Relation of omega-3 fatty acid and dietary fish intake with brachial artery flow-mediated vasodilation in the Multi-Ethnic Study of Atherosclerosis

ω-3 Polyunsaturated Fatty Acid Status Testing in Humans: A Narrative Review of Commercially Available Options

There is an increasing body of evidence supporting a link between low intakes of ω-3 long-chain polyunsaturated fatty acids (LCPUFA) and numerous diseases and health conditions. However, few people are achieving the levels of fish/seafood or eicosapentaenoic acid and docosahexaenoic acid intake recommended in national and international guidelines. Knowledge of a person's ω-3 LCPUFA status will benefit the interpretation of research results and could be expected to lead to an increased effort to increase intake. Dietary intake survey methods are often used as a surrogate for measuring ω-3 PUFA tissue status and its impact on health and functional outcomes. However, because individuals vary widely in their ability to digest and absorb ω-3 PUFA, analytical testing of biological samples is desirable to accurately evaluate ω-3 PUFA status. Adipose tissue is the reference biospecimen for measuring tissue fatty acids, but less-invasive methods, such as measurements in whole blood or its components (e.g., plasma, serum, red blood cell membranes) or breast milk are often used. Numerous commercial laboratories provide fatty acid testing of blood and breast milk samples by different methods and present their results in a variety of reports such as a full fatty acid profile, ω-3 and ω-6 fatty acid profiles, fatty acid ratios, as well as the Omega-3 Index, the Holman Omega-3 Test, OmegaScore, and OmegaCheck, among others. This narrative review provides information about the different ways to measure ω-3 LCPUFA status (including both dietary assessments and selected commercially available analytical tests of blood and breast milk samples) and discusses evidence linking increased ω-3 LCPUFA intake or status to improved health, focusing on cardiovascular, neurological, pregnancy, and eye health, in support of recommendations to increase ω-3 LCPUFA intake and testing.

Plant-Based Nutrition: Exploring Health Benefits for Atherosclerosis, Chronic Diseases, and Metabolic Syndrome-A Comprehensive Review

Atherosclerosis, chronic non-communicable diseases, and metabolic syndrome are highly interconnected and collectively contribute to global health concerns that reduce life expectancy and quality of life. These conditions arise from multiple risk factors, including inflammation, insulin resistance, impaired blood lipid profile, endothelial dysfunction, and increased cardiovascular risk. Adopting a plant-based diet has gained popularity as a viable alternative to promote health and mitigate the incidence of, and risk factors associated with, these three health conditions. Understanding the potential benefits of a plant-based diet for human health is crucial, particularly in the face of the rising prevalence of chronic diseases like diabetes, hypertension, dyslipidemia, atherosclerosis, and cancer. Thus, this review focused on the plausible advantages of consuming a type of food pattern for the prevention and/or treatment of chronic diseases, emphasizing the dietary aspects that contribute to these conditions and the evidence supporting the benefits of a plant-based diet for human health. To facilitate a more in-depth analysis, we present separate evidence for each of these three concepts, acknowledging their intrinsic connection while providing a specific focus on each one. This review underscores the potential of a plant-based diet to target the underlying causes of these chronic diseases and enhance health outcomes for individuals and populations.

The influence on fish and seafood consumption, and the attitudes and reasons for its consumption in the Croatian population

Fish makes an important part of the Mediterranean diet, which has been scientifically proven to help preserve human health by protecting against major chronic and inflammatory diseases. Eating fish and seafood is very important, not only for its proven health benefits but also for its positive impact on the environment. Due to many fish and seafood significant positive effects on human health, this study aimed to investigate the socio-demographic factors associated with the consumption of fish and seafood in the population of Primorsko-goranska County in Croatia. Another aim was to determine people's attitudes, choices, and reasons for the consumption of fish and seafood. Self-reported data from 2,910 participants were used. According to the European dietary recommendations for fish consumption, the participants were divided into two groups; the very low to low fish consumption group and the moderate to high fish consumption group, in order to examine the differences in socio-demographic and lifestyle variables, and their attitudes, opinions, and reasons for fish and seafood consumption. More fish and seafood were consumed by women, the elderly, the more educated, non-smokers, and more physically active participants. Age, the highest level of education, and a diet even moderately adherent to the Mediterranean diet was found to significantly increase the likelihood of recommended fish consumption. Participants considered the best reasons to consume more fish lower prices, buy much more locally produced fishery products, and prefer to eat wild-caught fish rather than farmed fish. The study has found a slight increase in fish consumption, although still lower than the European average. It also showed significant socio-demographic associations, also the reasons and attitudes toward higher fish and seafood consumption of the Croatian population. The obtained research data are valuable for planning future public health programs in Croatia aimed at greater consumption of fish and seafood, as well as their promotion as an important part of a sustainable diet.

A systematic review of the determinants of seafood consumption

Although seafood is considered to be an important part of a balanced diet, many national food consumption surveys suggest that seafood is not consumed in sufficient amounts. As consumers are moving to diversify their diet from animal-based protein, it is important to understand the factors influencing consumption of marine foods. This review aims to assess the characteristics of seafood consumers as well as the influences on seafood consumption in Europe, USA, Canada, Australia and New Zealand. Systematic search strategies were used to identify relevant journal articles from three electronic databases (PubMed, Web of Science and Embase). Three searches were carried out and identified 4405 unique publications from which 121 met the criteria for the review process. The reviewed studies revealed that seafood consumers were more likely to be older, more affluent and more physically active and were less likely to smoke compared with non-seafood consumers. Sex and BMI did not appear to have a directional association with seafood consumption. The most commonly reported barriers to seafood consumption were cost, followed by sensory or physical barriers, health and nutritional beliefs, habits, availability and cooking skills. The most commonly reported influences were beliefs about the contribution of seafood to health, environmental influences and personal preferences. Based on the findings of this review, future intervention strategies to increase seafood consumption may need to consider affordability and education in terms of health, nutrition and cooking skills. More research is needed to explore the effectiveness of specific interventions at increasing the consumption of seafood.

Eight weeks of fish oil supplementation does not prevent sitting-induced leg endothelial dysfunction

Prolonged sitting impairs leg endothelial function and this impairment is thought to be mediated by a sustained reduction in blood flow-induced shear stress. However, whether nutritional strategies can be used to prevent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that 8 weeks of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation would prevent endothelial dysfunction associated with sitting. Nineteen healthy men were randomly assigned to a placebo group or EPA+DHA group in a double-blind fashion. The EPA+DHA group was administered EPA-rich fish oil, containing 600 mg EPA and 260 mg DHA per day for 8 weeks. The placebo group received matching capsules for the same duration of time. Popliteal artery flow-mediated dilation (FMD) was measured at baseline and before and after a 3-h sitting period. During sitting, blood pressure, popliteal artery diameter, and blood velocity were measured every hour. Throughout the sitting period, popliteal artery blood flow and shear rate were markedly and similarly reduced in both groups (P < 0.05). However, counter to the hypothesis, 3 h of sitting impaired popliteal artery FMD to the same extent in both groups (P < 0.05). In conclusion, daily EPA and DHA supplementation is not effective at preventing the detrimental effects of prolonged sitting on leg endothelial function. Novelty We provide evidence that sitting-induced leg endothelial dysfunction in young healthy subjects cannot be remediated by a nutritional strategy known to produce cardiovascular benefits. This could be partially due to the low total dose of EPA and DHA administered.

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.

Impact of Blood or Erythrocyte Membrane Fatty Acids for Disease Risk Prediction: Focusing on Cardiovascular Disease and Chronic Kidney Disease

Fatty acids (FAs) are essential nutrients and main constituents of cell membranes that are involved in the signaling pathway and associated with health conditions. We investigated if blood or erythrocyte membrane FAs can predict the risk of cardiovascular disease (CVD), chronic kidney disease (CKD), and related complications. Omega-3 (n-3) FAs are important predictors for metabolic syndrome, diabetes, CVD, and CKD risks, and the n-3 index is also a good biomarker for sudden cardiac death in coronary artery disease. Linoleic acid, which is one of the major n-6 FAs reflecting recent dietary FA intake, may predict CVD risk and mortality in the general population and patients with CKD. Monounsaturated FAs (MUFAs) are also related to diabetes or diabetic nephropathy. Oleic acid, a major MUFA, is an emerging marker that is related to acute coronary syndrome, low glomerular filtration rate, and vascular calcification in patients with CKD, and can be modified by n-3 FA supplementation. Saturated FAs, trans-FAs, and FA desaturation/elongation are associated with CVD risk; however, few studies have been conducted on patients with CKD. In summary, blood or erythrocyte membrane FA measurements are important for CVD and CKD risk prediction and management. Further studies are needed to elucidate the FAs for their risk predictions.

Low linolenic and linoleic acid consumption are associated with chronic kidney disease in patients with type 2 diabetes

Aim

This cross-sectional study aimed to assess the association of the fat content in the diet with Diabetic Kidney Disease (DKD) in patients with type 2 diabetes.

Methodology

Patients from the Diabetes research clinic at Hospital de Clínicas de Porto Alegre (Brazil) were consecutively recruited. The inclusion criterion was the diagnosis of type 2 diabetes. The exclusion criteria were as follows: body mass index >40 kg/m², heart failure, gastroparesis, diabetic diarrhea, dietary counseling by a registered dietitian during the previous 12 months, and inability to perform the weighed diet records (WDR). The dietary fatty acids (saturated, monounsaturated and polyunsaturated) consumption was estimated by 3-day WDR. Compliance with the WDR technique was assessed by comparison of protein intake estimated from the 3-day WDR and from the 24-h urinary nitrogen output performed on the third day of the WDR period. The presence of DKD was defined as urinary albumin excretion (UAE) ≥ 30 mg / 24 h or/and glomerular filtration rate (eGFR) <60 ml/min/1.73 m². Urinary albumin was measured twice and eGFR was estimated by using the CKD-EPI equation.

Results

A total of 366 patients were evaluated; of these, 33% (n = 121) had DKD. Multivariate analysis showed that the intake of linolenic acid was negatively associated with DKD (OR = 0.57; 95% CI 0.35–0.93; P = 0.024), adjusted for gender, smoking, cardiovascular disease, ACE inhibitors and/or angiotensin receptor blocker use, systolic blood pressure, fasting plasma glucose and HDL cholesterol. In a separate model, similar results were observed for linoleic acid, adjusting to the same co-variables (OR = 0.95; 95% CI 0.91–0.99; P = 0.006).

Conclusion

The lower intake of polyunsaturated fatty acids, especially linolenic and linoleic acid, is associated with chronic kidney disease in patients with type 2 diabetes.

Alcohol and red wine consumption, but not fruit, vegetables, fish or dairy products, are associated with less endothelial dysfunction and less low-grade inflammation: the Hoorn Study

Purpose

Endothelial dysfunction and low-grade inflammation are key phenomena in the pathobiology of cardiovascular disease (CVD). Their dietary modification might explain the observed reduction in CVD that has been associated with a healthy diet rich in fruit, vegetables and fish, low in dairy products and with moderate alcohol and red wine consumption. We investigated the associations between the above food groups and endothelial dysfunction and low-grade inflammation in a population-based cohort of Dutch elderly individuals.

Methods

Diet was measured by food frequency questionnaire (n = 801; women = 399; age 68.5 ± 7.2 years). Endothelial dysfunction was determined (1) by combining von Willebrand factor, and soluble intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1, endothelial selectin and thrombomodulin, using Z-scores, into a biomarker score and (2) by flow-mediated vasodilation (FMD), and low-grade inflammation by combining C-reactive protein, serum amyloid A, interleukin 6, interleukin 8, tumour necrosis factor α and sICAM-1 into a biomarker score, with smaller FMD and higher scores representing more dysfunction and inflammation, respectively. We used linear regression analyses to adjust associations for sex, age, energy, glucose metabolism, body mass index, smoking, prior CVD, educational level, physical activity and each of the other food groups.

Results

Moderate [β (95% CI) −0.13 (−0.33; 0.07)] and high [−0.22 (−0.45; −0.003)] alcohol consumption, and red wine [−0.16 (−0.30; −0.01)] consumption, but none of the other food groups, were associated with a lower endothelial dysfunction biomarker score and a greater FMD. The associations for FMD were, however, not statistically significant. Only red wine consumption was associated with a lower low-grade inflammation biomarker score [−0.18 (−0.33; −0.04)].

Conclusions

Alcohol and red wine consumption may favourably influence processes involved in atherothrombosis.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-017-1420-4) contains supplementary material, which is available to authorized users.

Serum Phospholipid Docosahexaenoic Acid Is Inversely Associated with Arterial Stiffness in Metabolically Healthy Men

We hypothesized that lower proportion of serum phospholipid docosahexaenoic acid (DHA) is inversely associated with increased cardiovascular risk and vascular function in metabolically healthy men. To elucidate it, we first compared serum phospholipid free fatty acid (FA) compositions and cardiovascular risk parameters between healthy men (n = 499) and male patients with coronary artery disease (CAD, n = 111) (30-69 years) without metabolic syndrome, and then further-analyzed the association of serum phospholipid DHA composition with arterial stiffness expressed by brachial-ankle pulse wave velocity (ba-PWV) in metabolically healthy men. Basic parameters, lipid profiles, fasting glycemic status, adiponectin, high sensitivity C-reactive protein (hs-CRP) and LDL particle size, and serum phospholipid FA compositions were significantly different between the two subject groups. Serum phospholipid DHA was highly correlated with most of long-chain FAs. Metabolically healthy men were subdivided into tertile groups according to serum phospholipid DHA proportion: lower (< 2.061%), middle (2.061%-3.235%) and higher (> 3.235%). Fasting glucose, insulin resistance, hs-CRP and ba-PWVs were significantly higher and adiponectin and LDL particle size were significantly lower in the lower-DHA group than the higher-DHA group after adjusted for confounding factors. In metabolically healthy men, multiple stepwise regression analysis revealed that serum phospholipid DHA mainly contributed to arterial stiffness (β'-coefficients = -0.127, p = 0.006) together with age, systolic blood pressure, triglyceride (r = 0.548, p = 0.023). Lower proportion of serum phospholipid DHA was associated with increased cardiovascular risk and arterial stiffness in metabolically healthy men. It suggests that maintaining higher proportion of serum phospholipid DHA may be beneficial for reducing cardiovascular risk including arterial stiffness in metabolically healthy men.

Differences in nutrient composition and choice of side dishes between red meat and fish dinners in Norwegian adults

BACKGROUND

Food-based dietary guidelines often recommend increased consumption of fish and reduced intake of red and processed meat. However, little is known about how changing the main protein source from red meat to fish may influence the choice of side dishes.

OBJECTIVE

To investigate whether side dish choices differed between red meat and fish dinners. Moreover, to compare intakes of macronutrients and selected micronutrients in red meat and fish dinners and to see whether whole-day intakes of these nutrients differed between days with red meat dinners and days with fish dinners.

DESIGN

Data were collected in a cross-sectional nationwide Norwegian dietary survey using two non-consecutive telephone-administered 24-h recalls. The recalls were conducted approximately 4 weeks apart. In total, 2,277 dinners from 1,517 participants aged 18-70 were included in the analyses.

RESULTS

Fish dinners were more likely to include potatoes and carrots than red meat dinners, whereas red meat dinners more often contained bread, tomato sauce, and cheese. Red meat dinners contained more energy and iron; had higher percentages of energy (E%) from fat, saturated fat, and monounsaturated fat; and a lower E% from protein and polyunsaturated fat than fish dinners. Fish dinners contained more vitamin D, β-carotene, and folate than red meat dinners. Similar differences were found when comparing whole-day intakes of the same nutrients on days with red meat versus fish dinners.

CONCLUSION

Fish dinners were accompanied by different side dishes than red meat dinners. With regard to nutrient content, fish dinners generally had a healthier profile than red meat dinners. However, iron intake was higher for red meat dinners. Information about associated foods will be useful both for developing public health guidelines and when studying associations between dietary factors and health outcomes.

Endothelial function, arterial stiffness and adherence to the 2010 Dietary Guidelines for Americans: a cross-sectional analysis

Endothelial dysfunction and arterial stiffness are early predictors of CVD. Intervention studies have suggested that diet is related to vascular health, but most prior studies have tested individual foods or nutrients and relied on small samples of younger adults. The purpose of the present study was to examine the relationships between adherence to the 2010 Dietary Guidelines for Americans and vascular health in a large cross-sectional analysis. In 5887 adults in the Framingham Heart Study Offspring and Third Generation cohorts, diet quality was quantified with the 2010 Dietary Guidelines Adherence Index (DGAI-2010). Endothelial function was assessed via brachial artery ultrasound and arterial stiffness via arterial tonometry. In age-, sex- and cohort-adjusted analyses, a higher DGAI-2010 score (greater adherence) was modestly associated with a lower resting flow velocity, hyperaemic response, mean arterial pressure, carotid-femoral pulse wave velocity (PWV), and augmentation index, but not associated with resting arterial diameter or flow-mediated dilation (FMD). In multivariable models adjusting for cardiovascular risk factors, only the association of a higher DGAI-2010 score with a lower baseline flow velocity and augmentation index persisted (β = - 0·002, P= 0·003 and β = - 0·05 ± 0·02, P< 0·001, respectively). Age-stratified multivariate-adjusted analyses suggested that the relationship of higher DGAI-2010 scores with lower mean arterial pressure, PWV and augmentation index was more pronounced among adults younger than 50 years. Better adherence to the 2010 Dietary Guidelines for Americans, particularly in younger adults, is associated with a lower peripheral blood flow velocity and arterial wave reflection, but not FMD. The present results suggest a link between adherence to the Dietary Guidelines and favourable vascular health.

Clinical pharmacology of n-3 polyunsaturated fatty acids: non-lipidic metabolic and hemodynamic effects in human patients

A high dietary intake of n-3 long chain polyunsaturated fatty acids (PUFA), eicosapentaenoic and docosahexaenoic acids, is associated with a reduced incidence of coronary events. Supplementation with pharmacological doses of the same may improve survival in patients with previous myocardial infarction and established heart failure. Such protective effects may be explained by the action of n-3 PUFA on systemic inflammation, hypertension, endothelial dysfunction, thrombosis, cardiac arrhythmias, heart rate variability and atherosclerotic plaque instability, which are involved in the pathogenesis of these clinical conditions. In this short paper we will review the evidence in support of these pleiotropic effects of n-3 fatty acids.

Genetic ancestry and the relationship of cigarette smoking to lung function and per cent emphysema in four race/ethnic groups: a cross-sectional study

BACKGROUND

Cigarette smoking is the major cause of chronic obstructive pulmonary disease and emphysema. Recent studies suggest that susceptibility to cigarette smoke may vary by race/ethnicity; however, they were generally small and relied on self-reported race/ethnicity.

OBJECTIVE

To test the hypothesis that relationships of smoking to lung function and per cent emphysema differ by genetic ancestry and self-reported race/ethnicity among Caucasians, African-Americans, Hispanics and Chinese-Americans.

DESIGN

Cross-sectional population-based study of adults age 45-84 years in the USA.

MEASUREMENTS

Principal components of genetic ancestry and continental ancestry estimated from one million genome-wide single nucleotide polymorphisms; pack-years of smoking; spirometry measured for 3344 participants; and per cent emphysema on computed tomography for 8224 participants.

RESULTS

The prevalence of ever-smoking was: Caucasians, 57.6%; African-Americans, 56.4%; Hispanics, 46.7%; and Chinese-Americans, 26.8%. Every 10 pack-years was associated with -0.73% (95% CI -0.90% to -0.56%) decrement in the forced expiratory volume in 1 s to forced vital capacity (FEV1 to FVC) and a 0.23% (95% CI 0.08% to 0.38%) increase in per cent emphysema. There was no evidence that relationships of pack-years to the FEV1 to FVC, airflow obstruction and per cent emphysema varied by genetic ancestry (all p>0.10), self-reported race/ethnicity (all p>0.10) or, among African-Americans, African ancestry. There were small differences in relationships of pack-years to the FEV1 among male Chinese-Americans and to the FEV1 to FVC ratio with African and Native American ancestry among male Hispanics only.

CONCLUSIONS

In this large cohort, there was little to no evidence that the associations of smoking to lung function and per cent emphysema differed by genetic ancestry or self-reported race/ethnicity.

Docosahexaenoic acid supplementation, vascular function and risk factors for cardiovascular disease: a randomized controlled trial in young adults

Background

A high consumption of omega‐3 long‐chain polyunsaturated fatty acids, and particularly docosahexaenoic acid (DHA), has been suggested to reduce the risk of cardiovascular disease (CVD). However, while DHA supplementation may have benefits for secondary prevention, few studies have investigated the role of DHA in the primary prevention of CVD. Here, we tested the hypothesis that DHA supplementation improves endothelial function and risk factors for CVD.

Methods and Results

Healthy volunteers (n=328), aged 18 to 37 years, were randomly assigned to 1.6 g DHA/day (from a microalgae source) together with 2.4 g/day carrier oil (index group) or to 4.0 g/day olive oil (control) (both given in eight 500‐mg capsules/day for 16 weeks). Flow‐mediated endothelium‐dependent vasodilation (FMD) of the brachial artery (primary outcome) was measured before and after the intervention (n=268) using high‐resolution vascular ultrasound. FMD was the same in both groups at randomization (mean, SD; 0.27, 0.1 mm), but postintervention was higher in the control group (0.29, 0.1 mm) compared with the DHA‐supplemented group (0.26, 0.1 mm; mean difference −0.03 mm; 95% CI −0.005 to −0.06 mm; P=0.02). Of other outcomes, only triglyceride (mean difference −28%, 95% CI −40% to −15%; P<0.0001) and very low‐density lipoprotein concentrations were significant lower in DHA‐supplemented individuals compared with controls.

Conclusions

DHA supplementation did not improve endothelial function in healthy, young adults. Nevertheless, lower triglyceride concentrations with DHA supplementation was consistent with previous reports and could have benefits for the prevention of CVD.

Clinical Trial Registration Information

URL: http://www.controlled-trials.com/ Unique identifier: ISRCTN no: 19987575.

The acute and long-term effects of dietary fatty acids on vascular function in health and disease

PURPOSE OF REVIEW

Vascular function is recognized as an early and integrative marker of cardiovascular disease. While there is consistent evidence that the quantity of dietary fat has significant effects on vascular function, the differential effects of individual fatty acids is less clear. This review summarizes recent evidence from randomly controlled dietary studies on the impact of dietary fatty acids on vascular function, as determined by flow-mediated dilatation (FMD).

RECENT FINDINGS

Critical appraisal is given to five intervention studies (one acute, four chronic) which examined the impact of long-chain n-3 polyunsaturated fatty acid [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] on FMD. In the acute setting, a high dose of long-chain n-3 polyunsaturated fatty acid (4.9 g per 70 kg man) improved postprandial FMD significantly, compared with a saturated fatty acid-rich meal in healthy individuals. In longer-term studies, there was limited evidence for a significant effect of EPA/DHA on FMD in diseased groups.

SUMMARY

The strongest evidence for the benefits of EPA/DHA on vascular function is in the postprandial state. More evidence from randomly controlled intervention trials with foods will be required to substantiate the long-term effects of EPA/DHA, to inform public health and clinical recommendations.

Diet and lifestyle factors associated with fish consumption in men and women: a study of whether gender differences can result in gender-specific confounding

Background

Fish consumption and intake of omega-3 fatty acids from fish are associated with a lower risk of cardiovascular disease. However, a prospective study from northern Sweden showed that high consumption of fish is associated with an increased risk of stroke in men, but not in women. The current study aimed to determine if fish consumption is differently related to lifestyle in men compared with women in northern Sweden.

Methods

Lifestyle information on 32,782 men and 34,866 women (aged 30–60 years) was collected between 1992 and 2006 within the Västerbotten Intervention Programme (a health intervention in northern Sweden). Spearman correlations coefficients (R_s) were calculated between self-reported consumption of fish and other food items. Lifestyle variables were compared between fish consumption categories.

Results

Fish consumption was positively associated with other foods considered healthy (e.g., root vegetables, lettuce/cabbage/spinach/broccoli, chicken, and berries; R_s = 0.21-0.30), as well as with other healthy lifestyle factors (e.g., exercise and not smoking) and a higher educational level, in both men and women. The only gender difference found, concerned the association between fish consumption and alcohol consumption. Men who were high consumers of fish had a higher intake of all types of alcohol compared with low to moderate fish consumers. For women, this was true only for wine.

Conclusions

Except for alcohol, the association between fish consumption and healthy lifestyle did not differ between men and women in northern Sweden. It is important to adjust for other lifestyle variables and socioeconomic variables in studies concerning the effect of fish consumption on disease outcome.

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.

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.

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

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

Ethnicity, plasma phospholipid fatty acid composition and inflammatory/endothelial activation biomarkers in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND/OBJECTIVES

It has been recognized that certain long-chain polyunsaturated fatty acids (LC-PUFAs) are involved in inflammation and its resolution. It has also been shown that ethnicity may be a factor in affecting systemic inflammation, and limited evidence suggests it may influence plasma LC-PUFA composition. Given the links among these three factors, we aim to determine ethnicity-based differences in plasma LC-PUFA composition among White, Black, Hispanic and Chinese participants, and whether such differences contribute to variations in markers of inflammation and endothelial activation in a sub-cohort of the Multi-Ethnic Study of Atherosclerosis (MESA).

SUBJECTS/METHODS

Plasma phospholipid LC-PUFAs levels (%) were determined in 2848 MESA participants using gas chromatography-flame ionization detection. Enzyme immunoassays determined inflammatory markers levels for high-sensitivity C-reactive protein (n=2848), interleukin-6 (n=2796), soluble tumor necrosis factor-α receptor type 1 (n=998), and endothelial activation markers soluble intercellular adhesion molecule-1 (n=1192) and soluble E-selectin (n=998). The modifying influence of ethnicity was tested by linear regression analysis.

RESULTS

Chinese adults were found to have the highest mean levels of plasma eicosapentaenoic acid (EPA, 1.24%) and docosahexaenoic acid (DHA, 4.95%), and the lowest mean levels of γ-linolenic (0.10%), dihomo-γ-linolenic (DGLA, 2.96%) and arachidonic (10.72%) acids compared with the other ethnicities (all P ≤ 0.01). In contrast, Hispanics had the lowest mean levels of plasma EPA (0.70%) and DHA (3.49%), and the highest levels of DGLA (3.59%; all P ≤ 0.01). Significant differences in EPA and DHA among ethnicities were attenuated following adjustment for dietary non-fried fish and fish oil supplementation. Ethnicity did not modify the associations of LC-PUFAs with markers of inflammation or endothelial activation (all P (interaction)>0.05).

CONCLUSIONS

The absence of a modifying effect of ethnicity indicates that the putative benefits of LC-PUFAs with respect to inflammation are pan-ethnic. Future longitudinal studies may elucidate the origin(s) of ethnicity-based differences in LC-PUFA composition and whether certain patterns, that is, high plasma levels of DGLA and low levels of EPA/DHA, contribute to inflammation-associated health outcomes.

Effect of low doses of long-chain n-3 PUFAs on endothelial function and arterial stiffness: a randomized controlled trial

BACKGROUND

The dietary intake of n-3 (omega-3) long-chain PUFAs (LC-PUFAs) from fish may improve endothelial function and arterial stiffness.

OBJECTIVE

The objective was to test the hypothesis that increasing intakes of n-3 LC-PUFAs-equivalent to the consumption of 1, 2, or 4 portions of oily fish per week-favorably affects endothelial function and arterial stiffness.

DESIGN

A parallel-design, randomized, double-blind study compared daily doses of 0.45, 0.9, and 1.8 g n-3 LC-PUFAs (EPA:DHA ratio of 1.51:1) with placebo (refined olive oil). The primary and secondary outcomes were changes in flow-mediated dilatation (FMD) of the brachial artery, arterial stiffness, and blood pressure. Nonsmoking men (n = 142) and women (n = 225) aged 45-70 y were randomly assigned to treatment for 12 mo; 312 subjects completed the intervention.

RESULTS

Compliance with the intervention was corroborated by significant dose-dependent increases in the proportions of EPA and DHA in erythrocyte lipids and a 16.5% reduction in serum triacylglycerol concentrations with 1.8 g n-3 LC-PUFAs/d. FMD was lower in men than in women (P < 0.0001) and decreased with age (ρ = 0.270, P < 0.001) but was not significantly (P = 0.781) related to n-3 LC-PUFA intake. The mean changes in FMD (95% CIs) compared with placebo were 0.1% (-0.9%, 1.1%), -0.3% (-1.3%, 0.6%), and -0.3% (-1.3%, 0.7%) with daily intakes of 0.45, 0.9, and 1.8 g n-3 LC-PUFAs, respectively. No significant treatment effects were noted for arterial stiffness and central mean or 24-h ambulatory blood pressure.

CONCLUSION

Intakes of n-3 LC-PUFAs ≤1.8 g/d do not improve endothelial function in healthy adults. The trial is registered at controlled-trials.com as ISRCTN66664610.

Associations of plasma phospholipid omega-6 and omega-3 polyunsaturated Fatty Acid levels and MRI measures of cardiovascular structure and function: the multiethnic study of atherosclerosis

Background. The association between plasma omega-6 fatty acids and cardiovascular disease (CVD) is unclear, and discrepancy remains concerning the cardiovascular benefit of the omega-3 fatty acid alpha-linolenic acid. Methods. Associations of plasma phospholipid fatty acid levels (arachidonic acid, linoleic acid, eicosapentaenoic acid, docosahexaenoic acid (DHA), and alpha-linolenic acid) with cardiac magnetic resonance imaging measures of left ventricular (LV) mass, LV volume, ejection fraction, stroke volume, and aortic distensibility were investigated in 1,274 adults. Results. Results of multivariate analysis showed no statistically significant associations of plasma omega-6 or omega-3 levels with cardiac magnetic resonance imaging measures. Stratification by gender revealed a positive association between DHA and LV mass in women (β = 1.89, P = 0.02; P interaction = 0.003) and a trend for a positive association between DHA and ejection fraction in men (β = 0.009, P = 0.05; P interaction = 0.03). Conclusion. Additional research is warranted to clarify the effects of plasma DHA on cardiac structure and function in women versus men.

Fish consumption in relation to other foods in the diet

Our aim was to investigate whether fish consumption is associated with the consumption of other healthy foods. The study population consisted of 2605 men and 3199 women from the nationally representative Health 2000 survey and 114 professional fishermen and 114 fishermen's wives (the Fishermen substudy) in Finland. Dietary data were collected using a calibrated (i.e. determined to have relative validity) FFQ. Model-adjusted means for food consumption and P values for linear trend were calculated across fish consumption tertiles. Those with the highest fish consumption had the highest consumption of vegetables, fruit and berries, potatoes, oil and wine even after adjusting for other food groups. The consumption of red meat and sausages had a tendency to decrease across fish consumption tertiles but the associations were inconsistent in the study populations. In conclusion, fish consumption had a positive linear association with the consumption of some other healthy foods such as vegetables, fruit, berries, and oil both in the general population of Finland and in a population with high fish consumption. Additional adjustment for other food groups had a clear effect on some of the studied associations. Therefore, when evaluating the health effects of fish consumption, confounding by other foods characterising a healthy diet needs to be considered.