Effect of maternal n-3 long-chain polyunsaturated fatty acid supplementation during pregnancy and/or lactation on adiposity in childhood: a systematic review and meta-analysis of randomized controlled trials

It is hypothesized that prenatal and early postnatal exposure to n-3 long-chain polyunsaturated fatty acids (LCPUFAs) is negatively associated with adiposity later in life. We conducted a systematic review and meta-analysis to evaluate whether maternal n-3 LCPUFA supplementation in pregnancy and/or lactation exerts a beneficial effect on adiposity status in childhood. We searched six electronic databases till 20 May 2014 for randomized controlled trials (RCTs) of n-3 LCPUFA supplementation to pregnant and/or lactating women that reported data on body mass index (BMI), waist circumference, sum of skinfold thicknesses or body fat mass in children. Adiposity measures were grouped into three age categories: preschool children (<5 years), school-aged children (6-12 years), and adolescents (> 13 years). Trial quality was assessed. We conducted fixed-effect and random-effects meta-analyses to combine study-specific estimates of differences between the supplemented and control groups. A total of 6 RCTs (9 publications) involving 2847 participants were included. Summary estimates showed no effect of maternal supplementation on BMI in preschool (standardized mean difference (SMD) = 0.07, 95% confidence interval (CI) = -0.22, 0.36, P = 0.65) and school-aged children (SMD = 0.12, 95% CI = -0.06, 0.30, P = 0.20). Because of sparse data, it was not possible to pool study results relating to other adiposity measures. There is currently no evidence to support that n-3 LCPUFA supplementation during pregnancy and/or lactation favourably affects child adiposity. Further high-quality trials are needed.