The fat globule size distribution in human milk

Area of Science:

• * Nutritional Science
• * Biophysics

Background:

• * Human colostrum and milk contain a complex emulsion of fat globules.
• * Understanding fat globule size distribution is crucial for assessing milk composition and stability.
• * Previous studies have indicated variations in fat globule characteristics.

Purpose of the Study:

• * To analyze the size distribution of fat globules in human colostrum and milk.
• * To characterize different sub-populations of fat globules based on size.
• * To investigate changes in fat globule size parameters throughout lactation.

Main Methods:

• * Conductometric method used for measuring fat globule size.
• * Analysis of number-, surface-, and volume-frequency functions.
• * Calculation of parameters related to the stability of the fat emulsion.

Main Results:

• * Three distinct fat globule sub-populations identified: small (<1 micrometer), medium (~4 micrometer), and large (8-12 micrometer).
• * Small globules constitute 70-90% of the number but only a small fraction of the volume.
• * Volume/surface average diameter increased from 1.8 µm in colostrum to 4.0 µm by 4-5 months postpartum.
• * Human milk, particularly early lactation, contains more small fat globules than cow's milk.

Conclusions:

• * Human milk fat globule size distribution is heterogeneous, with significant variations in sub-population contributions.
• * Lactation stage influences fat globule size parameters, notably the average diameter.
• * The findings provide insights into the biophysical properties and nutritional implications of human milk fat.