Effect of omega 3 and omega 6 fatty acid intakes from diet and supplements on plasma fatty acid levels in the first 3 years of life

Background: The optimal method for conducting omega (n-)3 polyunsaturated fatty acid (PUFA) supplementation trials in children is unknown. Aim: To assess the impact of n-3 and n-6 PUFA intake from the background diet on plasma levels of n-3 and n-6 PUFA in children aged 0-3 years, with and without n-3 supplementation. Methods: Subjects were randomised antenatally to receive either n-3 PUFA supplements and low n-6 PUFA cooking oils and spreads or a control intervention, designed to maintain usual fatty acid intake. Dietary intake was assessed at 18 months by 3-day weighed food record and at 3 years by food frequency questionnaire. Plasma phospholipids were measured at both time points. Associations were tested by regression. Results: N-3 PUFA intake from background diet did not significantly affect plasma n-3 levels. In contrast, n-6 PUFA intake in background diet was positively related to plasma n-6 levels in both study groups. In addition, n-6 PUFA intake from diet was negatively associated with plasma n-3 levels at 18 months and 3 years (-0.16%/g n-6 intake, 95%CI -0.29 to -0.03 and -0.05%/g n-6 intake, 95%CI -0.09 to -0.01, respectively) in the active group, but not in the control group. Conclusion: Interventions intending to increase plasma n-3 PUFA in children by n-3 supplementation should also minimise n-6 PUFA intake in the background diet.