Oily fish have high levels of a little known compound called cetoleic acid. The role of this fatty acid is not understood. Herring have high levels of cetoleic acid.
Scientists at the Norwegian research centre Nofima think it might be involved in the absorption and or storage of omega 3 (O3). It might also change omega 3 into a long chain form.
The research is being done for commercial reasons to increase the levels of O3 in north atlantic farmed salmon and so increase the price.
Farmed salmon were fed high O3 sardine oil or high O3 herring oil. Those fed with the herring oil had 10% higher levels of O3 than the salmon fed with sardine oil.
Limited research has been done with human liver cells and it seems that cetoleic acid can cause the liver to change O3 from a short chain to the long chain fatty acid.
The results should be published later this year. Early signs indicate herring could be beneficial for human health by increasing the absorption and storage of O3 from other dietary sources.