title: Depressed mood and n-3 polyunsaturated fatty acid intake from fish: non-linear or confounded association?
abstract: There is increasing evidence of an association between low dietary intake of essential n-3 long chain polyunsaturated fatty acids (n-3 EFAs) and depressed mood. This study aimed to evaluate this association in a large population-based sample of UK individuals. N-3 EFA intake (intake from fish alone, and from all sources (fish and supplements)), depressed mood (assessed using the short-form Depression, Anxiety and Stress Scales) and demographic variables (sex, age, Index of Multiple Deprivation (IMD) based on postal code, and date of questionnaire completion) were obtained simultaneously by self-report questionnaire (N = 2982). Using polynomial regression, a non-linear relationship between depressed mood and n-3 EFA intake from fish was found, with the incremental decrease in depressed mood diminishing as n-3 EFA intake increased. However, this relationship was attenuated by adjustment for age and IMD. No relationship between depression and n-3 EFA intake from all sources was found. These findings suggest that higher levels of n-3 EFA intake from fish are associated with lower levels of depressed mood, but the association disappears after adjustment for age and social deprivation, and after inclusion of n-3 EFA intake from supplements. This study does have a number of limitations, but the findings available suggest that the apparent associations between depressed mood and n-3 EFA intake from fish may simply reflect a wider association between depressed mood and lifestyle.
authors.affiliation: School of Psychology, Queen's University of Belfast, 18-30 Malone Road, Belfast, BT9 5BP, UK. k.appleton@qub.ac.uk
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Appleton
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Peters
authors.forename: Robert C
authors.initials: RC
authors.lastname: Hayward
authors.forename: Susan V
authors.initials: SV
authors.lastname: Heatherley
authors.forename: Sarah A
authors.initials: SA
authors.lastname: McNaughton
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Rogers
authors.forename: David
authors.initials: D
authors.lastname: Gunnell
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Ness
authors.forename: David
authors.initials: D
authors.lastname: Kessler
mesh_terms: D000328:Adult; D000368:Aged; D001007:Anxiety / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D004435:Eating; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000378:metabolism*; D005260:Female; D005396:Fish Products / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D015525:Fatty Acids, Omega-3