in both sexes, and no association with dietary pattern. Results changed only marginally by excluding subjects with CVD, diabetes mellitus and use of cardioactive medication.

Conclusion

We hypothesized that HRV is associated with behavioural factors and therefore might be a mediator of the effect of behavioural risk factors on CVD, but this hypothesis was not confirmed by our results. These findings support the interpretation that there may be no true causal association of behavioural factors with HRV.