Despite popular belief that omega-3 fatty acids can combat anxiety and depression, omega-3 supplements likely offer little or no actual effect on symptoms, researchers reported online in The British Journal of Psychiatry.
Omega-3 fats are found in nuts, seeds, and fatty fish, such as salmon.
“Oily fish can be a very nutritious food as part of a balanced diet,” researcher Katherine H. O. Deane, PhD, of the University of East Anglia in England said. “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.”
For their meta-analysis, Dr. Deane and colleagues looked at 31 trials of more than 41,000 adults with and without depression and anxiety. The studies randomized participants to increase their consumption of long-chain omega-3 fats or to maintain their typical intake for 6 months or more.
Omega-3 supplements seemed to have little to no effect in preventing symptoms of depression or anxiety in participants, researchers reported. In people with existing depression, evidence of any effect on symptom severity and remission was of very low quality and unclear, the study found.
“This large systematic review included information from many thousands of people over long periods. Despite all this information, we don't see protective effects,” said study lead author Lee Hooper, PhD, of the University of East Anglia. “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.”
Deane KHO, Jimoh OF, Biswas P, et al. Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: systematic review and meta-analysis of randomised trials. The British Journal of Psychiatry. 2019 October 24;[Epub ahead of print].