Mackerel Oil Rich in Cetoleic Acid Boosts Certain Omega-3 Levels in Blood

This four-week clinical trial compared mackerel oil, which naturally contains a fatty acid called cetoleic acid, against a control fish oil in 49 healthy adults. Both oils contained similar amounts of omega-3 fatty acids, but the mackerel oil group showed higher blood levels of eicosapentaenoic acid (EPA) and eicosatetraenoic acid, a related omega-3 fatty acid.

Participants who took the cetoleic acid-rich mackerel oil also had higher levels of eicosatetraenoic acid in their red blood cell membranes, along with reduced activity of a gene called ELOVL5, which is involved in processing fatty acids in the body. These findings support earlier lab research suggesting cetoleic acid may help the body generate more omega-3 fatty acids.

No differences were found between the two groups in cholesterol, blood sugar, or C-reactive protein (a marker of inflammation), which was expected since all participants were healthy to begin with. The researchers note that future studies should look at people with metabolic or cardiovascular risk factors to see if these effects matter for health outcomes.