Erythrocytes Polyunsaturated Fatty Acids Mediate Relationship between Dietary Patterns and Depression

This study aimed to examine the association between depression and dietary patterns via the intermediary role of erythrocytes polyunsaturated fatty acids (PUFA). In this individually matched case-control study, the dietary patterns were extracted for 330 individuals using factor analysis. Furthermore, erythrocyte PUFAs including n-3 and n-6 were assessed using a GC-Mass spectrometry analytical method for 84 people. Depression was diagnosed using the criteria mentioned in the Diagnostic and Statistical Manual of Mental Disorders. The dietary patterns were also extracted using a valid and reliable semi-quantitative food frequency questionnaire. The findings showed that healthy dietary patterns were related to the risk of depression (P = 0.01, odds ratio (OR) = 0.31, 95% confidence interval (CI): 0.14-0.68) by the increase of ratio n-3 /n-6 PUFA (p ≤ 0.03) and decrease of ratio n-6 /n-3 PUFA (p ≤ 0.005). Moreover, the unhealthy dietary patterns were associated with the risk of depression (P = 0.02, OR = 2.7, 95%CI: 1.25-5.9) by the decrease of ratio n-3/n-6 PUFA (p ≤ 0.03) and increase of ratio n-6/n-3 PUFA (p ≤ 0.001). Based on the results, the type of dietary pattern is related to the risk of depression considering the changes in n-3 and n-6 PUFA as well as the ratio of n-3 to n-6 as the mediator variables. Of course, further studies are required in this area.