Table 1.
Lipid composition in milk fat globules.
| Fatty acidsa | % total fatty acids | Biological significance |
| Palmitic acid (16:0) | 18–23 | Energy metabolism (18); used in the synthesis of other bioactive lipids (18) |
| Oleic acid (18:1) | 20–35 | Energy storage and metabolism (19); alters cell membrane fluidity (13) |
| Linoleic acid (n-6 18:2) | 8–18 | Skin barrier function (20); precursor to ARA; competes with n-3 fatty acid metabolism (21) |
| Linolenic acid (n-3 18:3) | 0.43–1.33 | Precursor to EPA and DHA (22) |
| Arachidonic acid (n-6 20:4) | 0.36–0.49 | Eicosanoid synthesis (23); neurodevelopment (24) |
| Eicosapentaenoic acid (n-3 20:5) | 0.07–0.26 | Precursor to eicosanoids (23); immune function (23) |
| Docosahexaenoic acid (n-3 22:6) | 0.17–0.99 | Cell signaling; neurodevelopment and vision (25) |
| Phospholipidsb | % of total phospholipids | Biological significance |
| Phosphatidylinositol | 4.6 | Cell signaling; activation of Akt (26) |
| Phosphatidylcholine | 25.2 | Membrane structure; lipoprotein assembly and secretion (27) |
| Phosphatidylserine | 5.9 | Induction of apoptosis (28); carrier of DHA (29) |
| Phosphatidylethanolamine | 28.6 | Component of phospholipase D (30); cell proliferation and differentiation by regulation of pathways including MAPK and NF-kB (31) |
| Sphingomyelin | 35.7 | Metabolized to ceramide and sphingosine (32); vascular development (33); immune function (34) |
| Gangliosidesc | 14.8–26.8 mg/L in human milk | Cognitive development (35); altering membrane fluidity and function of enterocytes (36–39); cell-cell communication (40); gut maturation and immunity (41, 42) |
| Cholesterold | 90–150 mg/L in human milk | Structural maintenance of membranes (43); compartmentalization of membrane proteins to modulate functions (44); substrate for bile acids, vitamin D, hormones and oxysterols (45) |
a
Fatty acid content represents mature milk collected in nine countries (46).
b
Polar lipids were quantified using HPLC-ELSD (47).
c
Total ganglioside content represent Malaysian mother's milk quantified using HPLC-MS (48).
d
Total cholesterol content adapted from Koletzko (45).
ARA, Arachidonic acid; EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid.