Dr Nina Bailey

There is growing evidence for the role of omega3 fish oil, not only in the etiology of major depression, but also as a treatment method. Given the numerous and undesirable side effects associated with conventional pharmaceutical treatments it is no wonder that many individuals actively seek natural alternatives, and the pure EPA fish oil (eicosapentaenoic acid – EPA) may just be what the doctor ordered.

Indeed, several studies have highlighted that abnormal cell membrane fatty acid composition is related to risk and incidence of major depression, and that supplementation with omega-3, and specifically with EPA, appears to normalize fatty acid levels and reduce the symptoms associated with this condition. However different studies can report different findings, and whilst several studies may appear to give varied and often conflicting results, performing a meta-analysis gives an indication of general findings by ‘pooling’ the data from several studies to give an overall picture and therefore adding clarity to a concept.

A recent meta-analysis of 14 studies comparing the levels of polyunsaturated fatty acids between depressive patients and control subjects found that omega-3 polyunsaturated fatty acid levels were significantly lower in those individuals suffering from depression (Lin et al, 2010). Because the primary sources of these long-chain omega-3 fats are fish and shellfish, it is not surprising that those individuals with the highest consumption are the least likely to suffer from depression (Suominen-Taipale et al, 2010). Treating people who suffer with depression using fish oils is therefore a viable method for alleviating symptoms whilst restoring omega-3 levels. Given that low levels of omega-3 are also associated with increased risk of cardiovascular disease, as well as several other chronic disorders and conditions, the overall health benefits of raising omega-3 levels reach out much further as a nutritional approach to improving health.

Encouragingly, improvements in depressive symptoms can be seen as quickly as 8 weeks after commencing treatment. Indeed, a group of Montreal researchers have recently confirmed that taking omega 3 fish oil supplements, at doses higher than that normally consumed in an average diet, is superior to placebo in treating symptoms and that results can be observed within a two month time period (Lespérance et al, 2010). The results of this particular study also confirm EPA to be the predominant active ingredient responsible for the benefits of omega-3.

A meta-analysis of 28 trials investigating as to whether either EPA or docosahexanoeic acid (DHA) or both are responsible for the reported benefits showed that those trials in which EPA was the predominant or only fatty acid used, gave the most significant findings. Furthermore, it was suggested that the effects of 1g daily of EPA could be enhanced and prolonged by the addition of gamma-linolenic acid (GLA), an omega-6 fatty acid found in evening primrose oil (Martins 2009). Given that 1 in 4 individuals will suffer from depression at some point in their life, it is encouraging to know that there is a safe and natural way not only to treat depression but also as a method that could reduce the possibility of developing the condition in the first place.

Suominen-Taipale AL, Partonen T, Turunen AW, Männistö S, Jula A, Verkasalo PK.Fish consumption and omega-3 polyunsaturated Fatty acids in relation to depressive episodes: a cross-sectional analysis. PLoS One. 2010 May 7;5:e10530.