Earlier this year, an expert panel organized by the International Society for Nutritional Psychiatry Research concluded that omega-3 fatty acids should be recommended as adjuvant treatment for major depression in pregnant women, children, and the elderly, and as prevention in high-risk populations.
In the light of a brand new and extensive meta-analysis, that recommendation might seem a bit premature, if not plain wrong.
This meta-analysis, commissioned by the World Health Organisation as part of a larger project to assess the effects of polyunsaturated fatty acids on human health, gathered data from a total of 31 randomized controlled trials. Pretty much every study with a duration of at least 24 weeks published up until August 2019 looking at the effects of increasing omega-3 on depression and anxiety were included.
The results were not as positive as the conclusions of the mentioned expert panel. In fact, they were not positive at all. This review included information from thousands of people and long periods of time, yet the researchers could find no demonstrable effects of omega-3 on depression.
They found that if you increase your omega-3 intake through diet or supplements, it will likely have little to no effect on the risk of depression or anxiety symptoms. No matter the omega-3 dose, the duration of the supplementation or if the omega-3 fatty acids replaced other nutrients in the diet, the results were the same: no evidence that increasing omega-3 intake will have any effect at all.
Apparently, in some of the earlier trials where omega-3 showed an association with improved markers of depression, more than half of the subjects had been using antidepressants as well, which makes those results pretty useless.
Looking at the effects on depression severity, the researchers couldn’t come to any conclusions, simply because the evidence from the available trials was of very low quality. This means that any existing recommendations for omega-3 supplementation based on said trials are also of low scientific quality.
The meta-analysis concludes by stating that omega-3 should not be recommended for reducing the risk of depression or anxiety. In addition, any evidence of treating existing depression with omega-3 supplements is of such a low quality that recommendations would be based on pretty much nothing.
Fatty fish is nutritious, and most of us should probably eat more of it for health reasons. However, you probably shouldn’t take fish oil pills with the intention of preventing or treating depression.
Read more about omega-3 in our supplement guide: