The association of maternal diet and breast milk fatty acid composition

Background and objectives: Exclusive breastfeeding during the first six months after birth provides the infant with the most optimal start for life. Maternal diet is suggested to influence the composition of breast milk. However, little is known about the exact impact on nutrient level. Breast milk fatty acid content has been studied most in this context, therefore, this review aims to summarize the evidence on the role of maternal diet in breast milk fatty acid composition. Methods: A systematic PubMed search was carried out, limited to articles published between January 2015 and March 2021, based on the latest inclusion date of the earlier review on this topic of Bravi et al., 2016. Studies were included if they provided quantitative information and were conducted among apparently healthy mothers, of healthy term infants. This review combines the latest results published and those articles identified by Bravi and colleagues. Results: In total, 17 new publications were identified and combined with 12 studies described by Bravi et al. Among all fatty acids, PUFAs were studied most, by far. Maternal fish intake was predominantly significantly positively associated with breast milk ALA (r= 0.28 – 0.42), DHA (r= 0.24 – 0.46) and EPA (r= 0.25 – 0.28) content. Interestingly, seafood consumption showed mainly negative significant associations, for example with breast milk LA (r= -0.28 – -0.32), DPA (r= -0.32 – -0.51) and total PUFA (r= -0.26 – -0.31). Both, maternal DHA and EPA intake were significantly positively correlated with breast milk DHA content. ALA, EPA, total PUFA, n-3 PUFA, n-6 PUFA and SFA in breast milk were often positively associated with maternal dietary intake. Negative correlations were observed for maternal SFA intake and several fatty acids in breast milk. Conclusions: There are convincing indications that maternal diet is associated with breast milk fatty acid content, especially for fish intake and DHA concentrations. Yet, for most fatty acids in breast milk, it remains difficult to draw conclusions due to differences in study quality and large diversity in assessed exposure and outcome combinations. More high-quality studies assessing maternal diet and breast milk composition are needed, with strict sampling protocols and appropriate sample sizes.