Editorial: Omega-3 fatty acids: new studies, new data, new questions

Alternative sources of bioactive omega-3 fatty acids: what are the options?

PURPOSE OF REVIEW

The very-long chain (VLC) omega-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) promote optimal development, physiological function and healthy ageing and help to manage disease. EPA and DHA are sourced mainly from fish, which is not sustainable. This review explores alternative sustainable sources.

RECENT FINDINGS

Recent research confirms that higher intake and status of EPA and DHA are associated with health benefits including lower risk of incident type-2 diabetes and cardiovascular disease mortality. Meta-analyses confirm benefits of intravenous EPA and DHA in hospitalized adults. Algal oils and seed oils from some genetically modified (GM) plants are sources of EPA and DHA. An oil from GM camelina showed equivalence with fish oil in human trials. Ahiflower oil, a source of stearidonic acid, had biological effects in experimental studies that might translate into health benefits. An intravenous lipid emulsion based on Ahiflower oil has been tested in experimental research. Pine nut oil (PNO) is a source of pinolenic acid, which is not an omega-3 PUFA but has similar actions.

SUMMARY

Algal oils, oils from GM seed crops, Ahiflower oil and other sources of stearidonic acid, and nonomega-3 oils including PNO, are plant-sourced sustainable alternatives to fish-sourced VLC omega-3 PUFAs.

Pros and Cons of Long-Chain Omega-3 Polyunsaturated Fatty Acids in Cardiovascular Health

The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found in seafood, supplements, and concentrated pharmaceutical preparations. Prospective cohort studies demonstrate an association between higher intakes of EPA+DHA or higher levels of EPA and DHA in the body and lower risk of developing cardiovascular disease (CVD), especially coronary heart disease and myocardial infarction, and of cardiovascular mortality in the general population. The cardioprotective effect of EPA and DHA is due to the beneficial modulation of a number of risk factors for CVD. Some large trials support the use of EPA+DHA (or EPA alone) in high-risk patients, although the evidence is inconsistent. This review presents key studies of EPA and DHA in the primary and secondary prevention of CVD, briefly describes potential mechanisms of action, and discusses recently published RCTs and meta-analyses. Potential adverse aspects of long-chain omega-3 fatty acids in relation to CVD are discussed.

We are what we eat: The role of lipids in metabolic diseases

Lipids play a fundamental role, both structurally and functionally, for the correct functioning of the organism. In the last two decades, they have evolved from molecules involved only in energy storage to compounds that play an important role as components of cell membranes and signaling molecules that regulate cell homeostasis. For this reason, their interest as compounds involved in human health has been gaining weight. Indeed, lipids derived from dietary sources and endogenous biosynthesis are relevant for the pathophysiology of numerous diseases. There exist pathological conditions that are characterized by alterations in lipid metabolism. This is particularly true for metabolic diseases, such as liver steatosis, type 2 diabetes, cancer and cardiovascular diseases. The main issue to be considered is lipid homeostasis. A precise control of fat homeostasis is required for a correct regulation of metabolic pathways and safe and efficient energy storage in adipocytes. When this fails, a deregulation occurs in the maintenance of systemic metabolism. This happens because an increased concentrations of lipids impair cellular homeostasis and disrupt tissue function, giving rise to lipotoxicity. Fat accumulation results in many alterations in the physiology of the affected organs, mainly in metabolic tissues. These alterations include the activation of oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, increased inflammation, accumulation of bioactive molecules and modification of gene expression. In this chapter, we review the main metabolic diseases in which alterations in lipid homeostasis are involved and discuss their pathogenic mechanisms.

Review of recent clinical trials and their impact on the treatment of hypercholesterolemia

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death in the United States with incidence expected to increase in the coming decades. Recent years have produced a variety of new and novel therapeutics aimed at reducing the global burden of cardiovascular disease. This review highlights these recent advancements.

RECENT FINDINGS

In addition to more rigorous therapeutic thresholds for traditional LDL lowering agents such as statins, recent studies have developed new pathways of lipid lowering for both typical cardiovascular disease and complex, genetic lipid disorders. This includes inhibition of the cholesterol synthesis enzyme ATP citrate lyase with bempedoic acid, prevention of PCSK9 mRNA translation with inclisiran, inhibition of the lipoprotein lipase inhibitor angiopoetin like 3 protein with evinacumab and the use of anti-sense oligonucleotides to lower lipoprotein(a) levels. Icosapent ethyl, while remaining a topic of debate and controversy, demonstrates efficacy in cardiovascular risk reduction when all available data are examined. Lastly fibrate therapy continues to produce negative results in terms of cardiovascular disease reduction.

SUMMARY

Recent years have yielded breadth and depth to cardiovascular treatments. This expanded armamentarium will allow for more effective and more consistent treatment and prevention of cardiovascular disease.

Paternal preconceptional diet enriched with n-3 polyunsaturated fatty acids affects offspring brain function in mice

Recent studies demonstrate that paternal nutrition prior to conception may determine offspring development and health through epigenetic modification. This study aims to investigate the effects of paternal supplementation of n-3 polyunsaturated fatty acids (n-3 PUFAs) on the brain development and function, and associated gene imprinting in the offspring. Three to four-week-old male C57BL/6J mice (founder) were fed with an n-3 PUFA-deficient diet (n-3 D), and two n-3 PUFA supplementation diets – a normal n-3 PUFA content diet (n-3 N) and a high n-3 PUFA content diet (n-3 H) for 12 weeks. Then they were mated to 10-week-old virgin female C57BL/6J mice to generate the offspring. The results showed that paternal n-3 PUFA supplementation in preconception reduced the anxiety- and depressive-like behavior, and improved sociability, learning and memory in the offspring, along with increased synaptic number, upregulated expressions of neuron specific enolase, myelin basic protein, glial fibrillary acidic protein, brain-derived neurotrophic factor in the hippocampus and cerebral cortex, and altered expressions of genes associated with mitochondria biogenesis, fusion, fission and autophagy. Furthermore, with paternal n-3 PUFA supplementation, the expression of imprinted gene Snrpn was downregulated both in testes of the founder mice and their offspring, but upregulated in the cerebral cortex and hippocampus, with altered DNA methylation in its differentially methylated region. The data suggest that higher paternal intake of n-3 PUFAs in preconception may help to maintain optimal brain development and function in the offspring, and further raise the possibility of paternal nutritional intervention for mental health issues in subsequent generations.

Beneficial Outcomes of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on Human Health: An Update for 2021

Oxidative stress and inflammation have been recognized as important contributors to the risk of chronic non-communicable diseases. Polyunsaturated fatty acids (PUFAs) may regulate the antioxidant signaling pathway and modulate inflammatory processes. They also influence hepatic lipid metabolism and physiological responses of other organs, including the heart. Longitudinal prospective cohort studies demonstrate that there is an association between moderate intake of the omega-6 PUFA linoleic acid and lower risk of cardiovascular diseases (CVDs), most likely as a result of lower blood cholesterol concentration. Current evidence suggests that increasing intake of arachidonic acid (up to 1500 mg/day) has no adverse effect on platelet aggregation and blood clotting, immune function and markers of inflammation, but may benefit muscle and cognitive performance. Many studies show that higher intakes of omega-3 PUFAs, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with a lower incidence of chronic diseases characterized by elevated inflammation, including CVDs. This is because of the multiple molecular and cellular actions of EPA and DHA. Intervention trials using EPA + DHA indicate benefit on CVD mortality and a significant inverse linear dose-response relationship has been found between EPA + DHA intake and CVD outcomes. In addition to their antioxidant and anti-inflammatory roles, omega-3 fatty acids are considered to regulate platelet homeostasis and lower risk of thrombosis, which together indicate their potential use in COVID-19 therapy.

Icosapent ethyl: scientific and legal controversies

Icosapent ethyl (Vascepa) is a purified preparation of the omega-3 fatty acid eicosapentaenoic acid, which is marketed by Amarin Pharma based in Ireland. The product was initially approved by the US Food and Drug Administration for the use of a high dose (4 g/day) in the treatment of hypertriglyceridaemia. On the basis of the results of the REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl Intervention Trial), the agency later granted a label extension to include the additional indication of a reduction in risk of cardiovascular events in persons with serum triglyceride levels of 150 mg/dL or greater and established cardiovascular disease or diabetes. Data supporting the efficacy of omega-3 fatty acids in the prevention of cardiovascular disease have been inconsistent and controversial. The story of the development of icosapent ethyl has been fraught with challenges, including the invalidation of six core patents on the product, and recently, the completion of a new clinical trial, STRENGTH (Long-Term Outcomes Study to Assess STatin Residual Risk Reduction With EpaNova in HiGh CV Risk PatienTs With Hypertriglyceridemia), that directly contradicts REDUCE-IT and calls into question whether icosapent ethyl is actually effective in the secondary prevention of cardiovascular events. This article traces the course of the development of this fascinating product and discusses its complex medical, regulatory and legal history, which is still continuing to unfold.