A lack of properly controlled trials is preventing any firm conclusions about the possible benefits of omega-3 for bipolar disorder. Several observational studies have suggested that fish oils and omega-3 docosahexaenioc (DHA) and eicosapentaenoic (EPA) acids have positive effects on the symptoms of depression.

To examine the claims, Oxford University researchers Paul Montgomery, Ph.D., and Alex Richardson, Ph.D., undertook a systematic review of literature. They found that only five studies met the stringent inclusion criteria for a properly controlled study and of these only one was found worthy of review. In this single study of 75 patients, omega-3 supplements appeared to reduce the severity of depression but had no effect on symptoms of mania.

The market for omega-3 has increased substantially over the past few years. This, coupled with fears about dwindling fish stocks has encouraged some industries to invest in harvesting omega-3s from algae.

Omega-3 is consumed mainly from fish, nuts and seeds. Brain function is assumed to benefit from the action of EPA improving both blood flow and the immune system. DHA is thought to have an effect on brain chemistry, making it easier for cells to change shape and exchange electrical signals.

Several studies talk up the benefits to the brain of an intake of omega-3, but Montgomery feels the claims are exaggerated and states, "what evidence is currently available is of such a varied and oftentimes questionable nature that no reliable conclusions may be drawn."

These findings in no way dismiss the potential value of omega-3, which is recognized as beneficial to the cardiovascular system, fetal development, joint health and even certain cancers. It does however point to the fact that properly controlled trials are needed. There remains uncertainty quite how the various fatty acids affect the body, but the view of Montgomery is they might "play key roles in the brain structure and function."