Omega-3 fatty acids are "healthy" fats, which are thought to protect the body against heart disease. They help the heart beat more regularly, reducing blood "stickiness," therefore making it less likely to clot, and protecting the arteries from damage. They also help to maintain healthy joints, and are associated with beneficial improvements in our mood.

Fish oil contains two omega-3 fatty acids: EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). These are found in certain fatty fish,...