Omega-3 fats have little or no effect on anxiety and depression

Omega-3 fats found in oily fish and nuts have little or no effect on curbing anxiety and depression, reveals myth debunking research

  • Omega-3 fats are promoted for supposed power to alleviate mental health issues
  • Scientists at University of East Anglia in Norwich are urging a serious re-think
  • They examined outcomes from 31 clinical trials which increased omega-3 intake
  • Risk of depression only dropped by one per cent after consumption, study found

Eating fatty fish and nuts does not do wonders for your mental health, according to research which debunks the pre-conceived wisdom. 

Omega-3 fats are globally promoted for their supposed power to alleviate anxiety and depression. 

But scientists at the University of East Anglia are urging a serious re-think after they reviewed 31 clinical trials.

They found omega-3s cut the risk of depression by just one per cent for depression, and were equally as insignificant for anxiety. 

Omega-3 fats are globally promoted for their supposed power to alleviate anxiety and depression (file photo)

The studies involved more than 41,000 participants who were split into two groups. 

The first increased their omega-3 intake through fish oil supplements, and the other maintained their usual consumption levels. 

After a 24-week period, changes in their mental health were recorded either through ‘primary’ indicators such as a depression diagnosis or ‘secondary’ indicators such as quality of life, carer stress and self-harm based on questionnaires.



Both omega-3 and cod liver oil capsules contain the essential fatty acids EPA and DHA. 


Cod liver oil capsules as also contain high amounts of vitamin A and also vitamin D. The high levels of vitamin A mean that cod liver oil capsules are not advised for pregnant women as too much vitamin A may be harmful for their baby.


Krill oil is extracted from a shrimp-like, Antarctic crustacean. It is a rich source of the long-chain omega-3s, EPA and DHA. It also contains two powerful antioxidants, astaxanthin and canthaxanthin, which give it an attractive red colour. 

These pigments are derived from the algae on which krill feed, and are the same pigments that give flamingos their pink plumage. 

The combination of omega-3s plus antioxidants make krill a popular ‘super-supplement’ for reducing inflammation, and for beneficial effects on cholesterol balance. 

The research concluded omega-3 fats – while good for one’s health – had no tangible effect on depression and anxiety.   

Only one of the clinical trials provided data on the correlation between omega-3s and anxiety, and recorded a zero per cent change. 

Lead author Dr Lee Hooper has called on physicians to stop advising omega-3 fats for depression and anxiety patients.

He said: ‘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.’

Dr Katherine Deane, co-author from UEA’s School of Health Sciences, said: ‘Oily fish can be a very nutritious food as part of a balanced diet.

‘But we found that there is no demonstrable value in people taking omega-3 oil supplements for the prevention or treatment of depression and anxiety.

‘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.’

The study was funded by the World Health Organisation and published in the British Journal of Psychiatry.

In 2016, researchers from Melbourne University and Harvard suggested that omega-3 intake significantly improved mood when combined with antidepressants over a placebo.

They argued that, because omega-3s can easily travel through the brain cell membrane, they may interact with mood-related molecules inside the brain. 

The fatty acids also have anti-inflammatory actions which researchers thought may also help relieve depression. 

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