There is insufficient evidence that omega-3 fatty acid supplements are effective in treating major depressive disorders, according to new research.
The fatty acids, which are naturally found in fish and in some nuts and seeds, are widely available as supplements, and their popularity has increased hugely in the last decade.
The research gathered data from 26 randomised trials involving 1,458 participants. The trials investigated the impact of omega-3 supplements compared with placebos.
The study’s authors found that although people given the supplements reported lower symptom scores than those taking the placebo, the effect was too small to be sufficient as evidence. Their analysis found that a similar number of people experienced adverse side effects, although they say more data is required to understand the risks of taking omega-3 fatty acids.
Bournemouth University’s Katherine Appleton, the study’s lead author, 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.
‘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. It’s important that people who suffer from depression are aware of this, so that they can make more informed choices about treatment.’
Figures published by the World Health Organisation suggest that major depressive disorders will account for between six and seven per cent of global health problems by 2030.