When scientists added a type of omega-3 fatty acid called EPA to blood vessel cells in a dish, the cells made more of a helpful molecule (nitric oxide) and less of a harmful one (peroxynitrite), which might help keep blood vessels healthier and less inflamed.

When scientists added a specific type of omega-3 fat (DHA) to blood vessel cells in a dish, it made them release a little more of a helpful molecule (nitric oxide) that keeps blood vessels relaxed, but didn’t change a harmful molecule (peroxynitrite) — and this effect was smaller than what another omega-3 fat (EPA) does.

When scientists added a specific amount of omega-3 fish oil (EPA) to human blood vessel cells in a dish, the cells soaked up a lot more EPA and ended up with way more of it compared to the bad fats, which is a good sign the cells are using it properly.

When scientists added a small amount of a common fatty acid (arachidonic acid) to blood vessel cells in a dish, it didn’t change the levels of two key molecules involved in cell stress and signaling—so it seems this fatty acid doesn’t mess with the cell’s internal balance under these specific conditions.

Omega-3 fats from fish, called EPA and DHA, help your blood vessels relax and stay flexible by boosting a natural chemical (nitric oxide) that opens up arteries and reduces harmful stress in your body.