Fish May Cast Away Depression

Fish has long been recognized as a good source of protein, vitamins and essential nutrients, reports CBS News Corespondent John Roberts.

Societies where fish is a mainstay of diet have lower rates of heart disease. Now, there is growing evidence that fish isn't just good for the heart and body -- but the mind as well.

"Countries which eat a great deal of fish, such as Japan and Taiwan, have strikingly lower rates of depression than countries that do not eat very much fish," says Dr. Joseph Hibbeln of the National Institutes of Health.

Hibbeln has been leading research into the relationship between fish and mental health. He has found that countries with the least fish consumption, like New Zealand for example, have rates of depression 60 times higher than in Japan, where people eat the most fish.

What's at work, says Hibbeln, are compounds in fish oil, called omega-3 fatty acids -- substances that help lubricate the walls of brain cells and allow them to better use the powerful mood-elevating brain chemical seratonin.

"One of the striking findings we have is that plasma levels of these fatty acids appear to predict brain seratonin levels," he says.

The most popular anti-depressants, such as Prozac and Zoloft, work by elevating levels of seratonin in the brain.

Dr. Andrew Stoll has been treating manic depressive patients with concentrated omega-3 fatty acids and found that they achieve similar results.

"Giving the omega-3 fatty acids reduced the rates of episodes and stabilized their mood," says Stoll.

Because pregnancy depletes levels of omega-3s, studies are underway to see if fish oil might be useful in treating post-partum depression.

There's preliminary evidence to show that they may just generally balance mood.

"Even among Japanese students who eat a lot of fish...taking these omega-3 fatty acids reduced their levels of hostility and reduced their levels of aggression," says Hibbeln.

However, patients had to take large doses of the fish oil -- up to 14 capsules per day. These amounts would be difficult for many people to cope with. Meanwhile, scientists say that as intriguing as the research is, it's too early for patients who are depressed to put down their medications in favor of this natural alternative.

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