Plasma phospholipid fatty acid status and depressive symptoms: association only present in the clinical range

BACKGROUND: Long-chain polyunsaturated fatty acids (LCPUFA) have been implicated in depression, but their role in mood variability in the general population is still unclear. We investigated the associations between LCPUFA status or fish consumption on the one hand and depressive symptoms and chronicity of depressed mood on the other in a community-based sample. METHODS: Plasma phospholipid LCPUFA profiles of 241 participants of the Maastricht Aging Study (MAAS) were determined. Depressive symptoms were measured using the CES-D and SCL-90 questionnaires. Using linear regression analyses, associations between the actual level and longitudinal (12-year) variability in depressive symptoms on the one hand and LCPUFA concentrations or fish consumption on the other were examined. RESULTS: No linear associations were found in the total sample between depressive symptoms and LCPUFA concentrations or fish consumption. Chronicity of depressed mood was also not related to LCPUFA status or fish consumption. Post-hoc analyses, however, showed a negative correlation between docosahexaenoic acid (DHA, 22:6n-3) concentration and depressed mood in persons with CES-D scores above the clinical threshold. Regression analysis suggested a non-linear association between depressive symptoms and DHA concentration in the total sample. LIMITATIONS: The cross-sectional nature of the present study did not allow for inferences about causality. CONCLUSIONS: This study offers a first indication that a suboptimal LCPUFA status might accompany depressive symptoms primarily within the clinical spectrum