The effect of fish oil on physical aggression in schoolchildren--a randomized, double-blind, placebo-controlled trial.
OBJECTIVE
The aim of the study was to investigate whether fish oil supplementation affected Japanese schoolchildren's behavior, with changes in aggression over time as the primary endpoint.


METHODS
A placebo-controlled double-blind study with 166 schoolchildren 9-12 years of age was performed. The subjects of the fish oil group (n=83) took fish oil-fortified foods (bread, sausage and spaghetti). These foods were provided in amounts such that each subject in the fish oil group had an intake of 3600 mg of docosahexaenoic acid+840 mg of eicosapentaenoic acid (EPA)/week for 3 months. The rest (the controls, n=83) took control supplements. At the start and end of the study, psychological tests were performed to assess their aggression.


RESULTS
Physical aggression assessed by Hostility-Aggression Questionnaire for Children in girls increased significantly (median: 13 to 15, n=42) in the control group and did not change (13 to 13, n=43) in the fish oil group with a significant intergroup difference (P=.008) with baseline as covariate. The changes in physical aggression scores over time and those of the ratio of EPA/arachidonic acid in RBC (DeltaEPA/AA) were significantly correlated in girls who agreed to blood collection (r=-.53, P=.01, n=23). On the contrary, there were no significant changes in physical aggression in boys. Aggression against others (extraggression) assessed by Picture Frustration Study did not change in the control group (median: 5 to 5) but increased significantly in the fish oil group (4 to 5) with a significant intergroup difference (P=.02) with baseline as covariate. These changes in extraggression might be explained partly by significantly lower baseline values of extraggression in the fish oil group (P=.02) than in the control group. There were no significant correlations between Deltaextraggression and DeltaEPA/AA in blood-sampled children (n=49). Impulsivity of girls assessed by parents/guardians using the diagnostic criteria for attention deficit/hyperactivity disorder of DSM-IV was reduced in the fish oil group (1 to 0) with a significant (P=.008) intergroup difference from the control group (1 to 1). There were no significant correlations between Deltaimpulsivity and DeltaEPA/AA in blood-sampled girls. In males, impulsivity reduced in both groups without any intergroup differences.


CONCLUSIONS
There is a possibility that changes in fatty acid nutrition might affect physical aggression especially in girls.
Itomura
Miho
M
Division of Clinical Application, Department of Clinical Sciences, Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan 9300194.
Hamazaki
Kei
K
Sawazaki
Shigeki
S
Kobayashi
Makoto
M
Terasawa
Katsutoshi
K
Watanabe
Shiro
S
Hamazaki
Tomohito
T
D000374:Aggression / Q000187:drug effects / Q000502:physiology*; D001519:Behavior / Q000502:physiology; D002648:Child; D002664:Child Nutritional Physiological Phenomena / Q000502:physiology*; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D004281:Docosahexaenoic Acids / Q000008:administration & dosage; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010919:Placebos; D011795:Surveys and Questionnaires
D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D010919:Placebos; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid