An analysis of more than 258,000 adults in the UK Biobank found that higher blood levels of omega-3 fatty acids, including DHA, EPA, ALA, AND DPA, are consistently associated with lower incidence of suicidal ideation, history of self-harm, and future self-harm events. The findings, published in Lipids in Health and Disease, support the role of omega-3s in mental health, the researchers concluded.

Omega-3 levels were measured in participants via NMR spectroscopy, and were measured against both self-reported and medical record-verified outcomes related to self-harm and suicidal thoughts. Three outcomes were evaluated, including: passive suicidal ideation and contemplation of self-harm; lifetime and past-year self-harm (self-reported and from medical records); and future incident self-harm events.

Models adjusted for demographics, lifestyle factors, medication use, comorbidities, and mental health history. The median follow-up time was 13.7 years.

Higher DHA; higher sum total of EPA, ALA, and DPA; and higher total omega-3s consistently were associated with lower odds of passive suicidal ideation, lifetime self-harm, past-year self-harm, and future self-harm recorded in medical records.

Some notable figures included that people with the highest DHA quintile had 33% lower odds of a history of self-harm, and those with the highest non-DHA sum total omega-3s had a 14% lower rate of passive suicidal ideation in the past year.

The authors noted that the associations were strongest for medical record-based outcomes, suggesting that the study results weren’t driven by self-report bias.

“Our findings show that individuals with higher plasma omega-3 levels, across DHA, EPA, DPA, and ALA, consistently had lower risks of both past and future self-harm behaviors. While we cannot infer causality, the strength and consistency of these associations, particularly for medical-record-verified outcomes, point to a potentially important protective role for omega-3 fatty acids in mental health,” said W. Grant Franco, MD, the study’s lead author.

“Omega-3 fatty acids, especially DHA and EPA, are known to support brain function and reduce inflammation,” said William S. Harris, PhD, senior author, and president and founder of the Fatty Acid Research Institute (FARI). “Our results align with previous research linking low omega-3 status to higher suicide risk. Given that omega-3 levels are generally low in Western populations, improving dietary intake or supplementation patterns may be a simple, safe strategy to support mental well-being, especially among those at elevated risk.”

The results are observational in nature, and the authors emphasized the need for randomized, controlled trials to test whether increasing omega-3 levels can reduce self-harm behaviors or suicidal thoughts directly.