We showed no evidence that supplementation with n-3 fatty acids and instructions to reduce arachidonic acid intake during pregnancy and lactation relevantly affects fat mass in offspring during the first year of life. Prospective long-term studies are needed to explore the efficacy of this dietary approach for primary prevention. This trial was registered at clinicaltrials.gov as NCT00362089.

Background: There is some evidence that the n-6/n-3 long-chain polyunsaturated fatty acids (LCPUFAs) ratio in early nutrition, and thus in breast milk, could influence infant body composition. Methods:In an open-label randomized controlled trial (RCT), 208 healthy pregnant women were allocated to a dietary intervention (supplementation with 1,200 mg n-3 LCPUFAs per day and instructions to reduce arachidonic acid (AA) intake) from the 15th wk of gestation until 4 mo of lactation or to follow their habitual diet. Breast milk LCPUFAs at 6 wk and 4 mo postpartum were related to infant body composition assessed by skinfold thickness (SFT) measurements and ultrasonography during the first year of life. results: Dietary intervention significantly reduced breast milk n-6/n-3 LCPUFAs ratio. In the whole sample, early breast milk docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 LCPUFAs at 6 wk postpartum were positively related to the sum of four SFT measurements at age 1. Breast milk AA and n-6 LCPUFAs at 6 wk postpartum were negatively associated with weight, BMI, and lean body mass (LBM) up to 4 mo postpartum. conclusion: Breast milk n-3 LCPUFAs appear to stimulate fat mass growth over the first year of life, whereas AA seems to be involved in the regulation of overall growth, especially in the early postpartum period. t he amount of n-3 long-chain polyunsaturated fatty acids (LCPUFAs) in human breast milk is subject to maternal nutrition and further modified by maternal adipose tissue stores (1), gestational age and stage of lactation (2,3), and the individual's genetic constitution (variants in the FADS1/2 gene cluster) (4,5). There is an ongoing debate about whether the amount of n-3 LCPUFAs, and particularly the proportions of docosahexaenoic acid (DHA,, provided to the developing infant during the breastfeeding period may result in functional differences of health outcomes in the offspring.As recently reviewed, there is insufficient evidence from randomized controlled trials (RCTs) to support or refute the practice of giving n-3 LCPUFA supplementation ("fish oil") to breastfeeding mothers to improve infant growth, children's neurodevelopment, visual acuity, or allergy risk (6).An upcoming question in the context of fetal programming of later disease susceptibility is whether the balance between the n-6 and n-3 LCPUFAs in early nutrition, and thus in breast milk, could play a role in childhood obesity (7). Although prenatal and/or postnatal n-3 LCPUFA supplementation has been shown to reduce obesity in rodents (8,9), although not consistently proven (10,11), evidence in humans is limited and restricted to a few post hoc studies using in large part inadequate methods to assess infant fat mass (12).The INFAT (The Impact of Nutritional Fatty acids during pregnancy and lactation for early human Adipose Tissue development) study addresses the question as to whether lowering the n-6/n-3 long-chain fatty acid (FA) ratio in the diet of pregnant and breastfeeding women may reduce adipose tissue growth early ...

Maternal DHA, AA, total n-3 LCPUFAs and n-6 LCPUFAs might serve as prenatal growth factors, while n-6 LCPUFAs also seems to regulate postnatal growth. The maternal n-6/n-3 LCPUFA ratio does not appear to have a role in adipose tissue development during early postnatal life.