Two studies have identified the presence of flame retardant chemicals in the breast milk of a small population of lactating women in one group in central Texas, the other from across the country. While the headlines are cause for concern, they must be put in perspective.
Scientists have found that studying environmental chemicals in the milk of women who are breastfeeding is the most economical and non-invasive way to monitor environmental chemical levels in the general population in the United States. These chemicals are stored in the human body in fat, and human milk contains significant levels of fat. Therefore, using milk samples is a simple, convenient way to monitor the level of environmental chemical in the general population. Measuring chemical levels in fat depots in the general population would require drawing blood or taking a fat biopsy, a surgical procedure that is both invasive and expensive.
A third study not mentioned in the recent news articles, however, shows that newborns have the same level of these chemicals as their mothers. During pregnancy there is significant transmission to the fetus of chemicals present in the motherŐs body. The chemicals being reported are the bromine-based fire retardants. Polybrominated biphenyl ethers, known as PBDE, are used in many home and commercial settings. They are found in such things as television sets, automobiles, copy machines, and hair dryers.
These chemicals have been studied in small animals. Large doses of PBDEs (much higher than typical human exposure) have been associated with nervous system damage and reproductive problems in laboratory animals. There are no comparable studies in humans.
In the two recent studies, a total of 67 women participated. All of the women who were involved had measurable amounts of PBDEs in their milk. The levels found are much higher than the levels found in the milk of European women, as well as in the milk of U.S. women five years ago. The Environmental Protection Agency suggests that the level of PBDE's is doubling in humans every five years. Besides environmental sources, the EPA suspects that humans may be accumulating these chemicals from the animal fat they consume.
Two states, California and Maine, have begun to restrict the use of these chemicals. They are already banned in Europe.
What does this mean for our infants? The important thing to recognize is that since all women are at risk for having these chemicals in their bodies, all infants are exposed during pregnancy. This is a far greater exposure than through human milk. There are currently no data regarding the levels of PBDEs in cow milk or infant formula. There is also no indication that breastfeeding substantially increases the exposure of our infants to these chemicals.
At the same time, it is important to recognize the tremendous benefits of being breastfed. The extensive nutritional and immunologic value of human milk is still being understood. We know that human milk promotes brain growth and good development, protects against infection, offers immunologic protection against chronic disease and allergy, and cannot be duplicated. The tremendous value of breastfeeding far exceeds the theoretic risk of these recently reported chemicals.
We can expect to hear about more environmental chemicals being found in human milk, only because human milk has been selected as the human tissue best suited for monitoring the presence of and levels of chemicals in the general population.
At the same time, all of the scientists currently monitoring the chemicals found in human milk agree with the long-held conviction of the medical community that human milk is the optimal and safest food for human infants both nutritionally and immunologically. Despite elevated levels of chemical in human milk, women should still be encouraged to breastfeed.