Objective: To assess the effect of varying maternal intake of docosahexaenoic acid (DHA, 22 : 6n-3), in the absence of other dietary polyunsaturates, on breast milk fatty acids.
Design and intervention: Lactating mothers were randomised on day 5 post-partum to groups consuming equal numbers of capsules but containing either placebo or an oil containing DHA (43%) as its only polyunsaturate to receive 0, 0.2, 0.4, 0.9, 1.3 g DHA/day. Breast milk fatty acids as well as maternal plasma and erythrocyte phospholipids were assessed at 12 weeks post partum by capillary gas chromatography.
Results: Breast milk DHA levels ranged from 0.2 to 1.7% of total fatty acids and increased in a dose dependent manner (r2 = 0.89, P < 0.01). Maternal plasma (r2 = 0.71, P < 0.01) and erythrocyte (r2 = 0.77, P < 0.01) phospholipid DHA levels increased and were also strongly associated with dietary dose of DHA. Increasing maternal dietary doses of DHA did not affect breast milk arachidonic acid (AA, 20 : 4n-6) levels or antioxidant status as measured by plasma vitamin A or E levels.
Conclusions: Our results have demonstrated that DHA in the diet has a strong, specific and dose-dependent effect on breast milk DHA.