The widely promoted Omega 3 fatty acid supplements - believed to be essential for good health - may not be effective in treating major depressive disorders, a new study has found.
Omega 3 fatty acids are naturally found in fatty fish, such as tuna, seafood and some nuts and seeds. They have been widely promoted globally and are readily available, over-the-counter supplement.
These supplements have hugely increased in popularity over the last decade together with a range of other supplements including ginseng, garlic, green tea, as well as vitamins, minerals and herbal products.
There have been various studies that have suggested a role for Omega 3 fatty acid supplementation in treating major depressive disorder.
Adults with major depressive disorders are characterised by depressed mood or a lack of pleasure in previously enjoyed activities for at least two weeks, in the absence of any physical cause, that impact on everyday life.
Researchers from Bournemouth University in UK gathered data from 26 randomised trials involving a total of 1,458 participants.
The trials studied the impact of giving an Omega 3 fatty acid supplement in a capsule form and compared it to a placebo.
In one study, involving 40 participants, they also studied the impact of the same supplementation compared to an anti-depressant treatment.
Researchers found that while people who were given Omega 3 fatty acids reported lower symptom scores than people with the dummy pill, the effect was small and there were important limitations that undermined their confidence in the results.
Their analyses showed that although similar numbers of people experienced side effects, more data would be required to understand the risks of taking Omega 3 fatty acids.
"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," said lead author, Katherine Appleton from Bournemouth University.
"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," Appleton said.
"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," she said.
"It's important that people who suffer from depression are aware of this, so that they can make more informed choices about treatment," she said.
The study was published in the journal Cochrane Library.
