Our research focuses on a critical and underutilised opportunity for preventive health: the first days of life. By targeting this brief but transformative period, we aim to define interventions with the greatest long-term impact on child health.

The transition from fetus to newborn is the most complex adaptation in the human experience. The fetus leaves a sterile, aquatic environment—where physiology is deeply entwined with the mother’s—to suddenly breathe through the lungs, rely on external nutrition, and face exposure to billions of microbes.

At this crucial moment, the mother produces colostrum, the first milk, available during the first three days of life. Often called “liquid gold,” its composition appears uniquely tailored to support this transition. Yet, at least one in three newborns worldwide receives formula supplements during this period, as if colostrum alone were not sufficient.

While colostrum’s composition is well described, its specific long-term health benefits remain poorly documented, particularly outside of neonatal survival in low-resource settings. To fill this gap, we conduct preclinical and clinical research in birth cohorts from both low- and high-income countries to investigate whether exclusive colostrum feeding is essential to set infants on a healthy trajectory.

By integrating preclinical models with longitudinal cohorts from Australia, Kenya, Indonesia, Thailand and Switzerland, we are uncovering how this unique first milk programs immune and metabolic health and supports lifelong resilience. We specifically study the role of colostrum in shaping:

• Allergy
• Infection
• Respiratory health
• Neurodevelopment
• Growth
• Skin immunity
• Gut Immunity
• Microbiota
• Inflammation
• Metabolism
• Immune metabolism

This knowledge will support WHO guidelines implementation and drive the discovery of developmentally appropriate, colostrum-inspired strategies to prevent childhood diseases from the very first day of life.

Some consider the infant immune system to be immunodeficient—for example, because infants do not yet produce antibodies at levels comparable to adults. However, this view overlooks the maternal–infant immunological dyad. A full-term newborn receives antibodies via the placenta and continues to receive mucosal antibodies through breast milk. This illustrates the inadequacy of studying the child’s immune system in isolation, without considering the mother's contribution.

Beyond complementing the infant’s immune system, breast milk plays an active role in educating it. It shapes the infant’s gut microbiota by contributing to its initial seeding and by providing selective nutrients that support beneficial microbial growth. Breast milk also contains environmental antigens—derived from allergens and pathogens present in the maternal–child environment. We are investigating how antigen shedding via breast milk helps train the infant’s immune system to mount appropriate future responses: promoting tolerance toward allergens and effective defense against pathogens. This immune education is further modulated by a range of bioactive compounds in breast milk whose composition is influenced by the mother’s physiology and environment. Altogether, this supports the broader concept that breast milk reflects the maternal exposome and prepares the infant for life in their specific environment.

By investigating how the maternal environment shapes milk composition and, in turn, immune development, we are laying the groundwork for personalised guidance to help mothers optimise disease prevention through breastfeeding.

By studying how breast milk shapes early immune responses, we are generating essential knowledge to inform the development of infant-tailored therapeutics, such as next-generation vaccines.

Using data from an Australian birth cohort (the ORIGINS cohort), we demonstrated that a child’s diet at birth significantly influences their risk of developing peanut and multiple allergies within the first year of life, with colostrum emerging as highly protective. Our findings further suggest that adequate colostrum feeding may reduce the need for strict early peanut introduction, broadening the strategies available for peanut allergy prevention (Bhasin et al, 2025). Until now, formula supplementation has mainly been considered in the context of cow’s milk allergy risk. With this publication, we aim to raise broader awareness of how early formula use may interfere with colostrum feeding, with potential consequences for multiple aspects of child health—well beyond cow’s milk allergy.

Our research opens new perspectives for peanut allergy prevention, including the promotion of colostrum feeding and the development of colostrum-inspired therapeutics for infants at risk, who require formula for medical reasons or whose mothers are unwilling to breastfeed.

Our research challenged the allergen avoidance paradigm by demonstrating that egg allergens in maternal milk can educate the infant immune system toward immune tolerance, thereby reducing the risk of allergy (Verhasselt et al., 2008 (Verhasselt et al., 2020). We further uncovered why breast milk is more effective at promoting immune tolerance than direct allergen exposure: allergens in breast milk are present in very low amounts, and the presence of bioactive compounds such as cytokines, antibodies, and vitamins—all shaped by maternal physiology and the maternal exposome—modulates the efficacy of tolerance induction (Adel-Patient et al., 2020; Mosconi et al., 2010)(Rekima et al., 2017) Turfkuyer et. al, 2016). Our work contributed to the 2014 food allergy prevention guidelines, which were updated in 2020 (Halken et. al., 2021 Murano et al., 2014) and was summarised in our recent review emphasising the need to consider the infant’s immune requirements and maternal input through breast milk when designing targeted prevention strategies (Macchiaverni et al., 2021; Verhasselt 2024). In collaboration with an expert in dietary prevention of allergy, Debbie Palmer and the ORIGINS cohort, the LRF-CIBF continues to explore how to maximize the potential for allergy prevention through maternal intervention and breastfeeding, including researching the benefits of incorporating dietary recommendations for mothers—such as increased fibres intake (Divakara et.al., 2024).

Our findings support the broader concept that breast milk reflects the maternal exposome and is exquisitely suited to prepare the infant for life in their specific environment. This opens the door to targeted maternal recommendations during breastfeeding, aiming to optimise the early-life window for allergy prevention.

Pathogen antigen shedding in breast milk for optimal infant immune priming

Breastmilk is the most effective evidence-based strategy for preventing infectious diseases in early life, saving up to one million lives annually(Victora CG, 2016). One of its most powerful features is the real-time transfer of maternal antibodies against pathogens present in the shared maternal–child environment, representing one of the clearest examples of personalised medicine in nature Verhasselt 2024(Verhasselt et al., 2024). Building on our observations that certain antigens in maternal milk, such as house dust mite allergens, can stimulate long-term immune responses in offspring (Baiz et al., 2017; Macchiaverni et al., 2014; Rekima et al., 2020), we proposed that the transfer of microbial antigens via breast milk may have been evolutionarily selected to prime the infant immune system and actively promote protective immunity (Marchant et al., 2017; van den Elsen et al., 2022; Verhasselt, 2015). Pathogens or pathogen-derived antigens in breast milk could function as naturally attenuated vaccines or antigens accompanied by immune-modulatory compounds tailored to the infant’s developing mucosa (Marchant et al., 2017; van den Elsen et al., 2022; Verhasselt, 2015). We recently provided proof of concept for this hypothesis in the context of malaria, demonstrating that Plasmodium antigens are indeed present in human milk (van den Elsen, et al. 2022).

Learning from breast milk, whose most recognised effect is the prevention of infectious disease, will reveal the unique needs of the infant’s immune system for effective protection. It offers insights not only into reinforcing immune defences, but also into actively shaping immunity to pathogens for optimal long-term protection

Allergy prevention: Using data from an Australian birth cohort (the ORIGINS cohort), we demonstrated that a child’s diet at birth significantly influences their risk of developing peanut and multiple allergies within the first year of life, with colostrum emerging as highly protective. Importantly, we identified a dose-dependent protective effect of colostrum, with greater colostrum exposure associated with lower peanut allergy risk Bhasin et al, 2025). Until now, formula supplementation has mainly been considered in the context of cow’s milk allergy risk. With this publication, we aim to raise broader awareness of how early formula use may interfere with colostrum feeding, with potential consequences for multiple aspects of child health—well beyond cow’s milk allergy. We are now expanding this research through larger studies and longer-term follow-up within the ORIGINS cohort.

Our research opens new perspectives for peanut allergy prevention, including the promotion of colostrum feeding and the development of colostrum-inspired therapeutics for infants at risk, who require formula for medical reasons or whose mothers are unwilling to breastfeed.

Helminth infection: In a unique preclinical model of colostrum deprivation, we demonstrated that colostrum is essential for the expansion of key immune cells in the gut—type 2 innate lymphoid cells (ILC2s)—which are critical for controlling helminth infections Rekima et al (2024). In a proof-of-concept birth cohort in Uganda, we further found that providing newborns with the first drops of colostrum was associated with a significant reduction in helminth infections during childhood (Rekima et al., 2024). Globally, more than 1.5 billion people—approximately 25% of the world’s population—are infected with soil-transmitted helminths. Infected children often suffer from nutritional deficiencies, stunted growth, and impaired cognitive and physical development, with profound societal and economic consequences.

Stunting: Using the same preclinical model, we found that age-inappropriate feeding—specifically providing mature milk instead of colostrum at birth—leads to chronic inflammation and growth failure, despite mature milk being higher in energy and produced in larger volumes Van den Elsen et al . These findings strongly suggest that the primary role of colostrum in the first three days of life is not nutritional in the conventional sense, but rather to lay the foundation for regulated energy metabolism and healthy growth. Chronic undernutrition affects 200 million children and leads to irreversible developmental disorders such as growth failure, immune dysfunction and neurodevelopmental deficits, or death in 3 million children each year.

Our research has also shown that the diet in the first days of life plays a critical role in food allergy prevention. Ongoing studies suggest it may be equally important for supporting healthy skin development and preventing neurodevelopmental delays.

This research provides new evidence for an overlooked yet scalable solution to reduce major global disease burdens in both high- and low-resource settings, including malnutrition, helminth infections, and allergies: promoting colostrum feeding. It also paves the way for a paradigm shift in newborn care and precision prevention, inspired by the biological compounds found in colostrum and their specific targets in the developing infant.

Breastmilk is the most effective evidence-based strategy for preventing infectious diseases in early life, saving up to one million lives annually(Victora CG, 2016). One of its most powerful features is the real-time transfer of maternal antibodies against pathogens present in the shared maternal–child environment, representing one of the clearest examples of personalised medicine in nature Verhasselt 2024(Verhasselt et al., 2024). Building on our observations that certain antigens in maternal milk, such as house dust mite allergens, can stimulate long-term immune responses in offspring (Baiz et al., 2017; Macchiaverni et al., 2014; Rekima et al., 2020), we proposed that the transfer of microbial antigens via breast milk may have been evolutionarily selected to prime the infant immune system and actively promote protective immunity (Marchant et al., 2017; van den Elsen et al., 2022; Verhasselt, 2015). Pathogens or pathogen-derived antigens in breast milk could function as naturally attenuated vaccines or antigens accompanied by immune-modulatory compounds tailored to the infant’s developing mucosa (Marchant et al., 2017; van den Elsen et al., 2022; Verhasselt, 2015). We recently provided proof of concept for this hypothesis in the context of malaria, demonstrating that Plasmodium antigens are indeed present in human milk (van den Elsen, et al. 2022).

Learning from breast milk, whose most recognised effect is the prevention of infectious disease, will reveal the unique needs of the infant’s immune system for effective protection. It offers insights not only into reinforcing immune defences, but also into actively shaping immunity to pathogens for optimal long-term protection.