Depression and adipose polyunsaturated fatty acids in the survivors of the Seven Countries Study population of Crete

Abstract

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 150 elderly males from the island of Crete. The subjects were survivors of the Greek Seven Countries Study group. The mean age was 84 years. The number of subjects with complete data on all variables studied was 63. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the short form of the Geriatric Depression Scale (GDS-15). Depression correlated negatively with adipose tissue alpha-linolenic acid (C18:3n-3). Depressed subjects had significantly reduced (-10.5%) adipose tissue C18:3n-3 levels than non-depressed subjects. The observed negative relation between adipose tissue C18:3n-3 and depression, in the present study, appears to indicate increasing long-term dietary C18:3n-3 intakes with decreasing depression. This agrees with findings of other studies indicating an inverse relation between depression and consumption of fish and n-3 polyunsaturated fatty acids. This is the first literature report of a relation between adipose tissue C18:3n-3 and depression. Furthermore, this is the first report of a relation between adipose PUFA and depression in an elderly sample. Depression has been reported to be associated with elevated cytokines, such as, IL-1, IL-2, IL-6, INF-gamma and INF-alpha. Fish oil and omega-3 fatty acids, on the other hand, have been reported to inhibit cytokine production. The observed negative relation between adipose C18:3n-3 and depression, therefore, may stem from the inhibiting effect of C18:3n-3 or its long-chain metabolites on cytokine synthesis.