Fish intake may limit the increase in risk of coronary heart disease morbidity and mortality among heavy smokers. The Honolulu Heart Program

Fish Consumption and Coronary Heart Disease: A Meta-Analysis

Epidemiological studies on the impact of fish consumption on coronary heart disease (CHD) incidence have shown inconsistent results. In addition, in terms of CHD mortality, although previous meta-analyses showed that fish consumption reduces the risk of CHD, six newly incorporated studies show that fish consumption has no impact on CHD. Therefore, the results still need to be verified. The purpose of this study is to quantitatively evaluate the impact of fish consumption on CHD incidence and mortality. Relevant studies were identified from PubMed, Web of Science, and Embase databases up to October 2019. The multivariate-adjusted relative risks (RRs) for the highest versus the lowest fish consumption categories and the 95% confidence intervals were computed with a random-effect model. A restricted cubic spline regression model was used to assess the dose–response relationship between fish consumption and CHD incidence and mortality. Forty prospective cohort studies were incorporated into research. Among them, 22 studies investigated the association between fish consumption and CHD incidence (28,261 cases and 918,783 participants), and the summary estimate showed that higher fish consumption was significantly associated with a lower CHD incidence [RR: 0.91, 95% CI: (0.84, 0.97); I² = 47.4%]. Twenty-seven studies investigated the association between fish consumption and CHD mortality (10,568 events and 1,139,553 participants), and the summary estimate showed that higher fish intake was significantly associated with a lower CHD mortality [RR: 0.85, 95% CI: (0.77, 0.94); I² = 51.3%]. The dose–response analysis showed that the CHD incidence and mortality were reduced by 4%, respectively, with a 20 g/day increment in fish consumption. This meta-analysis indicates that fish consumption is associated with a lower CHD incidence and mortality.

Diet, Secondhand Smoke, and Glycated Hemoglobin (HbA1c) Levels among Singapore Chinese Adults

The combination of poor diet and exposure to secondhand smoke may increase hemoglobin A1c (HbA1c) levels, but few studies have explored this interaction. We explored an interaction among 574 never-smoking adults from the Singapore Chinese Health Study. At baseline (age 59 ± 8 years), intakes of omega-3 polyunsaturated fatty acids, vitamin C, vitamin E and fiber were estimated using a modified food frequency questionnaire. At follow-up (age 64 ± 9 years), HbA1c and cotinine were measured. A product term between cotinine (above or below the median value) and each nutrient (high or low intake) was included in separate linear regression models with HbA1c as the outcome. HbA1c among those with high cotinine and low omega-3 polyunsaturated fatty acids intakes were higher than would be expected due to the individual effects alone (p-for-interaction = 0.05). Among those with lower intakes of omega-3 polyunsaturated fatty acids, high cotinine levels were associated with 0.54% higher HbA1c levels (95% confidence interval [CI]: 0.02, 1.06). Conversely, among those with higher intakes of omega-3 polyunsaturated fatty acids, HbA1c differ not differ by exposure (−0.09%; 95% CI: −0.45, 0.30). No evidence of interaction was observed for other nutrients. Diets high in omega-3 polyunsaturated fatty acids may ameliorate secondhand smoke-induced increases in HbA1c.

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.

Interactions Between Diet and Exposure to Secondhand Smoke on Glycated Hemoglobin Levels Among US Children: Results From NHANES 2007-2012

Introduction

Antioxidant-rich diets may lessen the adverse metabolic responses triggered by exposure to secondhand smoke (SHS), but no studies have investigated these potential interactions.

Objective

To examine the interaction between diet and exposure to SHS on glycated hemoglobin (HbA1c) levels among 2551 children, ages 12-19 years, who participated in the 2007-2012 National Health and Nutrition Examination Survey (NHANES).

Methods

Exposure to SHS was assessed by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), cotinine, and self-report. Weighted linear regression models evaluated the cross-sectional association between exposure to SHS and HbA1c levels. Additive interaction was assessed by introducing product terms (with SHS) of individual nutrients (dietary fiber, eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], vitamin C, and vitamin E) to separate models.

Results

Over half of the children had NNAL or cotinine levels above the limit of detection (56% and 71%, respectively). The median HbA1c level was 5.2% (95% confidence interval: 5.17%, 5.23%). The interaction results suggest that the effects of exposure to SHS and certain dietary nutrients (EPA, DHA, vitamin C) on HbA1c levels may not be independent. For example, although there was only a slight difference in adjusted mean HbA1c levels across NNAL categories among children with high EPA intakes, the adjusted mean HbA1c level was 0.09% higher for high NNAL as compared to low NNAL among children with low EPA intakes.

Conclusions

Further research is needed to inform public health strategies for limiting increases in HbA1c levels among children. Messages may need to focus both on reducing exposure to SHS and improving diets to obtain the maximum benefit.

Implications

Our results suggest that the effects of exposure to SHS and diet on HbA1c levels may not be independent. For example, although there was little effect of exposure to SHS on HbA1c levels among children with high EPA intakes, high exposure to SHS was associated with an increase in HbA1c levels among children with low EPA intakes. Further research is necessary; however, based on these joint effects, strategies for limiting increases in HbA1c levels that focus both on reducing exposure to SHS and improving diets may achieve the largest public health benefits.

Pattern of omega-3 polyunsaturated fatty acid intake and fish consumption and retinal vascular caliber in children and adolescents: A cohort study

We aimed to investigate whether fish and long chain omega-3 polyunsaturated fatty acid (LCn-3 PUFA) consumption changed appreciably during adolescence. We also assessed whether these dietary variables are associated with retinal microvascular signs (possible markers of future cardiovascular disease risk). 633 children had dietary data at ages 12 and 17. Fish and LCn-3 PUFA [eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA)] intake was assessed by a food frequency questionnaire. Retinal vessel caliber was quantified from digital photographs using computer software. Mean energy-adjusted intakes (mg/day) of total LCn-3 PUFA, EPA, and DHA at age 12 were 297.1±261.1; 102.5±106.9; and 129.7±137.7, respectively; and this increased significantly at age 17 to: 347.0±324.0 (p<0.0001); 122.5±132.7 (p = 0.0001); and 160.3±171.4 (p <0.0001), respectively. Increasing quartiles of LCn-3PUFA intake were associated with widening of mean retinal arteriolar caliber among 17-year old girls ~3.9 μm (multivariable-adjusted P-trend = 0.001). Girls who consumed ≥2 serves of fish/week versus those who did not had ~2.1 μm wider retinal arterioles (p = 0.03). No associations were observed among boys or with retinal venules. Mean dietary intakes of LCn-3 PUFA increased during adolescence, but are still below recommended levels of consumption. These results suggest that LCn-3 PUFA and fish intake might have a beneficial influence.

Interactions between Diet and Exposure to Secondhand Smoke on the Prevalence of Childhood Obesity: Results from NHANES, 2007-2010

BACKGROUND

Exposure to secondhand smoke (SHS) may increase risk for obesity, but few studies have investigated the joint effects of exposure to SHS and diet.

OBJECTIVES

We examined the interaction of exposure to SHS and diet on the prevalence of obesity among 6- to 19-year-olds who participated in the 2007-2010 National Health and Nutrition Examination Survey.

METHODS

We characterized exposure using a novel biomarker [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)], an established biomarker (cotinine), and self-report. Multinomial logistic regression models examined the association of SHS exposure on the prevalence of overweight and obesity as separate outcomes (compared with normal/underweight). Interaction by diet was assessed by introducing interaction terms (with SHS) of the individual nutrients [dietary fiber, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), vitamin C, and vitamin E] into separate models.

RESULTS

Approximately half of the children had NNAL and cotinine levels above the limit of detection, indicating exposure to SHS. Interaction results suggest that the prevalence of obesity among children with both high exposure to SHS and low levels of certain nutrients (dietary fiber, DHA, or EPA) is greater than would be expected due to the effects of the individual exposures alone. Little or no evidence suggesting more or less than additive or multiplicative interaction was observed for vitamin C or vitamin E. The association between SHS and obesity did not appear to be modified by dietary vitamin C or vitamin E.

CONCLUSIONS

Childhood obesity prevention strategies aimed at reducing SHS exposures and improving diets may exceed the expected benefits based on targeting either risk factor alone.

CITATION

Moore BF, Clark ML, Bachand A, Reynolds SJ, Nelson TL, Peel JL. 2016. Interactions between diet and exposure to secondhand smoke on the prevalence of childhood obesity: results from NHANES, 2007-2010. Environ Health Perspect 124:1316-1322; http://dx.doi.org/10.1289/ehp.1510138.

Association of fish consumption and dietary intake of marine n-3 PUFA with myocardial infarction in a prospective Danish cohort study

Several studies have investigated the potential benefits of marine n-3 PUFA in CVD, generally suggesting a lower risk of CHD. However, recent trials have questioned these results. This study investigated the association of fish consumption with dietary intake of marine n-3 PUFA with incident myocardial infarction (MI). In a Danish cohort study, 57 053 subjects between 50 and 64 years of age were enrolled from 1993 to 1997. From national registries, we identified all cases of incident MI. Dietary fish consumption was assessed using a semi-quantitative food questionnaire, including twenty-six questions regarding fish intake. In addition, we calculated the intake of total and individual marine n-3 PUFA. During a median follow-up of 17·0 years, we identified 3089 cases of incident MI. For both men and women, a high intake of fatty fish was inversely related to incident MI. Thus, when comparing the highest and the lowest quintile of fatty fish intake, we found a 12 % lower relative risk of MI in men (hazard ratio (HR) 0·88; 95 % CI 0·77, 1·00) and a 22 % lower relative risk in women (HR 0·78; 95 % CI 0·63, 0·96) after adjustments. For women, similar associations were observed for individual and total marine n-3 PUFA. In contrast, intake of lean fish was not associated with MI. In conclusion, incident MI was inversely related to a high intake of fatty fish, but not lean fish. However, test for trends across quintiles was not statistically significant. In general, this study supports the view that consumption of fatty fish may protect against MI.

Fish-Free Diet in Patients with Phenylketonuria Is Not Associated with Early Atherosclerotic Changes and Enhanced Platelet Activation

Background and Purpose

Since patients with phenylketonuria (PKU) have to follow a lifelong restriction of natural protein to lower phenylalanine-intake, they never eat fish. This diet may lead to a chronic deficit of omega-3 and omega-6 fatty acids with the risk of early atherosclerotic changes. The aim of the study was to analyse the fatty acid profile of PKU patients and to correlate the results with surrogate markers of early atherosclerotic changes [enhanced carotid intima media thickness (CIMT) and ß-stiffness index] and platelet activation.

Methods

In 43 PKU patients and in 58 healthy controls we prospectively examined the fatty acid profile, CIMT, ß-stiffness index and platelet activation (flow cytometric determination of markers of platelet activation). CIMT was measured bilaterally by ultrasound. CIMT _mean was defined as the mean value of the sum of CIMT _left and CIMT _right.

Results

Despite of lower HDL-cholesterol and higher triglyceride concentrations in the PKU group, there was no significant difference in the omega-6 or omega-3 fatty acid profile, CIMT, ß-stiffness index between both groups. Platelet activation was not enhanced in the PKU group.

Conclusions

Fish-free diet does not induce early atherosclerotic changes or enhanced platelet activation in PKU patients.

Modification of the excess risk of coronary heart disease due to smoking by seafood/fish intake

Seafood/fish intake has been regarded as a protective factor for coronary heart disease (CHD), while smoking is a strong risk factor. To examine whether associations between smoking and risk of CHD are modified by seafood/fish intake, we studied 72,012 Japanese men and women aged 45-74 years who completed 2 food frequency questionnaires, 5 years apart, during the period 1995-2009. After 878,163 person-years of follow-up, 584 incident cases of CHD (101 fatal and 483 nonfatal), including 516 myocardial infarctions, were documented. There was a clear dose-response association between smoking and CHD risk among subjects with a low seafood/fish intake (<86 g/day) but not among those with a high seafood/fish intake (≥86 g/day). Compared with never smokers, the multivariable hazard ratios in light (1-19 cigarettes/day), moderate (20-29 cigarettes/day), and heavy (≥30 cigarettes/day) smokers were 2.39 (95% confidence interval (CI): 1.60, 3.56), 2.74 (95% CI: 1.90, 3.95), and 3.24 (95% CI: 2.12, 4.95), respectively, among low seafood/fish eaters and 1.13 (95% CI: 0.64, 1.99), 1.29 (95% CI: 0.95, 2.04), and 2.00 (95% CI: 1.18, 3.51), respectively, among high seafood/fish eaters. Compared with heavy smokers with a low seafood/fish intake, light smokers with a high seafood/fish intake had substantially reduced risk of CHD (hazard ratio = 0.57, 95% CI: 0.32, 0.98). High seafood/fish intake attenuated the positive association between smoking and risk of CHD.

Key role of dietary fats in coronary heart disease under progressive urbanization and nutritional transitionh

The increased vulnerability to non-communicable diseases (NCD) of developing populations experiencing a demographic and epidemiological transitions to increased risk of NCD at a time when the battle against infectious diseases, is ongoing. Apart from population growth, the major attributes of developmental transition are confined to changes in occupational pattern in family structure, lifestyle, dietary practices and progressive ageing of population. The emergence of the NCD is significantly associated with changes in dietary pattern, in most of the countries. Coronary heart disease (CHD) is the leading cause of death in developed countries and the incidence is increasing in developing countries, including India. The disease needs awareness of the risk factors responsible for prevention. The purpose of this review is to present an overview of the role of dietary fats in growth and development and in health and disease. Although the causation of CHD is multifaceted and the risk factors associated in general are several, there are specific and important elements, such as dietary fats and lifestyle. Dietary fats are an important component as they serve a number of functions in the body. The minimum desirable and upper limits of fat intake have been given, based on recommendations of expert groups. Sources of different fats are made available worldwide and the production, consumption, storage, oxidation and nomenclature are being discussed in the light of health and disease. The relative essentiality of the omega-6 and omega-3 fatty acids is recognized in terms of pharmacologically active eicosanoid metabolism. Nevertheless, epidemiological, physiological and clinical studies have demonstrated that long-chain omega-3 fatty acids present in fish oils have quite diverse health benefits. Appropriate guidelines need to be recommended at a national level consistent with dietary habits. The ratios of balanced fatty acids, namely omega-11, omega-9, omega-6 and omega-3, should be worked out appropriately in ameliorating nutrition-related disease states. Any simple dietary modification that can lead to a substantial reduction in morbidity and mortality from CHD would be of great medical, social and economic benefit.

n-3 fatty acids and cardiovascular disease: the story is not over yet

A large body of evidences suggest a beneficial role of n-3 poly-unsaturated fatty acids (n-3 PUFAs) on cardiovascular disease, but recent observations and meta-analyses have raised doubts on their real efficacy. Many of these analyses, however, should be interpreted with caution, because of methodological shortcomings, heterogeneity of population, variability of drug dose and composition and other interpretation issues, and are not able to convincingly confute the results of the major clinical trials. Indeed, they demonstrated the efficacy of n-3 PUFAs at least in particular subset of individuals, such as post-acute myocardial infarction patients, at high risk of ventricular arrhythmias. The utilization of n-3 poly-unsaturated fatty acids in the current clinical practice should not be withheld, yet.

Issues of fish consumption for cardiovascular disease risk reduction

Increasing fish consumption is recommended for intake of omega-3 (n-3) fatty acids and to confer benefits for the risk reduction of cardiovascular disease (CVD). Most Americans are not achieving intake levels that comply with current recommendations. It is the goal of this review to provide an overview of the issues affecting this shortfall of intake. Herein we describe the relationship between fish intake and CVD risk reduction as well as the other nutritional contributions of fish to the diet. Currently recommended intake levels are described and estimates of fish consumption at a food disappearance and individual level are reported. Risk and benefit factors influencing the choice to consume fish are outlined. The multiple factors influencing fish availability from global capture and aquaculture are described as are other pertinent issues of fish nutrition, production, sustainability, and consumption patterns. This review highlights some of the work that needs to be carried out to meet the demand for fish and to positively affect intake levels to meet fish intake recommendations for CVD risk reduction.

Beneficial effects of omega-3 fatty acids in the proteome of high-density lipoprotein proteome

Background

Omega-3 poly-unsaturated fatty acids (ω-3 PUFAs) have demonstrated to be beneficial in the prevention of cardiovascular disease, however, the mechanisms by which they perform their cardiovascular protection have not been clarified. Intriguingly, some of these protective effects have also been linked to HDL. The hypothesis of this study was that ω-3 PUFAs could modify the protein cargo of HDL particle in a triglyceride non-dependent mode. The objective of the study was to compare the proteome of HDL before and after ω-3 PUFAs supplemented diet.

Methods

A comparative proteomic analysis in 6 smoker subjects HDL before and after a 5 weeks ω-3 PUFAs enriched diet has been performed.

Results

Among the altered proteins, clusterin, paraoxonase, and apoAI were found to increase, while fibronectin, α-1-antitrypsin, complement C1r subcomponent and complement factor H decreased after diet supplementation with ω-3 PUFAs. Immunodetection assays confirmed these results. The up-regulated proteins are related to anti-oxidant, anti-inflammatory and anti-atherosclerotic properties of HDL, while the down-regulated proteins are related to regulation of complement activation and acute phase response.

Conclusions

Despite the low number of subjects included in the study, our findings demonstrate that ω-3 PUFAs supplementation modifies lipoprotein containing apoAI (LpAI) proteome and suggest that these protein changes improve the functionality of the particle.

Fish consumption and CHD mortality: an updated meta-analysis of seventeen cohort studies

OBJECTIVE

Results of studies on fish consumption and CHD mortality are inconsistent. The present updated meta-analysis was conducted to investigate the up-to-date pooling effects.

DESIGN

A random-effects model was used to pool the risk estimates. Generalized least-squares regression and restricted cubic splines were used to assess the possible dose-response relationship. Subgroup analyses were conducted to examine the sources of heterogeneity.

SETTING

PubMed and ISI Web of Science databases up to September 2010 were searched and secondary referencing qualified for inclusion in the study.

SUBJECTS

Seventeen cohorts with 315,812 participants and average follow-up period of 15·9 years were identified.

RESULTS

Compared with the lowest fish intake (<1 serving/month or 1-3 servings/month), the pooled relative risk (RR) of fish intake on CHD mortality was 0·84 (95% CI 0·75, 0·95) for low fish intake (1 serving/week), 0·79 (95% CI 0·67, 0·92) for moderate fish intake (2-4 servings/week) and 0·83 (95% CI 0·68, 1·01) for high fish intake (>5 servings/week). The dose-response analysis indicated that every 15 g/d increment of fish intake decreased the risk of CHD mortality by 6% (RR = 0·94; 95% CI 0·90, 0·98). The method of dietary assessment, gender and energy adjustment affected the results remarkably.

CONCLUSIONS

Our results indicate that either low (1 serving/week) or moderate fish consumption (2-4 servings/week) has a significantly beneficial effect on the prevention of CHD mortality. High fish consumption (>5 servings/week) possesses only a marginally protective effect on CHD mortality, possibly due to the limited studies included in this group.

Association between smoking and risk of bladder cancer among men and women

CONTEXT

Previous studies indicate that the population attributable risk (PAR) of bladder cancer for tobacco smoking is 50% to 65% in men and 20% to 30% in women and that current cigarette smoking triples bladder cancer risk relative to never smoking. During the last 30 years, incidence rates have remained stable in the United States in men (123.8 per 100,000 person-years to 142.2 per 100,000 person-years) and women (32.5 per 100,000 person-years to 33.2 per 100,000 person-years); however, changing smoking prevalence and cigarette composition warrant revisiting risk estimates for smoking and bladder cancer.

OBJECTIVE

To evaluate the association between tobacco smoking and bladder cancer.

DESIGN, SETTING, AND PARTICIPANTS

Men (n = 281,394) and women (n = 186,134) of the National Institutes of Health-AARP (NIH-AARP) Diet and Health Study cohort completed a lifestyle questionnaire and were followed up between October 25, 1995, and December 31, 2006. Previous prospective cohort studies of smoking and incident bladder cancer were identified by systematic review and relative risks were estimated from fixed-effects models with heterogeneity assessed by the I(2) statistic.

MAIN OUTCOME MEASURES

Hazard ratios (HRs), PARs, and number needed to harm (NNH).

RESULTS

During 4,518,941 person-years of follow-up, incident bladder cancer occurred in 3896 men (144.0 per 100,000 person-years) and 627 women (34.5 per 100,000 person-years). Former smokers (119.8 per 100,000 person-years; HR, 2.22; 95% confidence interval [CI], 2.03-2.44; NNH, 1250) and current smokers (177.3 per 100,000 person-years; HR, 4.06; 95% CI, 3.66-4.50; NNH, 727) had higher risks of bladder cancer than never smokers (39.8 per 100,000 person-years). In contrast, the summary risk estimate for current smoking in 7 previous studies (initiated between 1963 and 1987) was 2.94 (95% CI, 2.45-3.54; I(2) = 0.0%). The PAR for ever smoking in our study was 0.50 (95% CI, 0.45-0.54) in men and 0.52 (95% CI, 0.45-0.59) in women.

CONCLUSION

Compared with a pooled estimate of US data from cohorts initiated between 1963 and 1987, relative risks for smoking in the more recent NIH-AARP Diet and Health Study cohort were higher, with PARs for women comparable with those for men.

Activation of group IVC phospholipase A(2) by polycyclic aromatic hydrocarbons induces apoptosis of human coronary artery endothelial cells

Exposure to environmental pollutants, such as polycyclic aromatic hydrocarbons (PAHs) found in coal tar mixtures and tobacco sources, is considered a significant risk factor for the development of heart disease in humans. The goal of this study was to determine the influence of PAHs present at a Superfund site on human coronary artery endothelial cell (HCAEC) phospholipase A(2) (PLA(2)) activity and apoptosis. Extremely high levels of 12 out of 15 EPA high-priority PAHs were present in both the streambed and floodplain sediments at a site where an urban creek and its adjacent floodplain were extensively contaminated by PAHs and other coal tar compounds. Nine of the 12 compounds and a coal tar mixture (SRM 1597A) activated group IVC PLA(2) in HCAECs, and activation of this enzyme was associated with histone fragmentation and poly (ADP) ribose polymerase (PARP) cleavage. Genetic silencing of group IVC PLA(2) inhibited both (3)H-fatty acid release and histone fragmentation by PAHs and SRM 1597A, indicating that individual PAHs and a coal tar mixture induce apoptosis of HCAECs via a mechanism that involves group IVC PLA(2). Western blot analysis of aortas isolated from feral mice (Peromyscus leucopus) inhabiting the Superfund site showed increased PARP and caspase-3 cleavage when compared to reference mice. These data suggest that PAHs induce apoptosis of HCAECs via activation of group IVC PLA(2).

Macronutrient intake induces oxidative and inflammatory stress: potential relevance to atherosclerosis and insulin resistance

With the global increase in the epidemic of obesity and type 2 diabetes with a concomitant increase in atherosclerotic disease, an investigation into the effects of various macronutrients and food products has become necessary. Such investigation will allow us to better understand the relationship between the intake of various macronutrients and the pathogenesis of mechanisms underlying the regulation of insulin sensitivity and resistance, oxidative stress and inflammation, the regulation of hunger and satiety and atherogenesis. This review covers the first decade of work in this area relating the intake of usual foods and diets to their immediate and long term outcomes. The review also covers the exciting novel area of anti-inflammatory effects of certain foods. Hopefully, a comprehensive understanding of these actions of macronutrients and their long term effects will allow us to formulate food combinations which will lead to healthy eating habits and improvement in our overall health status.

Vitamin D status and falls, frailty, and fractures among postmenopausal Japanese women living in Hawaii

Vitamin D status and its relationship to physical performance, falls, and fractures in 495 postmenopausal women of Japanese ancestry in Hawaii were investigated. The mean 25-hydroxyvitamin D (25-OHD) was 31.94 ng/mL. No significant association of 25-OHD was demonstrated with most outcomes, possibly due to higher 25-OHD levels in this population.

INTRODUCTION

In this study, we investigated vitamin D status and its relationship to physical performance, muscle strength, falls, and fractures in postmenopausal Japanese females living in Hawaii.

METHODS

Of 510 community-dwelling women who participated in the eighth examination of the Hawaii Osteoporosis Study, 495 were included in these analyses. Multivariate regression models were used to evaluate the relationship of 25-OHD (D(3) and total) to eight performance-based measurements, 12 activities of daily living (ADLs), and muscle strength (grip, triceps, and quadriceps). Logistic regression analyses were performed to evaluate the relationship of 25-OHD to falls, vertebral fractures, and non-vertebral fractures.

RESULTS

The mean total 25-OHD was 31.94 +/- 9.46 ng/mL; 44% of subjects had values <30 ng/mL, while none had values <10-12 ng/mL. There was little evidence of seasonal variation. Among performance-based measures, ADLs, and strength tests, only quadriceps strength was significantly associated with total 25-OHD (p = 0.0063) and 25-OHD(3) (p = 0.0001). No significant association of 25-OHD was found with vertebral or non-vertebral fractures, or incidence of one or more falls.

CONCLUSIONS

Lack of serum 25-OHD relationship with falls and fractures or most physical performance measures in this study may be related to the low prevalence of very low 25-OHD levels in this population.

Are fish eaters healthier and do they consume less health-care resources?

Objective

Regular dietary intake of fish is associated with reduced risk of developing cardiovascular and other chronic diseases, and may improve general well-being. If fish eaters are healthier, they may use fewer health-care resources. The present study aimed to describe the reported intake of fish and fish products in a Danish general population, and to investigate whether fish consumption is associated with generic measures of self-reported health and consumption of health-care resources.

Design

Data on eating patterns and health status for 3422 Danish adults were obtained by telephone interview in the Funen County Health Survey. These data were merged with individual-level register data on health-care utilisation. Survey respondents were categorised into those consuming fish at least once weekly (fish eaters) and those consuming fish less frequently (non-fish eaters).

Results

People who reported eating fish twice monthly or once weekly had significantly better overall self-reported health than those who rarely eat fish, even after adjustment for age, gender, social characteristics and lifestyle factors. Fish eaters did not have significantly lower aggregated health-care costs, although their hospital utilisation was significantly lower than that for non-fish eaters.

Conclusions

Moderate fish consumption was associated with better self-reported general health even after controlling for possible confounding variables. Overall, fish eaters appeared to use the same amount of health-care resources as non-eaters, although fish eaters used more medicine but were less likely to be admitted to a hospital.

Increasing dietary fish intake has contributed to decreasing mortality from CHD among the older population in Hong Kong

Objective

To test whether change in the frequency of fish intake at population level would affect the trends of death from CHD and how many CHD events could be prevented in Hong Kong, a population among those with the highest fish consumption and the lowest CHD mortality in the world.

Design

Time trends analysis with data from repeated dietary surveys and death registration.

Setting

Hong Kong SAR, People’s Republic of China.

Subjects

A total of 3096 men and women aged 40–69 years who participated in territory-wide surveys in 1995 or 2003 were included in the analysis of changes in dietary fish intake; all adults aged 40–69 years in Hong Kong were included in the analysis of time trends of CHD mortality.

Results

Over the period, the frequency of fish intake increased and CHD mortality decreased significantly in the population age group of 50–69 years, while in the age group of 40–49 years little change in both fish intake and CHD mortality was observed. It was estimated that 240 CHD deaths (or 29 % of the total) were avoided among the population aged 40–69 years in 2003, as more than half of the population consumed fish every day in Hong Kong.

Conclusions

The time trend of CHD mortality was inversely related to the trend of fish intake. The frequency of fish intake may have a substantial impact on the population for the prevention of CHD deaths in Hong Kong.

Long-chain n-3 polyunsaturated fatty acids: new insights into mechanisms relating to inflammation and coronary heart disease

Evidence from observational studies, prospective cohort studies and randomized clinical intervention studies indicate that moderate doses of long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) significantly decrease risk of fatal coronary heart disease (CHD). Higher doses and longer duration of intervention may also protect from non-fatal CHD events. The exact mechanisms through which LC n-3 PUFA has an effect on CHD are not well established but may include a decrease in fasting and postprandial triacylglycerol levels, a decrease in arrhythmias, modulation of platelet aggregation and decreased synthesis of pro-inflammatory agents. The mechanistic relation between LC n-3 PUFA and inflammation has attracted great interest, and in vitro studies have revealed that these fatty acids decrease endothelial activation, affect eicosanoid metabolism (including epoxygenation pathways) and induce inflammatory resolution. However, the effects of LC n-3 PUFA on established biomarkers of inflammation and endothelial activation in vivo are not strong. Consequently we need new and more sensitive and systemic biomarkers to reveal the effects of LC n-3 PUFA on localized inflammatory processes.

Intakes of long-chain omega-3 fatty acid associated with reduced risk for death from coronary heart disease in healthy adults

Numerous organizations and national health agencies have begun to recommend consumption of the long-chain omega-3 fatty acids (FAs) eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA), respectively, in pill or fish form for general cardiovascular health. The purpose of this article is to present a rationale for an official target intake of 400 to 500 mg/d of EPA + DHA in the United States. Six epidemiologic studies reporting EPA + DHA intake and risk of coronary heart disease (CHD) death have been conducted in the United States, and five studies reported statistically significant inverse trends. Meta-analysis of these data showed a significant dose-response relationship between risk for CHD death and intake (P = 0.03), with relative risk reductions of 37% at an average EPA + DHA intake of 566 mg/d. Coincidentally, two servings per week of oily fish (the current American Heart Association recommendation) would provide 400 to 500 mg/d. We conclude, therefore, that an intake of 400 to 500 mg/d of EPA + DHA is achievable by diet alone and would be expected to significantly reduce risk for death from CHD in healthy adults.

Omega-3 fatty acid supplementation reduces one-year risk of atrial fibrillation in patients hospitalized with myocardial infarction

PURPOSE

Current strategies for avoiding atrial fibrillation (AF) are of limited value. We aim to assess the relationship between omega-3 fatty acids (n-3 PUFA) and AF occurrence in post-myocardial infarction (MI) patients.

METHODS

A population study, linking hospital discharge records, prescription databases, and vital statistics, was conducted and included all consecutive patients with MI (ICD-9: 410) in six Italian local health authorities over a 3-year period. A propensity score (PS)-based, 5-to-1, greedy 1:1 matching algorithm was used to check consistency of results. Sensitivity analysis was performed to assess the robustness of findings.

RESULTS

N-3 PUFA reduced the relative risk of the hospitalization for AF [hazard ratio (HR) 0.19, 95% CI 0.07-0.51] and was associated with a further and complementary reduction in all-cause mortality (HR 0.15, 95% CI 0.05-0.46). PS-based matched analysis and sensitivity analysis confirmed the main results.

CONCLUSION

n-3 PUFA reduced both all-cause mortality and incidence of 1-year AF in patients hospitalized with MI.

Bioavailability of alpha-linolenic acid in subjects after ingestion of three different forms of flaxseed

BACKGROUND

Dietary flaxseed may have significant health-related benefits due to its high content of the omega-3 fatty acid, alpha-linolenic acid (ALA). However, before extensive work can be undertaken in clinical populations to determine its efficacy, basic information on ALA bioavailability from flaxseed and the physiological effects of its ingestion need to be examined.

OBJECTIVE

The purpose of this study, therefore, was to determine the bioavailability of ALA when the flaxseed was ingested in the form of whole seed, milled seed or as flaxseed oil.

DESIGN

The flaxseed components (30 g of seed or 6 g of ALA in the oil) were baked into muffins for delivery over a 3 month test period in healthy male and female subjects.

RESULTS

Flaxseed ingestion over a 1 month period resulted in significant (P = 0.005) increases in plasma ALA levels in the flaxseed oil and the milled flaxseed supplemented groups. The former group had significantly (P = 0.004) higher ALA levels than the milled flaxseed group. The subjects supplemented with whole flaxseed did not achieve a significant (P > 0.05) increase in plasma ALA levels. An additional two months of flaxseed ingestion did not achieve significantly higher levels of plasma ALA in any of the groups. However, no significant increase was detected in plasma eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) levels in any of the flax-fed groups. There were no changes in plasma cholesterol or triglycerides or in platelet aggregation at any time point in any of the groups. Subjects in all of the groups exhibited some symptoms of gastro-intestinal discomfort during the early stages of the study but these disappeared in the oil and milled seed groups. However, compliance was a problem in the whole flaxseed group.

CONCLUSION

In summary, ingestion of flax oil and milled flaxseed delivered significant levels of ALA to the plasma whereas whole flaxseed did not. Whole seed and oil preparations induced adverse gastrointestinal effects within 4 weeks and these were severe enough to induce the withdrawal of some subjects from these two groups. No one withdrew from the group that ingested milled flaxseed and, therefore, may represent a good form of flaxseed to avoid serious side-effects and still provide significant increases in ALA to the body.

The omega-3 index as a risk factor for coronary heart disease

Because blood concentrations of n-3 (or omega-3) fatty acids (FAs) (eicosapentaenoic and docosahexaenoic acids) are a strong reflection of dietary intake, it is proposed that a n-3 FA biomarker, the omega-3 index (erythrocyte eicosapentaenoic acid plus docosahexaenoic acid), be considered as a potential risk factor for coronary heart disease mortality, especially sudden cardiac death. The omega-3 index fulfills many of the requirements for a risk factor including consistent epidemiologic evidence, a plausible mechanism of action, a reproducible assay, independence from classic risk factors, modifiability, and, most important, the demonstration that raising levels will reduce risk for cardiac events. Measuring membrane concentrations of n-3 FAs is a rational approach to biostatus assessment as these FAs appear to exert their beneficial metabolic effects because of their actions in membranes. They alter membrane physical characteristics and the activity of membrane-bound proteins, and, once released by intracellular phospholipases from membrane stores, they can interact with ion channels, be converted into a wide variety of bioactive eicosanoids, and serve as ligands for several nuclear transcription factors, thereby altering gene expression. The omega-3 index compares very favorably with other risk factors for sudden cardiac death. Proposed omega-3 index risk zones are (in percentages of erythrocyte FAs): high risk, <4%; intermediate risk, 4-8%; and low risk, >8%. Before assessment of n-3 FA biostatus can be used in routine clinical evaluation of patients, standardized laboratory methods and quality control materials must become available.

Dietary intake of n-3 polyunsaturated fatty acids is inversely associated with CRP levels, especially among male smokers

OBJECTIVE

To examine whether dietary intake of n-3 polyunsaturated fatty acid (n-3PUFA) is associated with serum C-reactive protein (CRP) levels with regard to smoking status in the Japanese general population in a cross-sectional study.

METHODS AND RESULTS

A total of 14,191 participants aged 40-69 years were enrolled and divided into quartile groups according to their intake of n-3PUFA. Multivariate-adjusted logarithm-transformed CRP levels were compared between the quartile groups with regard to smoking status after adjusting for traditional risk factors and intake of saturated fatty acids. Adjusted CRP levels were inversely associated with dietary intake of n-3PUFA for both the male subjects and female subjects (p<0.05 for trend). A linear trend was not seen between intake of n-3PUFA and adjusted CRP levels in male nonsmokers. Adjusted CRP level in the lowest quartile group of n-3PUFA was significantly higher than the levels in other groups in male smokers.

CONCLUSION

Sufficient dietary intake of n-3PUFA may attenuate inflammatory reaction and this effect is more evident among high-risk populations such as male smokers although the small numbers of female ex-smokers and nonsmokers limited statistical power to draw strong conclusions about these groups.

Coronary artery calcification in Japanese men in Japan and Hawaii

Explanations for the low prevalence of atherosclerosis in Japan versus the United States are often confounded with genetic variation. To help remove such confounding, the authors compared coronary artery calcification (CAC), a marker of subclinical atherosclerosis, between Japanese men in Japan and Japanese men in Hawaii. Findings were based on risk factors and CAC measured from 2001 to 2005 in 311 men in Japan and 300 men in Hawaii. Men were aged 40-50 years and without cardiovascular disease. After age adjustment, there was a threefold excess in the odds of prevalent CAC scores of > or = 10 in Hawaii versus Japan (relative odds = 3.2, 95% confidence interval: 2.1, 4.9). Whereas men in Hawaii had a generally poorer risk factor profile, men in Japan were four times more likely to smoke cigarettes (49.5% vs. 12.7%, p < 0.001). In spite of marked risk factor differences between the samples, none of the risk factors explained the low amounts of CAC in Japan. After risk factor adjustment, the relative odds of CAC scores of > or = 10 in Hawaii versus Japan was 4.0 (95% confidence interval: 2.2, 7.4). Further studies are needed to identify factors that protect against atherosclerosis in Japanese men in Japan.

Beyond the Mediterranean Diet: The Role of Omega‐3 Fatty Acids in the Prevention of Coronary Heart Disease

Evidence from epidemiologic and clinical secondary prevention trials suggest that the omega-3 polyunsaturated fatty acids (n-3 PUFAs) may have a significant role in the prevention of coronary heart disease. Dietary sources of n-3 PUFAs include fish oils, rich in eicosapentaenoic acid and docosahexaenoic acid, along with plants rich in a-linolenic acid. Randomized secondary prevention clinical trials with fish oils (eicosapentaenoic acid, docosahexaenoic acid) and a-linolenic acid have demonstrated reductions in risk that compare favorably to those seen in landmark secondary prevention trials with lipid-lowering drugs. Several mechanisms explaining the cardioprotective effect of the n-3 PUFA have been suggested including antiarrhythmic and antithrombotic roles. Although official US guidelines for the dietary intake of n-3 PUFA are not available, several international guidelines have been published. Fish is an important source of the n-3 PUFA in the US diet; however, vegetable sources including grains and oils offer an alternative source for those who are unable to regularly consume fish.

Modificaciones en el perfil lipídico tras el consumo regular de conservas de pescado. Influencia de la adición de isoflavonas, ácidos grasos omega-3 y fitoesteroles

BACKGROUND AND OBJECTIVE

Changes in dietary habits are associated with an improvement of lipid profile. We decided to assess changes in lipid profile reached with a dietary enrichment with canned tuna in olive oil and compared them with those reached with canned tuna with additional supplementation.

SUBJECTS AND METHOD

In a prospective, randomized, single blind study, 400 participants were assigned to a daily intake of canned tuna in olive oil alone (control group) or enriched with: isoflavones, omega-3 fatty acids of phytosterols, during three months. Plasmatic lipid levels were measured before and after intervention. Changes of lipid levels between basal and final visits and differences between the 4 types of supplementations were evaluated.

RESULTS

The mean age of the study population was 53 years, 45% of them being males. In all 4 groups a significant reduction of total cholesterol, low-density lipoprotein (LDL)-cholesterol levels and total cholesterol/high-density lipoprotein (HDL)-cholesterol ratio was observed after 3 months of follow-up; there were no significant changes of triglycerides nor HDL-cholesterol levels. The comparison between different types of supplementation revealed that only phytosterols addition reached a greater reduction of total cholesterol and LDL-cholesterol levels than canned tuna in olive oil alone (p < 0.05), and the differences between the remaining 2 supplementations and the control group were not significant.

CONCLUSIONS

Regular intake of enrichment with canned tuna supplementation is associated with improvement of lipid profile. The addition of isoflavones, omega-3 fatty acids or phytosterols supplementations increases fish consume effect, although only the enrichment with phytosterols reaches significantly better results.

Effect of Omega-3 Fatty Acid Supplementation on the Arachidonic Acid:Eicosapentaenoic Acid Ratio

STUDY OBJECTIVES

To determine the baseline arachidonic acid:eicosapentaenoic acid (AA:EPA) ratio in patients with coronary artery disease and healthy subjects, and whether supplementation of omega-3 fatty acids, administered as fish oil capsules, affects this ratio.

DESIGN

Prospective, open-label trial.

SETTING

University-affiliated cardiology clinic.

SUBJECTS

Thirty patients with stable coronary artery disease (CAD) and 30 healthy subjects.

INTERVENTION

All participants received omega-3 fatty acids 1.5 g/day for 4 weeks, followed by 3 g/day for an additional 4 weeks.

MEASUREMENTS AND MAIN RESULTS

For each participant, a lipid profile was determined at baseline and after 4 weeks of treatment with each dose. Other laboratory results analyzed were serum AA:EPA ratios, high-sensitivity C-reactive protein (hs-CRP) levels, and blood glucose levels. Mean +/- SD baseline AA:EPA ratios were 39.6 +/- 19.0 in healthy subjects and 23.7 +/- 12.5 in patients with CAD. These ratios decreased significantly in both groups after treatment with 1.5 g/day of omega-3 fatty acids: 9.0 +/- 4.2 in healthy subjects and 10.3 +/- 8.8 in patients with CAD. After treatment with 3 g/day, the ratios were further reduced: 5.1 +/- 3.2 in healthy subjects and 4.9 +/- 2.6 in patients with CAD. Supplementation with omega-3 fatty acids did not significantly affect hs-CRP, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or blood glucose levels. Triglyceride levels were not reduced in patients with CAD but were significantly decreased in healthy subjects (by 20% decrease with omega-3 fatty acids 1.5 g/day and by 32% decrease with 3 g/day).

CONCLUSION

Treatment with omega-3 fatty acids significantly reduced AA:EPA ratios in both healthy subjects and in patients with stable CAD. The treatment had no effect on hs-CRP levels in either group, and it reduced triglyceride levels in healthy subjects but not in patients with CAD.

Long-term fish consumption is associated with protection against arrhythmia in healthy persons in a Mediterranean region--the ATTICA study

BACKGROUND

Dietary habits have long been associated with many manifestations of cardiovascular disease.

OBJECTIVE

We sought to investigate whether a diet enriched with fish and n-3 fatty acid consumption are associated with changes in the potential duration of the electrical action, as represented by the QT duration on a resting electrocardiogram, in a population-based sample of Greek adults.

DESIGN

During 2001 and 2002, we randomly enrolled 1514 men (18-87 y old) and 1528 women (18-89 y old) stratified by age and sex distribution (in the 2001 Greek census) from the Attica area, Greece. We studied several demographic, anthropometric, lifestyle, dietary, and bioclinical factors of the participants. Dietary habits (including fish consumption) were evaluated by using a validated food-frequency questionnaire. All subjects underwent electrocardiography with a 12-lead surface, in which, along with several other indexes, QT duration was measured, and the heart rate-corrected QT (QTc) was calculated (corrected by using Bazett's rate). The tested hypothesis was evaluated through multiple linear regression analysis, after control for physical activity status, sex, age, medication intake, and several other potential confounders.

RESULTS

Compared with fish nonconsumers, those who consumed >300 g fish/wk had a mean 13.6% lower QTc (P<0.01). These findings were confirmed after adjustment for age, sex, physical activity status, BMI, smoking habits, intake of nuts, and other confounders. Moreover, compared with fish nonconsumers, those who consumed >or=300 g fish/wk had a 29.2% lower likelihood of having QTc intervals >0.45 s (P=0.03).

CONCLUSIONS

Long-term consumption of fish is associated with lower QTc interval in free-eating people without any evidence of cardiovascular disease. Thus, fish intake seems to provide antiarrhythmic protection at a population level.

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.

Omega-3 fatty acids and cardiovascular disease: a case for omega-3 index as a new risk factor

The omega-3 fatty acids (FAs) found in fish and fish oils (eicosapentaenoic and docosahexaenoic acids, EPA and DHA) have been reported to have a variety of beneficial effects in cardiovascular diseases. Ecological and prospective cohort studies as well as randomized, controlled trials have supported the view that the effects of these FAs are clinically relevant. They operate via several mechanisms, all beginning with the incorporation of EPA and DHA into cell membranes. From here, these omega-3 FA alter membrane physical characteristics and the activity of membrane-bound proteins, and once released by intracellular phospholipases, can interact with ion channels, be converted into a wide variety of bioactive eicosanoids, and serve as ligands for several nuclear transcription factors thereby altering gene expression. In as much as blood levels are a strong reflection of dietary intake, it is proposed that an omega-3 FA biomarker, the omega-3 index (erythrocyte EPA+DHA) be considered at least a marker, if not a risk factor, for coronary heart disease, especially sudden cardiac death. The omega-3 index fulfils many of the requirements for a risk factor including consistent epidemiological evidence, a plausible mechanism of action, a reproducible assay, independence from classical risk factors, modifiability, and most importantly, the demonstration that raising tissue levels will reduce risk for cardiac events. For these and a number of other reasons, the omega-3 index compares very favourably with other risk factors for sudden cardiac death.

Dietary omega-3 fatty acid intake and cardiovascular risk

Dietary omega-3 fatty acids decrease the risk of cardiovascular disease (CVD). Both epidemiologic and interventional studies have demonstrated beneficial effects of omega-3 fatty acids on many CVD end points, including all CVD (defined as all coronary artery disease [CAD], fatal and nonfatal myocardial infarction [MI], and stroke combined), all CAD, fatal and nonfatal MI, stroke, sudden cardiac death, and all-cause mortality. Much of the evidence comes from studies with fish oil and fish; to a lesser extent, data relate to plant-derived omega-3 fatty acids. Cardioprotective benefits have been observed with daily consumption of as little as 25 to 57 g (approximately 1 to 2 oz) of fish high in omega-3 fatty acids, an intake equivalent to >or=1 fish meal weekly or even monthly, with greater intakes decreasing risk further in a dose-dependent manner, up to about 5 servings per week. Fish, including farm-raised fish and their wild counterparts, are the major dietary sources of the longer-chain omega-3 fatty acids. Sources of plant-derived omega-3 fatty acids include flaxseed, flaxseed oil, walnuts, canola oil, and soybean oil. Because of the remarkable cardioprotective effects of omega-3 fatty acids, consumption of food sources that provide omega-3 fatty acids--especially the longer-chain fatty acids (>or=20 carbons) from marine sources--should be increased in the diet to decrease CVD risk significantly.

n−3 Fatty acids, cardiac arrhythmia and fatal coronary heart disease

n-3 Polyunsaturated fatty acids (n-3 PUFA) are suggested to prevent cardiac death via inhibition of cardiac arrhythmia. In this review we discuss the results of human studies on intake of n-3 PUFAs and heart disease and, more specifically, on cardiac arrhythmia. Observational studies indicate that intake of fish is associated with a lower incidence of fatal coronary heart disease in several populations. These studies are fairly consistent, but people that have a high intake of fatty fish might have a healthier lifestyle in general, and such confounding is difficult to remove completely with statistical adjustments and corrections. Evidence from trials is less clear. In two open label trials in patients with a previous myocardial infarction intake of fish or fish oil prevented fatal coronary heart disease. In contrast, a trial in patients with angina suggested a higher risk of sudden cardiac death in patients taking fish oil. Furthermore, results of trials in patients with an implantable cardioverter defibrillator (ICD) that investigated effects of fish oil on arrhythmia in patients already suffering from ventricular tachycardia are not consistent. Also, studies on relationships between intake of n-3 PUFA from fish and less life-threatening forms of arrhythmia, such as atrial fibrillation and premature ventricular complexes (PVCs) are equivocal. Thus, after 35 years of research the question whether fish prevents heart disease remains unanswered, and an anti-arrhythmic effect of fish oil remains unproven although the idea is still viable and is being actively tested in further trials.

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

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

n-3 fatty acids and cardiovascular disease

The results of prospective cohort studies indicate that consuming fish or fish oil containing the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with decreased cardiovascular death, whereas consumption of the vegetable oil-derived n-3 fatty acid a-linolenic acid is not as effective. Randomized control trials (RCTs) in the context of secondary prevention also indicate that the consumption of EPA plus DHA is protective at doses <1 g/d. The therapeutic effect appears to be due to suppression of fatal arrhythmias rather than stabilization of atherosclerotic plaques. At doses >3 g/d, EPA plus DHA can improve cardiovascular disease risk factors, including decreasing plasma triacylglycerols, blood pressure, platelet aggregation, and inflammation, while improving vascular reactivity. Mainly on the basis of the results of RCTs, the American Heart Association recommends that everyone eat oily fish twice per week and that those with coronary heart disease eat 1 g/d of EPA plus DHA from oily fish or supplements. Directions for future research include (1) RCTs to confirm the initial trials showing that EPA plus DHA decreases cardiovascular death and additional studies to determine whether this effect is due to EPA, DHA, or the combination; the dosage of the effective components; and whether the mechanism of action in humans is prevention of fatal arrhythmias. (2) Clinical studies to determine whether the reduction in cardiovascular disease risk factors is due to EPA, DHA, or the combination and the dosage of the effective components. (3) Clinical studies to determine whether vegetable oil-derived alpha-linolenic acid added to a diet enriched in n-6 fatty acids can effectively substitute for fish oil-derived EPA plus DHA.

n-3 fatty acid dietary recommendations and food sources to achieve essentiality and cardiovascular benefits

Dietary recommendations have been made for n-3 fatty acids, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) to achieve nutrient adequacy and to prevent and treat cardiovascular disease. These recommendations are based on a large body of evidence from epidemiologic and controlled clinical studies. The n-3 fatty acid recommendation to achieve nutritional adequacy, defined as the amount necessary to prevent deficiency symptoms, is 0.6-1.2% of energy for ALA; up to 10% of this can be provided by EPA or DHA. To achieve recommended ALA intakes, food sources including flaxseed and flaxseed oil, walnuts and walnut oil, and canola oil are recommended. The evidence base supports a dietary recommendation of approximately 500 mg/d of EPA and DHA for cardiovascular disease risk reduction. For treatment of existing cardiovascular disease, 1 g/d is recommended. These recommendations have been embraced by many health agencies worldwide. A dietary strategy for achieving the 500-mg/d recommendation is to consume 2 fish meals per week (preferably fatty fish). Foods enriched with EPA and DHA or fish oil supplements are a suitable alternate to achieve recommended intakes and may be necessary to achieve intakes of 1 g/d.

Fish oils--adjuvant therapy in chronic heart failure?

Despite advances in medical management and device therapy, chronic heart failure (CHF) remains a condition of high mortality and poor quality of life. Patients with CHF endure frequent admissions to hospital, with exacerbations of breathlessness or recurrent acute myocardial infarction and have a high incidence of sudden death. A high intake of marine polyunsaturated fatty acids (PUFAs) is associated with lower cardiovascular mortality in the general population, and diabetics, and can reduce cardiovascular deaths post-infarction. Many of the effects of PUFAs could be of benefit in CHF patients. They can improve endothelial function, reduce vascular tone, reduce platelet aggregability, improve myocardial relaxation, stabilize myocardial cells by prolonging the refractory period, and lead to increased appetite and weight gain. They also have potentially important immune-modulating effects, reducing cytokine production and release and altering prostaglandin metabolism. In this review article we discuss the potential benefits of PUFA supplementation in CHF patients using data from clinical trials and in vitro experiments.

Understanding omega-3's

Omega-3 fatty acids are a subset of polyunsaturated fatty acids found in marine sources as eicosapentaenoic acid and docosahexaenoic acid and in some leafy vegetables, nuts, and oils as alpha-linolenic acid (ALA). The metabolism of omega-3's may explain the cardioprotective effects observed in epidemiologic and experimental studies. Although most data for cardioprotective effects come from studies of marine sources, vegetable sources of omega-3 fatty acids (alpha-linolenic acid) may have similar effects through in vivo conversion to eicosapentaenoic acid and docosahexaenoic acid. This document will provide an overview of omega-3 fatty acids with a focus on specific sources, metabolism, safety issues, and their potential indication for cardiovascular prevention.

Fish consumption and the risk of developing acute coronary syndromes: the CARDIO2000 study

OBJECTIVE

The aim of this work was to investigate the association between fish consumption and the development of non-fatal acute coronary syndromes (ACS), in a Mediterranean population.

METHODS

During 2000-2001, we randomly and stratified selected, from all Greek regions, 848 hospitalised patients (695 males, 58+/-10 years old and 153 females, 65+/-9 years old) who had a first event of ACS and 1078 paired, by region-sex-age, controls without any clinical symptoms or signs of coronary heart disease.

RESULTS

On multivariate logistic regression analysis and, after controlling for several potential confounders, we found that fish consumption less than 150 g/week was associated with 38% lower odds of developing ACS as compared to no consumption (odds ratio=0.62, P-value<0.05). In contrast, moderate (150-300 g/week) and high (>300 g/week) fish consumption was not associated with the developing of the disease (odds ratios=1.10 and 1.01, respectively, P-value>0.1). The benefits from low fish consumption were also significant even amongst current smokers and diabetics.

CONCLUSION

Moderate fish consumption was independently associated with a significant reduction in the odds of developing ACS. The strength and consistency of this finding has implications for public health and should be explored further.

The relationship between fish consumption and the risk of developing acute coronary syndromes among smokers: the CARDIO2000 case-control study

BACKGROUND AND AIM

We sought to investigate the relationship between fish consumption and the risk of developing non-fatal acute coronary syndromes (ACS) among current smokers.

METHODS AND RESULTS

During 2000-2001, we conducted the CARDIO2000 case-control study that included patients hospitalized for a first event of ACS and matched (age, sex) individuals without clinical evidence of CHD (controls), from all the Greek regions. In the present analysis we studied data from 519 men (59+/-10 years old) and 45 women (62+/-9 years old) patients, as well as 444 men and 90 women controls, matched for age with the patients that reported current smoking. To evaluate the hypothesis tested we applied conditional logistic regression analysis after controlling for several potential confounders. Overall, 94% of controls and patients reported fish consumption at least once a week. Compared to low fish consumption (<60 g/week), moderate (60-180 g/week) intake was associated with 15% (p<0.05) lower risk of ACS, while increased (180-300 g/week, or >300 g/week) consumption was associated with 18% (p<0.05) and 19% (p = 0.53) higher risk, respectively.

CONCLUSION

Moderate fish consumption seems to moderate the deleterious effect of smoking on the occurrence of ACS. However, increased intake does not seem to confer any benefit on coronary risk.

Alpha-linolenic acid and heart rate variability in women examined for coronary artery disease

BACKGROUND AND AIM

Some studies suggest that alpha-linolenic acid (ALA) may protect against coronary artery disease (CAD) and CAD related death (i.e. sudden cardiac death). Thus, some limited data suggest an antiarrhythmic effect of ALA. We therefore investigated the association between ALA and 24-h heart rate variability (HRV), a strong predictor of arrhythmic events and sudden cardiac death, in women.

METHODS AND RESULTS

The content of ALA in adipose tissue and HRV was determined in 106 women referred for coronary angiography due to suspected CAD. Mean age was 59.5 years (+/-7) and the content of ALA in adipose tissue was 0.9% (+/-0.2). Smokers (n=33) had significantly lower HRV compared to non-smokers, whereas the two groups were otherwise comparable regarding clinical characteristics. If the patients were divided according to SDNN quartiles (the major HRV parameter), women belonging to the lowest quartile had the lowest ALA level (0.8% vs 0.9%, p < 0.01). Furthermore, a positive correlation was found between ALA and HRV, especially among smokers (r=0.5, p < 0.001). Linear multiple regression analysis revealed that ALA was independently and positively associated with HRV.

CONCLUSIONS

A positive and independent association was found between ALA in adipose tissue and HRV in women referred for coronary angiography due to suspected coronary artery disease. This association was even stronger for women who smoked. The results might suggest a possible antiarrhythmic effect of ALA in women, an effect which could explain results from previous studies. However, intervention trials with ALA in humans, not least women are warranted.

Association between fish consumption and all-cause and cause-specific mortality in Japan: NIPPON DATA80, 1980-99

PURPOSE

Although high consumption of fish may be one of the contributing factors for Japanese longevity, no epidemiological study using Japanese data has tested this hypothesis.

SUBJECTS AND METHODS

The relationship between fish consumption and all-cause as well as cause-specific mortality was analyzed using the database of NIPPON DATA80. At baseline in 1980, history, physical, and blood biochemical measurement and a nutritional survey by the food-frequency method were performed in randomly selected community-based subjects aged 30 years and over in Japan. After exclusion of subjects with significant comorbidities at baseline, we followed 3945 men and 4934 women for 19 years. Men and women were analyzed comprehensively. Age- and sex-adjusted and multivariate adjusted relative risk for all-cause or cause-specific mortality was calculated using a Cox proportional hazards model with delayed entry.

RESULTS

During 19 years of followup, there were 1745 deaths. Subjects were divided into 5 groups according to fish consumption frequency. The multivariate Cox analyses showed that relative risks for subjects who ate fish more than twice daily compared with those of subjects who ate 1 to 2 times weekly were 0.99 (95% confidence intervals: 0.77-1.27) for all-cause, 1.26 (0.70-2.29) for stroke, 0.92 (0.20-4.23) for cerebral hemorrhage, 1.09 (0.48-2.43) for cerebral infarction, and 0.91 (0.35-2.35) for coronary heart disease mortality.

CONCLUSION

Our results did not provide evidence in support of the fish hypothesis, perhaps because the majority of the Japanese subjects in the study ate fish more than the threshold level shown to be beneficial in the previous studies.

The mechanism of action of omega-3 fatty acids in secondary prevention post-myocardial infarction

BACKGROUND

Omega-3 fatty acids from fish and fish oils can protect against coronary heart disease (CHD), which is still the most common cause of death in the Western economies. Evidence from epidemiological and case cohort studies indicate that consumpton of fatty fish and omega-3 fatty acids reduces the risk of cardiovascular mortality.

OBJECTIVE

This article briefly reviews the evidence regarding omega-3 fatty acids and CHD and outlines the mechanisms through which omega-3 fatty acids might confer cardiac benefits over and above the standard secondary prevention strategies.

CONCLUSION

The conclusion reached is that omega-3 fatty acids play a significant role in secondary prevention post-myocardial infarction. The mechanisms through which two of these omega-3 fatty acids, eicosapentaenoic acid and docosahexanoic acid, exert their action appear to be distinct and adjuvant to the available standard secondary prevention therapies. The role to be played by the administration of a newly licensed 90% concentrate EPA + DHA formulation (1 g/day capsule: Omacor) is explored.