Supplementation of Omega-3 fatty acids may offer powerful protection against depression. A large Norwegian study of nearly 22,000 participants revealed that those who regularly took Omega-3 fatty acids supplement, were about 30% less likely to have symptoms of depression than those who did not. The longer the participants took the supplement, the less likely they were to have depression. Omega-3 fatty acids also helps to improve mood in those who are already suffering from depression.