So fish oil can have some benefits in very specific situations. Fish oil is a slight blood thinner, like aspirin, for example, and it can also stabilise the rhythm of the heart. So really the only people in whom fish oils have proven benefit is people who are prone to rhythm problems with the heart, like atrial fibrillation, for example, which is an irregular heartbeat, or people who need blood thinners, but can’t take aspirin.

Professor David Celermajer is Scandrett Professor of Cardiology and Head of Cardiology at the University of Sydney.