TOXIC POLLUTANTS IN BREAST MILK

For nutrition and infant health, authorities agree that the best food is breast milk.(1) Breast milk provides disease-fighting immune factors that infants' immature immune systems cannot provide for themselves. Compared with bottle-fed babies, those who are breast-fed have fewer infections of the intestine, brain, middle ear, respiratory tract, and urinary tract. They gain more benefit from vaccines,(2) and enjoy greater protection against allergies,(3) type 1 diabetes,(4) and ulcerative colitis and Crohn's disease.(5) Breast-feeding also enhances brain development.(6)

But for the past 50 years, breast milk has come with nasty extras—significant levels of persistent organic pollutants.

The story of breast milk contamination begins with DDT, the powerful pesticide. After the World War II, it was sprayed all over the U.S.(7) By 1951, DDT's chemical breakdown product, DDE, began showing up in human breast milk.(8)

DDE accumulates in breast tissue—and finds its way into breast milk—because the chemical is lipophilic, fat loving. When inhaled or ingested with food, it gets stored in fat tissue, and breast tissue is fatty. Once stored, DDE is not eliminated. It stays put, and accumulates over time. As women age and get exposed to more of the chemical, their breast levels increase.(9) Then, when they breast-feed, they pass accumulated DDE to their children. DDT production was banned in the U.S. in 1972. But mothers born years after the ban continue to pass DDE to their children—even today—because their mothers passed it to them.

Breast milk also contains polychlorinated biphenyls (PCBs)(10), a carcinogen and endocrine disruptor. In fact, by 1976, 99 percent of breast milk sampled in the U.S. contained PCBs. Approximately 25 percent of samples contained concentrations exceeding the legal limit of 2.5 parts per million. If such high concentrations were found in cow’s milk, it would be too contaminated to sell legally.(11) PCBs were banned in the U.S. in 1977, but continue to turn up in breast milk because these chemicals are so persistent in the environment.

In addition, breast milk contains many other fat-loving persistent organic pollutants, among them: many pesticides (heptachlor, chlordane, mirex, endrin, aldrin, and dieldrin)(12), and industrial chemicals (dioxin,(13) benzene, chloroform, methylene chloride, styrene, perchoroethylene, toluene, trichloroethylene, 1,1,1-trichloroethane, and xylene.)(14) Like DDT and PCBs, many of these compounds have been banned—but continue to pollute the breast milk of not only American women, but women worldwide. A study of breast-fed infants in Australia showed that 100 percent had heptachlor levels exceeding the World Health Organization’s Average Daily Intake Allowance. Eighty-eight percent had levels of aldrin and dielrin exceeding this standard, and 27 percent exceeded the standard for benzene.(15)

Breast milk contains only tiny amounts of persistent organic pollutants, but even these low concentrations are alarming. In just six months of breast-feeding, about 20 percent of the fat-stored pollutants in the mothers’ bodies transfer to their infants.(16) As a result, while breast-feeding, typical U.S. babies consume the maximum recommended lifetime dose of dioxin, and five times the allowable daily intake of PCBs set by international health standards for a 150 pound adult. In fact, during breast-feeding, infants are exposed to higher concentrations of PCBs, DDE and other persistent organic pollutants that any subsequent time in their lives.(17)

According to a study of more than 800 nursing mothers in North Carolina, first-born children ingest the most pollutants from breast milk. Concentrations of pollutant chemicals decrease significantly during the course of lactation, and subsequent children receive lower doses than their older siblings.(18)

Breast milk, with its immune factors, is supposed to improve infants’ resistance to infection. But two studies show that persistent organic pollutants in breast milk negate this protection. Researchers in the Netherlands discovered that among Dutch preschool children, increasing PCB levels from prenatal accumulation and breast-feeding are associated with significant immune impairment. Compared with children who had the lowest levels of PCBs in their bodies, those with the highest levels experienced eight times the risk of chickenpox and three times the risk of having suffered at least six ear infections.(19) A study of Inuit children corroborates these findings. As their exposure to persistent organic pollutants increased, so did their risk of severe infections during their first year of life.(20)

In addition, the North Carolina study showed that as PCB levels increase, children show poorer motor coordination, suggesting that pollutants in breast milk also cause neurological damage.(21) Other studies show that infants exposed to PCBs before birth or through breast milk have abnormally slow reflexes.(22)

As levels of PCBs and dioxin in breast milk rise, birth weights decline.(23) Low-birth-weight infants are at higher risk for many health and developmental problems.

Finally, some scientists speculate that prenatal and infant exposure to carcinogens such as dioxin and PCBs in the womb and from breast milk may explain increased rates of childhood cancers. A rarity before World War II, childhood cancer rates have increased about 30 percent since 1950,(24) and account for more childhood deaths than any other illness.(25)

Fortunately, concerted efforts to minimize exposure pay off. Since the 1970s, Sweden has taken steps to clean up PCBs, dioxin, and the pesticides mentioned earlier. A recent study shows modest decreases in the levels of these chemicals in Swedish breast milk.(26) A study in northern New York showed similar findings: When women limited their consumption of PCB-contaminated fish, PCB levels in their breast milk declined.(27)

In addition, some research shows that supplementation with the green algae, Chlorella pyrenoidosa, can eliminate significant amounts of dioxin from the body. Chlorella reduces body burden of mercury. Japanese researchers measured dioxin levels in the tissues of 44 pregnant women, and then gave half of them Chlorella supplements. Compared with those who did not take the supplement, the breast milk of women who did showed 30 percent less dioxin.(28)

Despite the contamination of breast milk, current evidence shows that it’s still the best nourishment for babies—better than formula or cow's milk, which are also contaminated with these same pollutants plus hormones, and antibiotics. But human breast milk is not as good for infants as it used to be, or could be. Breast milk should be clean, not defiled with even tiny amounts of DDE, dioxin, PCBs, and other persistent organic pollutants.

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21. Our Stolen Future, p. 191.
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