There is insufficient evidence for the use of taking an omega 3 fatty acid supplements in treating major depressive disorder, according to a Cochrane review of available research.
Omega 3 fatty acids are widely thought to be essential for good health and are naturally found in fatty fish, such as tuna, seafood and some nuts and seeds.
“We just don’t have enough high quality evidence to determine the effects of omega 3 fatty acids as a treatment for major depressive disorder”
They have been widely promoted globally and, more recently, various studies have suggested a role for them in treating major depressive disorders – characterised by depressed mood or a lack of pleasure in previously enjoyed activities for at least two weeks.
A new Cochrane review looked at data from 26 trials involving 1,458 participants. The trials investigated the impact of omega 3 fatty acid supplements in capsule form compared to placebo.
In one study, involving 40 participants, they also investigated the impact of the same supplementation compared to an anti-depressant treatment.
The Cochrane reviewers found that, while people given omega 3 fatty acids reported lower symptom scores than people with the placebo, the effect was small and there were important limitations that undermined their confidence in the results.
Their analyses – published today in the Cochrane Database of Systematic Reviews – also showed that more data would be required to understand the risks of taking omega 3 fatty acids.
Lead study author Katherine Appleton, from Bournemouth University, said: “We found a small-to-modest positive effect of omega 3 fatty acids compared to placebo, but the size of this effect is unlikely to be meaningful to people with depression, and we considered the evidence to be of low or very low quality.
“All studies contributing to our analyses were of direct relevance to our research question, but most of these studies are small and of low quality,” she said.
She added: “At present, we just don’t have enough high quality evidence to determine the effects of omega 3 fatty acids as a treatment for major depressive disorder.”