But a systematic review published yesterday (November 4th) in the British Journal of Psychiatry, funded by the World Health Organisation, found no demonstrable value in people taking omega-3 oil supplements for the prevention or treatment of depression and anxiety.
The research team looked at 31 trials of adults with and without depression or anxiety. More than 41,470 participants were randomised to consume more long-chain omega-3 fats (fish oils), or maintain their usual intake, for at least six months
They found that the supplements had little or no effect in preventing depression or anxiety symptoms.
Lead author Dr Lee Hooper, from UEA’s Norwich Medical School, said: “Our previous research has shown that long-chain omega-3 supplements, including fish oils, do not protect against conditions such as heart disease, stroke, diabetes or death.
“This large systematic review included information from many thousands of people over long periods. Despite all this information, we don’t see protective effects.
“The most trustworthy studies consistently showed little or no effect of long-chain omega-3 fats on depression or anxiety, and they should not be encouraged as a treatment.”
The report states that many adults are encouraged to take omega-3 supplements to improve their mental health and suggests that physicians stop recommending this supplement as any evidence to show its effectiveness is of 'very low quality'.
It concludes that further methodologically strong, long-term trials - with robust randomisation, allocation concealment, blinding, and adherence - are needed to drive practice in people with existing depression and anxiety.
Discussing the review's findings, Dr Katherine Deane, from UEA’s School of Health Sciences, added that the consumption of fish oil supplements seems 'unhelpful' considering the environmental impacts of fishing for fish oil sources.
"Considering the environmental concerns about industrial fishing and the impact it is having on fish stocks and plastic pollution in the oceans, it seems unhelpful to continue to swallow fish oil tablets that give no benefit."
However, Harry Rice, PhD, Vice President of Regulatory and Scientific Affairs at GOED, the global organisation for EPA and DHA, says the scientific data reviewed in this study was by no means conclusive.
"Due to diagnostic heterogeneity resulting in what can be very dissimilar subject pools, results from both observational and clinical research have been equivocal when it comes to the benefits of EPA/DHA for anxiety and depression.
"Anxiety and depression are not homogeneous entities and shouldn't be treated as such. While I consider the totality of the available scientific data in this area to be encouraging, I don't consider it to be conclusive by any means.
"While I assume the authors' publication was well-intentioned, it was too conclusive and only adds to the existing confusion in this area."
Source: British Journal of Psychiatry
Authors: Hooper. L., et al
‘Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: systematic review and meta-analysis of randomised trials’