To examine fatty acid profiles, their response to omega-3 fatty acid (Ω3) supplementation, and associations with clinical status and treatment response in youth with mood disorders.
In a placebo-controlled 2X2 design, 7-14 year-olds (N=95) in parallel pilot trials (depression N=72; bipolar N=23) were randomly assigned to 12 weeks of Ω3 supplementation (1.4g eicosapentaenoic acid [EPA], 0.2g docosahexaenoic acid [DHA], and 0.27g other Ω3 per day); psychoeducational psychotherapy (PEP); their combination; or placebo (mainly oleic and linoleic acid) alone. Blood was drawn at baseline (N=90) and endpoint (n=65). Fatty acid levels were expressed as percent of total plasma fatty acids. Correlational and moderator/mediator analyses were done with SPSS Statistics 23.
At baseline: (1) DHA correlated negatively with alpha-linolenic acid (ALA) (r=-0.23, p=0.029); (2) Arachidonic acid (AA, Ω6) correlated negatively with global functioning (r=-0.24, p=0.022); (3) Total Ω3 correlated negatively with age (r=-0.22, p=0.036) and diastolic blood pressure (r=-0.31, p=0.006). Moderation: Baseline ALA moderated response to Ω3 supplementation: ALA levels above the sample mean (lower DHA) predicted significantly better placebo-controlled response (p=0.04). Supplementation effects: Compared to placebo, 2g Ω3 per day increased EPA blood levels sevenfold and DHA levels by half (both p<0.001). Body weight correlated inversely with increased EPA (r=-0.52, p=0.004) and DHA (r=-0.54, p=0.003) and positively with clinical mood response. Mediation: EPA increase baseline-to-endpoint mediated placebo-controlled global function and depression improvement: the greater the EPA increase, the less the placebo-controlled Ω3 improvement.
Ω3 supplementation at 2g/day increases blood levels substantially, more so in smaller children. A possible U-shaped response curve should be explored.