Healthcare | Free Full-Text | Pollutants in Breast Milk: A Scoping Review of the Most Recent Data in 2024
1. Introduction
Recent investigations have spotlighted the critical need to assess the impact of pollutants, specifically metals and persistent organic pollutants (POPs), on child health. However, this crucial aspect has often been overlooked or insufficiently addressed, thereby underscoring the unique contribution of our study in illuminating these overlooked areas. Highlighting the interconnection between environmental quality and the health benefits of breastfeeding within the broader ‘One Health’ framework, our study reinforces the vital need for an integrated approach to environmental and health sciences. This approach emphasizes the inseparable relationships between human, animal, and environmental health, suggesting that the quality of human milk can serve as an indicator of overall environmental health. Thus, our research not only provides a contemporary perspective on this pressing issue but also introduces a novel approach by integrating lactation science within the ‘One Health’ concept.
This review aims to bridge this gap by meticulously evaluating the most recent data on breast milk pollutants, with a particular focus on the 2023 cut-off, thus ensuring the relevance and timeliness of our investigation. In light of the above, our study endeavors to extend the introduction with a comprehensive overview of the current state of research on breast milk contamination. We aim to contextualize the significance of our study against the backdrop of existing literature, further justifying our research’s novelty and the urgent need for its findings. Furthermore, by detailing the implications of environmental factors on the quality of human milk, our study aims to enrich the scientific discourse on how such factors may affect infant health and development. Moreover, our comprehensive review of prior findings and the addition of new insights significantly advance the field of perinatal environmental health.
2. Objectives
A scoping review was conducted in order to systematically map the research done on persistent POPs in breast milk, as well as to identify any existing gaps in knowledge about POP in breast milk.
3. Materials and Methods
3.1. Data Sources and Search Strategy
To identify potentially relevant documents, the bibliographic databases MEDLINE and Google Scholar were searched from 1995 to June 2023. Peer-reviewed journal articles were included if they were published between 1995 and 2023 in the English language, involved human participants and reported a measure of POP and heavy metals in breast milk, including the assay methods. In response to the review, we have clarified the assessment process for inclusion and exclusion criteria. Papers comparing infant formula and breast milk were also included.
3.2. Inclusion and Exclusion Criteria
Peer-reviewed journal articles were included if they were published between 1995 and 2023 in the English language, involved human participants, reported a measure of POP and heavy metals in breast milk, and included the methodology of the assays used. To further clarify, the decision-making process regarding study inclusion was rigorously structured and based on the relevance to our study’s objectives, ensuring alignment with our conceptual framework. Articles comparing infant formula and breast milk were also included.
Articles were excluded if they did not fit into the conceptual framework of the study. Our findings underscore the scarcity of recent research specifically targeting breastfeeding women and the need for comprehensive studies focusing on pollutant levels in breast milk. Our exploratory study has certain limitations. Acknowledging the reviewers’ insight, we emphasize that to make our study more feasible, we were only able to include a sample of the articles published in MEDLINE. Further bibliographic research would be necessary to obtain a more exhaustive bibliographic search in a future exploratory review in the field of pollutants in breast milk. This limitation highlights the need for broader bibliographic searches to encompass a wider array of studies for a future systematic review. The aim of this scoping review was to identify gaps in the literature that may guide a future systematic review. This study has not received any funding.
4. Results
4.1. Study Selection
In this exploratory study, we identified 341 primary studies on the presence of persistent organic pollutants in breast milk, published between 1998 and 2023. A total of 54 articles were ultimately selected.
4.2. POPs into Breast Milk
4.3. What Is the Origin of Major Contaminants in Breast Milk?
4.3.1. Dietary Origin
4.3.2. Environmental Origin
4.4. Impact of the Mother’s Obesity
4.5. Impact of Mother’s Age
4.6. Toxicokinetic Modeling
4.7. The Effect of Parity
4.8. What Are Their Effects on Child Health, in Particular Neurotoxicity?
4.9. Can We Compare Breast and Formula Milk? Which One Is Safer?
5. Discussion
5.1. Can We Predict Chemical Load in Breast Milk?
5.2. Some Recommendations to the Mothers and Decision-Makers
6. Perspectives
POPs are characterized by their lipophilicity and bioaccumulation, which accounts for the putative presence of these pollutants in breast milk. The main objectives of this literature review were to update the origins of these pollutants and the mechanisms leading to their transfer to breast milk, the factors that may contribute to their occurrence, and their possible impact on breastfed children.
The main recommendation that can be made is to inform mothers about the benefits of breastfeeding and the risks of not breastfeeding. It is critical to always compare two conditions for benefits and risks: breastfeeding vs. not breastfeeding. The current knowledge argues in favor of breastfeeding despite the risks represented by the presence of pollutants, and this is due to the important nutritional and immunological benefits of breastfeeding. Furthermore, formula-based diets may also contain contaminants which are often poorly characterized. The impact of the duration of breastfeeding is often raised; however, very few women actually breastfeed for a long time. Parents should also be aware that children can be contaminated at different periods of their development, from the prenatal period, the in-utero period and via total oral feeding. The more informed they are, based on objective, scientific data, the better informed their choice will be. We propose to conduct a comparative scoping review exploring pesticide and other environmental exposures that formula-fed infants are exposed to.
7. Conclusions
This comprehensive review underscores the pervasive presence of persistent organic pollutants (POPs) and heavy metals in breast milk, highlighting the critical need for ongoing vigilance and research in this area. The inclusion of PBPK modeling in future studies could enhance our ability to predict and mitigate the risks associated with these contaminants. Our findings reveal that despite global efforts to reduce environmental contamination, pollutants such as polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDT) continue to be detected in breast milk samples worldwide. The implications of these contaminants on infant health remain a significant concern, given the potential for adverse developmental and health outcomes.
Significantly, our analysis indicates that while breast milk remains the most beneficial source of nutrition for infants, the detection of these substances points to a broader environmental issue that requires comprehensive policy and regulatory action. This reaffirms the importance of adopting a One Health approach to address the multifaceted challenges of environmental contamination. The WHO’s endorsement of exclusive breastfeeding for the first six months of life underscores the importance of reducing environmental pollutant exposure to protect the health of both mothers and infants.
Future research should not only focus on longitudinal studies to assess the long-term health impacts of early-life exposure to these pollutants but also explore innovative strategies for reducing exposure through environmental and dietary interventions. Additionally, further efforts are needed to enhance the monitoring and regulation of environmental pollutants, aiming to minimize their presence in human milk. By addressing these challenges, we can safeguard the health benefits of breastfeeding and ensure a healthier start for future generations.
In light of these findings, it is imperative to continue risk reduction strategies and policies at both national and international levels to protect mothers and infants from the potential risks posed by contaminants in breast milk. Our review emphasizes the need for a collaborative effort involving policymakers, healthcare providers, environmental scientists, and the community to develop effective strategies for reducing pollutant exposure.