Because depression appears to be less common in countries where people more fish containing omega-3 fatty acids, researchers have been interested in whether omega-3 fatty acids could be used to prevent and/or treat depression and other mood disorders. While experts have recommended supplementation with omega-3 fatty acids to reduce the recurrence of depression in high-risk patients, studies investigating the use of these supplements to prevent depression in the general population have yielded mixed results.
In a recent study, Olivia Okereke, MD MS and colleagues from the Mass General Department of Psychiatry assessed the impact of omega-3 supplementation on risk for depression in a group of older adults taking part in the VITAL study. The VITAL study is a randomized controlled trial of 25,871 men and women in the US designed to investigate whether taking daily dietary supplements of vitamin D3 or omega-3 fatty acids reduces the risk for developing cancer, heart disease, and stroke. The VITAL-DEP (Vitamin D and Omega-3 Trial-Depression Endpoint Prevention) is an ancillary study examining the use of daily vitamin D or omega-3 supplements for preventing depression.
In this cohort, there were 1696 adults who were at risk for recurrent depression; these participants had a history of depression but had no current symptoms of clinical depression and received no treatment for depression within the past two years. A comparison group of 16,657 adults had no history of depression. Participants were randomized to receive marine omega-3 fatty acids (1 g/day of fish oil, including 465 mg of eicosapentaenoic acid and 375 mg of docosahexaenoic acid) or placebo; 9171 were randomized to omega-3 and 9182 were randomized to placebo and were followed for 5 to 7 years. Depressive symptoms were assessed using the Patient Health Questionnaire – 8 items (PHQ-8).
Among the 18,353 randomized participants (mean age, 67.5 years; 49.2% women), the median treatment duration was 5.3 years, and 90.5% completed the trial. There was a slight but nominally statistically significant increased risk of depression or clinically relevant depressive symptoms comparing those receiving the omega-3 supplements versus those receiving placebo. However, there were no significant differences between the two groups in terms of changes in mood scores over the entire follow-up. Overall, the researchers found no benefit of omega-3 supplements for preventing depression or improving mood in this large general adult sample.
To date, this is the largest long-term study of the effects of supplemental omega-3 fatty acids assessing risk for depression. In this study of older adults aged 50 years or older, omega-3 supplementation did not reduce risk for new onset or recurrence of depression. Thus, the findings of this study do not support the use of omega-3 fatty acids to prevent depression in the general adult population.
While there appeared to be no benefit in terms of preventing depression in this study, the authors of the study remind us that there are still health benefits associated with omega-3 fish oils. These supplements have been found to have benefits for cardiac disease prevention and treatment of inflammatory conditions, and omega-3 fatty acids may be beneficial for the treatment of depressive symptoms in some individuals.
Okereke OI, Vyas CM, Mischoulon D, Chang G, Cook NR, Weinberg A, Bubes V, Copeland T, Friedenberg G, Lee IM, Buring JE, Reynolds CF 3rd, Manson JE. Effect of Long-term Supplementation With Marine Omega-3 Fatty Acids vs Placebo on Risk of Depression or Clinically Relevant Depressive Symptoms and on Change in Mood Scores: A Randomized Clinical Trial. JAMA. 2021 Dec 21;326(23):2385-2394.
Other Members of MGH Psychiatry Contributing to this Research:
Chirag M Vyas, BS MB
David Mischoulon, MD PhD
Olivia Okereke, MD MS
