Research published in Nature Communications has revealed that the milk of Atlantic grey seals contains a level of sugar complexity that rivals that of human breast milk. This finding challenges the long-held belief that human milk is uniquely sophisticated among mammals. The study, led by Daniel Bojar and his team from the University of Gothenburg, highlights the significant role that milk oligosaccharides—sugars critical for infant health—play across various species.
The research was conducted on the Isle of May, Scotland, where the team analyzed milk samples from five wild Atlantic grey seals during their approximately 17-day nursing period. They identified a remarkable total of 332 different sugar molecules, successfully characterizing 240 of them. Notably, around two-thirds of these molecules, or 166, had not been documented in prior research. Some of the identified sugars reached sizes of up to 28 sugar units, surpassing the largest known sugars found in human milk by as many as ten units.
As the team investigated further, they discovered that the sugar composition of seal milk undergoes coordinated changes throughout the lactation period. This adaptability mirrors the dynamic shifts observed in human milk, which also modifies its composition to meet the evolving nutritional needs of infants.
The implications of this study extend beyond mere comparison. Several of the newly identified sugars exhibit antimicrobial and immunomodulatory properties, suggesting potential applications in biomedical science, particularly in areas related to infant nutrition, infection control, and immune system support.
This groundbreaking research not only reshapes our understanding of milk evolution among mammals but also opens up new avenues for discovering bioactive compounds. Such discoveries may enhance our approaches to infant health and nutrition, providing insights that could benefit both scientific research and public health.
The study received financial backing from several prestigious organizations, including the Branco Weiss Fellowship and the Knut and Alice Wallenberg Foundation. Additional support came from the Swiss National Science Foundation and the Natural Environment Research Council of the United Kingdom, which facilitated the sample collection from the grey seals.
The findings from this research underscore the importance of studying milk sugar diversity across different mammals, as previous studies have largely focused on human milk. Understanding the complexities of milk from other species can illuminate the evolutionary pathways and functional significance of these vital nutrients.
