On October 2019 researchers from Poland published their review of the medical scientific literature to assess the potential effects of air pollution on breast milk and whether breastfeeding can overcome the adverse health effects of air pollution exposure. Results suggest that breastfeeding has a protective effect on adverse outcomes of both indoor and outdoor air pollution exposure in respiratory (infections, lung function, asthma symptoms) and immune (allergic, nervous and cardiovascular) systems, as well as mortality in the under fives in both developing and developed countries. However, some studies have reported no protective effect of breastfeeding whilst others have even reported negative effects. Substances in breast milk which may be responsible for its protective effect against air pollutant exposure include long chain polyunsaturated fatty acids, vitamins, carotenoids, flavonoids, immunoglobins, and cytokines. However it should be noted that some of these substances are diet-dependent so the actual amounts found in breast milk will be dependent on the mother’s diet. There is also evidence that air pollutants the mother has been exposed to can pass into the breast milk as increased levels of pollutants have been found, eg polycyclic aromatic hydrocarbons or heavy metals in particulate matter. However, environmental studies have confirmed that the protective effects of breastfeeding outweigh its potential health risk to the infant.
Zielinska MA, Hamulka J. Protective Effect of Breastfeeding on the Adverse Health Effects Induced by Air Pollution: Current Evidence and Possible Mechanisms. Int J Environ Res Public Health. 2019 Oct 29;16(21).