Optical Analysis of Human Milk Improves Breastfeeding Research

Researchers are refining methods to analyze human milk using light, offering a potential breakthrough in understanding and addressing lactation challenges. The work, stemming from the University of Twente in the Netherlands, focuses on how the way light scatters when passing through breast milk can reveal crucial information about its composition, particularly fat content. This non-invasive approach could lead to better monitoring of milk intake and composition, benefiting both research and clinical practice.

Understanding Lactation Insufficiency

The World Health Organization (WHO) strongly advocates for exclusive breastfeeding for the first six months of life, recognizing its vital role in infant health. Still, a significant number of mothers struggle with initiating or continuing breastfeeding. While various factors contribute to these difficulties, a common concern is the perception of insufficient milk supply. Studies suggest that this isn’t simply a matter of perception; an estimated 10% to 15% of mothers experience genuine lactation insufficiency, a condition where the body doesn’t produce enough milk to meet the infant’s needs.

Pinpointing the underlying causes of lactation insufficiency remains a challenge. Objective and non-invasive tools to assess milk intake and composition are therefore crucial. What we have is where the University of Twente’s research comes into play, exploring the potential of optical analysis to provide valuable insights.

How Light Reveals Milk Composition

The research centers on the principle that the way light scatters when it interacts with human milk provides a wealth of information about its components, especially fat. Fat is the primary energy source in breast milk, and fluctuations in fat concentration can indicate adequate milk production. The team’s recent findings, published in Biophotonics Discovery, shed light on the optical properties of human milk and their relationship to its composition.

In their first study, researchers, collaborating with the University of Amsterdam, investigated the refractive indices – a measure of how light bends when passing through a substance – of the particles that scatter light in human milk. A key discovery was that the refractive indices of fat particles in human milk differ significantly from those found in cow’s milk. This finding underscores the unique composition of human milk and supports the need for specific values related to human milk in future research. Human milk contains distinct membrane-bound structures, including milk fat globules and extracellular vesicles, that package lipids, proteins, and nucleic acids for infant nutrition and immune regulation, as detailed in research on human milk composition.

The second study built upon this work, utilizing the measured refractive indices to predict how light scatters through human milk. Researchers as well analyzed the influence of other sample-specific properties, including fat concentration, the refractive index of the milk serum (the liquid portion of milk), and the size of the milk particles.

Fat Particle Size Matters

The primary finding from the second study was that light scattering behavior isn’t solely determined by fat concentration. The size distribution of fat particles within the milk also plays a significant role. Variations in the refractive index of particles between different milk samples, and other sample-specific properties, had a minimal impact on light scattering variations.

This suggests that analyzing the size and concentration of milk fat globules (MFGs) and extracellular vesicles (EVs) – components of human milk – through light scattering could provide a reliable and informative assessment of milk composition. Extracellular vesicles, as described in research from the National Institutes of Health, are released from cells and contain a diverse cargo of biological molecules.

Implications for Breastfeeding Support

The combined results of these studies pave the way for developing light-scattering-based methods for human milk analysis. These methods offer several advantages over existing techniques: they can be compact, fast, and, crucially, preserve the milk for infant consumption. This preservation aspect is particularly important, as it allows for the potential for inline monitoring of changes in milk composition during a single breastfeeding session.

Such real-time monitoring could provide a powerful tool for more in-depth research into lactation insufficiency and potentially aid in personalized breastfeeding support. The ability to quickly assess milk composition could help healthcare providers identify and address issues related to milk supply more effectively. Researchers are exploring the potential of these methods for monitoring infant milk intake in real-time.

Looking Ahead: The development of these light-scattering techniques represents a promising step towards a more nuanced understanding of human milk and lactation. Further research will focus on refining these methods and validating their accuracy in diverse populations. The ultimate goal is to provide clinicians and researchers with a reliable, non-invasive tool to support breastfeeding mothers and optimize infant nutrition.

Johanna Rebecca de Wolf et al, Refractive index of milk fat globules and extracellular vesicles in human milk, Biophotonics Discovery (2026). DOI: 10.1117/1.bios.3.1.012104

Wietske Verveld et al, Influence of sample-specific properties on light scattering by human milk, Biophotonics Discovery (2026). DOI: 10.1117/1.bios.3.1.012105

Key medical concepts: Agalactia (insufficient or absent lactation) and human breast milk.