Effect of omega-3 PUFAs in depression: A meta-analysis

The Publication

Increasingly, evidence is showing that supplementation with omega-3 PUFAs (DHA and EPA) are effective in alleviating depression. However, the mechanisms behind EPA and DHA could differ and the optimal dosing, ratio and extent to which supplementation exerts beneficial effects is yet to be determined.

This meta-analysis analysed 26 double-blind randomized control trials to assess the dose at which omega-3 PUFAs causes a therapeutic effect and whether this is influenced by differing proportions of EPA and DHA.

Collectively the meta-analysis confirmed that there was an overall beneficial effect of omega-3 PUFAs on symptoms of depression, corroborating previous research. EPA-pure and EPA-major formulations (≥ 60% EPA) given at a dosage ≥1 g/day yielded clinical benefits when compared with a placebo (p<0.05). However, DHA-pure and DHA-major formulations, at the same dosage, did not yield benefits. In addition, increasing the dosage (1.5g/day and 2g/day) showed no benefit in both DHA and EPA groups. Thus EPA at a dosage of between 1g-1.5g/day shows the most beneficial therapeutic effects on treating depression.

It is important to note that only two studies within the meta-analysis looked specifically at DHA-pure supplementation, so it is not sufficient to make any conclusions about DHA efficacy. An additional limitation, like much of the research in the field, is that many factors were not controlled for, including the severity of the depression. It is important to note that optimal dosages may differ between those with mild depression and those with more severe cases. For sound conclusions to be drawn, future research should look at dosages in specific subgroups of the population, accommodating for depression severity.

Our Response

This meta-analysis adds to the body of evidence which suggests omega-3 PUFA supplementation helps alleviate depression, reaffirming the impact that nutrition has on brain function. Gaining a better understanding on the optimal dosing and formulations that yield the most clinical benefits has key practical implications, particularly for the work that we do at Think Through Nutrition.