Pro-Resolving Mediators.

E-series resolvins are enzymatically derived from eicosapentaenoic acid, with 18-HEPE as the intermediate. Without EPA in the membrane phospholipid pool there is no substrate for that branch. Supplying pre-formed mediators and supplying their precursor are two different approaches to the same pathway. This is settled lipid biochemistry.

D-series resolvins, protectin D1 and the maresins are all oxygenated derivatives of docosahexaenoic acid, routed through 17-HDHA and 14-HDHA. DHA status therefore sets the ceiling on that whole family. Marine oil products that raise the omega-3 index raise the precursor pool. The relationship is substrate to product.

Conventional fish oil delivers EPA and DHA, the two fatty acids from which every specialised pro-resolving mediator is built. SPM-enriched oils differ by carrying measurable amounts of the monohydroxy intermediates as well. Trials of omega-3 supplementation report shifts in circulating lipid mediator profiles. Those are biomarker measurements rather than clinical outcomes.

Krill oil carries its omega-3s largely as phospholipid rather than triglyceride, which changes digestion and incorporation kinetics. The fatty acids delivered are the same substrates the mediator pathways use. Whether the phospholipid form changes mediator output specifically has not been established. Total EPA and DHA delivered is the comparable number.

Delta-6 desaturase handles both linoleic acid and alpha-linolenic acid, and a high omega-6 load occupies that shared capacity. Arachidonic acid and EPA also compete for the same cyclooxygenase and lipoxygenase enzymes, producing different mediator families. Dietary ratio therefore shifts which branch dominates. This is textbook eicosanoid biochemistry.

Highly unsaturated fatty acids oxidise readily, and tocopherol is the standard chain-breaking antioxidant added to marine oils for that reason. Higher polyunsaturated intake raises tocopherol turnover in tissue as well as in the bottle. Oxidised oil produces non-enzymatic lipid peroxides rather than the enzymatically derived mediators. This is formulation chemistry with a physiological tail.

Astaxanthin partitions into the lipid phase and slows peroxidation of highly unsaturated fatty acids. It is co-formulated with krill and fish oils partly for that reason. Protecting the substrate is not the same as raising mediator production, and no trial separates the two. Read the pairing as oxidative protection.

Carnosic acid and rosmarinic acid from rosemary extract are widely used to hold peroxide values down in polyunsaturated oils. Their role is protecting the oil, not adding activity in the person. Peroxide and anisidine values on the certificate of analysis are what this shows up in. The pairing is manufacturing practice.

Curcumin is reviewed for effects on the same NF-kB and eicosanoid signalling that the resolution pathways feed into, though it acts on the signalling side rather than as a lipid mediator. Formulas pair them for that overlap. The reviewed evidence for curcumin here is mechanistic and biomarker-level. No combination trial with SPM-enriched oil has been reported.

Vitamin D receptor signalling influences macrophage phenotype, and macrophage class switching is the step at which pro-resolving mediators act. The two are combined in formulas addressing normal immune balance. The overlap is at the level of cell biology, not of a measured combined effect. Confidence stays low for that reason.

Selenium-dependent glutathione peroxidases reduce lipid hydroperoxides, the same class of intermediates that sit alongside the enzymatic mediator pathways. Adequate selenium status is a precondition for that clean-up capacity. Higher polyunsaturated intake raises the load these enzymes handle. This is established cofactor biochemistry, not a supplement combination finding.

Marine oils are absorbed after emulsification and lipase action, and phospholipid emulsifiers improve dispersion of a lipid dose. Formulations use lecithin to make emulsions and self-emulsifying systems. The effect is on delivery of the substrate rather than on the pathway itself. Taking these oils with a fat-containing meal does much the same thing.

Dietary triglycerides are hydrolysed by pancreatic lipase to monoacylglycerol and free fatty acids before micellar uptake. Anything reducing lipase activity or bile flow reduces omega-3 absorption. Enzyme blends are added to fish oil products for this reason. The step is upstream of every mediator in the family.

Aspirin acetylates cyclooxygenase-2 and switches it to producing 17R-hydroxy intermediates, the origin of the aspirin-triggered mediator series. Willow bark supplies salicin, which yields salicylic acid rather than acetylsalicylic acid, and salicylic acid does not acetylate the enzyme. The mechanism therefore does not transfer from aspirin to willow bark. This is listed because the assumption is a common one and is not supported.

GLA is elongated to dihomo-gamma-linolenic acid and routed through the same enzymes that handle EPA and DHA. Combined omega-6 and omega-3 formulas are a real category, and the branches draw on shared capacity. The direction of the net shift depends on the ratio given. Read it as substrate competition inside one enzyme system.