There has been a large amount of press about a recent study that detected perchlorate in the breastmilk of American women.
What is perchlorate? Perchlorate is a salt that is found naturally in some areas of the world, and is also manufactured for various purposes. One of the perchlorate salts, ammonium perchlorate, is used as an oxidizer to help solid rocket fuel burn. Per the US Environmental Protection Agency, “Most of the perchlorate manufactured in the United States is used as the primary ingredient of solid rocket propellant. Wastes from the manufacture and improper disposal of perchlorate-containing chemicals are increasingly being discovered in soil and water.” Another perchlorate salt, potassium perchlorate, was used therapeutically for many years to treat certain types of hyperthyroidism.
Why might perchlorate be a problem? Perchlorate competes with iodine in the body. In large enough doses, perchlorate can inhibit iodine uptake into the thyroid and may inhibit the secretion of iodine into human milk (research is conflicting on this point).
Per The National Research Council’s Health Implications of Perchlorate Ingestion (p 30, 43-44), “Lower intakes [of iodine] are associated with increasing frequency of thyroid enlargement (goiter), biochemical evidence of thyroid hormone deficiency, and ultimately, in people with severe iodine deficiency, hypothyroidism… If inhibition of iodine uptake were prolonged, the result should be iodide deficiency in the thyroid, similar to that which occurs in dietary iodide deficiency, and with the same consequences and compensation.”
See Responses to Concerns for more information on perchlorate as it relates to breastfeeding.
Following are links with more information on perchlorate and breastfeeding.
- Information on the studies
- Texas Tech Study – September 2003
- Chilean Studies
- Responses to concerns
- More information
Comments by Author: Perchlorate in Breastmilk by Purnendu K Dasgupta. March 3, 2005.
Study: Kirk A, Martinelango PK , Tian K , Dutta A, Smith EE, Dasgupta P. Perchlorate and iodide in dairy and breast milk. Environmental Science and Technology. 2005.
Perchlorate found in dairy and breast milk samples from across the country. Press release from the American Chemical Society. Feb 23, 2005.
Scientists Find High Levels of the Toxic Rocket Fuel Chemical in Human Breast Milk. Study Information from the Environmental Working Group. Feb 22, 2005.
Rocket-fuel contaminant found in human breast milk. San Francisco Chronicle. Feb 24, 2005.
High levels of perchlorate found in U.S. mothers’ milk. Science News story from Environmental Science and Technology Online. Feb 23, 2005.
Kirk A, Dasgupta P, Tian K, Anderson T, Smith E. Occurrence of perchlorate in breast milk and milk available for purchase in the US. Poster Session Abstract from the Society of Environmental Toxicology and Chemistry 25th Annual Meeting. Portland, Oregon. 16 Nov 2004.
Chemical Toxin Found in Milk. The Press-Enterprise. September 20, 2003.
Kirk AB, Smith EE, Tian K , Anderson TA, Dasgupta PK. Perchlorate in Milk. Environmental Science and Technology. 2003;37(21):4979 -4981.
Committee to Assess the Health Implications of Perchlorate Ingestion, National Research Council. Health Implications of Perchlorate Ingestion. Washington, DC: The National Academies Press; 2005. See p. 69-70 for preliminary 2004 breastmilk data from Tellez’s study.
Crump C, Michaud P, Tellez R, Reyes C, Gonzalez G, Montgomery EL, et al. Does perchlorate in drinking water affect thyroid function in newborns or school-age children? J Occup Environ Med. 2000 Jun;42(6):603-12.
Perchlorate in Breastmilk by Purnendu K Dasgupta, principal author of the Texas Tech Breast Milk Study. March 3, 2005.
Toxins and Infant Feeding by Jack Newman, MD, FRCPC, 2009.
Contaminants have been found in human milk. Should I wean my baby? FAQ from LLLI. September 25, 2003.
Breastfeeding Remains Best Choice in a Polluted World, LLLI Media Release. August 2003.
Various Levels of Perchlorate Exposure Found Not to Be Harmful to Newborns, Pregnant Women, and Other Adults. American Thyroid Association Press Release. Oct 1, 2004.
Update on the Question of Perchlorate Exposure and Potential Effects on the Thyroid. American Thyroid Association Public Health Committee Statement. April 25, 2005.
Perchlorate: Questions and Answers from the US Food & Drug Administration
EPA Sets Reference Dose for Perchlorate. US EPA Press Release. Feb 18, 2005.
Perchlorate. General information from the US EPA.
Fact Sheet: Perchlorates in Water from the Texas Department of Health. Oct 2002.
Physician Fact Sheet: Perchlorate from the Texas Department of Health. Oct 30, 2002.
Committee to Assess the Health Implications of Perchlorate Ingestion, National Research Council. Health Implications of Perchlorate Ingestion. Washington, DC: The National Academies Press; 2005.