News Coverage
Breast milk toxin study troubles nursing moms
Published March 13, 2005
Quilts lined the floor and happy chatter filled the air as some two dozen women cradled babies in their laps at a weekly breast-feeding group in Glendale.
Here at Kangaroo Kids, a maternity support center, women can buy a baby sling, snack on organic food and swap advice with other moms on everything from diets to diapers. But mostly, they bask in the knowledge that by breast-feeding their babies, they are providing the most nourishing food their children can have.
Breast milk provides special nutrients that help infants ward off infections, allergies and childhood cancer, and even cavities, diabetes and multiple sclerosis later in life. Some studies suggest breast-feeding increases a child's confidence and IQ. It is, simply put, the elixir of life.
That's why it's so painful to tell eager new mothers that breast milk also contains toxic chemicals.
"What the hell!" one mother exclaimed during the group meeting when she heard about the latest study. Texas Tech University researchers found the rocket fuel ingredient perchlorate in samples of breast milk nationwide, including those from a woman in Missouri.
Perchlorate disrupts production of thyroid hormone, which is needed for growth and development. Low thyroid levels can cause mental retardation.
"We're not going to freak out; we're going to talk about it," insisted Kangaroo Kids owner Tanya Griffin, 36, an energetic mother of four who breast-feeds her 2-year-old daughter. "No one should stop breast-feeding because of this."
A growing number of studies have found industrial chemicals in human breast milk. Dioxin, PCBs, flame retardants and pesticides such as DDT tend to concentrate in the rich, fatty fluid, giving vulnerable infants a dose of chemicals associated with cancer and hormone malfunction. Mercury and lead, two potent neurotoxins, also can pass through breast milk.
Public health officials worldwide say that the benefits of breast-feeding still far outweigh concerns about pollution, and that antibodies passed from mother to child may help counteract the toxins' detrimental effects.
"The bottom line is, mothers are never encouraged to stop breast-feeding," said Katy Lebbing, who manages the breast-feeding information center at LaLeche League International, based in Schaumburg, Ill. "All these researchers are trying to say is, we live in a contaminated world and we need to clean it up."
Mothers and infants aren't the only ones exposed to these toxins; they pervade modern society, accumulating in all of our bodies.
DDT, a pesticide banned in the United States, travels the globe in dust storms. Polychlorinated biphenyls, or PCBs, persist in soil and water from industrial operations decades ago. Dioxin forged in incinerators spreads throughout the air.
Flame retardants used to keep computers, phones and carpets from catching on fire are common in most American households. Beauty products, building materials and household cleaners contain toxic solvents and metals. All of us drink, eat and breathe contaminants every day.
The U.S. Centers for Disease Control and Prevention keep tabs on the presence of some of these chemicals in humans through a process called biomonitoring. The CDC takes samples of blood and urine from thousands of Americans every few years. The latest report reviewing about 150 chemicals is due out this spring.
Dr. Jim Pirkle, a scientist with the CDC's environmental health Center, said the agency is concerned about measuring exposure to all Americans, "but especially women of childbearing age."
The CDC doesn't include breast milk in the national study because representative samples are difficult to obtain, Pirkle said. He also believes that contaminant levels in human milk can be accurately estimated based on the level in blood in the general population. Breast milk contains five times as much fat as blood, so it generally contains five times the level of contaminants, he said.
But Dr. Gina Solomon, a senior scientist with the Natural Resources Defense Council in San Francisco, said that's not always true.
Perchlorate, for example, doesn't concentrate in fat, yet researchers at Texas Tech University found concentrated levels of perchlorate in human breast milk.
"You'd never figure out (the high concentration) unless you tested the breast milk itself," Solomon said.
New standards
The recent breast milk study has attracted the attention of federal officials, who are now developing cleanup levels and safe drinking water standards for perchlorate.
Once mainly associated with spills from defense industry sites, particularly in California and Nevada, perchlorate turned up in almost all 200 samples of milk and lettuce nationwide in test results released in November by the U.S. Food and Drug Administration.
Tainted irrigation water in central California, the nation's salad bowl, appears to be spreading perchlorate far and wide. Certain foods, such as lettuce, tend to concentrate the chemical in their leaves. Even organic food tested positive in the FDA study.
"Perchlorate, up until now, has been treated as an isolated problem in communities with a known drinking water problem," said Bill Walker, an official in the Oakland, Calif., office of the nonprofit Environmental Working Group, which found similar results in its own studies.
"This discovery really takes it from being a local issue to being a national issue."
The Texas Tech study, published in the journal Environmental Science and Technology last month, provided the first evidence of perchlorate in human breast milk. Researchers found the chemical in each of 36 human milk samples from 18 states. The average level in breast milk was 10.5 parts per billion, five times higher than the average level in dairy milk sampled in the same study.
The Missouri mother's milk came in at 31.6 parts per billion, among the highest in the survey. Her identity and hometown was not disclosed for confidentiality reasons.
At levels like this, researchers said it was obvious that the "majority of infants" in the study would get a dose of perchlorate that exceeded a new safety standard set by the National Academy of Sciences.
The study also suggested that most exposure came from food rather than water or beverages, because levels measured in milk and water were generally much lower than in the mothers' breast milk.
A spokeswoman for the U.S. Environmental Protection Agency said the agency was reviewing the study as part of the process of setting a drinking water standard for perchlorate. In February, the EPA set a hypothetical safe drinking water level of 24.5 parts per billion, but the number doesn't take into account any exposure that comes from food.
Typically, a drinking water contaminant goal would be one-fifth of the hypothetical amount, which would translate to 4.9 parts per billion. In its final regulation, the EPA may adjust the amount based on cost and feasibility of water treatment.
The defense industry, which potentially faces hundreds of millions of dollars in cleanup costs, has argued for a drinking water standard of 200 parts per billion or more. A spokesman for the Department of Defense declined to answer questions on the subject.
Alarming news
Reaction to the perchlorate study among nursing mothers and their advocates has been strong and often skeptical.
"I wouldn't make such a big deal about this single study, since the research needs to be completed with at least a couple thousand samples before I would believe it," said Nan Pazdernik, a mother of two from O'Fallon, Ill., who coaches breast-feeding moms.
Many people feared that such studies would scare mothers away from breast feeding. Some even accused the authors of being funded by the infant formula industry.
In response to such charges, senior author Sandy Dasgupta, a chemistry professor at Texas Tech who has done several studies on perchlorate, posted a letter on a pro-breast-feeding Web site called kellymom.com.
"I truly regret if our paper caused anyone to stop breast-feeding for even a day," Dasgupta wrote, acknowledging the small sample size and the need for more follow-up. The study was funded by the university's own money, he wrote.
"It may be disconcerting, but I believe that we are ultimately better off knowing that all of the women tested had easily measured values of perchlorate in their breast milk, some at levels that nature surely did not intend," he continued.
The mothers at Kangaroo Kids were alarmed at the news about perchlorate and upset at their inability to prevent such chemicals from getting into their bodies.
Sang Maxwell of Maplewood said she does everything she can to protect her 8-month-old daughter, Malia.
"It's frustrating, because we do organic food for her and for us," said Maxwell, 32. "The idea is not to expose her to these toxins."
The study doesn't point to any specific health effect on any particular child, and physicians say it should not be cause for overreaction.
Dr. Andrew Zuckerman, a pediatrician at Clayton Pediatrics, said he's not aware of an epidemic of thyroid problems in infants that might be linked to perchlorate exposure. Nor do most mothers question him about environmental contaminants.
Finding out more about the health effects of these chemicals is extremely important, he said.
"We're exposed to so much more now than we ever were," he said. "That's cause for quite a bit of alarm. But we don't know what the extent of those problems are going to be."
"It's an outrage," said Griffin as she scurried around her shop in stocking feet. "But you can't get scared."