Meta-analysis of erythrocyte polyunsaturated fatty acid biostatus in bipolar disorder.

ABSTRACT

OBJECTIVES: Dietary deficiency in polyunsaturated fatty acids (PUFAs), including the omega-3 fatty acids eicosapentaenoic acid (EPA; 205n-3) and docosahexaenoic acid (DHA; 226n-3), and excesses in omega-6 fatty acids, including linoleic acid (LA; 182n-6) and arachidonic acid (AA; 204n-6), may be associated with the pathophysiology of bipolar disorder. In an effort to provide clarification regarding the relationship between PUFA biostatus and bipolar disorder, this meta-analysis investigated studies comparing erythrocyte (red blood cell) membrane PUFA composition in patients with bipolar disorder and healthy controls. METHODS: A meta-analysis was performed on case-control studies comparing erythrocyte PUFA (EPA, DHA, LA and AA) levels in patients with bipolar I disorder and healthy controls. Standardized effect sizes were calculated and combined using a random effects model. RESULTS: Six eligible case-control studies comprising n = 118 bipolar I patients and n = 147 healthy controls were included in the analysis. Compared with healthy controls, patients with bipolar I disorder exhibited robust erythrocyte DHA deficits (p = 0.0008) and there was a trend for lower EPA (p = 0.086). There were no significant differences in LA (p = 0.42) or AA (p = 0.64). CONCLUSIONS: Bipolar I disorder is associated with robust erythrocyte DHA deficits. These findings add to a growing body of evidence implicating omega-3 PUFA deficiency in the pathophysiology of bipolar disorder.