Feeling Depressed? Then check your Omega-3 Fatty Acid Intake
A new study supports growing evidence that depressive symptoms are more common in people with low omega-3 status.
Beydoun and colleagues assessed self-reported depressive symptoms in 1,746 adults (30-65y) living in Baltimore, MD. Using two 24-hr dietary recalls and a 20-item Center for Epidemiologic Studies-Depression Scale, they report a higher prevalence of depressive symptoms in women (25.6%) then men (18.1%). In women, depressive symptoms were more common in those with low omega-3 fatty acid intakes (% of energy) and n-3 PUFA:n-6 PUFA ratios. The relationship remained even after adjusting for sociodemographic, lifestyle and health-related potential confounders, including dietary intake. The authors acknowledge that the study is limited by its cross-sectional design, use of self-reported dietary intakes and depressive symptoms nature, and a lack of data on fatty acid intakes from dietary supplements. These limitations are not inconsequential.
However, we should remember that Lewis and colleagues measured serum fatty acids in 800 US military personnel who committed suicide and 800 controls matched for age, sex, rank, and year-of-incident. Risk of suicide death was 14% higher per suicide death in those with low docosahexaenoic acid (DHA) percentages. They also report that many military personnel had low serum DHA levels.
In a study involving patients at risk of self-harm, 2 gm daily of omega-3 fatty acids [1.2g eicosapentaenoic acid (EPA) and 0.9g DHA] for 12 weeks improved scores for depression, suicide and general well-being (vs volunteers receiving the placebo).
Rizzo and colleagues measured serum EPA and DHA concentrations in 76 female residents in a nursing home. Lower serum EPA and DHA levels were found in depressed patients. Omega-3 supplementation (2.5g/d for 8 weeks) increased whole blood and red blood cell membrane n-3 fatty acids and reduced the severity of depressive symptoms.
Omega-3 fatty acids, especially DHA, are needed to form cell membranes and to facilitate neuronal signaling within the brain. The evidence accumulates that inadequate intakes of DHA may affect brain hormones linked with depression and cognitive function. More studies are needed using direct biological measures of omega-3 status to elucidate the role of DHA (and EPA) on the structure and function of the brain.
Beydoun MA, Kuczmarski MT, Beydoun HA, Hibbeln JR, Evans MK, Zonderman AB. Omega-3 fatty acid intakes are inversely related to elevated depressive symptoms among United States women. 2013 J Nutr doi:10.3945/jn.113.179119
Lewis MD, Hibbeln JR, Johnson JE, Lin YH, Hyun DY, Loewke JD. Suicide deaths of active-duty US military and omega-3 fatty acid status: A case-control comparison. 2011 J Clin Psych doi:10.4088.JCP.11m06879
Hallahan B, Hibbeln JR, Davis JM, Garland MR. Omega-3 fatty acid supplementation in patients with recurrent self-harm. Single-centre double-blind randomized controlled trial. 2007 Br J Psych doi:10.1192/bjp.bp.106.022
Rizzo AM, Corsetto PA, Montorfano G, Opizzi A, Faliva M, Giacosa A, Ricevuti G, Berra B, Rondanelli M, Pelucchi C. Comparison between the AA/EPA ratio in depressed and non depressed elderly females: omega-3 fatty acid supplementation correlates with improved symptoms but does not change immunological parameters. 2012 Nutr J doi:10.1186/1475-2891-11-82