Controversies in the Use of Omega-3 Fatty Acids to Prevent Atherosclerosis

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

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

Effects of omega-3, omega-6, and total dietary polyunsaturated fatty acid supplementation in patients with atherosclerotic cardiovascular disease: a systematic review and meta-analysis

Background: Uncertainty exists about the link between omega-3 fatty acid, omega-6 fatty acid, and total polyunsaturated fatty acid (PUFA) intake and mortality in atherosclerotic cardiovascular disease (ASCVD) patients, and no meta-analyses summarize the relationship between these various types of PUFAs and ASCVD. Methods: Web of Science, PubMed, EBSCO and Cochrane Library up to November 30, 2022 were searched for prospective randomized controlled studies investigating the relationships among omega-3, omega-6, and PUFA intake and mortality and cardiovascular events in ASCVD patients. This study has been registered at PROSPERO (No. CRD42023407566). Results: This meta-analysis included 21 publications from 17 studies involving 40 861 participants published between 1965 and 2022. In ASCVD patients, omega-3 may lower all-cause mortality (RR: 0.90, 95% CI [0.83, 0.98], I2 = 8%), CVD mortality (RR: 0.82, 95% CI [0.73, 0.91], I2 = 34%) and CVD events (RR: 0.90, 95% CI [0.86, 0.93], I2 = 79%). Subgroup analyses showed that EPA or EPA ethyl ester supplementation reduced CVD events, while the mixture of EPA and DHA had no significant impact. Long-chain omega-3 consumption of 1.0-4.0 g per d reduced death risk by 3.5% for each 1 g per d increase. Omega-6 and PUFA had no significant effect on mortality or CVD events, with low-quality evidence and significant heterogeneity. Conclusions: omega-3 intake is associated with a reduced risk of all-cause mortality, CVD mortality, and CVD events in ASCVD patients, while omega-6 or total PUFA intake showed no significant association. Increasing the omega-3 intake by 1 g per d resulted in a 3.5% decrease in the risk of death. These findings support the recommendation of supplements with omega-3 fatty acids for the secondary prevention of ASCVD.

The relationship of fatty acids to ischaemic heart disease and lifespan in men and women using Mendelian randomization

BACKGROUND

Observationally, polyunsaturated fatty acids (PUFAs) have health benefits compared with saturated fatty acids (SFAs); randomized controlled trials suggest fewer benefits. We used uni- and multi-variable Mendelian randomization to assess the association of major fatty acids and their sub-species with ischaemic heart disease (IHD) overall and sex-specifically and with lifespan sex-specifically, given differing lifespan by sex.

METHODS

We obtained strong (P <5x10-8), independent (r2<0.001) genetic predictors of fatty acids from genome-wide association studies (GWAS) in a random subset of 114 999 UK Biobank participants. We applied these genetic predictors to the Cardiogram IHD GWAS (cases = 60 801, controls = 123 504) and to the Finngen consortium GWAS (cases = 31 640, controls = 187 152) for replication and to the UK Biobank for sex-specific IHD and for lifespan based on parental attained age (fathers = 415 311, mothers = 412 937). We used sensitivity analysis and assessed sex differences where applicable.

RESULTS

PUFAs were associated with IHD [odds ratio 1.23, 95% confidence interval (CI) 1.05 to 1.44] and lifespan in men (-0.76 years, 95% CI -1.34 to -0.17) but not women (0.20, 95% CI -0.32 to 0.70). Findings were similar for omega-6 fatty acids and linoleic acid. Independent associations of SFAs, mono-unsaturated fatty acids or omega-3 fatty acids with IHD overall or lifespan in men and women were limited.

CONCLUSIONS

PUFAs, via specific subspecies, may contribute to disparities in lifespan by sex. Sex-specific dietary advice might be a start towards personalized public health and addressing inequities.

Nutrition interventions for adults with dyslipidemia: A Clinical Perspective from the National Lipid Association

Lifestyle habits can have a profound impact on atherosclerotic cardiovascular disease (ASCVD) risk. The National Lipid Association previously published recommendations for lifestyle therapies to manage dyslipidemia. This Clinical Perspective provides an update with a focus on nutrition interventions for the three most common dyslipidemias in adults: 1) low-density lipoprotein cholesterol (LDL-C) elevation; 2) triglyceride (TG) elevation, including severe hypertriglyceridemia with chylomicronemia; and 3) combined dyslipidemia, with elevations in both LDL-C and TG levels. Lowering LDL-C and non-high-density lipoprotein cholesterol are the primary objectives for reducing ASCVD risk. With severe TG elevation (≥500 mg/dL), the primary objective is to prevent pancreatitis and ASCVD risk reduction is secondary. Nutrition interventions that lower LDL-C levels include reducing cholesterol-raising fatty acids and dietary cholesterol, as well as increasing intakes of unsaturated fatty acids, plant proteins, viscous fibers, and reducing adiposity for patients with overweight or obesity. Selected dietary supplements may be employed as dietary adjuncts. Nutrition interventions for all patients with elevated TG levels include restricting intakes of alcohol, added sugars, and refined starches. Additional lifestyle factors that reduce TG levels are participating in daily physical activity and reducing adiposity in patients with overweight or obesity. For patients with severe hypertriglyceridemia, an individualized approach is essential. Nutrition interventions for addressing concurrent elevations in LDL-C and TG include a combination of the strategies described for lowering LDL-C and TG. A multidisciplinary approach is recommended to facilitate success in making and sustaining dietary changes and the assistance of a registered dietitian nutritionist is highly recommended.

Omega-3 fatty acids and individual variability in plasma triglyceride response: A mini-review

Cardiovascular disease (CVD) is a leading cause of death worldwide. Supplementation with the marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with lower CVD risk. However, results from randomized controlled trials that examine the effect of omega-3 supplementation on CVD risk are inconsistent. This risk-reducing effect may be mediated by reducing inflammation, oxidative stress and serum triglyceride (TG) levels. However, not all individuals respond by reducing TG levels after omega-3 supplementation. This inter-individual variability in TG response to omega-3 supplementation is not fully understood. Hence, we aim to review the evidence for how interactions between omega-3 fatty acid supplementation and genetic variants, epigenetic and gene expression profiling, gut microbiota and habitual intake of omega-3 fatty acids can explain why the TG response differs between individuals. This may contribute to understanding the current controversies and play a role in defining future personalized guidelines to prevent CVD.

Microalgae as a Nutraceutical Tool to Antagonize the Impairment of Redox Status Induced by SNPs: Implications on Insulin Resistance

Microalgae represent a growing innovative source of nutraceuticals such as carotenoids and phenolic compound which are naturally present within these single-celled organisms or can be induced in response to specific growth conditions. The presence of the unfavourable allelic variant in genes involved in the control of oxidative stress, due to one or more SNPs in gene encoding protein involved in the regulation of redox balance, can lead to pathological conditions such as insulin resistance, which, in turn, is directly involved in the pathogenesis of type 2 diabetes mellitus. In this review we provide an overview of the main SNPs in antioxidant genes involved in the promotion of insulin resistance with a focus on the potential role of microalgae-derived antioxidant molecules as novel nutritional tools to mitigate oxidative stress and improve insulin sensitivity.

Inhibition of atherosclerosis progression by modular micelles

Atherosclerosis is a chronic disease initiated by lipid-mediated vascular inflammation. From the perspective of conventional treatment, it is difficult to achieve good therapeutic effects via regulation of a single lipid or anti-inflammatory effects. Herein, we designed an amphiphilic low molecular weight heparin-unsaturated fatty acid conjugate (LMWH-uFA) that acted as both an antiatherosclerotic agent and a nanocarrier with self-delivery properties. Structurally, LMWH-uFA self-assembled to form micelles with LMWH as the shell and uFA as the core, without any additives, which guaranteed their biosafety. Functionally, the hydrophilic segment, LMWH, prevented monocyte adhesion to inhibit early vascular inflammation, and the hydrophobic segment, uFA, could participate in the regulation of blood lipids. The anti-inflammatory drug rapamycin (RAP) was encapsulated in the micellar core, which improved its water solubility, and cooperated with LMWH to achieve targeted blockade of the vascular inflammation cascade at P-selectin. The three treatment modules, LMWH, uFA and RAP, were integrated into one system for different therapeutic targets in anticipation of better efficacy. In an atherosclerosis mouse model, RAP-loaded NPs significantly reduced the plaque area and showed satisfactory curative effects, which were related to the targeting of lipid regulation and inflammation. Thus, these modular micellar nanoparticles offer a promising approach for the clinical treatment of atherosclerosis.

Update on Omega-3 Polyunsaturated Fatty Acids on Cardiovascular Health

Twenty percent of deaths in the United States are secondary to cardiovascular diseases (CVD). In patients with hyperlipidemia and hypertriglyceridemia, studies have shown high atherosclerotic CVD (ASCVD) event rates despite the use of statins. Given the association of high triglyceride (TG) levels with elevated cholesterol and low levels of high-density lipoprotein cholesterol, the American Heart Association (AHA)/American College of Cardiology (ACC) cholesterol guidelines recommend using elevated TGs as a "risk-enhancing factor" for ASCVD and using omega 3 fatty acids (Ω3FAs) for patients with persistently elevated severe hypertriglyceridemia. Ω3FA, or fish oils (FOs), have been shown to reduce very high TG levels, hospitalizations, and CVD mortality in randomized controlled trials (RCTs). We have published the largest meta-analysis to date demonstrating significant effects on several CVD outcomes, especially fatal myocardial infarctions (MIs) and total MIs. Despite the most intensive research on Ω3FAs on CVD, their benefits have been demonstrated to cluster across multiple systems and pathologies, including autoimmune diseases, infectious diseases, chronic kidney disease, central nervous system diseases, and, most recently, the COVID-19 pandemic. A review and summary of the controversies surrounding Ω3FAs, some of the latest evidence-based findings, and the current and most updated recommendations on Ω3FAs are presented in this paper.