Beat the Blues

Higher fish consumption is associated with a decreased risk of depression, postpartum depression, and suicidal thoughts.

Patients with depression often have chronically elevated immune chemicals called cytokines, which the omega-3 fatty acid EPA can specifically reduce.

If you’re feeling down, it’s time to look at your diet. The lack of omega-3 fatty acids in typical western diets may be a significant factor in a number of neurological and psychological disorders, including depression. Rates of depression have risen significantly throughout the past century in western countries, at the same time dietary intake of omega-3 fatty acids has declined steadily.

Animal-rearing practices, particularly the feeding of grains and the mass introduction of omega-6-rich oils (corn, sunflower, safflower, cottonseed), has led to a skewed intake in favour of omega-6 fatty acids. Previously the dietary ratio of omega-6 to omega-3 had been close to 1:1, a ratio recommended by an international lipid panel in 1999 in the Journal of the American College of Nutrition. That’s quite distant from the current ratio, where omega-6 fats outnumber omega-3 by up to 20:1.

Omega-3 fatty acids are long-chain, polyunsaturated fatty acids found in fish, flax seed, canola oil, walnuts, avocados, and leafy green vegetables. Fatty marine fish contains the highest levels of the omega-3 fatty acids eicosapentaenoic and docosahexaenoic acids (EPA and DHA), which have direct physiological and structural activity in the brain. Plant-derived alpha-linolenic acid (ALA) is also a beneficial omega-3 fatty acid because it can be converted into EPA and DHA.

It is not entirely surprising that omega-3 fatty acids play an important role in brain function when one considers that the brain is about 60-per-cent fat.

Modern antidepressant medications can be effective and certainly improve quality of life in many depressed patients. Sadly, however, they don’t work for everyone. Although about half of patients on antidepressants note a 50-per-cent improvement in symptoms, about 30 per cent discontinue medication before a six-week trial is complete. Scientists are continuing to seek out new and effective means to ease depression. Research into omega-3 fatty acids may be the most exciting to occur in depression since antidepressants were first discovered 50 years ago.

A number of studies have shown correlation between fish consumption and lower rates of depression, postpartum depression, and seasonal affective disorder. Nations with higher fish consumption record a decreased risk of depression, postpartum depression, and suicidal thoughts. Fish consumption is also associated with higher self-reported mental health.

Even more convincing is the growing research demonstrating that patients with depression have low levels of omega-3 fatty acids in their blood and fat stores. Experimental studies have shown serious consequences in the central nervous systems of animals that have an inadequate supply of omega-3 fatty acids: lower levels of important neurotransmitters, particularly dopamine and serotonin which are critical to brain function and the regulation of mood, have been found in the brains of animals deficient in omega-3 fatty acids.

Omega-3 deficiency also results in reduced functional activity of brain cells, diminished blood flow to the brain, and abnormalities in the blood-brain barrier, a specialized network of vessels responsible for monitoring what can and cannot gain access to the delicate nervous system cells.

Patients with depression have been shown to have chronically elevated immune chemicals called cytokines, specifically interleukin-1 beta (IL-1b) and tumour necrosis factor a (TNF-a), which have been correlated with severity of depression and may be involved in altering normal neurotransmission. Depressed patients also have elevated levels of another inflammatory chemical called prostaglandin E2 (PGE2). Researchers note that the omega-3 fatty acid EPA can specifically reduce the production of cytokines and prostaglandin.

The background data and rationale for the use of omega-3 fatty acids in depression is sound, and in recent years, a number of studies have investigated the clinical use of fish oils in depression. The first controlled study, appearing in Archives of General Psychiatry in 1999, showed that 9.6 grams of EPA and DHA could lengthen the time of remission and improve depression in bipolar disorder (manic depression). Researchers from Taiwan recently showed that 6.6 grams of EPA and DHA daily (added to current antidepressant medication) could improve scores of depression compared with those on placebo and medication. These fairly large doses would require numerous daily capsules, possibly reducing compliance over the long run.

Recently, however, studies have shown that when the EPA component is administered alone, without DHA, significant improvement in depressive symptoms is possible at much lower doses. A study published in 2002 in the American Journal of Psychiatry showed that two grams of EPA added to antidepressants led to significant improvement over placebo and medication, while a separate 2002 study, in Archives of General Psychiatry showed that among various doses of EPA, one gram provided the best outcome in treatment-resistant depression. In addition, the one-gram dose of EPA was shown to be effective in reducing depression associated with the difficult-to-treat psychiatric condition called borderline personality disorder.

While EPA has been enjoying research success, a new study shows that two grams pure DHA is not effective in depression. For the time being, the evidence suggests that EPA is the main player in antidepressant effects, possibly because it inhibits cytokines and prostaglandin.

Further research will undoubtedly provide more answers. In the meantime, enteric-coated high-dose EPA is available in Canada and given the current omega-6 dietary excess, it should be considered as potentially valuable.

Depression is a serious condition and supplementation with EPA, or any other product, is not a substitute for appropriate medical evaluation and care. If you suspect you have clinical depression, or have already been diagnosed, talk to your health care provider before taking EPA.