Environmental contaminants in breast milk

Are there dangerous chemicals in my breast milk?

We are all exposed to contaminants that can harm our health. We breathe them in, consume them in food and drink, and absorb them through our skin. Some of these are found in breast milk, but the levels of contaminants that babies get through breastfeeding are generally much lower than the levels obtained in other ways. Studies indicate that the benefits of breastfeeding outweigh the risk of exposure to the generally low levels of contaminants found in breast milk. Infant formula can also contain contaminants. Mothers at risk of higher levels of contaminants should have their levels tested. Mothers with very high levels of lead should temporarily stop breastfeeding until this is addressed. 

A) Describing environmental contaminants

People are regularly exposed to organic pollutants, toxins from fungus (mycotoxins), pesticides, heavy metals such as arsenic, lead, and mercury, and other contaminants that can pose a risk to health (Rappazzo 2017). 

If environmental contaminants are in a pregnant mother’s body, babies will be exposed before birth. Exposure is also possible through breast milk but amounts are generally low and not a reason for stopping breastfeeding. 

For more information about heavy metals and other environmental risks in your area, please contact your local health agencies. 

B) Low levels of contaminants in human milk

Some environmental contaminants are found in human milk (Mogensen 2015). Levels vary depending on the mother’s levels and the nature of the contaminant. Breasts sometimes filter out these chemicals and breast milk can have lower levels than those in the mother’s body (Salmani 2007). For example, lead levels in breast milk are less than 3% of the level in a mother’s blood (AAP 2005).

The current research shows that babies exposed to environmental contaminants through breast milk are not at risk of health consequences (Doréa 2019; LaKind 2018). The benefits of breastfeeding outweigh the risks of exposure to the generally low breast milk levels of these contaminants (Boersma 2000; Lapillonne 2020; Mead 2008; Sundkvist 2010). In addition, breastfeeding may protect the baby's brain and nervous system against their harmful effects.

Rarely, mothers may need to temporarily stop breastfeeding if they have been acutely poisoned or have very high levels of toxins in their body (DHHS 2009; Mead 2008).

C) Other sources of contaminants

The amount of contaminants a baby takes in through breastfeeding can be much lower than the amounts obtained in other ways (Kim 2007). Contaminants can be breathed in or taken in by mouth from:

Lead and other contaminants can be present in water making it unsafe for use when preparing infant formula.

Infant formula can also be a source of contaminants but there is even less research about environmental contaminants in infant formula than in breast milk (Gardener 2019; Lehmann 2018).

D) Lead

Lead has many documented harmful effects and is particularly so to children (WHO 2019).  

While most mothers have low lead levels, others are at risk of higher levels (Ettinger 2020). This includes mothers who:

  • Have lived or live in areas where lead contamination has been caused by:
    • Leaded gasoline.
    • Industry.
  • Work in certain manufacturing industries:
    • Battery.
    • Ammunition.
    • Plastics.
  • Renovate lead-contaminated houses.
  • Use or work with lead-glazed pottery.
  • Eat lead-contaminated items such as herbs, spices, or other foods.
  • Use lead-contaminated cosmetics such as eye-liner (kohl) (Shawahna 2018).
  • Drink lead-contaminated water.

Mothers who are at risk of high lead levels should have their blood lead levels measured. If the levels are above 40 micrograms per 100 millilitres, they should not breastfeed but rather express and throw out their milk until they are treated, the source of the lead is removed, and the blood lead levels are acceptable (ACOG 2012).

References

American Academy of Pediatrics Committee on Environmental Health (AAP). Lead exposure in children: prevention, detection, and management. Pediatrics. 2005 Oct;116(4):1036-46
 
American College of Obstetricians and Gynecologists Committee on Obstetric Practice (ACOG). Committee opinion No. 533: lead screening during pregnancy and lactation. Obstet Gynecol. 2012 Aug;120(2 Pt 1):416-20
 
Boersma ER, Lanting CI. Environmental exposure to polychlorinated biphenyls (PCBs) and dioxins. Consequences for longterm neurological and cognitive development of the child lactation. Adv Exp Med Biol. 2000;478:271-87
 
Department of Health and Human Services (DHHS). Fourth National Report on Human Exposure to Environmental Chemicals. Atlanta; Center for Disease Control and Prevention: 2009
 
Dórea JG, Fenton SE. Estimating risk of neurotoxicity from early life exposure: Human milk is an appropriate matrix, but messages should not discourage breastfeeding. Sci Total Environ. 2019 Nov 25;693:133665

Ettinger AS, Egan KB, Homa DM, et al. Blood Lead Levels in U.S. Women of Childbearing Age, 1976-2016. Environ Health Perspect. 2020 Jan;128(1):17012

Gardener H, Bowen J, Callan SP. Lead and cadmium contamination in a large sample of United States infant formulas and baby foods. Sci Total Environ. 2019 Feb 15;651(Pt 1):822-827

Kim SR, Halden RU, Buckley TJ. Volatile organic compounds in human milk: methods and measurements. Environ Sci Technol. 2007 Mar 1;41(5):1662-7
 
LaKind JS, Lehmann GM, Davis MH, et al. Infant Dietary Exposures to Environmental Chemicals and Infant/Child Health: A Critical Assessment of the Literature. Environ Health Perspect. 2018 Sep;126(9):96002

Lapillonne A, Bocquet A, Briend A, et al.; Comité de Nutrition de la Société Française de Pédiatrie (CNSFP). Pollutants in Breast Milk: A Public Health Perspective - A Commentary of the Nutrition Committee of the French Society of Pediatrics. J Pediatr Gastroenterol Nutr. 2020 Aug 27

Lehmann GM, LaKind JS, Davis MH, et al. Environmental Chemicals in Breast Milk and Formula: Exposure and Risk Assessment Implications. Environ Health Perspect. 2018 Sep;126(9):96001
 
Mead MN. Contaminants in human milk: weighing the risks against the benefits of breastfeeding. Environmental Health Perspectives. 2008;116(10):A426-A434
 
Mogensen UB, Grandjean P, Nielsen F, et al. Breastfeeding as an Exposure Pathway for Perfluorinated Alkylates.Environ Sci Technol. 2015 Sep 1;49(17):10466-73
 
Rappazzo KM, Coffman E, Hines EP. Exposure to Perfluorinated Alkyl Substances and Health Outcomes in Children: A Systematic Review of the Epidemiologic Literature. International Journal of Environmental Research and Public Health. 2017;14(7):691
 
Salmani MH, Rezaie Z, Mozaffari-Khosravi H, et al. Arsenic exposure to breast-fed infants: contaminated breastfeeding in the first month of birth. Environ Sci Technol. 2007 Mar 1;41(5):1662-7
 
Shawahna R, Zyoud A, Dwikat J, et al. Lead in breastmilk samples from women living in the West Bank: a cross-sectional study. Lancet 2018 391(1):S29
 
Sundkvist AM, Olofsson U, Haglund P. Organophosphorus flame retardants and plasticizers in marine and fresh water biota and in human milk. J Environ Monit. 2010 Apr;12(4):943-51

World Health Organization. Lead poisoning and health. Fact Sheet. Geneva: World Health Organization; 2019