Purpose: Human milk (HM) composition is influenced by factors, like maternal diet and body stores, among other factors. For evaluating the influence of maternal fatty acid (FA) status on milk FA composition, the correlation between FA content in HM and in maternal plasma, erythrocytes, and adipose tissue was investigated.Methods: 223 European women who delivered at term, provided HM samples over first four months of lactation. Venous blood and adipose tissue (only from mothers who consented and underwent a C-section delivery) were sampled at delivery. FAs were assessed in plasma, erythrocytes, adipose tissue, and HM. Evolution of HM FAs over lactation and correlations between FA content in milk and tissues and between mother’s blood and cord blood were established.Results: During lactation, arachidonic acid (ARA) and docosahexaenoic acid (DHA) significantly decreased, while linoleic acid (LA), alpha-linolenic acid (ALA), and eicosapentaenoic acid (EPA) remained stable. Positive correlations were observed between HM and adipose tissue for palmitic, stearic, oleic, and polyunsaturated fatty acids (PUFAs). Correlations were found between milk and plasma for oleic, LA, ARA, ALA, DHA, monounsaturated fatty acids (MUFAs), and PUFAs. No correlation was observed between erythrocytes and HM FAs. LA and ALA were more concentrated in maternal blood than in infant blood, contrary to ARA and DHA, supporting that biomagnification of LCPUFAs may have occurred during pregnancy.Conclusions: These data show that maternal adipose tissue rather than erythrocytes may serve as reservoir of PUFAs and LCPUFAs for human milk. Plasma also supplies PUFAs and LCPUFAs to maternal milk. If both, adipose tissue and plasma PUFAs, are reflection of dietary intake, it is necessary to provide PUFAs and LCPUFAs during pregnancy or even before conception and lactation to ensure availability for mothers and enough supply for the infant via HM.

This work reviews available data on dietary intakes of total fat, saturated fatty acids (SFA) and individual polyunsaturated fatty acids (PUFA) in children in different countries worldwide and for the first time, compares them with recent international recommendations. Studies published before June 2021 reporting total fat, total SFA and individual PUFA intakes in children aged 1–7 y were included. Observed intakes were evaluated against FAO/WHO and EFSA recommendations. 65 studies from 33 countries were included. Fat intake was too low in 88% of studies in young children (1–3 y). SFA intake was >10%E in 69–73% of children, especially in Europe. Linoleic acid intake was <3%E in 24% of studies in 1–2 y olds and within FAO/WHO recommendations among all other ages. Alpha-linolenic acid intake was <0.5%E in almost half of studies. Docosahexaenoic acid (DHA) or eicosapentaenoic acid + DHA intakes were below recommendations in most studies. In summary, while total fat intake was too low among younger children, SFA intake was above, especially in Europe and n-3 PUFA intake, especially DHA, were below recommendations for all ages. Intake of n-3 PUFA, especially DHA, is generally suboptimal. More data, particularly from developing countries, are required to refine these findings and guide implementation of adapted nutrition policies.