The health benefits of breast-feeding are many -- everything from lower obesity rates to lower rates of asthma have been attributed to breast-feeding and other good nutritional habits early in life. For mothers, breast-feeding can actually lower the risk of heart disease, according to one recent study.
But as many as 6 million mothers worldwide are unable to either initiate breast-feeding or produce enough milk, leaving them and their children without the option of the most natural, nutritious diet available for the first months of life.
A new study suggests a novel, and disturbing reason why some mothers have trouble breast-feeding: dioxin pollution inhibits the normal growth of breasts during pregnancy.
The laboratory study of mice, conducted by the University of Rochester Medical Center and published in Toxicological Sciences, showed that "dioxin has a profound effect on breast tissue by causing mammary cells to stop their natural cycle of proliferation as early as six days into pregnancy, and lasting through mid-pregnancy," according to the University of Rochester Medical Center.
The effect was indeed profound: A 50% decrease in new breast tissue. In addition, dioxin altered milk-producing genes, resulting in fewer mature lobules and ductal branches which make and deliver milk. Future research will examine whether dioxin exposure cancels the breast cancer-fighting benefits of pregnancy.
Scientists found that mice could recover to an extent from early-pregnancy exposure to dioxins if there was no exposure later in pregnancy. Unfortunately, that result is "irrelevant to humans," as the lead author B. Paige Lawrence pointed out.
Why? Unless we radically change our diets (something pregnant women should not do without carefully consulting their doctors) there's little we can do to avoid dioxin exposure. Dioxins made news in 2004, when the chemical was used to poison Ukrainian President Viktor Yushchenko, and Agent Orange is perhaps the best-known dioxin -- but dioxins more typically poison in tiny amounts slowly over time. Exposure has previously been linked to cancer as well as damage to the immune, reproductive and neurological systems.
Dioxins are a byproduct of incineration, and are spread widely through the atmosphere -- which means they rain down on farms where livestock graze and in oceans where they can contaminate fish. Dioxins can be found in the fats of meat, dairy products, fish, shellfish ... and humans.
A 2001 study found that beef and dairy products are the main contributors to dioxin exposure in the American diet. Some recommend choosing only low-fat milk, since dioxins accumulate in fats. And reducing dioxin exposure is one more good reason to moderate the amount of meat in your diet.
Neither the Food and Drug Administration nor the Environmental Protection Agency recommend eliminating meat and dairy from your diet. However, due to dioxin contamination, they do recommend that we "choose meat and dairy products that are lean, low fat, or fat free and to increase consumption of fruits, vegetable, and whole grain products. Meat, milk, and fish are important sources of nutrients for the American public and an appropriate part of a balanced diet. ... Each of these foods provides high quality protein in the diet. Lean meat includes meats that are naturally lower in fat, and meat where visible fat has been trimmed. For fish and poultry you can reduce fat by removing the skin. Reducing the amount of butter or lard used in the preparation of foods and cooking methods that reduce fat (such as oven broiling) will also lower the risk of exposure to dioxin."
"Our goal is not to find a safe window of exposure for humans, but to better understand how dioxins affect our health," Lawrence, the study's lead author, said in a press release. "The best thing people who are concerned about this can do is think about what you eat and where your food comes from. We're not suggesting that we all become vegans -- but we hope this study raises awareness about how our food sources can increase the burden of pollutants in the body. Unfortunately, we have very little control over this, except perhaps through the legislative process."
Reported emissions of dioxin and dioxin-like compounds in the United States has generally decreased since 2000, when the Environmental Protection Agency required certain industries (not including, for instance, municipal waste incinerators) to report their pollution levels. Air emissions were down 62% as of 2007, and water discharges were down 59%. Landfilling, however, was up 39%. You can find out about local sources of pollution from regulated industries by using the EPA's Toxic Release Inventory. The latest data, from 2007, shows these 10 facilities as the top sources of dioxins to the air:
The top air pollution sources included waste-to-energy plants, aluminum manufacturers and cement plants.
The largest sources of dioxins disposed of in any way (not just to the air) in 2007 were:
Though they did not release copious dioxins to the air, the top overall sources of dioxin had much larger overall waste burdens. The largest sources were chemical plants of various kinds.
Those lists aside, the EPA calls "uncontrolled burning of residential waste" the single largest source of dioxins in the environment today, largely because other major sources have been reduced. Laws against backyard burning of waste are typically adopted town-by-town or county-by-county, so you can reduce local sources of dioxin by supporting local laws to limit or ban outdoor trash burning.
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