Writing in the peer-reviewed European Archives of Psychiatry & Clinical Neuroscience, researchers from the Tehran University of Medical Sciences report that six months of supplementation with 300 mg of both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) resulted in significant improvements in depression scores, as measured by the Geriatric Depression Scale-15.
“In this study, low-dose omega-3 PUFAs had some efficacy in the treatment of mild to moderate depression in elderly participants,” wrote the researchers.
Jury’s still out?
The link between omega-3 and mood is complex and data to date is contradictory. For example, in researchers from Norway reported that regular and long-term intake of omega-3 fatty acid-rich cod liver oil may protect people from symptoms of depression.
The study, published in the Journal of Affective Disorders, followed 21,835 subjects aged between 40 and 49 and 70 and 74 years, and found that the prevalence of depressive symptoms was 29 per cent lower in regular cod liver oil users than the rest of the population.
Moreover, a joint Anglo-Iranian study reported that depression ratings were cut by 50 per cent following daily one gram supplements of EPA, an effect similar to that obtained by the antidepressant drug fluoxetine, according to findings published in the Australian and New Zealand Journal of Psychiatry.
"To our knowledge this is the first report of EPA monotherapy in major depressive disorder," wrote the researchers from Tehran University of Medical Sciences and Swallownest Court Hospital in Sheffield (UK).
When the researchers provided the omega-3 supplement in combination with fluoxetine, depression ratings were cut by 81 per cent.
Despite this growing number of studies, the science overall is unsufficient to support a link between omega-3 and depression, said the British Medical Journal's Drug and Therapeutics Bulletin (DTB) in February 2007.
"Despite observational evidence linking depression with reduced intake of long-chain omega-3 fatty acids, there is no convincing basis for using these nutrients as a [means of alleviating] the condition," stated the DTB.
The review also states that, when used in combination with antidepressant drugs, there is also only limited evidence.
New data
The new Iranian study adds to the ongoing debate, and concludes that omega-3 fatty acids were “clinically more effective in treating depression in comparison with the placebo”.
The researchers recruited 66 over-65 year olds and randomly assigned them to received an omega-3 supplement – one gram of fish oil per day, providing 300 mg of both EPA and DHA – or placebo for six months.
Results of the double-blind, randomized, placebo-controlled study indicated that “after adjusting for cholesterol, BMI, and history of thyroid dysfunctions, a statistically significant difference was seen in GDS-15 scores between both groups”, said the researchers.
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Polyunsaturated fatty acids (PUFAs) from fish oil include EPA and DHA. EPA is proposed to function by increasing blood flow in the body. It is also suggested to affect hormones and the immune system, both of which have a direct effect on brain function. DHA, on the other hand, is involved in the membrane of ion channels in the brain, making it easier for them to change shape and transit electrical signals.
Source: European Archives of Psychiatry & Clinical Neuroscience
Published online ahead of print, doi: 10.1007/s00406-011-0191-9
“The effect of low-dose omega 3 fatty acids on the treatment of mild to moderate depression in the elderly: a double-blind, randomized, placebo-controlled study”
Authros: Y. Tajalizadekhoob, F. Sharifi, H. Fakhrzadeh, M. Mirarefin, M. Ghaderpanahi, z. Badamchizade, S. Azimipour