Fish oil supplements may not reduce anxiety, depression

Omega-3 fats have little or no effect on anxiety and depression, according to new research from the University of East Anglia in Norwich, England, and published in the British Journal of Psychiatry.

The systemic review, which was funded by the World Health Organization, looked at 31 trials of adults with and without depression or anxiety. More than 41,470 participants were randomized to consume more long-chain omega-3 fats, or maintain their usual intake, for at least six months.

The researchers found the supplements had little or no effect in preventing depression or anxiety symptoms.

Increased consumption of omega-3 fats is widely promoted globally because of a common belief that it will protect against, or even reverse, conditions such as anxiety and depression. Small amounts are essential for good health and can be found in foods including nuts, seeds, and fatty fish, such as salmon. Omega-3 fats are also readily available as over-the-counter supplements and they are widely bought and used.

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, according to Lee Hooper, PhD, SRD, lead author of the study.

"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,” she said in a statement.

However, Katherine Deane, PhD, first author of the study, said omega-3 fats such as oily fish can be a 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,” said Deane in a statement. “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."