You are what you eat … and your mood could be affected by your diet, as well.

For the last decade, researchers and alternative medicine practitioners have been exploring a new, natural way to treat those suffering from depression and other psychiatric disorders. And what they've found is that improving your mood could be as simple as making minor adjustments to your diet.

One lead researcher, Dr. Joseph Hibbeln, chief of the outpatient clinic at the National Institutes of Alcohol Abuse and Alcoholism in Bethesda, Md., published a study in 1998 in the journal The Lancet that showed a connection between countries that consume large amounts of fish and low rates of depression. On the other hand, countries where people did not eat a lot of fish had significantly higher rates of depression.

This study led other researchers to wonder whether the polyunsaturated fats known as omega-3 fatty acids found in fish could be the reason for the difference.

Dr. Andrew Stoll, director of the psychopharmacology research laboratory at McLean Hospital in Belmont, Mass., conducted a study that focused specifically on patients with bipolar disorder. Half of the subjects were given fish oil tablets and the other half were given a placebo.

After four months, "half of the placebo cases had already relapsed into depression, where as only two out of the 15 fish-oil patients had gotten sick, and that was a huge difference," says Stoll.

The significance of these two studies sparked additional research over the last couple of years that have shown similarly promising results on the ability of omega-3 fatty acids to relieve depression.

Getting Enough Omega-3

While additional research needs to be done to prove definitively omega-3s' impact on different psychiatric disorders, some psychiatrists are now feeling confident enough to recommend that their depressed patients increase their consumption of these fatty acids. So, what are the best sources for omega-3s, and how much is needed to make a difference?

The best source for omega-3s is any type of seafood — including salmon, lobster and shrimp. For people who find seafood a bit fishy, walnuts and olive oil are also good sources for the fatty acid.

"People should not fall below 650 milligrams [of omega-3] per day," says Hibbeln. "A 100-gram serving of fish on average is going to contain about a gram or 1,000 milligrams of omega-3. So, 650 milligrams is about a serving of fish every other day."

However, for most people it may be unrealistic, or unappealing, to eat fish every other day. For those people, doctors recommend fish oil supplements that can be found in any health-food or nutrition store.

Additional Effects of Eating More Fish

In addition to the possibility of relieving depression, omega-3s have proven to be important in cardiovascular health. Numerous studies led the American Heart Association two years ago to make a recommendation that consuming two to three servings of fish per week could provide significant cardiovascular benefit.

Omega-3s have also proved promising in preliminary results for the prevention and treatment of certain cancers, including colon cancer, and with inflammatory conditions, such as rheumatoid arthritis.

In addition, pregnant and breast-feeding mothers are encouraged to get enough omega-3 to help the development of their babies' brains. However, some predatory fish like tuna, swordfish and shark may be dangerous to pregnant mothers due to the high levels of mercury. So, sticking with fish like salmon is a safer bet for those expecting a child, without the unwanted effects of consuming mercury.

The only reported down side to consuming more of these fatty acids through fish or fish-oil tablets may be an increase in dyspepsia, or indigestion often resulting in gas.

"People may get a little bit of dyspepsia, but if they just start with a low dose and work their way up, it shouldn't be a problem," says Dr. Harold G. Koenig, associate professor of psychiatry and medicine at the Duke University Medical Center in Durham, N.C. "That's a fairly mild side effect for all the good things that could potentially result."

"Not only are the fish oil supplements relatively inexpensive," says Hibbeln, "and not only are they safe and recommended for pregnant mothers, but all of the side effects, except for belching, are beneficial."

The Future of Omega-3s and Depression

While the existing results of studies involving omega-3s and depression have proven promising, there still remains skepticism as to how significant the impact will be on the continued need for prescription antidepressant medication.

Therefore, further studies need to be done to see which patients will benefit the most from an increase in omega-3s and to see how well this new diet works in combination with antidepressant drugs.

But, in the meantime, some psychiatrists are encouraging patients who haven't been successful with the drugs to incorporate this new approach.

"For patients who are taking adequate doses of antidepressants, and maybe they tried one, maybe they tried two or three," says Koenig, "then why not encourage them to take this pill that's likely to have a benefit for their cardiovascular system and it might help to stabilize their emotional condition, as well?"