Size Distribution of Fat Globules in Human Colostrum, Breast Milk, and Infant Formula

Abstract

Only a few results are available on the size of human milk fat globules (MFG), despite its significance regarding fat digestion in the infant, and no data are available at <24 h postpartum (PP). We measured the MFG size distribution in colostrum and transitional human milk in comparison with fat globules of mature milk and infant formula. Colostrum and transitional milk samples from 18 mothers were collected regularly during 4 d PP and compared with mature milk samples of 17 different mothers and 4 infant formulas. The size distribution was measured by laser light scattering. For further characterization, the zeta-potential of some mature MFG was measured by laser Doppler electrophoresis. The MFG diameter decreased sigmoidally in the first days. At <12 h PP, the mode diameter was 8.9 +/- 1.0 microm vs 2.8 +/-0.3 microm at 96 h PP. Thus, the surface area of MFG increased from 1.1 +/-0.3 to 5.4 +/-0.7 m2/g between colostrum and transitional milk. In mature milk, the MFG diameter was 4 microm on average and increased with advancing lactation, whereas the droplets in infant formula measured 0.4 microm. The zeta potential of mature MFG was -7.8 +/- 0.1 mV. The fat globules are larger in early colostrum than in transitional and mature human milk and in contrast with the small-sized fat droplets in infant formula. Human MFG also have a low negative surface charge compared with bovine globules. These structural differences can be of nutritional significance for the infant.

Size and phospholipid coating of lipid droplets in the diet of young mice modify body fat accumulation in adulthood

“…Besides distinct differences in FA composition and lipid classes, HM and IMF show a clear difference in the physical structure of lipids: raw milk lipid droplets are larger and coated with a native milk fat globule membrane as compared with lipid droplets in infant formula, which are predominantly covered with milk proteins (16).…”

“…The lipid droplet size ranges between 1 and 10 µm, with an average mode diameter of 4 µm in mature milk (17). In contrast, lipid droplets produced during processing of IMF have a diameter of ~0.3-1.0 µm and consist of a triglyceride core with milk proteins adhering to the globule surface (16).…”

“…Dietary lipids are a key source of energy and essential nutrients during infancy. A comparison between lipids in mature HM and those in current infant milk formulas (IMFs) shows differences in lipid classes (14), fatty acid (FA) composition (15), and physical structure (16). HM lipid globules are secreted from the mammary epithelial cells through exocytosis into the alveolar lumen.…”

Lipídios estruturados: alternativa para a produção de sucedâneos da gordura do leite humano

“…15,28,29 A gordura apresenta-se na forma de glóbulos de cerca de 4 µm de diâmetro em emulsão de óleo em água, estabilizada por uma membrana contendo fosfolipídios e proteínas. 30,31 Valores médios para os teores de gordura do leite humano, incluindo os ácidos graxos, estão disponíveis nos dados de nutrição do United States Departament of Agriculture. 32 Agostoni et al 33 estudaram o conteúdo de gordura total e os ácidos graxos no colostro e ao longo de 12 meses de lactação, o total de ácidos graxos poliinsaturados (PUFAs), as concentrações de ácido araquidônico (AA -20:4 n-6) e de ácido docosaexaenóico (DHA -22:6 n-3), que permaneceram estáveis do colostro até os 12 meses de lactação.…”

Evolution of lactation: nutritionv.protection with special reference to five mammalian species

“…XOR and butyrophilin are essential for the normal secretion of the milk fat globule (7,116,117) . Milk fat globules vary in size, from less than 1 mm up to 12 mm in humans and the smaller milk fat globules increase the rate of gastric emptying as well as the rate of fat absorption (118) . In addition, the milk fat globule membrane contains sphingomyelins, neutral glycosylceramides and gangliosides that are synthesised in the lactocytes, make up , 1 % of the milk fat, and are involved in central nervous system myelinisation and the development of the retina (119) .…”