Cow's Milk Antigens Content in Human Milk: A Scoping Review

The evolution of nutritional care in children with food allergies - With a focus on cow's milk allergy

Cow's milk allergy (CMA) remains one of the most common and complex paediatric food allergies. In the last decade, our understanding has advanced in terms of immunoglobulin E (IgE)-mediated CMA and focus is now also paid to non-IgE-mediated CMA, particularly in some Western countries where incidence rates are high. We have had significant progress in the last 10 years in relation to our understanding of existing supportive tests for IgE-mediated CMA, with the advancement of newer tests, such as the basophil activation test (BAT), which have shown great promise. However, little advancement has been made in terms of tests for non-IgE-mediated CMA, and controversy still exists around symptoms. Our understanding of the natural history of CMA has also advanced with more awareness of different phenotypes. While the mainstay of management remains cow's milk elimination, the importance of supporting breastfeeding and avoidance of unwarranted cow's milk elimination diets in breastfeeding mothers has been highlighted. For non-breastfed children, there has been some advancement in the formulas offered for the management of CMA, including the recognition of hydrolysed rice-based formulas and increased demand for nutritionally complete plant-based options, some of which are currently being assessed. The addition of pro, pre and synbiotics is considered safe to use, although research and guidance on routine use remain absent. Knowledge of tolerance induction from studies on the early introduction of peanuts has also highlighted the importance of a more active approach to managing CMA with the use of milk ladders, primarily in non-IgE-mediated CMA and baked milk (BM) introduction in IgE-mediated CMA. In addition, modulation of the microbiome and diet diversity during complementary feeding has been a major advancement in the last 10 years. While data on poor growth and feeding difficulties in children with CMA has not changed much, increased rates of obesity are now also reported. Finally, novel approaches, including oral immunotherapy, the use of milk ladders and earlier consideration of BM, have advanced somewhat in the last decade, although the risks and benefits of these novel approaches require further research. While CMA remains a complicated allergy to diagnose and manage, the evolution of science has advanced our knowledge and brought some novel innovations, which combined have enhanced our practice.

Transfer of celiac disease-associated immunogenic gluten peptides in breast milk: variability in kinetics of secretion

Background

Exposure to antigens is crucial for child immune system development, aiding disease prevention and promoting infant health. Some common food antigen proteins are found in human breast milk. However, it is unclear whether gluten antigens linked to celiac disease (CD) are transmitted through breast milk, potentially impacting the development of the infant's immune system.

Objective

This study aimed to analyze the passage of gluten immunogenic peptides (GIP) into human breast milk. We evaluated the dynamics of GIP secretion after lactating mothers adopted a controlled gluten-rich diet.

Methods

We prospectively enrolled 96 non-CD and 23 CD lactating mothers, assessing total proteins and casein in breast milk, and GIP levels in breast milk and urine. Subsequently, a longitudinal study was conducted in a subgroup of 12 non-CD lactating mothers who adopted a controlled gluten-rich diet. GIP levels in breast milk and urine samples were assayed by multiple sample collections over 96 hours.

Results

Analysis of a single sample revealed that 24% of non-CD lactating mothers on a regular unrestricted diet tested positive for GIP in breast milk, and 90% tested positive in urine, with significantly lower concentrations in breast milk. Nevertheless, on a controlled gluten-rich diet and the collection of multiple samples, GIP were detected in 75% and 100% of non-CD participants in breast milk and urine, respectively. The transfer dynamics in breast milk samples were long-enduring and GIP secretion persisted from 0 to 72 h. In contrast, GIP secretion in urine samples was limited to the first 24 h, with inter-individual variations. In the cohort of CD mothers, 82.6% and 87% tested negative for GIP in breast milk and urine, respectively.

Conclusions

This study definitively established the presence of GIP in breast milk, with substantial inter-individual variations in secretion dynamics. Our findings provide insights into distinct GIP kinetics observed in sequentially collected breast milk and urine samples, suggesting differential gluten metabolism patterns depending on the organ or system involved. Future research is essential to understand whether GIP functions as sensitizing or tolerogenic agents in the immune system of breastfed infants.