The notion that omega-3 fatty acids (EPA and DHA) from seafood support brain and mood health enjoys very substantial support.

The American Psychiatric Association (APA) examined the evidence in 2006 and concluded that people who get lots of omega-3s from seafood (EPA and DHA) enjoy a reduced risk for depression (see > “Top Psych Panel Says Omega-3s Deter Depression, Bipolar Disorder”).

And most of the evidence reviews published since then have affirmed the APA's finding (Lin PY et al. 2007; Bloch MH et al. 2011; Sublette ME et al. 2011; Sarris J et al. 2012).

Two recent studies had mixed outcomes, with an epidemiological (diet-health) study finding no links, while a clinical trial in older women confirmed real mood benefits from omega-3s … see “Omega-3s for Mood: Mixed Findings in Women”.

Now, a well-designed epidemiological study links higher estimated intakes of omega-3s to a sharply lower risk of depression.

The effect was only seen in women, who suffer higher rates of depression than men, and therefore stand to gain more mood benefits from fishy diets. 

And the study's outcomes echoes prior findings showing that the high ratio of omega-6 to omega-3 fatty acids in the standard American diet promote depression.

For more on the effects of this imbalance, see “Omega-6 Overload Linked to Depression” and “America's Sickening ‘Omega Imbalance'”.) 

High omega-3 levels and omega-3/6 ratios reduce women's depression risk
A team led by May Beydoun, PhD, from the National Institute on Aging looked for links between omega-3 intakes and depression (Beydoun MA et al. 2013).

They examined diet and mental health data collected from 1,746 adult African American and white men and women (755 men and 991 women) aged 30 to 65, from Baltimore, Maryland.

The team compared the participants' estimated omega-3 intakes (based on two diet questionnaires) to their scores on tests for depression symptoms.

Compared with women reporting the lowest omega-3 intakes, the risk for depression was just half (49 percent) among the women with the highest intakes of omega-3s from seafood or supplements (EPA and DHA).

A similar result was obtained when they compared the female volunteers' depression scores with the intake ratio of omega-3 to omega-6 fatty acids.

However, the male participants with higher omega-3 intakes did not enjoy a significant reduction in depression risk

Dr. Beydoun and her group proposed three explanations for the observed benefits:
  1. The brain's serotonin system is regulated by omega-3s (Hibbeln JR et al. 1998), and anti-depressants like Prozac work in part by raising serotonin levels.
  2. Omega-3s are known to promote the formation of anti-inflammatory compounds and resolve inflammation (Dalli J et al. 2012). In contrast, omega-6s promote formation of pro-inflammatory compounds, which can provoke or worsen symptoms of depression.
  3. People with depression tend to suffer from impaired metabolism of brain phospholipids and problems in the system that sends signals between cells via fatty acids (Maes M et al. 1995; McNamara RK et al. 2006). Some evidence suggests that the mood stabilizing effects of omega-3s may result from their normalizing effects on such “cell signaling” pathways and ability to stabilize and optimize brain cell membranes.
Stay tuned for future reports on research into this critical realm.

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  • Bloch MH, Hannestad J. Omega-3 fatty acids for the treatment of depression: systematic review and meta-analysis. Mol Psychiatry. 2012 Dec;17(12):1272-82. doi: 10.1038/mp.2011.100. Epub 2011 Sep 20. Review. 
  • Colangelo LA, He K, Whooley MA, Daviglus ML, Liu K. Higher dietary intake of long-chain omega-3 polyunsaturated fatty acids is inversely associated with depressive symptoms in women. Nutrition. 2009 Oct;25(10):1011-9. doi: 10.1016/j.nut.2008.12.008. Epub 2009 Feb 4. 
  • Dalli J, Winkler JW, Colas RA, Arnardottir H, Cheng CY, Chiang N, Petasis NA, Serhan CN. Resolvin d3 and aspirin-triggered resolvin d3 are potent immunoresolvents. Chem Biol. 2013 Feb 21;20(2):188-201. doi: 10.1016/j.chembiol.2012.11.010. 
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  • Hibbeln JR, Linnoila M, Umhau JC, Rawlings R, George DT, Salem N Jr. Essential fatty acids predict metabolites of serotonin and dopamine in cerebrospinal fluid among healthy control subjects, and early- and late-onset alcoholics. Biol Psychiatry 1998; 44: 235-242. 
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