Mental retardation is associated with plasma omega-3 fatty acid levels and the omega-3/omega-6 ratio in children

There is evidence that alteration in plasma fatty acid composition may play a role in certain neurological disorders. This case control study was conducted to evaluate the association between plasma fatty acid levels and mental retardation in Korean children. Plasma phospholipid fatty acids, plasma lipids, dietary fatty acids and selected nutrients were measured in 31 mentally retarded boys (mean age 9.93 ±1.5 yrs) and matched controls. Total plasma omega-3 fatty acids (Σω3), docosahexaenoic acid (DHA) and high density lipoprotein (HDL) concentrations were significantly lower and the Σomega-6/Σomega-3 ratio was significantly higher in cases than in controls. The odds in favor of mental retardation increased by 69 % for each unit increase in the Σomega-6/Σomega-3 ratio (adjusted odds ratio = 1.69, 95% CI = 1.25-2.29). Significant variation in plasma Σomega-3 and the Σomega-6/Σomega-3 ratio was explained by mental retardation and plasma HDL concentrations (45% and 37 % respectively). There was a significant inverse association between plasma DHA and mental retardation. For each unit increase in plasma DHA, odds of mental retardation decreased by 74 %. There was no significant difference in either total dietary fat or fatty acids intakes between cases and controls. The energy intake of cases was significantly higher than the controls. These results suggest that proportion of plasma Σomega-3 fatty acids, particularly, DHA, and the Σomega-6/Σomega-3 ratio are associated with mental retardation in children in this study.