Associations of fish intake and dietary n-3 polyunsaturated fatty acids with a hypocoagulable profile. The Atherosclerosis Risk in Communities (ARIC) Study

Is the Habitual Dietary Intake of Foods of Plant or Animal Origin Associated with Circulating Hemostatic Factors?-Results of the Population-Based KORA-Fit Study

Blood coagulation is a complex physiological process critical for maintaining hemostasis, and disruptions in this system can lead to various health complications. Since the effects of specific food groups on a series of circulating coagulation parameters in the population are not well established, this study examines such associations in the population-based KORA-Fit study. A total of 595 subjects (263 men and 332 women) born between 1945 and 1964 and living in the study region of Augsburg were included in the study. Habitual food intake was estimated based on a combination of repeated 24-h food lists (24HFLs) and a food frequency questionnaire (FFQ). Antithrombin III, D-dimers, factor VIII, fibrinogen, protein C, protein S, aPTT, Quick value and INR were measured in citrate plasma. Multivariable linear regression models were applied to investigate associations between the consumption of specific foods of plant or animal origin and hemostatic factors. We found that the consumption of plant-based food groups, including green leafy vegetables (rich in vitamin K1), were hardly associated with coagulation parameters. Surprisingly, a high consumption of dairy products and especially butter were associated with higher D-dimer concentrations. These findings need further evaluation in prospective studies.

Omega-3 Polyunsaturated Fatty Acids-Vascular and Cardiac Effects on the Cellular and Molecular Level (Narrative Review)

In the prevention and treatment of cardiovascular disease, in addition to the already proven effective treatment of dyslipidemia, hypertension and diabetes mellitus, omega-3 polyunsaturated fatty acids (n-3 PUFAs) are considered as substances with additive effects on cardiovascular health. N-3 PUFAs combine their indirect effects on metabolic, inflammatory and thrombogenic parameters with direct effects on the cellular level. Eicosapentaenoic acid (EPA) seems to be more efficient than docosahexaenoic acid (DHA) in the favorable mitigation of atherothrombosis due to its specific molecular properties. The inferred mechanism is a more favorable effect on the cell membrane. In addition, the anti-fibrotic effects of n-3 PUFA were described, with potential impacts on heart failure with a preserved ejection fraction. Furthermore, n-3 PUFA can modify ion channels, with a favorable impact on arrhythmias. However, despite recent evidence in the prevention of cardiovascular disease by a relatively high dose of icosapent ethyl (EPA derivative), there is still a paucity of data describing the exact mechanisms of n-3 PUFAs, including the role of their particular metabolites. The purpose of this review is to discuss the effects of n-3 PUFAs at several levels of the cardiovascular system, including controversies.

The Type and Amount of Dietary Fat Affect Plasma Factor VIIc, Fibrinogen, and PAI-1 in Healthy Individuals and Individuals at High Cardiovascular Disease Risk: 2 Randomized Controlled Trials

BACKGROUND

Factor VIIc, fibrinogen, and plasminogen activator inhibitor 1 (PAI-1) are cardiovascular disease (CVD) risk factors and are modulated, in part, by fat type and amount.

OBJECTIVE

We evaluated fat type and amount on the primary outcomes: factor VIIc, fibrinogen, and PAI-1.

METHODS

In the Dietary Effects on Lipoproteins and Thrombogenic Activity (DELTA) Trial, 2 controlled crossover feeding studies evaluated substituting carbohydrate or MUFAs for SFAs. Study 1: healthy participants (n = 103) were provided with (8 wk) an average American diet [AAD; designed to provide 37% of energy (%E) as fat, 16% SFA], a Step 1 diet (30%E fat, 9% SFA), and a diet low in SFA (Low-Sat; 26%E fat, 5% SFA). Study 2: participants (n = 85) at risk for CVD and metabolic syndrome (MetSyn) were provided with (7 wk) an AAD, a step 1 diet, and a high-MUFA diet (designed to provide 37%E fat, 8% SFA, 22% MUFA).

RESULTS

Study 1: compared with AAD, the Step 1 and Low-Sat diets decreased mean factor VIIc by 1.8% and 2.6% (overall P = 0.0001), increased mean fibrinogen by 1.2% and 2.8% (P = 0.0141), and increased mean square root PAI-1 by 0.0% and 6.0% (P = 0.0037), respectively. Study 2: compared with AAD, the Step 1 and high-MUFA diets decreased mean factor VIIc by 4.1% and 3.2% (overall P < 0.0001), increased mean fibrinogen by 3.9% and 1.5% (P = 0.0083), and increased mean square-root PAI-1 by 2.0% and 5.8% (P = 0.1319), respectively.

CONCLUSIONS

Replacing SFA with carbohydrate decreased factor VIIc and increased fibrinogen in healthy and metabolically unhealthy individuals and also increased PAI-1 in healthy subjects. Replacing SFA with MUFA decreased factor VIIc and increased fibrinogen but less than carbohydrate. Our results indicate an uncertain effect of replacing SFA with carbohydrate or MUFA on cardiometabolic risk because of small changes in hemostatic factors and directionally different responses to decreasing SFA. This trial was registered at https://clinicaltrials.gov/ct2/show/NCT00000538?term=NCT00000538&rank=1 as NCT00000538.

The Physiological Effect of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) Intake and Exercise on Hemorheology, Microvascular Function, and Physical Performance in Health and Cardiovascular Diseases; Is There an Interaction of Exercise and Dietary n-3 PUFA Intake?

Physical activity has a beneficial effect on systemic hemodynamics, physical strength, and cardiac function in cardiovascular (CV) patients. Potential beneficial effects of dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs), such as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on hemorheology, vascular function, inflammation and potential to improve physical performance as well as other CV parameters are currently investigated. Recent meta-analysis suggests no effect of n-3 PUFA supplementation on CV function and outcomes of CV diseases. On the other hand, some studies support beneficial effects of n-3 PUFAs dietary intake on CV and muscular system, as well as on immune responses in healthy and in CV patients. Furthermore, the interaction of exercise and dietary n-3 PUFA intake is understudied. Supplementation of n-3 PUFAs has been shown to have antithrombotic effects (by decreasing blood viscosity, decreasing coagulation factor and PAI-1 levels and platelet aggregation/reactivity, enhancing fibrinolysis, but without effects on erythrocyte deformability). They decrease inflammation by decreasing IL-6, MCP-1, TNFα and hsCRP levels, expression of endothelial cell adhesion molecules and significantly affect blood composition of fatty acids. Treatment with n-3 PUFAs enhances brachial artery blood flow and conductance during exercise and enhances microvascular post-occlusive hyperemic response in healthy humans, however, the effects are unknown in cardiovascular patients. Supplementation of n-3 PUFAs may improve anaerobic endurance and may modulate oxygen consumption during intense exercise, may increase metabolic capacity, enhance endurance capacity delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function in humans and animal models. In addition, n-3 PUFAs have anti-inflammatory and anti-nociceptive effects and may attenuate delayed-onset muscle soreness and muscle stiffness, and preserve joint mobility. On the other hand, effects of n-3 PUFAs were variably observed in men and women and they vary depending on dietary protocol, type of supplementation and type of sports activity undertaken, both in healthy and cardiovascular patients. In this review we will discuss the physiological effects of n-3 PUFA intake and exercise on hemorheology, microvascular function, immunomodulation and inflammation and physical performance in healthy persons and in cardiovascular diseases; elucidating if there is an interaction of exercise and diet.

The Role of Omega-3 Fatty Acids in the Setting of Coronary Artery Disease and COPD: A Review

Chronic obstructive pulmonary disease (COPD) is a growing healthcare concern and will represent the third leading cause of death worldwide within the next decade. COPD is the result of a complex interaction between environmental factors, especially cigarette smoking, air pollution, and genetic preconditions, which result in persistent inflammation of the airways. There is growing evidence that the chronic inflammatory state, measurable by increased levels of circulating cytokines, chemokines, and acute phase proteins, may not be confined to the lungs. Cardiovascular disease (CVD) and especially coronary artery disease (CAD) are common comorbidities of COPD, and low-grade systemic inflammation plays a decisive role in its pathogenesis. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) exert multiple functions in humans and are crucially involved in limiting and resolving inflammatory processes. n-3 PUFAs have been intensively studied for their ability to improve morbidity and mortality in patients with CVD and CAD. This review aims to summarize the current knowledge on the effects of n-3 PUFA on inflammation and its impact on CAD in COPD from a clinical perspective.

Pleiotropic effects of n-6 and n-3 fatty acid-related genetic variants on circulating hemostatic variables

INTRODUCTION

Data from epidemiological studies and clinical trials suggest an influence of dietary and circulating polyunsaturated fatty acids (PUFAs) on the hemostasis profile. Genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) related to plasma PUFAs levels. We aimed to investigate whether the SNPs related to plasma PUFAs levels were also associated with plasma levels of hemostatic variables.

MATERIALS AND METHODS

We tested the associations between 9 PUFA-related SNPs and 6 hemostatic variables in 9035 European Americans (EAs) and 2702 African Americans (AAs) in the Atherosclerosis Risk in Communities (ARIC) Study. We then conducted a replication study by looking-up our novel observed associations in three published GWAS for hemostatic factors in different EA populations.

RESULTS

We observed a novel linoleic acid-related locus at the JMJD1C region associated with factor VII activity (FVIIc): rs10740118 and rs1935, Beta (p) = -1.31 (1 × 10-3) and 1.37 (5 × 10-4) in EAs, respectively, and - 1.24 (5 × 10-4) and 1.28 (3 × 10-4) in meta-analysis of EAs and AAs of ARIC. This novel association was replicated in two of three independent EA populations (p = 0.01 and 0.03 in meta-analyses). We confirmed previously reported associations at the docosapentaenoic acid-related GCKR locus with protein C and FVIIc and at JMJD1C with fibrinogen. Adjustment for plasma PUFAs did not abolish the associations between these loci and hemostatic variables.

CONCLUSIONS

Our study identified a novel association for FVIIc at JMJD1C, a histone demethylase that plays a role in DNA repair and possibly transcription regulation and RNA processing.

From Neighborhood to Genome: Three Decades of Nutrition-Related Research from the Atherosclerosis Risk in Communities Study

For 30 years, the Atherosclerosis Risk in Communities (ARIC) cohort study has examined the etiology and progression of atherosclerosis and atherosclerotic diseases.1 This research has evaluated variation in cardiovascular disease (CVD) risk in relation to age, race, gender, location and lifestyle factors, including diet. In this commentary, we describe ARIC research that illustrates an expanded view of the relationship between diet and health and suggest ways that future cohort studies may influence the direction of nutrition and dietetics practice.

Venous thromboembolism in Asia – an unrecognised and under-treated problem?

Venous thromboembolism (VTE) has been perceived for a long time to be less common in Asian populations, particularly in the Far East, than in Western populations. Generally, thromboprophylaxis is not implemented as frequently as it should be in high-risk patients. However, recent prospective studies undertaken in Asian countries have demonstrated higher rates of VTE after major surgery and in medical wards, approaching those observed in Western populations. Risk factors for VTE are not different in Asian patients from those of Western patients with the exception of thrombophilic mutations. Deficiencies of the natural anticoagulants (protein S, protein C, and antithrombin) are the predominant thrombophilias in Asia whereas factor V Leiden and prothrombin G20210A gene mutation are not found or rarely reported. Further large well-designed clinical studies are needed to evaluate the magnitude of the risk of VTE and the appropriate use of thromboprophylaxis in different clinical situations.

Coagulation profile of Sudanese children with homozygous sickle cell disease and the effect of treatment with omega-3 fatty acid on the coagulation parameters

Background

It has been reported that patients with SCD do have an abnormal coagulation profile. Coagulopathy is thought to be one of the key factors that contribute to the vaso-occlusive crisis that characterises sickle cell disease (SCD). In this study, we investigated whether Sudanese sickle cell patients have an abnormal coagulation profile. In addition, the effect of treatment with either omega-3 fatty acids or hydroxyurea on coagulation profile was assessed.

Methods

Homozygous SCD patients untreated (n = 52), omega-3 treated (n = 44), hydroxyurea (HU) treated (n = 8) and healthy (HbAA) controls (n = 52) matched for age (4–20 years), gender and socioeconomic status were enrolled. Patients on omega-3 fatty acids, according to age, received one to four capsules containing 277.8 mg DHA and 39.0 mg eicosapentnoic. Patients on Hydroxyurea were in on dosage more than 20 mg/kg/day. The steady state levels of the coagulation parameters and the effect of the treatments with either HU or omega-3 fatty acids on markers of coagulation were investigated.

Results

Compared to the healthy controls, treated and untreated HbSS patients had lower hemoglobin, plasma Protein C, proteins S and higher white blood cell count (WBC), platelets count (PLTs) and plasma D-dimer levels,(p < 0.05). In comparison to untreated HbSS, treatment with neither omega-3 nor HU had effect on the WBC, plasma proteins C and S, (p > 0.05). HU treated group had a lower PLTs count compared to HbSS untreated group (p < 0.5). The prothrombin and activated partial thromboplastin times and international normalized ratio (INR) of untreated patients are significantly higher than n-3 treated, HU-treated patients and health controls, (p < 0.05). Patients treated with omega-3 had lowered D-dimer levels in comparison to HU-treated and untreated HbSS patients, (p < 0.001).

Conclusion

This study provides evidence that Sudanes patients have abnormal coagulation profile and treatment with either HU or omega-3 fatty acids might partially ameliorate SCD-associated chronic coagulopathic state.

Dietary and genetic influences on hemostasis in a Yup'ik Alaska Native population

Fish and marine animals are important components of the subsistence diet of Alaska Native people, resulting in a high ω3 PUFA intake. The historical record for circumpolar populations highlights a tendency for facile bleeding, possibly related to ω3 PUFA effects on platelet activation and/or vitamin K-dependent clotting factors. To evaluate these two scenarios in Yup'ik people of southwestern Alaska, we examined the association between dietary ω3 PUFA intake and activities of clotting factor II, V, fibrinogen, PT, INR, PTT, and sP-selectin in 733 study participants, using the nitrogen isotope ratio of red blood cells as a biomarker of ω3 PUFA consumption. sP-selectin alone correlated strongly and inversely with ω3 PUFA consumption. Approximately 36% of study participants exhibited PIVKA-II values above the threshold of 2 ng/ml, indicative of low vitamin K status. To assess genetic influences on vitamin K status, study participants were genotyped for common vitamin K cycle polymorphisms in VKORC1, GGCX and CYP4F2. Only CYP4F2*3 associated significantly with vitamin K status, for both acute (plasma vitamin K) and long-term (PIVKA-II) measures. These findings suggest: (i) a primary association of ω3 PUFAs on platelet activation, as opposed to vitamin K-dependent clotting factor activity, (ii) that reduced CYP4F2 enzyme activity associates with vitamin K status. We conclude that high ω3 PUFA intake promotes an anti-platelet effect and speculate that the high frequency of the CYP4F2*3 allele in Yup'ik people (~45%) evolved in response to a need to conserve body stores of vitamin K due to environmental limitations on its availability.

Fish oil LC-PUFAs do not affect blood coagulation parameters and bleeding manifestations: Analysis of 8 clinical studies with selected patient groups on omega-3-enriched medical nutrition

BACKGROUND & AIMS

The increased consumption of fish oil enriched-products exposes a wide diversity of people, including elderly and those with impaired health to relatively high amounts of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs). There is an ongoing debate around the possible adverse effects of n-3 LC-PUFAs on bleeding risk, particularly relevant in people with a medical history of cardiovascular events or using antithrombotic drugs.

METHODS

This analysis of 8 clinical intervention studies conducted with enteral medical nutrition products containing fish oil as a source of n-3 LC-PUFAs addresses the occurrence of bleeding-related adverse events and effects on key coagulation parameters (Prothrombin Time [PT], (activated) and Partial Thromboplastin Time [(a)PTT]).

RESULTS

In all the patients considered (over 600 subjects treated with the active product in total), with moderate to severe disease, with or without concomitant use of antithrombotic agents, at home or in an Intensive Care Unit (ICU), no evidence of increased risk of bleeding with use of n-3 LC-PUFAs was observed. Furthermore there were no statistically significant changes from baseline in measured coagulation parameters.

CONCLUSION

These findings further support the safe consumption of n-3 LC-PUFAs, even at short-term doses up to 10 g/day of eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) or consumed for up to 52 weeks above 1.5 g/day, in selected vulnerable and sensitive populations such as subjects with gastrointestinal cancer or patients in an ICU. We found no evidence to support any concern raised with regards to the application of n-3 LC-PUFAs and the potentially increased risk for the occurrence of adverse bleeding manifestations in these selected patient populations consuming fish oil enriched medical nutrition.

Association between Dietary Xanthophyll (Lutein and Zeaxanthin) Intake and Early Age-Related Macular Degeneration: The Atherosclerosis Risk in Communities Study

PURPOSE

To examine the association between xanthophyll intake and prevalent early age-related macular degeneration (AMD) using data from the Atherosclerosis Risk in Communities Study (n = 10,295). Potential effect modification by genetic polymorphisms and biomarkers of high-density lipoprotein (HDL) metabolism was explored.

METHODS

Xanthophyll intake was assessed at visit 1 (1987-1989) using food frequency questionnaires. Prevalent early AMD was assessed at visit 3 (1993-1995) via retinal photographs. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for AMD by quintiles of xanthophyll intake, adjusted for age, sex, race, field center, and pack-years of smoking. To evaluate effect modification, the association between tertiles (T) of xanthophyll intake and AMD was stratified by complement factor H (CFH) rs1061170 and age-related maculopathy susceptibility 2 (ARMS2) rs10490924 genotypes, as well as by median cutpoints of HDL biomarkers.

RESULTS

Xanthophyll intake was not associated with AMD in the overall sample, Caucasians (n = 8257), or African-Americans (n = 2038). Exploratory analyses observed that the association between xanthophyll intake and AMD varied statistically significantly by CFH rs1061170 genotype among Caucasians (p for interaction = 0.045) but not African Americans. No interactions were observed between xanthophyll intake and ARMS2 rs10490924. Moreover, higher xanthophyll intake was associated with decreased odds of AMD among participants with lower HDL (OR = 0.79, 95% CI 0.57-1.09) but not higher HDL (p for interaction = 0.048).

CONCLUSION

Xanthophyll intake was not associated with early AMD. Further studies to investigate this association by genetic susceptibility or variations in HDL metabolism are needed.

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

Background

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

Results

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

Conclusions

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

Electronic supplementary material

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

Omega-3 polyunsaturated fatty acids and oxygenated metabolism in atherothrombosis

Numerous epidemiological studies and clinical trials have reported the health benefits of omega-3 polyunsaturated fatty acids (PUFA), including a lower risk of coronary heart diseases. This review mainly focuses on the effects of alpha-linolenic (ALA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on some risk factors associated with atherothrombosis, including platelet activation, plasma lipid concentrations and oxidative modification of low-density lipoproteins (LDL). Special focus is given to the effects of marine PUFA on the formation of eicosanoids and docosanoids, and to the bioactive properties of some oxygenated metabolites of omega-3 PUFA produced by cyclooxygenases and lipoxygenases. The antioxidant effects of marine omega-3 PUFA at low concentrations and the pro-oxidant effects of DHA at high concentrations on the redox status of platelets and LDL are highlighted. Non enzymatic peroxidation end-products deriving from omega-3 PUFA such as hydroxy-hexenals, neuroketals and EPA-derived isoprostanes are also considered in relation to atherosclerosis. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Reduction of prothrombin and Factor V levels following supplementation with omega-3 fatty acids is sex dependent: a randomised controlled study

BACKGROUND

LCn-3PUFA comprised of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) offer cardioprotection involving a decrease in coagulant activity; however, the evidence is equivocal. We have previously demonstrated that the acute (24 h) effects and chronic (4 weeks) effects of LCn-3PUFA supplementation on platelet aggregation in human subjects are sex specific. This study investigated the mechanisms of the sex-dependent effects of LCn-3PUFA with 4 weeks supplementation of EPA-rich vs. DHA-rich oils on procoagulant and platelet activity in healthy subjects.

DESIGN

A double-blinded, placebo-controlled randomised trial was conducted in 94 healthy adults: male (n=41) and female (n=53). Platelet coagulation parameters including factors I, II, V, VII, VIII, IX, X, vWF:Ag and endogenous thrombin potential were measured at baseline and 4 weeks postsupplementation with EPA-rich or DHA-rich oil capsules.

RESULTS

We have previously reported that platelet aggregation is specifically reduced by supplementation with EPA in males and DHA in females. This sex-specific effect was also observed for decreases in plasma levels of Factor II (-7.9 ± 3.8%, P=.026), Factor V (-6.5 ± 4.5%, P=.022) and vWF:Ag (-7.3 ± 2.1%, P=.034) and was most pronounced in males supplemented with EPA. In contrast, DHA-mediated reduction in platelet aggregation in females was not accompanied by any significant changes in the coagulation parameters tested.

CONCLUSION

Significant interactions between sex and specific LCn-3PUFA exist to reduce procoagulant activity differentially in males vs. females and could have profound effects on managing risk of thrombotic disease.

High fish plus fish oil intake is associated with slightly reduced risk of venous thromboembolism: the Tromsø Study

Current knowledge of the effect of fish consumption on risk of venous thromboembolism (VTE) is scarce and diverging. Therefore, the purpose of the present study was to investigate the impact of fish consumption and fish oil supplements on the risk of VTE in a population-based cohort. Weekly intake of fish for dinner and intake of fish oil supplements during the previous year were registered in 23,621 persons aged 25-97 y who participated in the Tromsø Study from 1994 to 1995. Incident VTE events were registered throughout follow-up (31 December 2010). Cox-regression models were used to calculate HRs for VTE, adjusted for age, body mass index, sex, triglycerides, HDL cholesterol, physical activity, and education level. During a median of 15.8 y of follow-up there were 536 incident VTE events. High fish consumption was associated with a slightly reduced risk of VTE. Participants who ate fish ≥3 times/wk had 22% lower risk of VTE than those who consumed fish 1-1.9 times/wk (multivariable HR: 0.78; 95% CI: 0.60, 1.01; P = 0.06). The addition of fish oil supplements strengthened the inverse association with risk of VTE. Participants who consumed fish ≥3 times/wk who additionally used fish oil supplements had 48% lower risk than those who consumed fish 1-1.9 times/wk but did not use fish oil supplements (HR: 0.52; 95% CI: 0.34, 0.79; P = 0.002). In conclusion, a high weekly intake (≥3 times/wk) of fish was associated with a slightly reduced risk of VTE, and the addition of fish oil supplements strengthened the inverse effect.

In-vitro platelet hyperaggregation and hypersecretion associated with the use of fish oil in healthy children

OBJECTIVE

The aim of this study is to evaluate how fish oil supplementation in children affects platelet function tests in vitro.

MATERIALS AND METHODS

The study included 62 children (20 healthy children without any medications and 42 healthy children who volunteered to take fish oil supplementation) aged between 2 and 12 years. In the group of children taking fish oil supplementation, the baseline, fourth week, and eighth week values for platelet function tests were obtained.

RESULTS

In the platelet aggregation tests induced by high dose of ADP after 8 weeks, the values were significantly higher compared with the values measured before the use of fish oil. The fish oil-supplemented group's values showed an increase in the fourth-week measurements compared with the control group and the baseline measurements in terms of platelet secretion test induced by collagen, standard dose of thrombin, and high-dose thrombin. Platelet secretion tests induced by standard dose of ADP at the end of the eighth week showed an increase compared with baseline test values.

CONCLUSION

This study was done in in-vitro conditions wherein the platelet function in the pediatric age group was analyzed and it was found that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) present in fish oil especially exhibit in-vitro hyperaggregation and increase the secretion of platelets. As a result of this, we consider that it is necessary to be careful while using fish oil supplementation in children as an antithrombotic agent and for a variety of other indications.

Eicosapentaenoic and docosahexaenoic acid supplementations reduce platelet aggregation and hemostatic markers differentially in men and women

Although long-chain n3 polyunsaturated fatty acids [n3 PUFAs; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] have been reported to reduce platelet aggregation, the available evidence on this is equivocal. We previously demonstrated that the acute effects of n3 PUFA supplementation on platelet aggregation are sex specific. We aimed to determine if this gender bias is maintained during long-term n3 PUFA supplementation and whether this translates to other hemostatic markers. A double-blinded, randomized, placebo controlled trial was conducted in 94 healthy men and women. Platelet aggregation, thromboxane (TX) B2, P-selectin (P-sel), von Willebrand factor (vWF), and plasminogen activator inhibitor-1 were measured at baseline and 4 wk postsupplementation with EPA-rich (1000 mg EPA:200 mg DHA) or DHA-rich (200 mg EPA:1000 mg DHA) oil capsules daily. The effects of n3 PUFA on platelet activity were compared between men and women. In men and women combined, EPA and DHA reduced platelet aggregation following 4 wk of supplementation relative to placebo (-11.8%, P = 0.016; and -14.8%, P = 0.001, respectively). In subgroup analyses, in men, only the EPA treatment reduced platelet aggregation by -18.4% compared with placebo (P = 0.005) and women (P = 0.011). In contrast, in women, only the DHA treatment reduced platelet aggregation (-18.9%) compared with placebo (P = 0.001) and men (P = 0.017). Significant sex × treatment interactions were also observed on hemostatic markers and uptake of n3 PUFAs. The significant interactions between sex and specific, supplemental, long-chain n3 PUFAs result in platelet aggregation being differentially affected in men and women. With respect to thrombotic disease risk, men are more likely to benefit from supplementation with EPA, whereas women are more responsive to DHA.

Significant inverse association of marine n-3 fatty acids with plasma fibrinogen levels in Japanese in Japan but not in whites or Japanese Americans

BACKGROUND/OBJECTIVES

Numerous studies reported beneficial effects of marine n-3 fatty acids (n-3 FAs) on cardiovascular disease (CVD) and its risk factors. However, the association of marine n-3 FAs with plasma fibrinogen, a risk factor for CVD, remains uncertain.

SUBJECTS/METHODS

In a population-based, cross-sectional study of 795 men aged 40-49 without CVD (262 whites in Allegheny County, Pennsylvania, USA, 302 Japanese in Kusatsu, Japan and 229 Japanese Americans in Honolulu, Hawaii, USA), we examined the association of marine n-3 FAs with plasma fibrinogen. Serum FAs were measured by capillary gas-liquid chromatography. Marine n-3 FAs were defined as the sum of docosahexaenoic, eicosapentaenoic and docosapentaenoic acids. Plasma fibrinogen was measured by an automated clot-rate assay. Multiple linear regression analyses were performed to assess the association.

RESULTS

White, Japanese and Japanese-American men had mean marine n-3 FAs levels of 3.47%, 8.78% and 4.46%, respectively. Japanese men had a significant inverse association of marine n-3 FAs with fibrinogen (standardized regression coefficient of -0.11, P=0.049), after adjusting for age, body-mass index and current smoking. The significant inverse association remained after further adjusting for diabetes, C-reactive protein, triglycerides and other variables. White or Japanese-American men did not show a significant association.

CONCLUSIONS

We observed the significant inverse association of marine n-3 FAs with fibrinogen in Japanese, but not in whites or Japanese Americans. The observation suggests that marine n-3 FAs at very high levels, as seen in the Japanese, may decrease plasma fibrinogen levels.

Low vegetable intake is strongly associated with venous thromboembolism in Thai population

Recent studies have demonstrated a much higher incidence of venous thromboembolism (VTE) among Asian patients compared with previous studies. This study aims to determine dietary and behavioral factors that may have contributed to this increase. A case-control study was conducted. Cases were objectively confirmed VTE between 2006 and 2009 at King Chulalongkorn Memorial Hospital. Patients with underlying cancer, antiphospholipid syndrome and arterial thrombosis were excluded. Controls were age and sex-matched healthy volunteers. Food consumption was assessed using a food frequency questionnaire modified from the Thailand National Health Examination Survey III previously validated in the Thai population. There were 97 cases and 195 controls. The mean age was 54.6 years and 70% were women. VTE patients consumed significantly less vegetable, fish and spicy food compared with normal individuals with an odds ratio (OR) for venous thrombosis of 3.74 [95% confidence interval (CI) 2.24-6.26, P < 0.001], 2.05 (95% CI 1.24-3.41, P = 0.005) and 2.30 (95% CI 1.29-4.11, P = 0.01), respectively. Additionally, thrombosis was associated with overweight (OR 2.1, 95% CI 1.21-3.62, P = 0.002), obesity (OR 3.1, 95% CI 1.46-6.74, P = 0.001) and estrogen uses (OR 3.7, 95% CI 1.05-13.2, P = 0.02), but not with smoking or lack of exercise. A multivariate analysis showed that low vegetable consumption (OR 3.74, 95% CI 1.85-7.55, P < 0.001), female hormones (OR 5.80, 95% CI 1.51-22.22, P = 0.011) and body mass index (BMI, P = 0.048) were independently associated with VTE. Low vegetable intake, hormonal use and high BMI are the risk factors for noncancer-related VTE in Thai population.

The utility of omega-3 fatty acids in cardiovascular disease

We reviewed the use of marine-derived omega-3 fatty acids in cardiovascular disease by discussing key epidemiologic and placebo-controlled studies in people with and without prior cardiovascular disease at baseline. In addition, studies on the antitriglyceridemic, antihypertensive, hemostatic, antiarrhythmic, and antiatherogenic properties of omega-3 fatty acids were examined. Lastly, we discussed current dietary and safety recommendations regarding fish and fish oil capsules as stated by the US Food and Drug Administration and the US Environmental Protection Agency. We found that omega-3 fatty acids have shown to significantly reduce coronary mortality and sudden death in people without prior cardiovascular disease and reduce all-cause death and cardiac mortality in secondary prevention studies. Studies on stroke are still unclear and more studies need to focus on stroke subtypes. The beneficial effects of omega-3 fatty acids might be the result of their ability to reduce triglyceride levels, blood pressure, platelet aggregation, arrhythmia, and atherogenesis. Currently, the general public is recommended to consume two fatty fish meals per week (0.3-0.5 grams per day eicosapentaenoic acid and docosahexaenoic acid). Pregnant mothers and children should refrain from eating fish high in methylmercury levels while limiting their consumption of other fish varieties to 12 ounces per week. Patients with coronary heart disease should have 1 g per day of eicosapentaenoic acid and docosahexaenoic acid, whereas patients with hypertriglyceridemia should take 3 to 5 g per day of eicosapentaenoic acid and docosahexaenoic acid under a physician's supervision.

Omega-3 fatty acids and the cardiometabolic syndrome

Benefits of fish consumption in patients with the cardiometabolic syndrome relate to the high biologic value of protein, omega-3 fatty acids, as well as certain minerals and vitamins in fish. Recently, the American Heart Association issued new guidelines for the intake of omega-3 oils for the prevention of coronary heart disease. The objective of this paper is to evaluate the potential health benefits of fish consumption and/or fish oil supplements in reducing cardiometabolic syndrome risk factors. The consumption of fish or fish oil containing omega-3 polyunsaturated fatty acids reduces the risk of coronary heart disease, decreases triglyceride, blood pressure, and inflammatory markers, improves endothelial function, prevents certain cardiac arrhythmias, reduces platelet aggregation (including reactivity and adhesion), reduces vasoconstriction, enhances fibrinolysis, reduces fibrin formation, and decreases the risk of microalbuminuria and sudden cardiac death. Thus, fish intake or fish oil supplement use is beneficial to reduce cardiometabolic risk factors.

n-3 Fatty acids and cardiovascular disease: mechanisms underlying beneficial effects

Dietary n-3 fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, are important nutrients through the life cycle. Evidence from observational, clinical, animal, and in vitro studies indicates a beneficial role of n-3 fatty acids in the prevention and management of cardiovascular disease. Although the precise mechanisms are still unclear, clinical and preclinical studies indicate that the cardioprotective effects of n-3 fatty acids may be attributed to a number of distinct biological effects on lipid and lipoprotein metabolism, blood pressure, platelet function, arterial cholesterol delivery, vascular function, and inflammatory responses.

New approaches to therapy with omega-3 fatty acids

With greater focus on chronic disease prevention, renewed attention has been directed toward understanding the pathophysiology of various medical conditions and the development of newer medical treatments to prevent and treat complications. There has been immense interest in evaluating societal lifestyles, cultural attitudes toward health, and dietary influences on health conditions. The omega-3 fatty acids have become a focus of interest, and recent research and trial evidence have highlighted their effects, including potential clinical advantages. Despite this progress, the precise mechanisms through which omega-3 fatty acids act remain poorly understood. These agents are now recommended as secondary prevention after acute myocardial infarction, and ongoing large clinical trials should provide insight into the use of omega-3 fatty acids in heart failure and the primary prevention of cardiovascular disease.

Enteral immuno-enhanced diets with arginine are safe and beneficial for patients early after esophageal cancer surgery

We previously reported that provision of immediate enteral nutrition (EN) with a certain amount of omega (omega)-3 fatty acids (FAs) in patients after esophageal cancer surgery resulted in reduced platelet aggregation, coagulation activity, and cytokine production. We investigated whether EN using immuno-enhanced diet (IED) containing a large amount of omega-3 FAs as well as arginine and RNA affected the above-described responses. We also attempted to reveal whether arginine in the IED can potentially harm patients who undergo esophageal cancer surgery. Twenty-nine patients with esophageal cancer who underwent similar surgical procedures were selected. All patients received EN starting immediately after surgery. Fourteen patients received the formula with fewer omega-3 FAs, and fifteen patients received the IED. Administration of the IED tended to inhibit postoperative decrease in platelet count. Prothrombin activity and thrombin-antithrombin III complex levels were significantly reduced in the IED group. Plasma IL-8 levels were significantly lower (P < 0.05) in patients without the IED on the fifth postoperative day (POD). The proportion of T-cells was significantly higher (P < 0.05) in the IED group on PODs 1 and 7. Nitrate/nitrite levels did not differ significantly between the two groups. Early EN with an IED may enhance the inhibitory effects on postoperative platelet aggregation and hypercoagulation, and appeared to be advantageous to T-cell proliferation. These effects are expected to be beneficial in patients at risk of developing infectious complications. This study also showed that the IED could be safely used without any adverse effects for patients early after a radical surgery for the esophageal cancer.

Diet and haemostatic processes

Diet plays an important role in the primary and secondary prevention of cardiovascular disease. The growing perception that abnormal haemostatic processes of coagulation, platelet aggregation and fibrinolysis contribute to cardiovascular disease aetiology motivated this review on the relationships of diet, specific foods and nutrients with haemostatic function. Functional endpoints that reflect the function and status of some of these processes and which can be measured in dietary trials are identified. The effects of energy intake and expenditure, alcohol, total fat and specific fatty acids, non-starch polysaccharides (dietary fibre), antioxidant nutrients and some foods on a variety of haemostatic markers are reviewed. The results indicate that the prudent low-fat, high-fibre diet and maintenance of ideal body weight recommended to protect against and treat hyperlipidaemia and coronary heart disease will also benefit haemostatic profiles. It is concluded that more research on specific effects is needed for improved recommendations on a population level for prevention of cardiovascular disease.

Measurement error adjustment in essential fatty acid intake from a food frequency questionnaire: alternative approaches and methods

Background

We aimed at assessing the degree of measurement error in essential fatty acid intakes from a food frequency questionnaire and the impact of correcting for such an error on precision and bias of odds ratios in logistic models. To assess these impacts, and for illustrative purposes, alternative approaches and methods were used with the binary outcome of cognitive decline in verbal fluency.

Methods

Using the Atherosclerosis Risk in Communities (ARIC) study, we conducted a sensitivity analysis. The error-prone exposure – visit 1 fatty acid intake (1987–89) – was available for 7,814 subjects 50 years or older at baseline with complete data on cognitive decline between visits 2 (1990–92) and 4 (1996–98). Our binary outcome of interest was clinically significant decline in verbal fluency. Point estimates and 95% confidence intervals were compared between naïve and measurement-error adjusted odds ratios of decline with every SD increase in fatty acid intake as % of energy. Two approaches were explored for adjustment: (A) External validation against biomarkers (plasma fatty acids in cholesteryl esters and phospholipids) and (B) Internal repeat measurements at visits 2 and 3. The main difference between the two is that Approach B makes a stronger assumption regarding lack of error correlations in the structural model. Additionally, we compared results from regression calibration (RCAL) to those from simulation extrapolation (SIMEX). Finally, using structural equations modeling, we estimated attenuation factors associated with each dietary exposure to assess degree of measurement error in a bivariate scenario for regression calibration of logistic regression model.

Results and conclusion

Attenuation factors for Approach A were smaller than B, suggesting a larger amount of measurement error in the dietary exposure. Replicate measures (Approach B) unlike concentration biomarkers (Approach A) may lead to imprecise odds ratios due to larger standard errors. Using SIMEX rather than RCAL models tends to preserve precision of odds ratios. We found in many cases that bias in naïve odds ratios was towards the null. RCAL tended to correct for a larger amount of effect bias than SIMEX, particularly for Approach A.

n-3 Fatty acids, hypertension and risk of cognitive decline among older adults in the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

Recent research indicates that n-3 fatty acids can inhibit cognitive decline, perhaps differentially by hypertensive status.

DESIGN

We tested these hypotheses in a prospective cohort study (the Atherosclerosis Risk in Communities). Dietary assessment using a food-frequency questionnaire and plasma fatty acid exposure by gas chromatography were completed in 1987-1989 (visit 1), while cognitive assessment with three screening tools--the Delayed Word Recall Test, the Digit Symbol Substitution Test of the Wechsler Adult Intelligence Scale-Revised and the Word Fluency Test (WFT)--was completed in 1990-1992 (visit 2) and 1996-1998 (visit 4). Regression calibration and simulation extrapolation were used to control for measurement error in dietary exposures.

SETTING

Four US communities--Forsyth County (North Carolina), Jackson (Mississippi), suburbs of Minneapolis (Minnesota) and Washington County (Maryland).

SUBJECTS

Men and women aged 50-65 years at visit 1 with complete dietary data (n = 7814); white men and women in same age group in the Minnesota field centre with complete plasma fatty acid data (n = 2251).

RESULTS

Findings indicated that an increase of one standard deviation in dietary long-chain n-3 fatty acids (% of energy intake) and balancing long-chain n-3/n-6 decreased the risk of 6-year cognitive decline in verbal fluency with an odds ratio (95% confidence interval) of 0.79 (0.66-0.95) and 0.81 (0.68-0.96), respectively, among hypertensives. An interaction with hypertensive status was found for dietary long-chain n-3 fatty acids (g day-1) and WFT decline (likelihood ratio test, P = 0.06). This exposure in plasma cholesteryl esters was also protective against WFT decline, particularly among hypertensives (OR = 0.51, P < 0.05).

CONCLUSION

One implication from our study is that diets rich in fatty acids of marine origin should be considered for middle-aged hypertensive subjects. To this end, randomised clinical trials are needed.

Nuts: source of energy and macronutrients

On the basis of the high fat content of nuts, they are traditionally considered as foods that provide a high amount of energy. However, epidemiologic and clinical observations do not indicate an association between nut intake and increased BMI. There is a notorious variability in macronutrient composition among nuts, although they have some consistent patterns. Nuts contain all major macronutrients: protein, carbohydrate, and fat. The total protein content is relatively high, which makes them a good source of plant protein (especially for vegetarians). Although nuts contain low amounts of some essential amino acids, this is not a nutritional concern due to the complement of protein. In addition, nuts have a low lysine:arginine ratio, which is inversely associated with the risk of developing hypercholesterolemia and atherosclerosis. Carbohydrates are the second highest macronutrient in nuts in terms of total calories provided. The fat fraction is characterized by a high amount of unsaturated fatty acids and a low content of saturated fatty acids. In conclusion, the high content in unsaturated fatty acids, the low lysine:arginine ratio, and the presence of other bioactive molecules (such as fibre, phytosterols, vitamin and other antioxidants, and minerals) make the addition of nuts to healthy diets a useful tool for the prevention of cardiovascular heart diseases.

Long-chain n-3 fatty acid supplementation in men increases resistance to activated protein C

It has recently and controversially been demonstrated that fish oil supplementation may not be beneficial for everyone, but to date there have been no biological explanations. We suggest that resistance to the anticoagulant, activated protein C (APC), be considered as a potential mechanism, because it has been demonstrated that the type of fatty acids on phospholipids modulates function of the APC pathway. The APC ratio in plasma was decreased by 7% after fish oil supplementation in healthy men (P<.005; n=35). The decrease in APC ratio equates to an increase in APC resistance. Fish oil lowered the APC ratio by (1) increasing low-density lipoprotein (LDL) cholesterol (P<.01) and apolipoprotein B (P<.05) and (2) increasing platelet microparticles (P<.05). In vitro, purified LDL decreased the APC ratio and increased microparticle formation. These changes affecting the anticoagulant APC could contribute toward a prothrombotic state, potentially explaining the recent observation that fish oil supplementation may not always be of benefit. These findings will need to be repeated in different disease states.

Plasma n-3 fatty acids and the risk of cognitive decline in older adults: the Atherosclerosis Risk in Communities Study

BACKGROUND

Plasma fatty acids may affect the risk of cognitive decline in older adults.

OBJECTIVES

We prospectively studied the association between plasma fatty acids and cognitive decline in adults aged 50-65 y at baseline and conducted a subgroup analysis.

DESIGN

From 1987 through 1989, the Atherosclerosis Risk in Communities (ARIC) Study analyzed plasma fatty acids in cholesteryl esters and phospholipids in whites residing in Minneapolis, MN. From 1990 through 1992 and from 1996 through 1998, 3 neuropsychological tests in the domains of delayed word recall, psychomotor speed, and verbal fluency were administered. We selected cutoffs for statistically reliable cognitive decline in each of these domains and a measure of global cognitive change computed by principal-components analysis. Multivariate logistic regression was conducted. Focusing on n-3 highly unsaturated fatty acids (HUFAs), a subgroup analysis assessed differential association across potential effect modifiers implicated in oxidative stress and increased risk of neurodegenerative disease.

RESULTS

In the 2251 study subjects, the risk of global cognitive decline increased with elevated palmitic acid in both fractions and with high arachidonic acid and low linoleic acid in cholesteryl esters. Higher n-3 HUFAs reduced the risk of decline in verbal fluency, particularly in hypertensive and dyslipidemic subjects. No significant findings were shown for psychomotor speed or delayed word recall.

CONCLUSIONS

Promoting higher intakes of n-3 HUFAs in the diet of hypertensive and dyslipidemic persons may have substantial benefits in reducing their risk of cognitive decline in the area of verbal fluency. However, clinical trials are needed to confirm this finding.

Subdural hematoma after a fall in an elderly patient taking high-dose omega-3 fatty acids with warfarin and aspirin: case report and review of the literature

The elderly population is at an increased risk for major bleeding, possibly due to increased sensitivity to anticoagulation, multiple comorbidities, and polypharmacy. Elderly patients receiving antiplatelet and anticoagulant therapy have an additional risk for bleeding. Omega-3 fatty acids, also known as fish oil, have been used for hyperlipidemia, coronary heart disease, hypertension, and other conditions. Some studies have demonstrated that consumption of fish oil concentrate, n-3 polyunsaturated fatty acid (n-3 PUFA), results in cardiovascular benefits that include reductions in mortality, sudden death, nonfatal myocardial infarction, and thrombotic stoke, as well as improvement in graft patency. The mechanism of action of n-3 PUFA is not completely understood, but a dual antiplatelet and anticoagulant effect has been proposed. Few data exist on whether or not fish oil can be used safely with other antiplatelet or anticoagulant drugs. We report the case of a patient who after a minor fall developed a subdural hematoma requiring craniotomy that likely was precipitated by concomitant use of high-dose omega-3 fatty acids 6 g/day with both aspirin and warfarin. These findings are important because of the wide availability of omega-3 fatty acids and the propensity for use of complementary and alternative medicine in patients with cardiovascular disease who are already taking antiplatelet and/or anticoagulant agents. Judicious use of these combinations is advised, and pharmacists can play an important role in educating patients and other health care providers about the bleeding risks associated with combination therapy.

Plasma triacylglycerol and coagulation factor concentrations predict the anticoagulant effect of dietary fish oil in overweight subjects

Fish oil, containing (n-3) PUFA, is associated with a moderate reduction in cardiovascular disease through a multifactorial mechanism involving a decrease in plasma lipids and anticoagulant activity. Two intervention studies on subjects at risk were performed to determine the relation of these 2 fish-oil effects. In study 1, 54 overweight subjects consumed 3.1 g (n-3) PUFA daily. In study 2, which involved 42 overweight patients with type 2 diabetes, 20 subjects consumed (n-3) PUFA, whereas 22 others ingested a preparation rich in (n-6) PUFA. Tissue factor-induced thrombin generation (thrombin potential) was determined as an integrated measure of plasma coagulant activity. In both studies, multivariate analysis indicated a strong clustering of fasting concentrations of triacylglycerols, prothrombin, factor V, factor VII, and factor X with one another at baseline. This cluster of factors determined partly the interindividual variation in thrombin generation, of which prothrombin and triacylglycerol concentrations were the main determinants. In both healthy subjects and diabetes patients, high triacylglycerol concentrations (>1.69 mmol/L) at baseline were closely linked to a strong fish oil-induced lowering of triacylglycerol and coagulation factor V, VII, and X concentrations, and thrombin generation. We conclude that high fasting triacylglycerol concentrations predict high procoagulant activity and a lowering of thrombin potential with dietary fish oil.

Oily fish reduces plasma triacylglycerols: a primary prevention study in overweight men and women

OBJECTIVE

Previous studies have demonstrated benefits of high-dose long-chain omega-3 polyunsaturated fatty acid (LC omega-3 PUFA) supplements on metabolic risk. Effects of increased dietary omega-3 PUFA, via oily fish and/or plant-derived omega-3 PUFAs, are less clear and may be modulated by the omega-6:omega-3 PUFA of the habitual diet. This study examined the effect on cardiovascular disease risk markers of reducing dietary omega-6:omega-3 PUFA by changes in linoleic acid:alpha-linolenic acid (LA:LNA) and/or increasing LC omega-3 PUFA. It tested whether decreases in LA:LNA modulate effects of LC omega-3 PUFA.

METHODS

One hundred forty-two subjects, recruited to a 24-wk randomized study, were assigned to a control group or one of four interventions. Intervention groups received two portions of oily fish (4.5 g eicosapentaenoic acid + docosahexanoic acid) or white fish (0.7 g eicosapentaenoic acid + docosahexanoic acid) per week, and replaced habitual household fats with ones high in sunflower (high LA:LNA) or rapeseed (low LA:LNA) oil.

RESULTS

Modest dietary manipulations of omega-6 and omega-3 PUFAs resulted in significant group x time interactions for serum triacylglycerols (TAGs; P = 0.05); at 24 wk the control and two oily fish groups showed lower TAG than did the white fish/sunflower group (P = 0.05). Reductions in TAG, associated with increased oily fish intakes, were maximized when combined with lower dietary LA:LNA. There were no significant changes in several other cardiovascular disease risk markers.

CONCLUSIONS

Two portions of oily fish per week led to significant reductions in TAG relative to consumption of two portions of white fish per week. Changes in TAG were maximized when combined with lower LA:LNA.

Nutrition, lipids, and cardiovascular disease

The evolving epidemic of cardiovascular disease in many newly industrialized societies will bankrupt their health care systems and reduce the available resources for other health priorities. Therefore, the prevention of this epidemic, or at least slowing the increase, is of the highest priority. The development of coronary heart disease (CHD) is an example of a common source epidemic due to increased consumption of saturated fat and cholesterol, low intakes of polyunsaturated fat, and increasing obesity. Hypertension, cigarette smoking, and diabetes mellitus contribute to risk of disease. The prevention of atherosclerosis beginning in young adults is of paramount importance. Careful monitoring of the evolving epidemic of CHD, including noninvasive evaluation of atherosclerosis, is important. A high-risk approach is very successful but expensive.

Nut and seed consumption and inflammatory markers in the multi-ethnic study of atherosclerosis

Nuts and seeds are rich in unsaturated fat and other nutrients that may reduce inflammation. Frequent nut consumption is associated with lower risk of cardiovascular disease and type 2 diabetes. The authors examined associations between nut and seed consumption and C-reactive protein, interleukin-6, and fibrinogen in the Multi-Ethnic Study of Atherosclerosis. This 2000 cross-sectional analysis included 6,080 US participants aged 45-84 years with adequate information on diet and biomarkers. Nut and seed consumption was categorized as never/rare, less than once/week, 1-4 times/week, and five or more times/week. After adjustment for age, gender, race/ethnicity, site, education, income, smoking, physical activity, use of fish oil supplements, and other dietary factors, mean biomarker levels in categories of increasing consumption were as follows: C-reactive protein-1.98, 1.97, 1.80, and 1.72 mg/liter; interleukin-6-1.25, 1.24, 1.21, and 1.15 pg/ml; and fibrinogen-343, 338, 338, and 331 mg/dl (all p's for trend < 0.01). Further adjustment for hypertension, diabetes, medication use, and lipid levels yielded similar results. Additional adjustment for body mass index moderately attenuated the magnitude of the associations, yielding borderline statistical significance. Associations of nut and seed consumption with these biomarkers were not modified by body mass index, waist:hip ratio, or race/ethnicity. Frequent nut and seed consumption was associated with lower levels of inflammatory markers, which may partially explain the inverse association of nut consumption with cardiovascular disease and diabetes risk.

Fish Consumption Among Healthy Adults Is Associated With Decreased Levels of Inflammatory Markers Related to Cardiovascular Disease

OBJECTIVES

The aim of this work was to investigate the association between fish consumption and levels of various inflammatory markers among adults without any evidence of cardiovascular disease.

BACKGROUND

Fish consumption has been associated with reduced risk of coronary heart disease, but the mechanisms have not been well understood or appreciated.

METHODS

The ATTICA study is a cross-sectional survey that enrolled 1,514 men (age 18 to 87 years) and 1,528 women (age 18 to 89 years) from the Attica region, Greece. Of them, 5% of men and 3% of women were excluded due to a history of cardiovascular disease. Among others, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, serum amyloid A (SAA), and white blood cells (WBC) were measured, and dietary habits (including fish consumption) were evaluated using a validated food frequency questionnaire.

RESULTS

A total of 88% of men and 91% of women reported fish consumption at least once a month. Compared to non-fish consumers, those who consumed >300 g of fish per week had on average 33% lower CRP, 33% lower IL-6, 21% lower TNF-alpha, 28% lower SAA levels, and 4% lower WBC counts (all p < 0.05). Significant results were also observed when lower quantities (150 to 300 g/week) of fish were consumed. All associations remained significant after various adjustments were made.

CONCLUSIONS

Fish consumption was independently associated with lower inflammatory markers levels, among healthy adults. The strength and consistency of this finding has implications for public health and should be explored further.

The role of omega-3 long-chain polyunsaturated fatty acids in health and disease of the retina

In this work we advance the hypothesis that omega-3 (omega-3) long-chain polyunsaturated fatty acids (LCPUFAs) exhibit cytoprotective and cytotherapeutic actions contributing to a number of anti-angiogenic and neuroprotective mechanisms within the retina. omega-3 LCPUFAs may modulate metabolic processes and attenuate effects of environmental exposures that activate molecules implicated in pathogenesis of vasoproliferative and neurodegenerative retinal diseases. These processes and exposures include ischemia, chronic light exposure, oxidative stress, inflammation, cellular signaling mechanisms, and aging. A number of bioactive molecules within the retina affect, and are effected by such conditions. These molecules operate within complex systems and include compounds classified as eicosanoids, angiogenic factors, matrix metalloproteinases, reactive oxygen species, cyclic nucleotides, neurotransmitters and neuromodulators, pro-inflammatory and immunoregulatory cytokines, and inflammatory phospholipids. We discuss the relationship of LCPUFAs with these bioactivators and bioactive compounds in the context of three blinding retinal diseases of public health significance that exhibit both vascular and neural pathology. How is omega-3 LCPUFA status related to retinal structure and function? Docosahexaenoic acid (DHA), a major dietary omega-3 LCPUFA, is also a major structural lipid of retinal photoreceptor outer segment membranes. Biophysical and biochemical properties of DHA may affect photoreceptor membrane function by altering permeability, fluidity, thickness, and lipid phase properties. Tissue DHA status affects retinal cell signaling mechanisms involved in phototransduction. DHA may operate in signaling cascades to enhance activation of membrane-bound retinal proteins and may also be involved in rhodopsin regeneration. Tissue DHA insufficiency is associated with alterations in retinal function. Visual processing deficits have been ameliorated with DHA supplementation in some cases. What evidence exists to suggest that LCPUFAs modulate factors and processes implicated in diseases of the vascular and neural retina? Tissue status of LCPUFAs is modifiable by and dependent upon dietary intake. Certain LCPUFAs are selectively accreted and efficiently conserved within the neural retina. On the most basic level, omega-3 LCPUFAs influence retinal cell gene expression, cellular differentiation, and cellular survival. DHA activates a number of nuclear hormone receptors that operate as transcription factors for molecules that modulate reduction-oxidation-sensitive and proinflammatory genes; these include the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) and the retinoid X receptor. In the case of PPAR-alpha, this action is thought to prevent endothelial cell dysfunction and vascular remodeling through inhibition of: vascular smooth muscle cell proliferation, inducible nitric oxide synthase production, interleukin-1 induced cyclooxygenase (COX)-2 production, and thrombin-induced endothelin 1 production. Research on model systems demonstrates that omega-3 LCPUFAs also have the capacity to affect production and activation of angiogenic growth factors, arachidonic acid (AA)-based vasoregulatory eicosanoids, and MMPs. Eicosapentaenoic acid (EPA), a substrate for DHA, is the parent fatty acid for a family of eicosanoids that have the potential to affect AA-derived eicosanoids implicated in abnormal retinal neovascularization, vascular permeability, and inflammation. EPA depresses vascular endothelial growth factor (VEGF)-specific tyrosine kinase receptor activation and expression. VEGF plays an essential role in induction of: endothelial cell migration and proliferation, microvascular permeability, endothelial cell release of metalloproteinases and interstitial collagenases, and endothelial cell tube formation. The mechanism of VEGF receptor down-regulation is believed to occur at the tyrosine kinase nuclear factor-kappa B (NFkappaB). NFkappaB is a nuclear transcription factor that up-regulates COX-2 expression, intracellular adhesion molecule, thrombin, and nitric oxide synthase. All four factors are associated with vascular instability. COX-2 drives conversion of AA to a number angiogenic and proinflammatory eicosanoids. Our general conclusion is that there is consistent evidence to suggest that omega-3 LCPUFAs may act in a protective role against ischemia-, light-, oxygen-, inflammatory-, and age-associated pathology of the vascular and neural retina.

Dietary n-6 and n-3 fatty acid balance and cardiovascular health

Epidemiological and clinical studies have established that the n-6 fatty acid, linoleic acid (LA), and the n-3 fatty acids, linolenic acid (LNA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) collectively protect against coronary heart disease (CHD). LA is the major dietary fatty acid regulating low-density lipoprotein (LDL)-C metabolism by downregulating LDL-C production and enhancing its clearance. Further, the available mass of LA is a critical factor determining the hyperlipemic effects of other dietary fat components, such as saturated and trans fatty acids, as well as cholesterol. By contrast, n-3 fatty acids, especially EPA and DHA, are potent antiarryhthmic agents. EPA and DHA also improve vascular endothelial function and help lower blood pressure, platelet sensitivity, and the serum triglyceride level. The distinct functions of these two families make the balance between dietary n-6 and n-3 fatty acids an important consideration influencing cardiovascular health. Based on published literature describing practical dietary intakes, we suggest that consumption of ~6% en LA, 0.75% en LNA, and 0.25% en EPA + DHA represents adequate and achievable intakes for most healthy adults. This corresponds to an n-6/n-3 ratio of ~6:1. However, the absolute mass of essential fatty acids consumed, rather than their n-6/n-3 ratio, should be the first consideration when contemplating lifelong dietary habits affecting cardiovascular benefit from their intake.

Dietary fatty acids, hemostasis, and cardiovascular disease risk

The cause of many myocardial infarctions is occlusive thrombosis, or a blood clot that stops blood flow in a coronary artery. Hemostasis involves a complex system of factors, which normally form and degrade blood clots, that work within a delicate balance. Emerging evidence suggests that some hemostatic factors, including factor VII, fibrinogen, and plasminogen activator inhibitor-1, are associated with increased risk for cardiovascular disease (CVD). Accumulating evidence suggests a relationship between dietary fatty acids and emerging hemostatic CVD risk factors, although much of this evidence is incomplete or conflicting. Dietary supplementation with marine n-3 fatty acids prolongs bleeding time and may decrease risk for thrombosis. Factor VII coagulant activity modestly decreases with reductions in saturated fatty acid (SFA) intake and thereby may contribute to the beneficial effects of low SFA diets. Large triglyceride-rich particles formed during postprandial lipemia can support the assembly and function of coagulation complexes and seem to play a role in the activation of factor VII, and thus may partially explain increased CVD risk associated with increased postprandial triglyceridemia. As our understanding of the role of dietary fatty acids and hemostasis evolves, it is likely that we will be able to make specific dietary recommendations to further decrease CVD risk. At this juncture, however, increasing marine n-3 fatty acids and decreasing certain SFAs are leading strategies to reduce hemostatic CVD risk factors. An array of dietary strategies that target multiple CVD risk factors could have a greater impact on CVD than a single risk factor intervention strategy.

Fish oil interaction with warfarin

OBJECTIVE

To report a case of elevated international normalized ratio (INR) in a patient taking fish oil and warfarin.

CASE SUMMARY

A 67-year-old white woman had been taking warfarin for 1(1/2) years due to recurrent transient ischemic attacks. Her medical history included hypothyroidism, hyperlipidemia, osteopenia, hypertension, and coronary artery disease. She also experienced an inferior myocardial infarction in 1995 requiring angioplasty, surgical repair of her femoral artery in 1995, and hernia repair in 1996. This patient has her INR checked in the anticoagulation clinic and is followed monthly by the clinical pharmacist. Prior to the interaction, her INR was therapeutic for 5 months while she was taking warfarin 1.5 mg/d. The patient admitted to doubling her fish oil dose from 1000 to 2000 mg/d. Without dietary, lifestyle, or medication changes, the INR increased from 2.8 to 4.3 within 1 month. The INR decreased to 1.6 one week after subsequent fish oil reduction, necessitating a return to the original warfarin dosing regimen.

DISCUSSION

Fish oil supplementation could have provided additional anticoagulation with warfarin therapy. Fish oil, an omega-3 polyunsaturated fatty acid, consists of eicosapentaenoic acid and docosahexaenoic acid. This fatty acid may affect platelet aggregation and/or vitamin K-dependent coagulation factors. Omega-3 fatty acids may lower thromboxane A(2) supplies within the platelet as well as decrease factor VII levels. Although controversial, this case report illustrates that fish oil can provide additive anticoagulant effects when given with warfarin.

CONCLUSIONS

This case reveals a significant rise in INR after the dose of concomitant fish oil was doubled. Patients undergoing anticoagulation therapy with warfarin should be educated about and monitored for possible drug-herb interactions. Pharmacists can play a crucial role in identifying possible drug interactions by asking patients taking warfarin about herbal and other alternative medicine product use.

Fish oil consumption and reduction of arterial disease

Fish oil consumption may help to normalize the prethrombotic state and reduce arterial disease. This antithrombotic potential of fish oil, rich in (n-3) polyunsaturated fatty acids (PUFA), has been attributed to a reduction in platelet activation, a lowering of plasma triglycerides and (vitamin K-dependent) coagulation factors and/or a decrease in vascular tone. Most intervention studies have shown only moderate effects of (n-3) PUFA on these hemostatic variables. On the other hand, the usually small prolongation in bleeding time with fish oil does not appear to lead to bruising or hemorrhage, at least in healthy subjects. This contrasts with the increased bleeding risk accompanying the more prominent antihemostatic effects of antiplatelet and anticoagulant drugs. Here we propose that the beneficial effect of (n-3) PUFA diet is related to down-regulation of the mutually positive interactions of platelet activation and coagulation. In addition, we consider the possibility that the dietary effect on hemostatic and lipid factors involves transcription regulation of multiple genes, perhaps in a subject-dependent manner.

Effects of purified eicosapentaenoic acid and docosahexaenoic acid on platelet, fibrinolytic and vascular function in hypertensive type 2 diabetic patients

BACKGROUND

Type 2 diabetes and hypertension are both associated with an increased risk of atherothrombosis. We assessed whether purified eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil have differential effects on platelet, fibrinolytic and vascular function in patients with both conditions.

METHODS

In a double-blind placebo-controlled trial of parallel design, 59 treated-hypertensive Type 2 diabetic men and postmenopausal women, were randomised to 4 g/day of EPA, DHA or olive oil (placebo) for 6 weeks. Collagen and PAF-stimulated platelet aggregation, collagen-stimulated thromboxane release (TXB2), plasma tPA and PAI-1 antigens, von Willebrand factor, p-selectin, and flow-mediated and glyceryl-trinitrate-mediated dilatation of the brachial artery, were examined before and at the end of intervention.

RESULTS

Thirty-nine men and 12 women aged 61.2+/-1.2 year completed the study. Relative to placebo, DHA but not EPA supplementation significantly reduced collagen aggregation (16.9%, P=0.05) and TXB2 (18.8%, P=0.03). There were no significant changes in either PAF-stimulated platelet aggregation, fibrinolytic function or vascular function in either the EPA or DHA group relative to placebo.

CONCLUSION

Highly purified DHA may be a more effective anti-thrombotic agent than EPA. However, longer-term studies assessing morbidity and mortality are needed in order to establish if DHA contributes to reducing CHD amongst Type 2 diabetic patients with treated hypertension.