Comparing Fish Oil and Krill Oil: Effects on Liver and Brain Fats in Mice

This laboratory study fed mice a high-fat diet alone, or supplemented with either fish oil or krill oil, for six weeks. Researchers then used detailed lipid-mapping techniques to examine how each oil changed the types and amounts of fats stored in the liver and brain.

Both oils raised levels of the omega-3s EPA and DHA in tissues while lowering two other fatty acids (linoleic acid and arachidonic acid). Fish oil caused a decrease in linoleic acid across nearly all fat classes, while krill oil’s effect on this fatty acid was more limited.

The two oils also produced different patterns in minor lipid classes linked to inflammation and insulin signaling. In the liver, krill oil reduced ceramides and diacylglycerols and increased cholesteryl esters, while fish oil reduced plasmalogens. In the brain, both oils lowered diacylglycerols (krill oil more so), while fish oil increased ceramides and lactosylceramides more than krill oil did.