“No net benefit” for the prevention of depression?


Supplementing with fish oil doesn’t help prevent depression or improve mood, new research shows.

The VITAL-DEP study included more than 18,000 participants. In adults aged 50 or older who did not initially have clinically relevant depressive symptoms, long-term use of marine omega-3 (omega-3) fatty acid supplements did not reduce the risk of depression. or clinically relevant depressive symptoms – neither made a difference in the quality of mood.

In fact, a slight increase in the risk of depression or depressive symptoms has been seen with omega-3 supplements.

“While a slight increase in the risk of depression was within the statistical range of significance, there was no harmful or beneficial effect of omega-3s on overall mood changes over the 5-7. years of follow-up approximately, ”said lead author Olivia. I. Okereke, MD, Massachusetts General Hospital and Harvard Medical School, Boston, said Medscape Medical News.

“The takeaway from our study is that there is no clear benefit to long-term use of omega-3 fish oil daily supplements to prevent depression or improve mood,” Okereke said.

The results were published online today in the Journal of the American Medical Association.

Risk assessment for the general population

For many years, experts have recommended omega-3 supplements to reduce the recurrence of depression in some high-risk patients, Okereke noted.

“However, there are no guidelines for the use of omega-3 supplements to prevent depression in the general population. Therefore, we undertook this study to clarify the problem,” he said. she declared.

The VITAL-DEP study included 18,353 elderly people (mean age, 67.5 years; 49% women). Of these, 16,657 were at risk for incident depression, defined as having no history of depression; and 1,696 were at risk for recurrent depression, defined as having a history of depression but not having received treatment for depression in the past 2 years.

About half of the participants were randomized to receive marine omega-3 fatty acids (1 g / d of fish oil, of which 465 mg of eicosapentaenoic acid [EPA] and 375 mg of docosahexaenoic acid [DHA]) and the other half to the corresponding placebo for 5.3 years on average.

“Due to the large sample size and the long follow-up, we were able to test the effects of daily omega-3 fish oil supplements on the universal prevention of depression in the adult population,” Okereke said.

No significant benefit

The results showed that the risk of depression or clinically relevant depressive symptoms (total of incident and recurrent cases) was not significantly different between the omega-3 group and the placebo group.

The omega-3 group had 651 clinically relevant depressions or depressive symptomatic events (13.9 per 1,000 person-years), and the placebo group had 583 clinically relevant depressions or depressive symptomatic events (12.3 per 1,000 person-years). The risk ratio was 1.13 (95% CI, 1.01 – 1.26; P = .03).

There were also no significant differences between groups in longitudinal mood scores. The mean difference in change in the 8-item Patient Health Questionnaire (PHQ-8) score was 0.03 points (95% CI: -0.01 to 0.07; P = .19).

“Patients, physicians, and other clinicians should understand that there are still many reasons why some people, under the direction of their healthcare providers, take omega-3 fish oil supplements,” he said. noted Okereke.

“These supplements have been shown to be increasingly beneficial for the prevention of heart disease and the treatment of inflammatory conditions, in addition to being used for the management of existing depressive disorders in some high-risk patients,” she said. declared.

“However, the results of our study indicate that there is no reason why adults in the general population should take omega-3 fish oil supplements daily for the sole purpose of preventing depression or maintaining a healthy diet. positive mood, ”she added.

Okereke noted, however, that the VITAL-DEP study used 1g / day of omega-3 fatty acids and that it may be more beneficial to take higher doses, such as 4g / day.

Caution Notes

Commenting on the study of Medscape Medical News, Kuan-Pin Su, MD, PhD, head of the general psychiatry department, China Medical University, Taichung, Taiwan, pointed out some of the limitations cited by investigators.

First, depression or depressive symptoms were defined using self-report scales, which are “convenient for screening for depressive disorders, but a high score obtained on a self-report scale does not indicate not necessarily the presence of depressive psychopathology, ”said Su, who was not involved in the research.

He also noted that the use of 465 mg of EPA and 375 mg of DHA in VITAL-DEP “might be too low” to have an impact.

Finally, Su said it was “very important to also address the potential for Type I error, which makes secondary and subgroup analyzes less reliable.”

VITAL-DEP was supported by a grant from the National Institute of Mental Health. Pronova BioPharma donated the fish oil and corresponding placebo. Okereke said he received royalties from Springer Publishing. Su is a member of the founding committee of the International Society for Nutritional Psychiatry Research, director of the board of directors of the International Society for the Study of Fatty Acids, and associate editor of the journal. Brain, behavior and immunity.

JAMA. Published online December 21, 2021. Full text

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