Aim: To study the relationship between polyunsaturated fatty acids (PUFA) status and depression in adolescents with eating disorders (ED) and weight loss.

Methods: Erythrocyte membranes from 217 adolescents (209 girls, 8 boys) with ED were analysed for fatty acids (FA). ED and depression were diagnosed by clinical interviews and supported by self-report instruments.

Results: Adolescents with ED and depression did not differ from those with ED only in terms of age, BMI, weight loss and duration of disease. In their FA profile depressed adolescents had lower proportions of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), the end products of the ω3 PUFA series. The ratio of long chain (>18 carbons) ω6/ω3 PUFA was therefore higher in depressed adolescents. Indices of desaturase activites did not differ between depressed and not depressed adolescents.

Conclusion: Low ω3 status is related to depression in adolescents with ED. This cannot be explained by differences in weight (loss) and duration of disease, nor by differences in PUFA processing by desaturases. Data suggest a lower dietary intake of ω3 PUFA in those with depression. Further investigations should determine whether ω3 PUFA status improves by refeeding only or whether supplementation with PUFA is warranted.