A number of studies published in the last few years have highlighted not only the disease risk reduction associated with omega-3 fatty acids, specifically EPA and DHA, but also provided clinical guidance on which patients are most likely to benefit. A recent review published in Current Atherosclerosis Reports describes well-known cardiovascular protective mechanisms ascribed to omega-3s, such as cell membrane modulation and anti-inflammatory effects, but also includes relatively newer ones, including increased levels of specialized pro-resolving mediators (SPMs) and modulation of the gut microbiome. This review discusses recent large trial results, such as the Bayesian re-analysis of the VITamin D and OmegA-3 TriaL (VITAL) trial, which found that EPA/DHA supplementation robustly lowered the risk of coronary events when used for primary prevention, as well as smaller studies, such as a controlled trial that found EPA/DHA improved heart rate variability among children with overweight/obesity. Here, we review updates on mechanisms, recent clinical trials and meta-analyses, genetic variants that influence omega-3 metabolism, and therapeutic targets of supplementation.
For cardiovascular risk reduction, lowering triglycerides is often considered the primary mechanism of action for omega-3s, though other mechanisms likely contribute, as evidenced by the fact that triglyceride-lowering interventions don’t confer the same benefits as omega-3s. In a transcriptomics study published in 2025, EPA was shown to downregulate the expression of immune-response genes (723 genes, including HLA-DRA, CD69, etc.) and upregulate the expression of genes (447 genes, including NQO1 and others linked to Nrf2) involved in oxidative stress protection in non-active CD4+ T cells. This outlines a distinct antioxidant and anti-inflammatory role for EPA (DHA was not evaluated) that is triglyceride-independent.
In a recent review of immunomodulatory effects of omega-3s, a wide range of effects of EPA/DHA are documented, including well-established mechanisms, such as increasing membrane fluidity, as well as a growing list of diverse impacts on signaling pathways and gene expression. For example, a 2022 multi-omics study evaluating the effects of omega-3s and omega-6 fatty acids on macrophage function found that omega-3s strongly upregulated tyrosine-protein kinase CSK (which in turn downregulates inflammatory signals, including interleukin-6 and TNF-α), catalase (a key antioxidant enzyme), and acetyl-CoA acetyltransferase, a critical enzyme involved in fatty acid metabolism and ketone body formation. It’s clear that omega-3 fatty acids modulate a large network of signaling molecules, mostly those involved in the normal inflammatory process.
The importance of SPMs, derivatives of EPA/DHA, has gained recognition in recent years as well. For example, D-series resolvins, a type of SPM, also modulate macrophage metabolism to a more anti-inflammatory state; they promote fatty acid oxidation and tissue repair, and are involved in processes that influence atherosclerosis, cardiovascular tissue repair, attenuate mitochondrial dysfunction, and are relevant to conditions ranging from autoimmune disease and metabolic disease to musculoskeletal pathologies (reviewed here). For example, in a metabolomic study of patients with rheumatoid arthritis, the success of treatment with disease-modifying antirheumatic drugs (DMARDs) at 6 months could be predicted with up to 89% accuracy using the baseline plasma concentrations of SPMs (which were also diagnostic of distinct joint disease pathotypes). Trials are currently underway, but it appears that supplementation with EPA/DHA increases plasma concentrations of some SPMs (or their precursors) associated with DMARD responsiveness, including 17-HDHA (RvD4 precursor). A role for SPMs in other autoimmune conditions also seems quite likely, given their role in the resolution of inflammation.
Frontiers in Nutrition published a review in 2025 that describes the modulation of the gut microbiome by omega-3 fatty acids. Among the purported mechanisms are an upregulation of the abundance of beneficial bacteria, such as Bifidobacterium, Lactobacillus, and Akkermansia, enhanced secretion of the enzyme (intestinal alkaline phosphatase, known to detoxify lipopolysaccharide (LPS)), as well as a reduction in the abundance of LPS-producing bacteria. Additionally, omega-3s provide support for the intestinal mucus barrier by enhancing tight junctions, stimulating submucosal collagen production, etc., and upregulating short-chain fatty acid production. For example, in one small clinical trial that enrolled adult twins, even a small dose of omega-3 fatty acid supplementation had similar effects to the prebiotic inulin, marked by increases in Coprococcus spp. and Bacteroides spp, the short-chain fatty acids iso-butyrate and isovalerate, as well as significant decreases in the fatty-liver associated Collinsella spp. A higher intake of omega-3s has also been linked to a lower risk of colorectal adenoma development, an association potentially mediated by alterations to the relative abundance of gut microbiota.
The review in Frontiers in Nutrition suggests that omega-3 and omega-6 fatty acids have opposing effects on gut microbiota, and thus the intake ratio between the two is likely to be a critical factor in determining omega-3 efficacy. One example the authors cite was the lack of benefit for somatic symptoms (although fatigue symptoms improved) among people with major depression following omega-3 supplementation in one clinical trial, yet improvement in similar symptoms were observed in a previous trial. The authors point out that a subsequent analysis found no change in the ratio of omega-6s to omega-3s in the red blood cell membranes of participants in the first study, in contrast to a significant decrease in the second. An awareness of this ratio should be included both in clinical trials as well as for individuals.
Among the more important controlled trials was one published in early 2026 in the New England Journal of Medicine, a double-blind, randomized, placebo-controlled trial evaluating the efficacy of omega-3 supplementation in reducing cardiovascular disease among people receiving hemodialysis. Across 26 centers, over 1200 participants received either 4g omega-3s (1.6g EPA/0.8g DHA) or corn oil, with a primary endpoint being a composite of serious cardiovascular events. After an average follow-up of 3.5 years, fish oil supplementation was associated with a significant 43% reduction in serious cardiovascular events, as well as a 23% reduction in non-cardiovascular causes of death. Cardiac death was reduced 45%, fatal and non-fatal myocardial infarctions were reduced by 44%, fatal & non-fatal strokes by 73%, with significant reductions in amputations and death from any cause. Given that people receiving hemodialysis have a rate of cardiovascular mortality 10-20 times the average population, this is a substantial reduction in absolute risk.
As mentioned above, the American Journal of Clinical Nutrition published a Bayesian analysis of the VITAL Trial, which included over 25,000 older adults followed for a median of 5.3 years. In this analysis, randomized omega-3 supplementation was associated with a reduction in total coronary heart disease by 7% to 12% and total myocardial infarction by 10% to 18%. The probabilities of omega-3s being effective were “99.7% for coronary artery disease, 99.6% for total myocardial infarction, 98.4% for cardiovascular disease, 98.8% for all-cause death, 99.8% for cardiovascular death, and 33.7% for stroke,” providing a firm evidence base for their use in primary prevention.
A 2025 network meta-analysis published in Advances in Nutrition evaluated the use of omega-3 supplementation for heart failure management. Fourteen randomized and controlled trials with over 9,000 participants were included, finding that long-term (>1 year) doses of 2-4 g/d omega-3 fatty acids, particularly EPA and DHA, were associated with improved left ventricular ejection fraction and peak VO2 compared to controls, without any increased risk for adverse events. These benefits were attributed to anti-inflammatory and membrane-stabilizing properties, antioxidant effects, improved endothelial function, regulation of autonomic nervous system activity, and potentially a reduction in adverse ventricular remodeling. This last mechanism is especially important, as it is a long-term, gradual process, highlighting the need for long-term supplementation.
Another important study was published at the end of 2025 in the Journal of the American Heart Association, describing the association between omega-3 fatty acid intake and the risk for atrial fibrillation. This study was done to address concerns generated from previous studies, which found that pharmaceutical formulations of fish oil at high doses were associated with a greater risk for atrial fibrillation. For example, the first of these found that 4g per day of icosapent ethyl omega-3s lowered the risk for ischemic events, including cardiovascular death, when taken by participants with elevated triglycerides (despite statin use); yet the risk for atrial fibrillation was elevated in this group, 3.1% vs. 2.1% with placebo. Notably, the icosapent ethyl form of omega-3s has been associated with an elevated risk for atrial fibrillation compared to supplementation with EPA/DHA in a retrospective cohort study. It’s also worth noting that the benefits attributed to icosapent ethyl omega-3s have been called into question, in part because of the choice of placebo. For example, the REDUCE-IT trial, published in the New England Journal of Medicine, used mineral oil as a placebo. Rather than a neutral placebo, mineral oil appears to worsen atherosclerotic risk markers (potentially overestimating the benefit of the icosapent ethyl form).
So, the recent study attempted to clarify any association between omega-3s and atrial fibrillation with a retrospective analysis of UK Biobank data, with plasma omega-3 levels from over 260,000 participants and self-reported fish oil supplementation in over 460,000. They found that not only was the increased risk of atrial fibrillation absent, but people with the highest plasma omega-3 levels (both those who supplemented and those who didn’t) also had the lowest risk. The increased risk reported previously using UK Biobank data was also nullified when age was adjusted for (continuously rather than dichotomously). A roughly 6 to 10% lower risk for atrial fibrillation was observed for those with the highest plasma levels.
Regarding cardiovascular disease in general, a meta-analysis of 24 randomized and controlled trials evaluating supplementation with omega-3s was published in Nutrition, Metabolism, and Cardiovascular Diseases in April of 2026. Significant improvements in markers of cardiovascular and metabolic risk included reductions in triglycerides, HbA1c, LDL-C, and total cholesterol, with increases in adiponectin and HDL-C. A systematic review and meta-analysis of 14 studies found that an omega-3 intake of ≥500 mg/day was associated with a 48% lower risk of sight-threatening retinopathy among people with diabetes (with a stronger protective effect in type 2 vs. type 1 diabetes), with significant reductions observed in both randomized and non-randomized trials. Lastly, a 2024 meta-analysis published in the Journal of Clinical Medicine evaluated 10 prospective cohort studies (over 300,000 total participants) with an average follow-up of 8.7 years, and found an inverse relationship between circulating omega-3 fatty acids and sudden cardiac death. When comparing high vs. low omega-3 levels (EPA, DHA, and docosapentaenoic acid (DPA)) in serum plasma phospholipids, there was a 45% lower risk for sudden death and cardiovascular mortality, and a 33% lower risk when comparing high vs. low red blood cell levels of EPA and DHA.
As cardiovascular disease is the leading cause of death in the United States, it’s appropriate that the cardiovascular risk reduction associated with omega-3 supplementation gets the most attention. But many other clinical trials have also been published recently; in a meta-analysis of 41 randomized and controlled clinical trials, supplementation with EPA/DHA was found to have significant benefits for exercise and sports performance. Published in FASEB J in April 2026, significant improvements in IL-6, tumor necrosis factor-α, creatine kinase, and delayed-onset muscle soreness were reported, with the strongest effects at doses of 2 g/day or more of mixed EPA + DHA, and a minimum duration of 6 weeks.
In September of 2025, the journal Nutrition Reviews published a systematic review and meta-analysis of randomized controlled trials and found a significant reduction in headache frequency, intensity, duration, and HIT-6 score (Headache Impact Test, which assesses daily function) among migraineurs. Indeed, a 2024 network meta-analysis of 40 randomized controlled trials, published in Advances in Nutrition, found that high-dose omega-3 supplementation (defined as EPA & DHA > 1.5 g/d) had the largest prophylactic effect of any migraine intervention on frequency and severity, with fewer adverse effects than all the included pharmacological comparisons.
In 2025, Scientific Reports published a systematic review and dose-response meta-analysis of the effects of omega-3 supplementation on cognitive function. Fifty-eight randomized controlled trials were included, enrolling cognitively healthy adults and people with cognitive impairment, with estimates of the change in cognitive function per 2 g/day (total omega-3, not EPA/DHA) increment in dose, and certainty evaluated using the GRADE approach. Omega-3s were associated with improvement in perceptual speed, language, primary memory, visuospatial function, and global cognitive ability, especially among cognitively healthy adults. The optimal dose (specifically for benefits to primary and episodic memory, visuospatial functions, and global cognitive ability) appeared to be between 1000 and 2500 mg per day, a dosage range with no adverse effects reported.
The Journal of Nutrition published a cross-sectional analysis in 2026 using UK Biobank data that examined the relationship between plasma omega-3 levels (including fish oil supplementation) and anxiety and depression. This included data from over 258,000 participants whose plasma levels had been measured, and found that all omega-3s were inversely associated with both a history of anxiety and depression. When comparing the highest omega-3 quintile to the lowest, there was a 15-33% lower risk for depression, and a 19-22% lower risk for anxiety. Fish oil supplementation was associated with a 9-10% lower risk for a history of depression or anxiety, and a 20% lower risk for recent anxiety.
Lastly, a meta-analysis of 9 randomized and controlled trials published in Seizure suggests that omega-3 supplementation may be beneficial for drug-resistant epilepsy. Although limited by small sample sizes (the largest included 99 people) and short study duration, overall, omega-3s from fish oil at doses of 0.3 to 1.7 g/day demonstrated a reduction of 7.67 seizures per month compared to placebo, and when limited to the larger trials, this increased to nearly 10 per month.
In addition to well-known variants in the FADS1, FADS2, and ELOVL2 genes that encode the rate-limiting enzymes involved in fatty acid metabolism, several other polymorphisms have emerged that may also influence both omega-3 and -6 metabolism. For example, carriers of the APOE4 allele, a risk factor for Alzheimer’s disease, may decrease the brain bioavailability of omega-3s, requiring larger supplemental doses. This was first shown in a small clinical trial with DHA supplementation, in which CSF EPA levels were found to be 3-fold higher in non-APOE4 carriers vs. APOE4 carriers. A number of mechanisms, including accelerated DHA catabolism and compromised circulatory function among ApoE4 carriers, have been suggested, highlighting the potential benefits from early and higher dose supplementation.
One final takeaway is the clinical utility of the omega-3 index, the percentage of total red blood cell membrane fatty acid content that is comprised of EPA and DHA. While initially developed as a cardiovascular risk marker, a recent review in Current Opinion in Clinical Nutrition and Metabolic Care points out that it has now been shown to be predictive of brain health, diabetes risk, chronic kidney disease, all-cause mortality, etc. It provides a therapeutic goal as well, as an omega-3 index of 8% or higher has generally been associated with the most favorable outcomes across a wide range of studies. This may be especially relevant among people with polymorphisms that impair the conversion of plant-based omega-3s to EPA/DHA, or other genetic variants that impact bioavailability; having a reliable biomarker of omega-3 status may, to some extent, provide a therapeutic target not dependent on genetic risk factors.
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