A study conducted in Spain reported that consumption of both polyunsaturated fatty acids, (found in nuts, seeds, fish, and leafy green vegetables), and monounsaturated fatty acids, (found in olive oil, avocados, and nuts), decreases the risk for depression over time. However, there were clear dose-response relationships between dietary intake of trans fats and depression risk, whereas other data support an association between trans fats and ischemic stroke risk. Trans fats are found extensively in processed foods, including many commercial chocolates, (hence, check that label when considering dietary intake of chocolate. Also, only the highest levels of dark cocoa contain healthy antioxidants, not milk chocolate). A deficiency in polyunsaturated fatty acids has been linked to attention deficit/hyperactivity disorder in children. Thanks to their high levels of polyunsaturated fatty acids, namely omega-3 fatty acids, fish can help fend off numerous diseases of the brain. A 2010 study correlated fish consumption with a lower risk for psychotic symptoms, and concurrent work suggested that fish oil may help prevent psychosis in high-risk individuals. Although data are conflicting, new research shows that the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid are beneficial in depression and postpartum depression, respectively, and other research suggests that omega-3 deficiency may be a risk factor for suicide. Oily, cold-water fish, such as salmon, herring, and mackerel, have the highest omega-3 levels. Keep in mind that Atlantic fish have elevated levels of mercury and PCB’s compared to Alaskan/Pacific fish, and that farm raised fish contain very little healthy omega 3 fatty acids, due to the confined breeding of farm raised fish.