A longitudinal study of the association of the eicosapentaenoic acid/arachidonic acid ratio derived from fish consumption with the serum lipid levels: a pilot study

The Effects of Omega 3 and Omega 6 Fatty Acids on Glucose Metabolism: An Updated Review

Massive changes have occurred in our diet. A growing consumption of vegetal oils rich in omega-6 (ω-6) and a depletion of omega-3 (ω-3) fatty acids (FAs) in our food has led to an imbalance between ω-3 and ω-6. In particular, eicosapentaenoic (EPA)/arachidonic acid (AA) ratio seems to be an indicator of this derangement, whose reduction is associated to the development of metabolic diseases, such as diabetes mellitus. Our aim was therefore to investigate the literature on the effects of ω-3 and ω-6 FAs on glucose metabolism. We discussed emerging evidence from pre-clinical studies and from clinical trials. Notably, conflicting results emerged. Source of ω-3, sample size, ethnicity, study duration and food cooking method may be responsible for the lack of univocal results. High EPA/AA ratio seems to be a promising indicator of better glycemic control and reduced inflammation. On the other hand, linoleic acid (LA) appears to be also associated to a minor incidence of type 2 diabetes mellitus, although it is still not clear if the outcome is related to a reduced production of AA or to its intrinsic effect. More data derived from multicenter, prospective randomized clinical trials are needed.

Effects of Arachidonic Acid Metabolites on Cardiovascular Health and Disease

Arachidonic acid (AA) is an essential fatty acid that is released by phospholipids in cell membranes and metabolized by cyclooxygenase (COX), cytochrome P450 (CYP) enzymes, and lipid oxygenase (LOX) pathways to regulate complex cardiovascular function under physiological and pathological conditions. Various AA metabolites include prostaglandins, prostacyclin, thromboxanes, hydroxyeicosatetraenoic acids, leukotrienes, lipoxins, and epoxyeicosatrienoic acids. The AA metabolites play important and differential roles in the modulation of vascular tone, and cardiovascular complications including atherosclerosis, hypertension, and myocardial infarction upon actions to different receptors and vascular beds. This article reviews the roles of AA metabolism in cardiovascular health and disease as well as their potential therapeutic implication.

Gender differences in the associations among fish intake, lifestyle, and non-HDL-C level in Japanese subjects over the age of 50 years: Anti-atherosclerotic effect of fish consumption

BACKGROUND AND AIMS

Higher fish consumption may lead to the suppression of atherogenesis. The present study was aimed at investigating the gender differences in association with the frequency of fish intake, lifestyle behaviors and serum non-high-density lipoprotein cholesterol (non-HDL-C) levels.

METHODS AND RESULTS

This cross-sectional study was conducted in a cohort of 4320 (2479 males, 1570 females) healthy Japanese subjects over 50 years of age registered at the Health Planning Center of Nihon University Hospital between April 2018 and March 2019. The average weekly frequency of fish intake was 2.58 ± 1.39 days in males and 2.42 ± 1.36 days in females. In males, the serum non-HDL-C level decreased significantly as the weekly frequency of fish intake (0-1 days, 2-3 days, 4-5 days, or 6-7 days) increased (p < 0.0001). Multiple stepwise regression analysis identified the weekly frequency of fish intake (β = -0.056, p = 0.004) and habitual aerobic exercise (β = -0.063, p = 0.001) as independent determinants of the serum non-HDL-C level. On the other hand, no such associations were observed in females. However, the proportion of subjects engaging in habitual aerobic exercise increased as the frequency of fish intake increased even among females.

CONCLUSIONS

A higher frequency of fish intake may be associated with healthier lifestyle behaviors and lower non-HDL-C levels in males, but not in females. There appear to be gender differences in the relationships between the intake of fish and lifestyle behaviors on lipid metabolism.

CLINICAL TRIAL REGISTRATION

umin (http://www.umin.ac.jp/) Study ID: UMIN000035899.

Association among daily fish intake, white blood cell count, and healthy lifestyle behaviors in an apparently healthy Japanese population: implication for the anti-atherosclerotic effect of fish consumption

Higher fish consumption has been reported to be associated with a lower incidence of coronary artery disease. We hypothesized that a higher frequency of fish intake may be associated with lower peripheral white blood cell (WBC) counts, a marker of chronic inflammation, which is known to be involved in the development of atherosclerotic cardiovascular disease (ASCVD), and a healthy lifestyle. This cross-sectional study was conducted between April 2018 and August 2018 at the Health Planning Center of Nihon University Hospital in a cohort of 4105 apparently healthy subjects. The average frequency of fish intake was 2.3 ± 1.3 days per week. The WBC count decreased significantly as the frequency of fish intake (0-2 days, 3-4 days, or 5-7 days per week) increased (s < 0.0001). Multivariate linear regression analysis identified higher weekly frequency of fish intake as a significant independent determinant of a lower WBC count (β =  - 0.051, p = 0.001). Furthermore, as the weekly frequency of fish intake increased, the proportion of habitual cigarette smokers decreased (p = 0.021), that of subjects engaging in habitual aerobic exercises increased (p < 0.0001), and the weekly alcohol intake frequency increased (p < 0.0001). Moreover, the above-mentioned lifestyle behaviors were also independent determinants of the WBC count. These results suggest that a high frequency of fish intake might be associated with healthier lifestyle behaviors as well as lower WBC counts, and thus may both exert beneficial anti-inflammatory effects and represent a component of healthier lifestyle behaviors associated with a lower risk of ASCVD in Japanese. This association may be partially related to the preventive effects of a higher fish intake on ASCVD events. CLINICAL TRIAL REGISTRATION: UMIN ( http://www.umin.ac.jp/ ) Study ID: UMIN000039197 retrospectively registered 1 February 2020.

Association of daily fish intake with serum non-high-density lipoprotein cholesterol levels and healthy lifestyle behaviours in apparently healthy males over the age of 50 years in Japanese: Implication for the anti-atherosclerotic effect of fish consumption

BACKGROUND AND AIM

Higher fish consumption has been reported to be associated with a lower incidence of coronary artery disease (CAD). We hypothesized that higher fish intake may be associated with lower serum level of non-high-density lipoprotein cholesterol (non-HDL-C) levels, representing the entire dyslipidemia spectrum, and a healthy lifestyle.

METHODS AND RESULTS

This cross-sectional study was conducted in a population of 1270 apparently healthy males over the age of 50 years without lipid-modifying therapy at the Health Planning Center of Nihon University Hospital between April and August 2018. The average number of days of fish intake per week was 2.6 ± 1.4. We performed analysis of variance using fish consumption as a categorical variable (0-1 day, 2-3 days, 4-5 days, or 6-7 days per week). The serum non-HDL-C levels in the 6-7 days fish intake group were significantly lower than those in the 0-1 and 2-3days fish intake groups. Furthermore, with increasing frequency of fish intake per week, the proportion of subjects with cigarette smoking decreased (p = 0.026), that of subjects engaging in habitual aerobic exercises increased (p = 0.034), and the sleep duration of the subjects increased (p < 0.0001).

CONCLUSIONS

These results suggest that a high frequency of fish intake, that is a fish intake of 6-7 days per week, was associated with healthier lifestyle behaviours as well as lower non-HDL-C levels, and thus may represent a component of a healthy lifestyle associated with a lower risk of CAD in Japanese males over the age of 50.

CLINICAL TRIAL REGISTRATION

UMIN (http://www.umin.ac.jp/).

STUDY ID

UMIN000035899.

Administration of eicosapentaenoic acid may alter high-density lipoprotein heterogeneity in statin-treated patients with stable coronary artery disease: A 6-month randomized trial

BACKGROUND

Combined statin plus eicosapentaenoic acid (EPA) therapy might be a potentially effective treatment option to prevent coronary artery disease (CAD). The serum EPA/arachidonic acid (AA) ratio has been identified as a potential new risk marker for CAD. Few data exist whether administration of EPA could affect high-density lipoprotein (HDL) particle size. We hypothesized that the addition of EPA to ongoing statin therapy may result in altered HDL heterogeneity.

METHODS

We conducted this 6-month, single-center, prospective, randomized open-label clinical trial to investigate the effect of the additional administration of EPA on the HDL heterogeneity (HDL₂, HDL_3, and HDL₂/HDL₃ ratio) in stable CAD patients receiving treatment with statins. We assigned stable CAD patients already receiving statin therapy to the EPA group (1800mg/day: n=50) or the control group (n=50).

RESULTS

A significant decrease in the serum HDL₃ level (-4.7% vs. -0.5%, p=0.037), but not of the serum HDL₂ level, and a significant increase in the HDL₂/HDL₃ ratio (5.5% vs. -5.1%, p=0.032) were observed in the EPA group as compared to the control group. Multiple regression analysis with adjustments for coronary risk factors identified the achieved EPA/ AA ratio as an independent and significant predictor of an increase of the HDL₂/HDL₃ ratio (β=0.295, p=0.001). Furthermore, the change in the serum cholesterol ester transfer protein mass was positively correlated with the change in the EPA/AA ratio in the EPA group (r=0.286, p=0.044), but not in the control group (r=0.121, p=0.401).

CONCLUSION

Administration of EPA might decrease the serum HDL₃ level, resulting in an increase in the HDL₂/HDL₃ ratio. Furthermore, increased EPA/AA ratio by the addition of EPA to ongoing statin therapy might be an indicator of an increase in the HDL₂/HDL₃ ratio, thereby regulating HDL particle size.

CLINICAL TRIAL REGISTRATION

UMIN (http://www.umin.ac.jp/) Study ID: UMIN000010452.

Omega 3 rich diet modulates energy metabolism via GPR120-Nrf2 crosstalk in a novel antioxidant mouse model

With obesity rates reaching epidemic proportions, more studies concentrated on reducing the risk and treating this epidemic are vital. Redox stress is an important metabolic regulator involved in the pathophysiology of cardiovascular disease, Type 2 diabetes, and obesity. Oxygen and nitrogen-derived free radicals alter glucose and lipid homeostasis in key metabolic tissues, leading to increases in risk of developing metabolic syndrome. Oxidants derived from dietary fat differ in their metabolic regulation, with numerous studies showing benefits from a high omega 3 rich diet compared to the frequently consumed "western diet" rich in saturated fat. Omega 3 (OM3) fatty acids improve lipid profile, lower inflammation, and ameliorate insulin resistance, possibly through maintaining redox homeostasis. This study is based on the hypothesis that altering endogenous antioxidant production and/or increasing OM3 rich diet consumption will improve energy metabolism and maintain insulin sensitivity. We tested the comparative metabolic effects of a diet rich in saturated fat (HFD) and an omega 3-enriched diet (OM3) in the newly developed 'stress-less' mice model that overexpresses the endogenous antioxidant catalase. Eight weeks of dietary intervention showed that mice overexpressing endogenous catalase compared to their wild-type controls when fed an OM3 enriched diet, in contrast to HFD, activated GPR120-Nrf2 cross-talk to maintain balanced energy metabolism, normal circadian rhythm, and insulin sensitivity. These findings suggest that redox regulation of GPR120/FFAR4 might be an important target in reducing risk of metabolic syndrome and associated diseases.