No isolated aspect of the diet explains all of its benefits, but it is believed that the ingredient of the diet that most helps to reduce the risk of heart disease is the high amount of omega-3 fatty acids. Omega-3 fatty acids are found in fatty fish as well as in nuts and certain oils. Several studies of patients with either known heart disease or risk factors for heart disease have shown a reduction in heart disease events, such as heart attacks, as well as markers of heart disease risk when patients followed a Mediterranean diet. Other studies have shown that giving a supplement that contains omega-3 fatty acids to patients with heart disease or risk factors for heart disease also reduces heart disease events and markers of heart disease risk.