Long-chain n-3 polyunsaturated fatty acids intake and cardiovascular disease mortality risk in Japanese: a 24-year follow-up of NIPPON DATA80

Dietary Macronutrient Intake and Cardiovascular Disease Risk and Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Many epidemiological studies have evaluated the intake of macronutrients and the risk of mortality and cardiovascular disease (CVD). However, current evidence is conflicting and warrants further investigation. Therefore, we carried out an umbrella review to examine and quantify the potential dose-response association of dietary macronutrient intake with CVD morbidity and mortality. Prospective cohort studies from PubMed, Embase, and CENTRAL were reviewed, which reported associations of macronutrients (protein, fat, and carbohydrate) with all-cause, CVD, cancer mortality, or CVD events. Multivariable relative risks (RR) were pooled, and heterogeneity was assessed. The results of 124 prospective cohort studies were included in the systematic review and 101 in the meta-analysis. During the follow-up period from 2.2 to 30 years, 506,086 deaths and 79,585 CVD events occurred among 5,107,821 participants. High total protein intake was associated with low CVD morbidity (RR 0.88, 95% confidence interval 0.82-0.94), while high total carbohydrate intake was associated with high CVD morbidity (1.08, 1.02-1.13). For fats, a high intake of total fat was associated with a decreased all-cause mortality risk (0.92, 0.85-0.99). Saturated fatty acid intake was only associated with cancer mortality (1.10, 1.06-1.14); Both monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) intake was associated with all-cause mortality (MUFA: 0.92, 0.86-0.98; PUFA: 0.91, 0.86-0.96). This meta-analysis supports that protein intake is associated with a decreased risk of CVD morbidity, while carbohydrate intake is associated with an increased risk of CVD morbidity. High total fat intake is associated with a low risk of all-cause mortality, and this effect was different in an analysis stratified by the type of fat.

Dietary intake, biomarkers and supplementation of fatty acids and risk of coronary events: a systematic review and dose-response meta-analysis of randomized controlled trials and prospective observational studies

We aimed to review the association of dietary fats and risk of coronary events in adults. We searched PubMed, Embase, CENTRAL, Scopus, and Web of Sciences to April 2022 for prospective cohorts and randomized trials investigating the association of dietary intake and biomarkers of fats and fatty acid interventions and the risk of coronary events. We performed random-effects meta-analyses to estimate relative risk (RR) for the top versus bottom tertiles of exposures. One-hundered sixty-five prospective cohorts and randomized trials were included. Dietary intake and biomarkers of total fat and saturated, monounsaturated, and polyunsaturated fatty acids were not associated with the risk of coronary events. Dietary intake of trans fatty acids, palmitic acid, stearic acid, and saturated fatty acids from meat and unprocessed meat was modestly associated with a higher risk and, in contrast, intake of alpha-linolenic acid, long-chain omega-3 fatty acids, and linoleic acid was modestly associated with a lower risk. Supplementation with long-chain omega-3 fatty acids and increasing the consumption of alpha-linolenic and linoleic acids in place of saturated fats reduced the risk of coronary events. Existing evidence, in its totality, provides a modest support in favor of current recommendations suggesting replacement of saturated fats with polyunsaturated fats.

Dietary Factors, Dietary Patterns, and Cardiovascular Disease Risk in Representative Japanese Cohorts: NIPPON DATA80/90

Diet is one of the most important factors affecting healthy life expectancy through the onset of cardiovascular disease (CVD) risk as well as various chronic diseases. Because dietary habits and disease structure differ depending on the country, region, and/or race, evidence from each population is required. NIPPON DATA80/90 is a long-term cohort study of a representative Japanese population that participated in national nutrition surveys. Among the many findings of this cohort study, a dietary pattern with higher intake of fruits, vegetables, fish (n-3 polyunsaturated fatty acids), and dietary fiber and lower intake of salt as well as sodium-to-potassium ratio was found to be associated with a lower risk of CVD mortality. The results from our cohort study would be useful for effectively preventing CVD. This article reviews the published studies from the NIPPON DATA80/90 to highlight the significant findings that may be used to develop risk prevention strategies for CVD.

Are total omega-3 and omega-6 polyunsaturated fatty acids predictors of fatal stroke in the Adventist Health Study 2 prospective cohort?

Introduction

The effects of omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFA) on cerebrovascular disease remain unsettled. However, most studies have focused on marine sourced n-3 PUFA rather than total n-3 PUFA, of which the majority in the American diet is plant derived. This study therefore intended to investigate these effects in a cohort for which the vegetarian diet was more prevalent than the general public.

Methods

Cox proportional hazards with fatal stroke as the outcome was performed on the approximately 96,000 subject Adventist Health Study 2 prospective cohort. Stratification by race and sex was performed on models with a priori covariables, comparing 90^th to 10^th percentile daily intakes of energy-adjusted total n-3 PUFA, total n-6 PUFA, and the n-6 / n-3 PUFA ratio as variables of interest.

Results

For the main analytical group (78,335 subjects), the hazard ratio (95% confidence interval) for total n-3 PUFA was 0.65 (0.51–0.83), and for total n-6 PUFA was 1.37 (1.02–1.82), while adjusting for both fatty acids in the model. The n-6 / n-3 PUFA ratio was harmful with a HR of 1.40 (1.16–1.69), whereas the inclusion of total n-3 PUFA slightly attenuated the HR to 1.33(1.02–1.74). Effects were similar for the non-black sex-combined and sex-specific analyses.

Conclusion

In most analytic groups, subjects with greater total n-3 PUFA intakes have lower risk of fatal stroke, and those with a higher n-6 / n-3 PUFA ratio had higher risk. However, the n-6 / n-3 PUFA ratio remains statistically significant even after adjusting for total n-3 PUFA or total n-6 PUFA, suggesting that the ratio is of epidemiologic interest for cerebrovascular disease research.

Differential Association of Serum n-3 Polyunsaturated Fatty Acids with Various Cerebrovascular Lesions in Japanese Men

BACKGROUND

An association between a high intake of marine-derived n-3 polyunsaturated fatty acids (n-3 PUFAs) with a lower risk of coronary heart disease was previously reported. However, the association between n-3 PUFAs and cerebrovascular lesions remains unclear. We evaluated this association in a general-population-based sample of Japanese men.

METHODS

Participants were community-dwelling men (40-79 years old) living in Kusatsu City, Shiga, Japan. Serum concentrations of n-3 PUFAs, defined as the sum of eicosapentaenoic and docosahexaenoic acids, were measured via gas-liquid chromatography between 2006 and 2008. Magnetic resonance imaging was used to assess cerebrovascular lesions (including intracerebral large-artery stenosis, lacunar infarction, and microbleeds) and white matter lesions between 2012 and 2015. Logistic regression adjusting for conventional cardiovascular risk factors was used to estimate the odds ratio of prevalent cerebrovascular lesions per 1 standard deviation higher serum concentration of n-3 PUFAs.

RESULTS

Of a total of 739 men, the numbers (crude prevalence in %) of prevalent cerebral large-artery stenoses, lacunar infarctions, microbleeds, and white matter lesions were 222 (30.0), 162 (21.9), 103 (13.9), and 164 (22.2), respectively. A 1 standard deviation higher concentration of n-3 PUFAs (30.5 μmol/L) was independently associated with lower odds of cerebral large-artery stenosis (multivariable-adjusted odds ratio, 0.80; 95% confidential interval, 0.67-0.97). There were no significant associations of n-3 PUFAs with the other types of lesions.

CONCLUSIONS

n-3 PUFAs may have protective effects against large-artery stenosis, but not small vessel lesions, in the brain.

Independent factors affecting hemorrhagic and ischemic stroke in patients aged 40-69 years: a cross-sectional study

Background

Intracerebral hemorrhage (ICH) and acute ischemic stroke (AIS) have common vascular risk factors; however, ICH often occurs in adults aged < 70 years. Intracerebral hemorrhage and AIS in adults aged < 70 years should be preventable; however, it is unclear why different subtypes of ICH or AIS occur among adults aged < 70 years with vascular risk factors. This study aimed to identify independent variables for ICH or AIS onset in patients aged < 70 years.

Methods

We included patients aged 40–69 years who experienced ICH or AIS between August 2016 and July 2019. Patients aged < 40 years were excluded because other diseases, rather than vascular risk factors, are often associated with stroke etiology in this age group. Data on age, systolic blood pressure (SBP), serum lipids, and serum fatty acid levels were compared between patients with ICH and those with AIS. In addition, we conducted multivariable logistic regression analyses to identify independent factors among the variables, such as blood pressure or biomarkers, with significant differences between the two groups.

Results

Of the 1252 acute stroke patients screened, 74 patients with ICH and 149 patients with AIS met the inclusion criteria. After excluding variables with multicollinearity, SBP, glycated hemoglobin (HbA1c), and eicosapentaenoic acid (EPA) proportion (%) of total fatty acids were identified as independent factors affecting ICH and AIS. The SBP and EPA% threshold values for ICH compared to AIS were ≥ 158 mmHg and ≤ 2.3%, respectively. The HbA1c threshold value for AIS compared to ICH was ≥ 6.1%.

Conclusions

Systolic blood pressure, HbA1c, and EPA%, were independent factors between ICH and AIS. Patients aged 40–69 years with high SBP and low EPA% were at a higher risk of ICH than AIS, and those with a high HbA1c were at a higher risk of AIS than ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02625-6.

Association between Milk Intake and Incident Stroke among Japanese Community Dwellers: The Iwate-KENCO Study

We aimed to evaluate the association between the milk consumption and incident stroke in a Japanese population, where milk consumption is lower than that of Western countries. In total, 14,121 participants (4253 men and 9868 women) aged 40–69 years, free from cardiovascular diseases (CVD) were prospectively followed for 10.7 years. Participants were categorized into four groups according to the milk intake frequency obtained from a brief-type self-administered diet questionnaire. The adjusted HRs of total stroke, ischemic stroke and haemorrhagic stroke associated with milk intake frequency were calculated using the Cox proportional hazards model. During the follow-up, 478 stroke cases were detected (208 men and 270 women). Compared to women with a milk intake of <2 cups/week, those with an intake of 7 to <12 cups/week had a significantly low risk of ischemic stroke in a model adjusting CVD risk factors; the HR (95% CI) was 0.53 (0.32–0.88). No significant associations were found in men. This study suggested that milk intake of 7 to <12 cups/week decreased the risk of ischemic stroke in Japanese women. Milk intake of about 1 to <2 cups/day may be effective in the primary prevention of ischemic stroke in a population with low milk intake.

Interaction between cognitive leisure activity and long-chain polyunsaturated fatty acid intake on global cognitive decline in a Japanese longitudinal cohort study: National Institute for Longevity Sciences-Longitudinal Study of Aging

Background

There is a growing interest in the significance of adopting a variety of lifestyle habits for maintaining cognitive function among older adults. A lifestyle that is easy to modify, simple, and less burdensome for older people is ideal. We investigated the longitudinal association between global cognitive decline and cognitive leisure activities (CLAs) combined with long-chain polyunsaturated fatty acids (LCPUFAs) intake.

Methods

The National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA) enrolled community-dwelling middle-aged and older men and women who were randomly selected from Obu-City and Higashiura Town, Aichi, Japan. Baseline data (2006–2008), including CLAs and dietary intake, were obtained from 517 participants (aged 60–84 years) with normal cognition. Global cognitive decline, defined as the Mini-Mental State Examination (MMSE) score ≤ 27, was assessed at baseline and four years later. Interaction between CLAs and LCPUFAs on cognitive decline was investigated using a multiple logistic analysis with adjustment for confounders. CLA engagement and LCPUFA intake were divided into high and low groups according to the frequency at which each participant engaged in the activity and the median intake level according to sex, respectively.

Results

A significant interaction was detected for the combination of CLA engagement and LCPUFA intake. Logistic regression coefficients revealed significant interactions when participants engaged in more than five CLA varieties. One of the CLAs, art appreciation, produced a significant main effect against cognitive decline and a significant interaction in combination with LCPUFA intake. The major LCPUFAs—docosahexaenoic acid and arachidonic acid—also exhibited a significant interaction. The combination of high LCPUFA intake and high art appreciation frequency yielded a lower adjusted odds ratio for cognitive decline than the combination of low LCPUFA and low art appreciation [0.25 (95 % confidence intervals, 0.11–0.56)].

Conclusions

Preserving cognitive function might be associated with a combination of varied and high-frequency engagement in CLAs combined with high LCPUFA intake.

Intake of Fish and Marine n-3 Polyunsaturated Fatty Acids and Risk of Cardiovascular Disease Mortality: A Meta-Analysis of Prospective Cohort Studies

Previous epidemiological studies have investigated the association of fish and marine n-3 polyunsaturated fatty acids (n-3 PUFA) consumption with cardiovascular disease (CVD) mortality risk. However, the results were inconsistent. The purpose of this meta-analysis is to quantitatively evaluate the association between marine n-3 PUFA, fish and CVD mortality risk with prospective cohort studies. A systematic search was performed on PubMed, Web of Science, Embase and MEDLINE databases from the establishment of the database to May 2021. A total of 25 cohort studies were included with 2,027,512 participants and 103,734 CVD deaths. The results indicated that the fish consumption was inversely associated with the CVD mortality risk [relevant risk (RR) = 0.91; 95% confidence intervals (CI) 0.85−0.98]. The higher marine n-3 PUFA intake was associated with the reduced risk of CVD mortality (RR = 0.87; 95% CI: 0.85–0.89). Dose-response analysis suggested that the risk of CVD mortality was decreased by 4% with an increase of 20 g of fish intake (RR = 0.96; 95% CI: 0.94–0.99) or 80 milligrams of marine n-3 PUFA intake (RR = 0.96; 95% CI: 0.94–0.98) per day. The current work provides evidence that the intake of fish and marine n-3 PUFA are inversely associated with the risk of CVD mortality.

Composition of Dietary Fatty Acids and Health Risks in Japanese Youths

In the overall composition of dietary fatty acids (FAs), the quantity of each FA is interrelated with that of others. We examined the associations between dietary FA composition and cardiometabolic risk in Japanese youths. Risk factors (anthropometric characteristics, serum lipid and liver enzyme levels, and blood pressure) were measured in 5485 junior-high-school students. Dietary intake was assessed using a food frequency questionnaire. The mean saturated FA (SFA), monounsaturated FA (MUFA), omega-6 polyunsaturated FAs (PUFAs), and omega-3 PUFAs intake were 9.6%E, 10.3%E, 6.3%E, and 1.1%E, respectively. In compositional regression analysis controlled for confounders, a high intake of omega-6 PUFAs relative to others was associated with low low-density-lipoprotein cholesterol levels (LDL-C; p = 0.003), and relative SFA intake was associated with high levels of gamma-glutamyl transpeptidase (p = 0.019). Relative omega-3 PUFAs intake was associated with low blood pressure (p = 0.005–0.034) but had unfavorable effects on adiposity and alanine transaminase. Substitutional models showed similar results for omega-6 PUFAs on LDL-C, but MUFA had inconsistent effects on risk factors. The results from the compositional data analysis were consistent with previous studies and clinical practice/knowledge. Focusing on increasing omega-6 PUFAs in Japanese youths could have favorable consequences in the long term.

The Association of Dietary Choline and Betaine With the Risk of Type 2 Diabetes: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

To examine the association between dietary intake of choline and betaine and the risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

Among 13,440 Atherosclerosis Risk in Communities (ARIC) study participants, the prospective longitudinal association between dietary choline and betaine intake and the risk of type 2 diabetes was assessed using interval-censored Cox proportional hazards and logistic regression models adjusted for baseline potential confounding variables.

RESULTS

Among 13,440 participants (55% women, mean age 54 [SD 7.4] years), 1,396 developed incident type 2 diabetes during median follow-up of 9 years from 1987 to 1998. There was no statistically significant association between every 1-SD increase in dietary choline and risk of type 2 diabetes (hazard ratio [HR] 1.01 [95% CI 0.87, 1.16]) nor between dietary betaine intake and the risk of type 2 diabetes (HR 1.01 [0.94, 1.10]). Those in the highest quartile of dietary choline intake did not have a statistically significant higher risk of type 2 diabetes than those in the lowest choline quartile (HR 1.09 [0.84, 1.42]); similarly, dietary betaine intake was not associated with the risk of type 2 diabetes comparing the highest quartile to the lowest (HR 1.06 [0.87, 1.29]). Among women, there was a higher risk of type 2 diabetes, comparing the highest to lowest dietary choline quartile (HR 1.54 [1.06, 2.25]), while in men, the association was null (HR 0.82 [0.57, 1.17]). Nevertheless, there was a nonsignificant interaction between high choline intake and sex on the risk of type 2 diabetes (P = 0.07). The results from logistic regression were similar.

CONCLUSIONS

Overall and among male participants, dietary choline or betaine intakes were not associated with the risk of type 2 diabetes. Among female participants, there was a trend for a modestly higher risk of type 2 diabetes among those with the highest as compared with the lowest quartile of dietary choline intake. Our study should inform clinical trials on dietary choline and betaine supplementation in relationship with the risk of type 2 diabetes.

Association of Serum Fatty Acids at Admission with the Age of Onset of Intracerebral Hemorrhage

Dietary triglycerides influence the serum concentrations of fatty acids (FA) and their weight percentages (wt%), which might be associated with the age of onset of intracerebral hemorrhage (ICH). We investigated the correlation between serum FA levels and proportions at admission, and the age at onset of ICH. We included patients admitted between 2016 and 2019 within 24 h of the onset of ICH, and calculated the correlation coefficients between their age, serum FA concentration, and FA wt%. We performed multiple linear regression analysis to identify individual FAs related to the age at onset of ICH. Furthermore, we estimated the threshold values of FAs that were independently associated with the age at onset of ICH <65 years, using receiver operating characteristic curves by logistic regression. Our inclusion criteria were met by 141 patients (mean age, 67 years). The concentration of dihomo-gamma-linolenic acid (DGLA) and the wt% of eicosapentaenoic acid (EPA) were significant independent variables for the age at onset of ICH. The ROC curves for the age of onset <65 years were ≥108.6 µmol/L for DGLA and ≤1.7% for EPA. Increased DGLA concentration and decreased EPA wt% were significantly associated with young-onset ICH.

Features of Serum Fatty Acids at Acute Ischemic Stroke Onset in Statin-Treated Patients with Hypercholesterolemia

In addition to diet therapy, statins are used to prevent cardiovascular disease in patients with hypercholesterolemia (HC). However, acute ischemic stroke (AIS) still occurs in statin-treated patients. How strictly statin-treated patients follow diet therapy before they experience AIS and whether they increase seafood consumption remains unknown. We investigated the serum concentrations and proportions (weight percentages: wt %) of fatty acids (FAs) at AIS onset in statin-treated patients (statin group), compared to those in non-treated patients with HC (6.465 mmol/L or higher) as controls (non-treated group). We included patients with AIS admitted between 2016 and 2019 within 24 h of AIS onset who underwent analysis of serum FAs. During the study period, 188 patients met the inclusion criteria: 133 in the statin group and 55 in the non-treated group. Interestingly, serum FA concentrations in the statin group were lower than those in the non-treated group. However, serum FA wt % in the statin group was almost identical to that in the non-treated group. In conclusion, statin-treated AIS patients had low FA concentrations and identical FA wt %, compared to non-treated AIS patients with HC.

Intake of fish and long-chain n-3 polyunsaturated fatty acids and risk of diseases in a Japanese population: a narrative review

Since the 1970s, the potential benefit of fish intake in terms of noncommunicable diseases has been one of the most important themes in disease prevention. Epidemiological studies have revealed the extent to which fish consumption affects the incidence of and mortality from diseases. Meta-analyses summarized the effect of fish and long-chain n-3 polyunsaturated fatty acid intake on noncommunicable diseases, especially cardiovascular diseases in Western countries. However, few reviews have spotlighted the effect of fish intake in East-Asian countries that have high population levels of fish intake such as Japan. We narratively reviewed the epidemiological studies concerned with the associations of fish and long-chain n-3 polyunsaturated fatty acid intake with risk of noncommunicable diseases, mainly of cardiovascular disease, among Japanese, whose fish intake has been twice or more than that of most Westerners. Overall, fish or long-chain n-3 polyunsaturated fatty acid intake may be beneficial for prevention of noncommunicable diseases, especially coronary heart disease and heart failure in Japanese as well as in Westerners. However, the beneficial effects of their intakes seemed to be nonlinear and varied according to disease severity and culture. Studies on other noncommunicable disease were also narratively reviewed.

Association of Serum Fatty Acids at Admission with the Age of Onset of Acute Ischemic Stroke

Dietary triglycerides influence fatty acid (FA) serum concentrations and weight percentages (wt %), which may be associated with the age of onset of acute ischemic stroke (AIS). We investigated the correlations between serum FA levels and proportions at admission and the age of onset of AIS. We evaluated patients with AIS admitted between 2016 and 2019 within 24 h of AIS onset and calculated the correlation coefficients between their ages, serum FA concentrations, and FA wt % values. Multiple linear regression analysis was performed to identify independent FAs indicating AIS age of onset. Furthermore, we estimated the threshold values of independent FAs for age of onset <60 years using receiver operating characteristic curves by logistic regression. A total of 525 patients (median age: 75 years) met the inclusion criteria. The concentration of dihomo-gamma-linolenic acid (DGLA) and wt % of docosahexaenoic acid (DHA) were significant independent variables for age of onset of AIS, and receiver operating characteristic curves for age of onset <60 years showed thresholds of ≥117.7 µmol/L for DGLA and ≤3.7% for DHA. An increased DGLA concentration and decreased DHA wt % were significantly associated with onset of AIS at a younger age.

Features of serum fatty acids in acute ischaemic stroke patients aged 50 years or older

Background

Serum fatty acid (s-FA) compositions and their correlation with serum lipids (s-LPs) such as total cholesterol (T-CHO) and triglycerides (TG) have been reported in healthy young subjects. However, little is known about such features in acute ischaemic stroke (AIS). The aim of our study was to investigate s-FA characteristics and their correlation with AIS in elderly patients.

Methods

We conducted a cross-sectional study of patients aged 50 years or older who were admitted between September 2015 and March 2017 within 24 h of the first AIS onset. We evaluated concentrations and compositions of s-FAs and their association with s-LPs, age, and ischaemic stroke subtypes, including large-artery atherosclerosis (LAA), small-vessel occlusion (SVO), and cardioembolism (CE) or others.

Results

One hundred ninety-one patients met our inclusion criteria. Their average age was 74.4 years, mean T-CHO and median TG were 203.4 and 94.5 mg/dl, respectively, and median or mean concentrations of palmitic acid (PA), oleic acid (OlA), linoleic acid (LiA), and docosahexaenoic acid (DHA) were 680.7, 602.5, 795.2, and 136.9 μg/ml, respectively, with mean compositions of 23.7, 21.3, 27.1, and 4.4%, respectively. PA, OlA, and LiA concentrations were weakly negatively associated with age and positively correlated with TG. In LAA or SVO (LAA_SVO) and CE or others (CE_O), mean age was 71.9 and 77.4 years (p < 0.001), mean T-CHO was 213.9 and 191.2 mg/dl (p < 0.0001), median TG was 106.5 and 88.5 mg/dl (p < 0.01), median PA was 717.2 and 648.4 μg/ml (p < 0.01), median OlA was 638.2 and 567.5 μg/ml (p < 0.01), and median LiA was 844.7 and 728.5 μg/ml (p < 0.01), respectively. DHA composition was weakly positively correlated with age. There were no differences in PA, OlA, LiA, and DHA compositions between LAA_SVO and CE_O.

Conclusions

In AIS elderly patients, concentrations, rather than compositions of PA, OlA, and LiA, correlated with age, TG, and ischaemic stroke subtypes. Patients with LAA_SVO were younger and had higher concentrations of PA, OlA, and LiA than those with CE_O. There were no differences in such compositions between LAA_SVO and CE_O.

Prevention of Cardiovascular Events with Omega-3 Polyunsaturated Fatty Acids and the Mechanism Involved

An epidemiological study of Greenlandic Inuit suggested that fish oil, or omega-3 polyunsaturated fatty acids (PUFA), was important in preventing atherosclerotic disease. After this landmark study, many large-scale epidemiological studies and meta-analyses have examined the health benefits of omega-3 PUFA as part of a fatty acid-rich diet to demonstrate its beneficial roles in the prevention of cardiovascular diseases. Recent research has also focused attention on the anti-inflammatory effects of omega-3 PUFA and on specialized pro-resolving mediators. Findings of these studies have led to the development of omega-3 PUFA preparations for the treatment of dyslipidemia, including a highly purified eicosapentaenoic acid (EPA)-ethyl ester product (Epadel®) in Japan and an EPA/docosahexaenoic acid (DHA) preparation (Lotriga®) in the United States and Europe. Although various large-scale clinical trials on the cardiovascular preventive effect of omega-3 PUFA were conducted and reported, the results were not always consistent. The issues of not targeting subjects with hypertriglyceridemia and using low dose of omega-3 PUFA have been suggested to contribute to the failure of demonstrating the preventive effect of omega-3 PUFA in these clinical trials. Taking into account the above issues, the REDUCE-IT trial evaluated a highly purified EPA preparation at a high dose of 4 g/day in patients with hypertriglyceridemia and high cardiovascular risk, and demonstrated an extraordinary outcome of 25% relative reduction in cardiovascular events. This article reviews studies on omega-3 fatty acids during the last 50 years, including the progress in elucidating molecular mechanisms and recent large-scale clinical studies.

Association of blood levels of marine omega-3 fatty acids with coronary calcification and calcium density in Japanese men

BACKGROUND/OBJECTIVES

Clinical trials of eicosapentaenoic acid (EPA) among high-risk groups in Japan in which consumption of mairne-omega-3 fatty acids (OM3) is much higher than other countries showed slower progression of coronary atherosclerosis. We aimed to determine the cross-sectional associations of coronary artery calcification (CAC) and calcium density with OM3, EPA, and docosahexaenoic acid (DHA), two principal OM3, in the general population in Japan.

SUBJECTS/METHODS

The Shiga Epidemiological Study of Subclinical Atherosclerosis examined a population-based sample of 1074 men aged 40-79 in 2006-08 for computed tomography-measured CAC score (CCS), a well-established biomarker of coronary atherosclerosis, CAC density score (CDS), a potential marker of plaque stabilization, serum levels of OM3, and risk factors.

RESULTS

Prevalence of CCS > 0, ≥ 100, and ≥ 300 was 65.8%, 25.9%, and 12.9%, respectively; the mean (SD) OM3, EPA, and DHA were 10.1% (3.2), 3.2% (1.7), and 5.9% (1.6), respectively. Odds ratios (95% CI, p-value) of CCS 0, 100, and 300 in ordinal logistic regression associated with 1 SD increase of OM3, EPA, and DHA were 0.91 (0.81-1.03, p = 0.12), 0.99 (0.88-1.11, p = 0.87) and 0.84 (0.74-0.94, p = < 0.01), respectively. The inverse association of DHA with CCS remained significant in multivariate-adjusted model: odds ratio of 0.87 (0.77-0.99, p = 0.03). Blood levels of OM3, EPA, or DHA did not have any significant associations with CDS.

CONCLUSIONS

DHA but not EPA had a significant inverse association with coronary atherosclerosis in the general population with high levels of OM3. Future trials are warranted comparing the effect of high-dose DHA and EPA on atherosclerosis and cardiovascular outcomes.

Cardiovascular Risk Assessment Chart by Dietary Factors in Japan - NIPPON DATA80

BACKGROUND

Many studies show that dietary factors such as vegetables, fruit, and salt are associated with cardiovascular disease (CVD) risk. However, a risk assessment chart for CVD mortality according to combinations of dietary factors has not been established.Methods and Results:Participants were 9,115 men and women aged 30-79 years enrolled in the National Nutritional Survey of Japan in 1980 with a 29-year follow-up. Dietary intake was assessed using a 3-day weighed dietary record at baseline. Cox regression models were used to estimate the hazard ratio (HR) of CVD mortality stratified by vegetables, fruit, fish, and salt consumption. HRs of CVD mortality according to combinations of dietary factors were color coded on an assessment chart. Higher intakes of vegetables, fruit, and fish, and lower salt intake were associated with lower CVD mortality risk. HRs calculated from combinations of dietary factors were displayed using 5 colors corresponding to the magnitude of the HR. People with the lowest intake of vegetables, fruit, and fish, and higher salt intake had a HR of 2.87 compared with those with the highest intake of vegetables, fruit, and fish, and lower salt intake.

CONCLUSIONS

Vegetables, fruit, fish, and salt intake were independently associated with CVD mortality risk. The assessment chart generated could be used in Japan as an educational tool for CVD prevention.

Long-term incidence and risk factors of cardiovascular events in Asian populations: systematic review and meta-analysis of population-based cohort studies

BACKGROUND

Scientific studies on cardiovascular disease (CVD) burden and risk factors are predominantly based on short-term risk in Westerner populations, and such information may not be applicable to Asian populations, especially over the longer term. This review aims to estimate the long-term (>10 years) CVD burden, including coronary heart disease (CHD) and stroke, as well as associated risk factors in Asian populations.

METHODS

PubMed, Embase and Web of Science were systematically searched, and hits screened on: Asian adults, free of CVD at baseline; cohort study design (follow-up >10 years). Primary outcomes were fatal and non-fatal CVD events. Pooled estimates and between-study heterogeneity were calculated using random effects models, Q and I² statistics.

RESULTS

Overall, 32 studies were eligible for inclusion (follow-up: 11-29 years). The average long-term rate of fatal CVD is 3.68 per 1000 person-years (95% CI 2.84-4.53), the long-term cumulative risk 6.35% (95% CI 4.69%-8.01%, mean 20.13 years) and the cumulative fatal stroke/CHD risk ratio 1.5:1. Important risk factors for long-term fatal CVD (RR, 95% CI) were male gender (1.49, 1.36-1.64), age over 60/65 years (7.55, 5.59-10.19) and current smoking (1.68, 1.26-2.24). High non-HDL-c, and β- and γ-tocopherol serum were associated only with CHD (HR 2.46 [95% CI 1.29-4.71] and 2.47 [1.10-5.61] respectively), while stage 1 and 2 hypertensions were associated only with fatal stroke (2.02 [1.19-3.44] and 2.89 [1.68-4.96] respectively).

CONCLUSIONS

Over a 10 year + follow-up period Asian subjects had a higher risk of stroke than CHD. Contrary to CVD prevention in Western countries, strategies should also consider stroke instead of CHD only.

Vegetable Protein Intake was Inversely Associated with Cardiovascular Mortality in a 15-Year Follow-Up Study of the General Japanese Population

AIM

To examine the relationship between the intake of dietary vegetable protein and CVD mortality in a 15-year follow-up study of a representative sample of the Japanese population.

METHODS

A total of 7,744 participants aged 30 years or older (3,224 males and 4,520 females) who were free of CVD at baseline were included in this analysis. Vegetable protein intake (% energy) was assessed using a three-day semi-weighed dietary record at baseline. Multivariable-adjusted hazard ratios (HRs) were calculated using Cox's proportional hazards model after adjusting for confounding factors.

RESULTS

The total person-years studied were 107,988 with a mean follow-up period of 13.9 years. There were 1,213 deaths during the follow-up period, among which 354 (29.2%) were due to CVD. Vegetable protein intake was associated inversely with CVD and cerebral hemorrhage mortality, with the HRs for a 1% energy increment in vegetable protein intake being 0.86 (95% CI, 0.75-0.99) and 0.58 (95% CI, 0.35-0.95), respectively. In the subgroup analysis of participants with or without hypertension, the inverse association between vegetable protein intake and CVD mortality was more evident in the nonhypertensive group, with the HRs for CVD and stroke being 0.68 (95% CI, 0.50-0.94) and 0.50 (95% CI, 0.30-0.84), respectively.

CONCLUSIONS

Vegetable protein intake may prevent future CVD, particularly in nonhypertensive subjects in the Japanese population. However, further studies are necessary to examine the biological mechanisms of this effect.

Longitudinal Association between n-3 Long-Chain Polyunsaturated Fatty Acid Intake and Depressive Symptoms: A Population-Based Cohort Study in Japan

It remains unclear whether n-3 long-chain polyunsaturated fatty acids (LCPUFA) have a preventive effect on depression in the general population. This study investigated the longitudinal association between n-3 LCPUFA intake and depressive symptoms in community-dwelling Japanese participants. The participants were aged 40–79 years at baseline in the cohort study, wherein examinations, including the assessment of depressive symptoms and nutritional status, were biennially conducted from 1997 to 2012. The subjects (n = 2335) who had a Center for Epidemiologic Studies Depression Scale (CES-D) score < 16 at the first examination and who participated in the follow-up study at least once were included in the analysis. The follow-up end point was the first onset (CES-D ≥ 16) or the last examination participation. Hazard ratios (95% CIs) for CES-D ≥ 16 were estimated using the adjusted Cox proportional hazards model. Overall, 22.1% participants showed depressive symptoms during follow-up (average; 8.1 years). Compared with the lowest tertile, the highest HR for EPA was 0.74 (0.60–0.93), and highest and middle HRs for DHA were 0.79 (0.63–0.98) and 0.80 (0.65–0.99) (P for trend = 0.009 and 0.032), respectively. Among populations with high fish consumption, higher n-3 LCPUFA intake may be associated with a low risk of depressive symptoms.

Serum Fatty Acid and Risk of Coronary Artery Disease - Circulatory Risk in Communities Study (CIRCS)

BACKGROUND

Few prospective studies have explored the association between fatty acids (FA) and risk of CAD. Understanding of the role of each individual serum FA as a coronary risk or protective factor is still limited. The aim was to investigate which serum FA are associated with the incidence of CAD in Japanese subjects. Methods and Results: A prospective nested case-control study of 40-85-year-old Japanese subjects was undertaken using frozen serum samples collected from 12,840 participants who participated in cardiovascular risk surveys from 1984 to 1998 for 1 community and 1989-1997 for 2 other communities. Three control subjects per case were matched by sex, age, community, year of serum storage and fasting status. By 2005 we had identified 152 incident cases of CAD. Mean n-3-polyunsaturated and saturated FA did not differ between cases and controls, while mean n-6-polyunsaturated FA was higher in controls compared with cases. The multivariable OR of CAD for the highest vs. lowest quartiles of miristic acid (14:0), palmitic acid (16:0), palmitoleic acid (16:1), and linoleic acid (18:2) were 2.8 (95% CI: 1.5-5.2), 2.7 (95% CI: 1.4-5.5), 3.2 (95% CI: 1.7-6.1) and 0.4 (95% CI: 0.2-0.7), respectively.

CONCLUSIONS

High serum miristic acid, palmitic acid and palmitoleic acid have an adverse effect, and high serum linoleic acid had a protective effect, on the risk of CAD.

Plasma levels of n-3 fatty acids and risk of coronary heart disease among Japanese: The Japan Public Health Center-based (JPHC) study

BACKGROUND AND AIMS

Higher intake of fish or n-3 polyunsaturated fatty acids (PUFAs) has been associated with reduced risk of coronary heart disease (CHD). However, it is unclear whether increased blood levels of n-3 PUFAs are associated with reduced risk of CHD in the Japanese population.

METHODS

The relationship between circulating levels of n-3 PUFAs (eicosapentaenoic acid + docosapentaenoic acid + docosahexaenoic acid) and risk of CHD was examined in a nested case-control study among participants in the Japan Public Health Center (JPHC)-based Study Cohort. Plasma n-3 PUFA phospholipid levels were measured at baseline by gas chromatography in 209 cases with CHD and 418 controls matched for sex, age, date of blood draw, time elapsed since last meal before blood collection, and study location. The CHD cases (n = 209) comprised 168 cases of myocardial infarction and 41 of sudden cardiac death, otherwise classified as 157 non-fatal and 52 fatal coronary events, respectively. Mean duration of follow-up was 13.5 years.

RESULTS

Multivariate conditional logistic analysis showed no significant association between n-3 PUFAs and risk of total CHD. The odds ratio (OR) for the highest versus lowest quartiles of plasma n-3 PUFAs was 0.79 (95% confidence interval [95% CI]: 0.41-1.51, p for trend = 0.51). Subtype analysis of CHD revealed that the multivariate ORs for the highest versus lowest quartiles for n-3 PUFAs were 0.91 (95% CI: 0.43-1.89, p for trend = 0.90) for myocardial infarction, 0.08 (95% CI: 0.01-0.88, p for trend = 0.04) for sudden cardiac death, 0.89 (95% CI: 0.42-1.89, p for trend = 0.97) for nonfatal coronary events, and 0.12 (95% CI: 0.02-0.75, p for trend = 0.03) for fatal coronary events.

CONCLUSIONS

Plasma n-3 PUFA levels were not associated with risk of total CHD but were inversely associated with risks of sudden cardiac death and fatal coronary events among middle-aged Japanese individuals.

Omega-3 polyunsaturated fatty acids for cardiovascular diseases: present, past and future

INTRODUCTION

Large-scale epidemiological studies on Greenlandic, Canadian and Alaskan Eskimos have examined the health benefits of omega-3 fatty acids consumed as part of the diet, and found statistically significant relative reduction in cardiovascular risk in people consuming omega-3 fatty acids. Areas covered: This article reviews studies on omega-3 fatty acids during the last 50 years, and identifies issues relevant to future studies on cardiovascular (CV) risk. Expert commentary: Although a meta-analysis of large-scale prospective cohort studies and randomized studies reported that fish and fish oil consumption reduced coronary heart disease-related mortality and sudden cardiac death, omega-3 fatty acids have not yet been shown to be effective in secondary prevention trials on patients with multiple cardiovascular disease (CVD) risk factors. The ongoing long-term CV interventional outcome studies investigate high-dose, prescription-strength omega-3 fatty acids. The results are expected to clarify the potential role of omega-3 fatty acids in reducing CV risk. The anti-inflammatory properties of omega-3 fatty acids are also important. Future clinical trials should also focus on the role of these anti-inflammatory mediators in human arteriosclerotic diseases as well as inflammatory diseases.

A Meta-Analysis of Randomized Controlled Trials and Prospective Cohort Studies of Eicosapentaenoic and Docosahexaenoic Long-Chain Omega-3 Fatty Acids and Coronary Heart Disease Risk

OBJECTIVE

To conduct meta-analyses of randomized controlled trials (RCTs) to estimate the effect of eicosapentaenoic and docosahexaenoic acid (EPA+DHA) on coronary heart disease (CHD), and to conduct meta-analyses of prospective cohort studies to estimate the association between EPA+DHA intake and CHD risk.

METHODS

A systematic literature search of Ovid/Medline, PubMed, Embase, and the Cochrane Library from January 1, 1947, to November 2, 2015, was conducted; 18 RCTs and 16 prospective cohort studies examining EPA+DHA from foods or supplements and CHD, including myocardial infarction, sudden cardiac death, coronary death, and angina, were identified. Random-effects meta-analysis models were used to generate summary relative risk estimates (SRREs) and 95% CIs. Heterogeneity was examined in subgroup and sensitivity analyses and by meta-regression. Dose-response was evaluated in stratified dose or intake analyses. Publication bias assessments were performed.

RESULTS

Among RCTs, there was a nonstatistically significant reduction in CHD risk with EPA+DHA provision (SRRE=0.94; 95% CI, 0.85-1.05). Subgroup analyses of data from RCTs indicated a statistically significant CHD risk reduction with EPA+DHA provision among higher-risk populations, including participants with elevated triglyceride levels (SRRE=0.84; 95% CI, 0.72-0.98) and elevated low-density lipoprotein cholesterol (SRRE=0.86; 95% CI, 0.76-0.98). Meta-analysis of data from prospective cohort studies resulted in a statistically significant SRRE of 0.82 (95% CI, 0.74-0.92) for higher intakes of EPA+DHA and risk of any CHD event.

CONCLUSION

Results indicate that EPA+DHA may be associated with reducing CHD risk, with a greater benefit observed among higher-risk populations in RCTs.

Dietary tofu intake and long-term risk of death from stroke in a general population

BACKGROUND & AIM

Although dietary soy intake is linked with health benefits, a relation with stroke has not been established. The present study examined the association between the intake of tofu, the richest source of dietary soy, with stroke mortality in a general population cohort of Japanese men and women.

METHODS

Data comprise 9244 Japanese enrolled in the National Nutrition Survey of Japan in 1980. Participants were free of cardiovascular disease and followed for 24 years. Dietary intake was estimated from 3-day weighed food records. Multivariable Cox regression models were used to estimate hazard ratios across levels of tofu intake.

RESULTS

During follow-up, there were 417 deaths due to stroke (88 cerebral hemorrhage [CH], 245 cerebral infarction [CI], and 84 of other subtypes). Among all men, and in women aged 65 years or more, tofu intake was unrelated to each form of stroke. For young women (<65 years of age), a significantly lower risk of CH in the top versus bottom quartile of tofu intake was observed (Multivariable-adjusted HR = 0.26, 95% CI: 0.08-0.85).

CONCLUSIONS

In this large prospective study with long follow-up of Japanese men and women, consumption of tofu was unrelated to the risk of stroke except for CH in women <65 years of age. Whether the association in younger women is real or due to chance alone warrants further study.

Isoflavone supplementation in postmenopausal women does not affect leukocyte LDL receptor and scavenger receptor CD36 expression: A double-blind, randomized, placebo-controlled trial

SCOPE

Isoflavones are discussed to improve serum lipoproteins and body composition and to reduce cardiovascular disease risk in postmenopausal women (PMW). LDL receptors (LDLR) and scavenger receptor CD36 (CD36) play a pivotal role in the regulation of plasma LDL-cholesterol concentrations (LDL-chol). We investigated the impact of isoflavones on the receptor expression of both receptors in leukocytes of PMW.

METHODS AND RESULTS

A randomized, double-blind, placebo-controlled trial in parallel design was conducted to assess the effects of an isoflavone-enriched soy extract (117.4 mg/day isoflavone aglycone equivalents) for 12 weeks on serum LDL-chol, LDLR, and CD36 expression on leukocytes in 170 healthy PMW. Baseline and after 12 weeks, blood lipid concentrations, anthropometric data and body composition were determined. Receptor expression on leukocytes was measured by means of flow cytometry. After the intervention, no significant differences were found for LDLR and CD36 expression on leukocytes. A significant increase of serum LDL-chol was shown for the isoflavone group (p = 0.03) after 12 weeks. Body fat content and VAT were not affected.

CONCLUSION

Isoflavone supplementation for 12 weeks did not change LDLR and CD36 expression on leukocytes of PMW and did not affect body fat content and visceral adipose tissue (VAT), but slightly increased serum LDL-chol.

N-3 long-chain polyunsaturated fatty acids and risk of all-cause mortality among general populations: a meta-analysis

Prospective observational studies have shown inconsistent associations of dietary or circulating n-3 long-chain polyunsaturated fatty acids (LCPUFA) with risk of all-cause mortality. A meta-analysis was performed to evaluate the associations. Potentially eligible studies were identified by searching PubMed and EMBASE databases. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random-effects model. Eleven prospective studies involving 371 965 participants from general populations and 31 185 death events were included. The summary RR of all-cause mortality for high-versus-low n-3 LCPUFA intake was 0.91 (95% CI: 0.84–0.98). The summary RR for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake was 0.83 (95% CI: 0.75–0.92) and 0.81 (95% CI: 0.74–0.95), respectively. In the dose-response analysis, each 0.3 g/d increment in n-3 LCPUFA intake was associated with 6% lower risk of all-cause mortality (RR = 0.94, 95% CI: 0.89–0.99); and each 1% increment in the proportions of circulating EPA and DHA in total fatty acids in blood was associated with 20% (RR = 0.80, 95% CI: 0.65–0.98) and 21% (RR = 0.79, 95% CI: 0.63–0.99) decreased risk of all-cause mortality, respectively. Moderate to high heterogeneity was observed across our anlayses. Our findings suggest that both dietary and circulating LCPUFA are inversely associated with all-cause mortality.

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.

Cross-sectional association between serum concentrations of n-3 long-chain PUFA and depressive symptoms: results in Japanese community dwellers

The effect of n-3 long-chain PUFA (n-3 LCPUFA) on depression in healthy subjects is unclear, and most of the previous studies have focused on populations eating Western diets with lower fish intake. The present study investigated the association between blood levels of n-3 LCPUFA and depressive symptoms in Japanese community dwellers with higher n-3 LCPUFA blood levels. A cross-sectional study was conducted from 2006 to 2008, including 1050 men and 1073 women aged 40 years or older from the National Institute for Longevity Sciences – the Longitudinal Study of Aging. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depressive symptoms. Multiple logistic regression analysis was performed to estimate the OR and 95 % CI for a CES-D score ≥16. Serum concentrations of n-3 PUFA, but not n-6 PUFA, were inversely associated with depressive symptoms. Compared with the lowest quintile, the adjusted OR for serum EPA at the fourth and fifth quintiles were 0·55 (95 % CI 0·35, 0·85) and 0·64 (95 % CI 0·42, 0·98), respectively, and at the fifth quintile for DHA it was 0·58 (95 % CI 0·37, 0·92), for the presence of depressive symptoms (P_{for trend}=0·013 and 0·011, respectively). Serum levels of EPA and DHA were inversely associated with depressive symptoms in Japanese community dwellers with higher blood levels of n-3 LCPUFA, suggesting that n-3 LCPUFA intakes corresponding to higher levels in a Japanese population may have implications for a lower prevalence of depression.

Multiple differences between patients who initiate fish oil supplementation post-myocardial infarction and those who do not: the TRIUMPH Study

The utility of fish oil supplements (FOS) in patients who survive an acute myocardial infarction (MI) remains controversial, with randomized trials showing less benefit than observational studies would suggest. The differences in the characteristics of MI patients who use FOS in routine clinical care are unknown but may help explain this discrepancy. We used data from a 24-site registry study in which extensive information was available on 4340 MI patients at admission and 1, 6, and 12 months postdischarge. After excluding those using FOS at admission (n = 651), those who died before the 1-month follow-up visit (n = 63), and those with missing data at 1 month (n = 1228), 2398 remained. Of them, 377 (16%) started FOS within 1 month of their MI. We analyzed 53 patient characteristics associated with FOS use. We observed differences (P < .001) in 20 demographic, socioeconomic, treatment, disease severity, and health status domains. The FOS users were more likely than nonusers to be white, married, financially secure, highly educated, and eating fish. They also had a higher ejection fraction at discharge, were more likely to have had in-hospital percutaneous coronary interventions, and were more likely to have participated in cardiac rehabilitation programs. The FOS users were less likely to have a history of diabetes, alcohol abuse, stroke, MI, and angina. In conclusion, post-MI patients who initiate FOS within 1 month of discharge in routine clinical practice differ substantially from those who do not. These differences are strongly associated with a better post-MI prognosis and may illuminate several sources of unmeasured confounding in observational studies.

Recent findings of long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFAs) on atherosclerosis and coronary heart disease (CHD) contrasting studies in Western countries to Japan

Recent long-term randomized clinical trials (RCTs) of long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFAs) on coronary heart disease (CHD) among high-risk patients conducted in Western countries all failed to show their clinical benefits. In striking contrast, an RCT of LCn-3 PUFAs on CHD conducted in Japan, which is a combination of secondary and primary prevention, showed a significant 19% reduction. Potential reasons for this discrepancy are large differences in doses of LCn-3 PUFAs administered (300-900 mg/day in Western countries vs. 1800 mg/day in Japan) and background dietary intake of LCn-3 PUFAs (<300 mg/day in Western countries vs. >1000 mg/day in Japan). These observations suggest that higher doses of LCn-3 PUFAs than examined in RCTs in Western countries may be cardio-protective. Atherosclerosis is the major underlying cause of CHD. Recent observational studies and an RCT of LCn-3 PUFAs on atherosclerosis in Japan show that LCn-3 PUFAs are anti-atherogenic. In this brief review, we focus on recent epidemiological and clinical findings of LCn-3 PUFAs on atherosclerosis and CHD, contrasting studies in Western countries to those in Japan. We also discuss mechanisms of high-dose LCn-3 PUFAs on atherosclerosis.

BMI Affects the Relationship between Long Chain N-3 Polyunsaturated Fatty Acid Intake and Stroke Risk: a Meta-Analysis

We performed a meta-analysis to clarify the relationship between long chain n-3 polyunsaturated fatty acid (PUFA) intake and stroke risk. Relevant studies were identified by searching online databases through May 2015. Log relative risks (RRs) of the highest versus the lowest for cohort studies were weighed by the inverse variance method to obtain pooled RRs. Fourteen prospective cohort studies including 514,483 individuals and 9,065 strokes were included. The pooled RR of overall stroke risk for long chain n-3 PUFA intake was 0.87 [95% confidence interval (CI), 0.79–0.95]. Stratification analysis showed that higher long chain n-3 PUFAs intake was associated with reduced fatal stroke risk (RR = 0.84; 95% CI, 0.73–0.97), reduced stroke risk for BMI < 24 (RR = 0.86; 95% CI, 0.75–0.98) and reduced stroke risk for females (RR = 0.81; 95% CI, 0.71–0.92), but was not associated with stroke risk for either BMI ≥ 24 or men. This meta-analysis reveals that higher long chain n-3 PUFA intake is inversely associated with risk of stroke morbidity and mortality with BMI and sex as key factors influencing this risk. Individuals should be encouraged to manage their body weight while increasing their intake of long chain n-3 PUFAs.

Effects of n-3 polyunsaturated fatty acids (ω-3) supplementation on some cardiovascular risk factors with a ketogenic Mediterranean diet

Background: the ketogenic diet (KD) has become a widely used nutritional approach for weight loss. Some of the KD’s positive effects on metabolism and cardiovascular risk factors are similar to those seen after n-3 polyunsaturated fatty acids (ω-3) supplementation. We hypothesized that a ketogenic Mediterranean diet with phytoextracts combined with ω-3 supplementation may have increased positive effects on cardiovascular risk factors and inflammation. Methods: We analyzed 34 male overweight subjects; aged between 25 and 65 years who were overall healthy apart from overweight. The subjects followed a ketogenic diet protocol for four weeks; with (KDO3) or without (KD) ω-3 supplementation. Results: All subjects experienced a significant loss of body weight and body fat and there was no significant differences between treatment (body weight: KD—4.7 kg, KDO3—4.03 kg, body fat KD—5.41 kg, KDO3—5.86 kg). There were also significant decreases in total cholesterol, LDL-c, and glucose levels. Triglycerides and insulin levels decreased more in KDO3 vs. KD subjects, with a significant difference. All the investigated inflammatory cytokines (IL-1β, IL-6, TNF-α) decreased significantly in KDO3 subjects whilst only TNF-α showed a significant decrease in KD subjects over the 12 month study period. No significant changes were observed in anti-inflammatory cytokines (IL-10 and IL-1Ra), creatinine, urea and uric acid. Adiponectin increased significantly only in the KDO3 group. Conclusions: ω-3 supplementation improved the positive effects of a ketogenic Mediterranean diet with phytoextracts on some cardiovascular/metabolic risk factors and inflammatory state.

Purine receptors are required for DHA-mediated neuroprotection against oxygen and glucose deprivation in hippocampal slices

Docosahexaenoic acid (DHA) is important for central nervous system function during pathological states such as ischemia. DHA reduces neuronal injury in experimental brain ischemia; however, the underlying mechanisms are not well understood. In the present study, we investigated the effects of DHA on acute hippocampal slices subjected to experimental ischemia by transient oxygen and glucose deprivation (OGD) and re-oxygenation and the possible involvement of purinergic receptors as the mechanism underlying DHA-mediated neuroprotection. We observed that cellular viability reduction induced by experimental ischemia as well as cell damage and thiobarbituric acid reactive substances (TBARS) production induced by glutamate (10 mM) were prevented by hippocampal slices pretreated with DHA (5 μM). However, glutamate uptake reduction induced by OGD and re-oxygenation was not prevented by DHA. The beneficial effect of DHA against cellular viability reduction induced by OGD and re-oxygenation was blocked with PPADS (3 μM), a nonselective P2X1-5 receptor antagonist as well as with a combination of TNP-APT (100 nM) plus brilliant blue (100 nM), which blocked P2X1, P2X3, P2X2/3, and P2X7 receptors, respectively. Moreover, adenosine receptors blockade with A1 receptor antagonist DPCPX (100 nM) or with A2B receptor antagonist alloxazine (100 nM) inhibited DHA-mediated neuroprotection. The addition of an A2A receptor antagonist ZM241385 (50 nM), or A3 receptor antagonist VUF5574 (1 μM) was ineffective. Taken together, our results indicated that neuroprotective actions of DHA may depend on P2X, A1, and A2B purinergic receptors activation. Our results reinforce the notion that dietary DHA may act as a local purinergic modulator in order to prevent neurodegenerative diseases.