Essential fatty acids include omega-3 and omega-6 fatty acids. Omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both DHA and EPA are synthesized from the breakdown of ALA, but the process is inefficient; fish oil supplies a better source of DHA and EPA. Omega-3 fatty acids have shown some benefit in the treatment of clinical depression. Like all substances, omega-3 fatty acids can have side effects; always talk with your medical practitioner before increasing your intake of essential fatty acids, particularly from supplements.
Sources
The omega-3 fatty acids DHA and EPA occur in the highest amounts in large, cold-water fatty fish such as herring, lake trout, mackerel, salmon, sardines and albacore tuna. Flaxseed and some nuts contain ALA. Omega-3 supplements include both fish oil and flaxseed oil. Fish oil supplements contain differing amounts of DHA and EPA, with 120 mg of DHA and 180 mg of EPA commonly found in over-the-counter supplements.
Levels
In several clinical trials, people with clinical depression were found to have lower amounts of omega-3 fatty acids in their blood and fat tissues. A 2002 study by the University of Crete found that mildly depressed persons had 34 percent less DHA in their fatty tissue than people who were not depressed. A Belgian study in 1999 reported similar findings, with decreased levels of DHA in blood.
Causes
It's not yet known whether low levels of fatty acids cause depression or occur as a result of depression. Low levels of omega-3 fatty acids may interfere with neurotransmitters that can affect mood. Omega-3 fatty acids may also inhibit cytokines, inflammatory substances that have direct effects on the central nervous system, according to a 2004 article by Alan Logan of the Integrative Care Centre of Toronto in "Lipid in Health and Disease."
Effects
In clinical trials, adding DHA alone or EPA and DHA has had mixed results. A 2005 New Zealand study showed no benefit from 8 g of fish oil over olive oil when added to traditional treatments for depression, while several studies using EPA alone have shown benefit in reducing depressive symptoms, according to Logan. More clinical trials may establish whether a single essential fatty acid has benefit over a combination and what the optimal dosage is.
Risks
Depression is a life-threatening illness. Do not attempt to treat depression on your own with essential fatty acids. Clinical trials on fatty acids and depression have used supplements as an adjunct treatment, not as a substitute for traditional medications and therapy. Omega-3 fatty acids can also increase the risk of bleeding. If you take blood thinners or have a medical condition that increases bleeding, do not take supplements without your doctor's permission.
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