Greater decreases in total colonic fatty acid content after 12 weeks of omega-3 fatty acid supplementation are associated with larger reductions in colonic prostaglandin-E2 concentrations, accounting for 18.7% of inter-individual variability, indicating that lipid metabolism dynamics in the colon modulate anti-inflammatory responses.

When omega-3 fats enter the colon, they replace other fats in cell membranes and reduce the total amount of fat present. This lowers the availability of arachidonic acid, the raw material for inflammation-causing molecules, and removes fats that normally boost the activity of the enzyme that makes those molecules. As a result, the enzyme produces less of the inflammatory compound prostaglandin-E2.