Letter to EHP

Thomas J. Goehl

Editor in Chief

Environmental Health Perspectives


PO Box 12233

Research Triangle Park, NC 27709-2233, USA
E-mail: [email protected]
30 September 2004.

Re.: Letter to the Editor

In their article on “Breast milk: an optimal food”,1 Pronczuk and collaborators state that “in most cases, mothers can and should be reassured that breast milk is by far the best food to give to their babies”,

despite the evidence that “a myriad of potential chemical contaminants … can be detected in breast milk”, mainly because a) levels of environmental contaminants, as determined by subsequent surveys, continue to decrease; b) exposure through breast milk may be less important than exposure in utero; and c) there is little evidence that exposure through breastmilk is associated with damage.

We believe that there is probably a fourth good reason in support of their recommendation. There is in fact some evidence that breastfeeding may counteract some of the negative effects of exposure to environmental contaminants in utero. For example:

– Boersma and Lanting showed that at 6 years of age cognitive development is affected by prenatal exposure to PCBs and dioxins. Breast fed children, however, when compared to formula fed children, had an advantage

in terms of quality of movements, fluency and cognitive development tests at 18 and 42 months of age and

at 6 years, despite a higher PCB exposure from breast milk.

 Ribas-Fito and collaborators, studying a birth cohort of 92 mother-infant pairs highly exposed to organochlorine compounds, found that prenatal exposure was associated with a delay in mental and psychomotor development at 13 months and that long-term breastfeeding counterbalanced this damage because it was associated with better performance on both the mental and motor scales compared to short-term or no breastfeeding.3

· Vreugdenhil and collaborators found that children breast fed for at least 16 weeks did not show

the delays in development of the central nervous system which are shown by children breast fed for 6 to 16

weeks or formula-fed, despite a similar prenatal exposure to PCBs.4

This evidence is not conclusive (but scientific evidence rarely is), but we believe that it should not be omitted in an article on environmental contaminants and breastfeeding.

Adriano Cattaneo, Unit for Health Services Research and International Health, Child Health Institute, Trieste, Italy ([email protected])
Maryse Lehners, Institute for Improvements around Birth (Initiativ Liewensufank), Luxembourg ([email protected])


1. Pronczuk J, Moy G, Vallenas C. Breast milk: an optimal food. Environ Health Perspect 2004;

2. 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
3. Ribas-Fito N, Cardo E, Sala M, Eulalia dM, Mazon C, Verdu A, Kogevinas M, Grimalt JO,

Sunyer J. Breastfeeding, exposure to organochlorine compounds, and neurodevelopment in infants. Pediatrics 2003;111:e580-e585

4.  Vreugdenhil HJ, Van Zanten GA, Brocaar MP, Mulder PG, Weisglas-Kuperus N. Prenatal exposure to polychlorinated biphenyls and breastfeeding: opposing effects on auditory P300 latencies in 9-year-old Dutch children. Dev Med Child Neurol 2004;46:398-405