Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA and DHA

Abstract

Omega-3 polyunsaturated fatty acids (PUFAs) exhibit neuroprotective properties and represent a potential treatment for a variety of neurodegenerative and neurological disorders. However, traditionally there has been a lack of discrimination between the different omega-3 PUFAs and effects have been broadly accredited to the series as a whole. Evidence for unique effects of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and more recently docosapentaenoic acid (DPA) is growing. For example, beneficial effects in mood disorders have more consistently been reported in clinical trials using EPA; whereas, with neurodegenerative conditions such as Alzheimer’s disease, the focus has been on DHA. DHA is quantitatively the most important omega-3 PUFA in the brain, and consequently the most studied, whereas the availability of high purity DPA preparations has been extremely limited until recently, limiting research into its effects. However, there is now a growing body of evidence indicating both independent and shared effects of EPA, DPA and DHA. The purpose of this review is to highlight how a detailed understanding of these effects is essential to improving understanding of their therapeutic potential. The review begins with an overview of omega-3 PUFA biochemistry and metabolism, with particular focus on the central nervous system (CNS), where DHA has unique and indispensable roles in neuronal membranes with levels preserved by multiple mechanisms. This is followed by a review of the different enzyme-derived anti-inflammatory mediators produced from EPA, DPA and DHA. Lastly, the relative protective effects of EPA, DPA and DHA in normal brain aging and the most common neurodegenerative disorders are discussed. With a greater understanding of the individual roles of EPA, DPA and DHA in brain health and repair it is hoped that appropriate dietary recommendations can be established and therapeutic interventions can be more targeted and refined.

Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways

“…It may therefore be that some of the effects of omega-3 PUFAs on hippocampal neurogenesis are mediated via interaction with endocannabinoid signaling pathways. Furthermore, recent evidence suggests EPA and DHA have independent and divergent effects in the brain in both normal aging and neurodegenerative conditions (Dyall, 2015). Therefore, the aim of this study was to evaluate the effects of DHA and EPA on NSC fate and the potential role of endocannabinoid signalling pathways in these effects.…”

Effect of docosahexaenoic acid on traumatic brain injury in rats

“…Docosahexaenoic acid (DHA) is a kind of polyunsaturated fatty acid, which is predominantly extracted from deep-sea fishes and algae (15). DHA is not only an important polyunsaturated fatty acid in the central nervous system, but it is also the main constituent of n-3 polyunsaturated fatty acids in cell membranes of cortical gray matter neurons (16). There is limited research on the impact of supplementation with PUFAs on TBI (17)(18)(19).…”

Focusing on Omega-3 Fatty Acids for Treatment of Obstructive Sleep Apnea and its Cardiovascular Complications

“…On the contrary, a recent study found no difference in the change in AHI among OSA patients randomized to surgically induced weight loss or weight loss achieved through very low-energy diet, despite the greater weight loss being achieved in the surgically systems [18] . Since severe OSA is associated with increased expression of several pro-inflammatory cytokines (especially increased levels of IL-6, TNF-α) and oxidative stress within the muscular compartments of upper airway tissue [19] , the tissue concentration of the antiinflammatory and anti-oxidative n-3 PUFAs may increase upperairway muscle-contractile function via an improved upper airway muscle force-generating capacity of dilator muscles (Figure 1).…”