A new cross-sectional analysis published in The Journal of Nutrition provides compelling evidence that higher plasma levels of omega-3 fatty acids—particularly EPA-rich, non-DHA omega-3s—are associated with lower rates of depression and anxiety.

The study was led by researchers at the Fatty Acid Research Institute (FARI) and evaluated more than 250,000 adults with plasma fatty acid measurements and more than 460,000 adults with detailed fish oil supplement use in the UK Biobank—the largest biomarker-based mental health study of its kind.

According to FARI, critical depression and anxiety outcomes were drawn from physician-diagnosed ICD-10 codes, not self-reported—making the results more clinically relevant. Statistical models were adjusted for age, sex, ethnicity, BMI, smoking, diet, alcohol use, exercise, socioeconomic stats, etc.

The findings show individuals with the highest omega-3 index had 15-33 percent lower odds of a lifetime history of depression and 19-22 percent lower odds of a lifetime history of anxiety compared with those with the lowest levels. The non-DHA omega-3 fraction—primarily EPA—showed some of the strongest associations with reduced risk.

The study also found that fish oil supplement users had 9-10 percent lower risk of a history of depression or anxiety and 20 percent lower risk of recent anxiety independent of fish intake.

“Our findings from more than a quarter-million adults show a clear and consistent link between higher omega-3 status and lower chance of having a history of both depression and anxiety,” said Dr. William S. Harris, lead author and president of FARI. “When you consider the biological roles of EPA and DHA in inflammation, neuronal function, and neurotransmitter signaling, these associations make a great deal of sense. This study adds significant weight to the growing evidence that omega-3 fatty acids—especially EPA—may help protect mental health.”

“The strength of this research lies in both its scale and its use of plasma omega-3 measurements. The biomarker data give us a much clearer picture than self-reported diet alone, and the consistency across multiple omega-3 metrics strengthens confidence in the overall conclusions,” added Nathan L. Tintle, PhD, co-author, biostatistician, and executive director of FARI. 

For more information, visit www.omegaquant.com.