Is Breast Milk Really Pure?
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Is Breast Milk Really Pure?

Published on Jun 20, 2022 and last reviewed on Nov 25, 2022   -  4 min read


Despite the possibility of harm from contamination, breastfeeding is still recommended best for infants. This article is detailed on contaminants in breast milk.


Breast milk is the best source of nutrition for newborns and infants. Almost all public health organizations recommend breastfeeding for infants for the first six months and continuing breastfeeding until the mother and baby desire to achieve optimal growth and development. Even in the case of premature birth, consumption of human breast milk is known to reduce the chances of infectious complications. Many studies suggest that breast milk was associated with better cognitive development and a lower rate of hospital administration.

There are numerous health benefits associated with breastfeeding. It decreases the risks of infection, allergy, asthma, arthritis, diabetes, obesity, cardiovascular disease, and even various forms of cancers in childhood and adulthood.

Nevertheless, there is a tendency for persistent organic pollutants (POPs), pesticides, and heavy metals to accumulate in human milk. Researchers and parents wonder whether it can reduce or override the health benefits.

What Are Environmental Contaminants in Breast Milk?

A baby devoid of breastfeeding suffers from a loss of immunologic protection from mothers' milk “colostrum,” which is secreted during the initial days of breastfeeding. Breast milk also contains various bioactive factors that help build the immune response in children. Although the health benefits of breast milk are tremendous, some contaminants can pollute breast milk, which might affect the infant's health.

Some toxic components from the environment can be a source of contaminants that can be transferred from mother to infant while breastfeeding. Lead, mercury, arsenic, cadmium, and other potentially toxic metals dispersed throughout the environment thus are of concern to nursing newborns.

Persistent organic pollutants (POPs) are lipophilic stable chemicals that can accumulate in the adipose tissue and lead to lasting toxic body effects. Breastfeeding provides a significant source of exposure to POPs that might ill affect newborns and infants.

What Are Chemical Contaminants in Breast Milk?

The various studies limit the focus on a small panel of persistent organic pollutants. However, there is a possibility that a wide range of additional chemical contaminants may also enter breast milk. Despite these limitations, it is possible to draw some conclusions. Some studies show available data on levels of organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs), polybrominated diphenyl ethers (PBDEs), metals, and solvents in breast milk. Some reports suggest that organochlorine pesticides, PCBs, and dioxins have declined in breast milk in many countries where these chemicals have been banned or otherwise regulated. In contrast, the levels of PBDEs are noticed rising.

Diet is a significant factor that possesses an influence on breast milk. The levels of persistent organic pollutants and fish consumption play an important role.

Some improved global breast milk monitoring programs need to be conducted in various countries to get more consistent data on trends over time and the detection of new xenobiotics in breast milk.

How Could Breast Milk Contamination Occur in the Neonatal Care Unit?

When newborns are admitted to the neonatal intensive care unit (NICU), lactating mothers cannot directly feed their babies with breast milk, and she needs to express the milk out of their breast to feed their babies. Breast milk is not always sterile, and hence microorganisms can invade and multiply in the milk if the handling of milk is not done correctly. It can even lead to severe complications in those vulnerable newborns.

Some commonly known bacteria in expressed breast milk (EBM) areStaphylococcus aureus, including MRSA, β-hemolytic Streptococci, Pseudomonas species, Klebsiella species, Proteus species, and Enterobacteria. These bacteria can lead to infection in the infant at risk. Some reports suggest an association between breast milk Enterobacter and neonatal sepsis. The possible causes of expressed breast milk contamination are improper hand washing, lack of appropriate breast hygiene, storage, and transportation.

What Is the Associated Risk With Medications in Breast Milk?

Initially, the risks associated with drugs with breastfeeding were not a pronounced clinical concern. This is because low usage of medications in postpartum women stimulated little interest in studying medication use in the breastfeeding mother. However, the enclosure of many new pharmacologic agents, concerns over environmental contaminants, and a significant increase in breastfeeding altered the interest in this clinical issue. Providers of health care to women and children often are asked to advise breastfeeding women on the choice and risks of a particular medication. Healthcare professionals discourage using medications while breastfeeding when this situation arises. However, under unavoidable circumstances, a drug that does not reach breast milk is recommended to the mothers.

Feeding infants with breast milk to achieve the optimum growth requirements is essential for all mothers. The presence of contaminants can affect the newborn's health and development. To inhibit the negative impacts of contamination, we may follow these ways to prevent breast milk contamination.

  • Avoid exposure to chemical and environmental agents during pregnancy and breastfeeding.

  • Appropriate breast hygiene.

  • Hand sanitization.

  • Avoiding medication.

  • Taking only prescribed medications.


The benefits of human milk for human infants are commendable. But the concern that creates havoc is the exposure of infants to contaminants in human milk. The number and the sources of such pollutants are unknown, but their extent is rapidly growing. Maintaining proper hygiene can prevent the milk from being contaminated. Research is being conducted to evaluate whether the bioactive components of human milk may somehow compensate for these milk-borne pollutants, and there are undergoing studies to detect the types of toxicants.

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Last reviewed at:
25 Nov 2022  -  4 min read




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