Higher Fish and DHA/EPA Intakes Associated with Less Depressive Symptoms in Japanese Adolescents
Reference:
Murakami et al., Pediatrics, 126: e623-e630 , 2010
Dept. of Social and Preventive Epidemiology , School of Public Health , University of Tokyo, Tokyo , Japan
Summary:
This cross-sectional study was conducted in a number of public junior high schools in Japan and included 7912 students ranging in age from 12-15 years. A diet – history questionnaire was used to determine food intakes (including various types of fish) and Standard Tables of Food Composition provided estimates on the intake of the fish-based omerga-3 fatty acids including DHA and EPA. A Center for Epidemiologic Studies Depression scale (CED-S) was used for the depression evaluations with a score of 16 or greater considered to be an indication for the presence of depressive symptoms.
A highly significant inverse relation between fish intakes and the prevalence of depressive symptoms was found in the adolescent males but not the females. Those in the highest quintile (top 20 %) with respect to fish intakes (29.1 grams /1000 Calories) had a 27 % lower prevalence of depressive symptoms as compared to those in the lowest quintile (9.1 grams of fish/1000 Calories). Based on DHA plus EPA intakes , those boys in the highest quintile (median intakes at 0.79 % of energy intakes) had a 28 % lower prevalence as compared to those in the lowest quintile (0.073 % of energy).
I will try and simplify the intake data as published in this study by converting the fish intakes into servings/week and the omegas-3 fatty acid intakes into mg /day . Firstly , it should be pointed out that the average intake of fish for all students was 17.9 grams/1000 Calories which , based on their daily energy intakes and assigning 75 grams to one fish serving , converts into 3.7 fish servings/week. It should be noted that this intake is approximately 4 times the amount of fish consumed weekly in North America . Furthermore , it has been determined that the average intake of fish by US children is less than one fish serving/week (Imm et al., Environ. Res., 103: 198-209 (2007)). Also, The average (DHA plus EPA) intake for all students was 417 mg/day which is also approx. 4 times North American intakes. Those students in the highest quintile for fish intakes (see above) had median intakes of 6 servings/week as compared to 2 servings/week for those in the lowest quintile. Interestingly, those in the lowest quintile for fish intake in Japan consume considerably more fish that the average adolescent in North America and in much of the world. Those boys with the highest quintile for (DHA plus EPA) intakes had median intakes of 728 mg/day as compared to 179 mg/day for those in the lowest quintile. A dramatic increase in fish and and DHA/EPA intakes would be needed amongst adolescents in most parts of the world if public health attempts were made to approach those intakes in the highest quintiles as associated with a lower prevalence of depressive symptoms based on this Japanese study.