Depression and adipose polyunsaturated fatty acids in an adolescent group

The purpose of the present study was to investigate the relation between adipose tissue polyunsaturated fatty acids, an index of long-term or habitual fatty acid dietary intake and depression. The sample consisted of 90 adolescents from the island of Crete. There were 54 girls and 36 boys, aged 13-18. The mean age was 15.2 years. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the Beck Depression Inventory (BDI) and the Center for Epidemiologic Studies Depression Scale (CES-D). Unlike other studies, there were no significant relations between adipose tissue n-3 or n-6 polyunsaturated fatty acids and depression. BDI correlated positively with adipose tissue C20:3n-6/C18:3n-6 ratio, while CES-D correlated positively with adipose tissue (C20:3n-6+C22:5n-3)/(C18:3n-6+C20:5n-3) ratio. Depressed subjects (BDI>16, CES-D>16) had significantly elevated adipose tissue C20:3n-6/C18:3n-6 and (C20:3n-6+C22:5n-3)/(C18:3n-6+C20:5n-3) ratios, than non-depressed subjects. The observed positive relation between depression and the particular fatty acid ratios, in the present study, appears to indicate increasing activity of elongases, the enzymes responsible for elongating polyunsaturated fatty acids into their longer-chain derivatives, with increasing depression. This is the first literature report of a possible relation between elongases and depression. The observed relation may stem from a possible over-expression of the HELO1 (ELOVL5) gene, the gene encoding a protein responsible for elongating long-chain polyunsaturated fatty acids, in the adipose tissue of depressed adolescents.