Herring is one of the many fatty fish known to contain hefty doses of the omega-3 fats, DHA and EPA. Researchers at Nofima Research Institute in Norway report that omega-3-rich herring also contain a fat, called cetoleic acid, that promotes health. In this study, human liver cells and salmon liver cells produced greater amounts of DHA and EPA when exposed to cetoleic acid. Salmon fed cetoleic acid-rich herring had higher levels of cetoleic acid and 10% higher levels of DHA and EPA in their tissues, compared to salmon fed sardine oil rich only in DHA and EPA. Lower incidence of fatty liver in farmed fish also was noted when herring oil was added to the feed. The researchers speculate that this implies that herring-fed fish (and possibly humans fed herring-rich diets) have a higher level of fat metabolism.
Ross A, Svelander C, Undeland I, et al: Herring and beef meals lead to differences in plasma 2-aminoadipic acid, beta alanine, 4-hydroxyproline, cetoleic acid, and docosahexaenoic acid concentrations in overweight men. Journal of Nutrition 2015;145:2456-2463.