Higher omega-3 levels in plasma associated with reduced risk of self-harm, study shows | Nutritional Outlook

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Higher levels of omega-3 fatty acids (FAs) may support mental health, a new study suggests.1 The study notes that self-harm and suicidal ideation is a growing mental health concern globally, and that research on the anti-inflammatory properties of omega-3 FAs suggests the nutrients may offer benefits for brain health and mental health. The aim of this research was to examine the relationship between plasma levels of omega-3 FAs and the prevalence of self-harm in a population group from United Kingdom Biobank (UKBB). The study, “The association between plasma omega-3 fatty acids and suicidal ideation/self-harm in the United Kingdom Biobank,” was published in Lipids in Health and Disease in November 2025.

Study design: measuring omega-3 FAs and self-harm

Data on plasma levels of omega-3 fatty acids (including DHA, non-DHA [ALA+EPA+DPA], and total omega-3) were analyzed from 258,012 participants in the prospective, population-based UKBB. Data on passive suicidal ideation, history of self-harm, and future self-harm was analyzed, including data based in medical records. Plasma levels were measured using Nuclear Magnetic Resonance (NMR). Statistics were adjusted for covariates.

A secondary analysis examined a subset of 80,745 participants with more detailed responses on lifetime variables.

Results: an inverse relationship between omega-3s and self-harm

An inverse relationship was demonstrated between suicidal ideation, history of self-harm, and future self-harm and omega-3 FAs levels in plasma. Notable results included:

  • A 14% lower risk of passive suicidal ideation in the last year was seen in participants who were in the highest quintile of non-DHA levels
  • 33% lower odds of a history of self-harm were associated with the highest DHA levels
  • These associations were associated more with outcomes based in medical records than in self-reported outcomes

“This study provides evidence that higher omega-3 FA levels, both DHA and non-DHA, are associated with reduced risks of self-harm and suicidal ideation,” the researchers concluded. “These findings suggest that omega-3 FAs may play a protective role in mental health, highlighting the potential of dietary interventions to mitigate self-harm behaviors.”

The combination of the non-DHA FAs meant that researchers were not able to identify which one was most responsible for the associations.

Omega-3 FAs supplementation for mental health

“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,” explained Dr. W. Grant Franco, lead author for the study, in a press release from OmegaQuant.2 “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.”

Omega-3s are essential for neuronal cell membrane fluidity, neurotransmission, and brain function, the researchers noted.

“Omega-3 fatty acids, especially DHA and EPA, are known to support brain function and reduce inflammation,” added Dr. William S. Harris, senior study author, and president and founder of the nonprofit foundation 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.”

Previous research has also linked omega-3 supplementation with a lower risk of major depressive disorder, the researchers noted. To establish causality, future studies should include randomized controlled trials and also establish a dosage and duration of the supplementation for mental health benefits.

References

  1. Franco, W.G.; Tintle, N.; Westra, J. et al. The association between plasma omega-3 fatty acids and suicidal ideation/self-harm in the United Kingdom Biobank. Lipids Health Dis 2025. 24(364). DOI: 10.1186/s12944-025-02689-1
  2. OmegaQuant. New UK Biobank Study Links Higher Omega-3 Levels to Lower Risk of Self-Harm & Suicidal Ideation. December 2, 2025. https://omegaquant.com/new-uk-biobank-study-links-higher-omega-3-levels-to-lower-risk-of-self-harm-suicidal-ideation/ (accessed 2025-12-02).