In some people depression may be caused by omega-3 deficiency which results from not eating enough nuts, seeds, whole grains, beans or deep-water fish.

Many psychiatrists treat depression with drugs that raise brain levels of serotonin. Now we learn that a diet deficient in omega-3 fatty acids may lower brain levels of serotonin and can cause depression. Studies show that depression is associated with low levels of red blood cell membrane and low intake of omega-3 fatty acids, that increased ratio of omega-6 to omega-3 fatty acids is associated with increased severity of depression. Depression is 60 times more common in New Zealand (6 percent) than in Japan (.12 percent); the difference may be explained by the high intake of omega-3-rich fish by the Japanese.

Post-partum depression is common in women after they give birth. Pregnancy uses up huge amounts of omega-3 fatty acids. Women with the lowest blood levels of omega-3s are the ones most likely to suffer post-partum depression.

Depression increases a person's chances of getting a heart attack. Depressed people often have low blood levels of omega-3s, and so do people who are likely to suffer heart attacks. So the association of depression with heart attacks may be explained by both being caused by low omega-3 fatty acid levels. If these studies can be supported by further studies, some cases of depression may be prevented and treated by eating plenty of deep-water fish, nuts, seeds, beans and whole grains.