Researchers at Harvard University found that ω–3 fatty acids and uridine- two naturally occurring substances in many foods such as fish, walnuts, molasses and sugar beets- prevented the development of symptoms of depression in rats as effectively as antidepressant drugs. In these studies, investigators examined how ω–3 fatty acids and uridine affected the behavior of rats exposed to stress. Generally, when tested repeatedly under stressful conditions, the rats quickly developed symptoms of learned helpless behavior. But, when injected with uridine or fed a diet enriched with high levels of omega-3 fatty acids, they showed fewer signs than untreated rats. These studies supports the observations that higher national consumption of fish rich in ω-3 fatty acids in some countries results in lower rates of depression compared to countries consuming the least amount of fish. In some cases, these findings suggest, eating the right foods could produce the same benefits as taking traditional antidepressant medications.