Does low omega-3 status increase cardiometabolic risk?

Clinical and epidemiological evidence

A low circulating omega-3 status, assessed by the erythrocyte Omega-3 Index, is a robust, independent predictor of adverse cardiovascular disease (CVD) outcomes:

• Cardiovascular hazard: Data from the Framingham Heart Study Offspring cohort indicate that individuals with a low Omega-3 Index face a significantly higher hazard of total mortality and incident CVD events.
• Cardiometabolic biomarkers: Low omega-3 levels correlate with unfavorable lipid profiles, marked by elevated triglycerides, a higher ratio of triglyceride-rich lipoprotein particles, and increased HOMA-IR. Clinical trials indicate that restoring status using therapeutic doses of 2 to 4 g/day of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) consistently achieves dose-dependent reductions in circulating triglycerides.

Mechanistic regulation of hepatic lipoprotein metabolism

Omega-3 fatty acids directly modulate hepatic lipid homeostasis via three primary transcriptional and post-translational pathways:

• SREBP-1c suppression: Omega-3 fatty acids accelerate SREBP-1c mRNA decay and inhibit its proteolytic processing. A deficiency in omega-3 levels increases SREBP-1c activity, upregulating lipogenesis and expanding hepatic triglyceride pools.
• PPARalpha activation: These fatty acids serve as ligands for PPARalpha, inducing mitochondrial and peroxisomal beta-oxidation to divert fatty acyl-CoAs away from esterification.
• ApoB-100 degradation: Docosahexaenoic acid (DHA) promotes intracellular lipid peroxidation, triggering post-ER presecretory proteolysis (PERPP) and autophagic degradation of poorly lipidated apoB-100, which limits the assembly and secretion of very-low-density lipoproteins (VLDL).

Inflammation-resolution signaling mechanisms

Omega-3 fatty acids serve as essential precursors for the enzymatic synthesis of specialized pro-resolving mediators (SPMs) that actively terminate inflammation:

• SPM generation: EPA and DHA are converted via cyclooxygenase (COX) and lipoxygenase (LOX) pathways into resolvins, protectins, and maresins.
• Receptor-mediated resolution: E-series resolvins (RvE1) bind to the ChemR23 receptor, while D-series resolvins bind to the ALX/FPR2 receptor. This binding prevents IkappaBalpha phosphorylation and NF-κB nuclear translocation, suppressing the expression of pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6) in the vascular wall.

Bottom line

• Low omega-3 fatty acid status is robustly associated with increased cardiometabolic risk. This association is driven by a lack of SREBP-1c suppression and PPARalpha activation, which elevates hepatic VLDL-triglyceride secretion, alongside diminished SPM-mediated ChemR23 and ALX/FPR2 signaling, which compromises the active resolution of vascular inflammation.