APRIL 2008

The U.S. government's National Toxicology Program (NTP) yesterday agreed with a scientific panel that recently reviewed 700 studies on BPA and expressed concern about physiological changes that occur in people when they ingest BPA that has leached from plastics into their food or drinks. The Canadian government is considering declaring the chemical toxic, reports the New York Times. This could set the stage for banning it from plastic baby bottles, water bottles, and food containers. At the very least, some people will be even more eager to buy foods and beverages in BPA-free containers.

Bisphenol A (BPA), is a compound that makes plastics flexible and shatter-resistant and is found in hard, clear polycarbonate plastics (e.g., water and baby bottles, the linings of formula cans, microwavable food and drink packaging, and canned goods). The chemical is leached from bottles and cans into the water and food. However, exposing the plastic to boiling temperatures can release the chemical 55 times faster than normal, new research suggests.

BPA appears to mimic the effects of estrogen, interfering with hormone levels and cell signaling systems. Previous studies have shown that people exposed to high levels of BPA have a greater risk of developing uterine fibroids, breast cancer, decreased sperm counts, and prostate cancer. Other BPA health concerns include cancer, diabetes, obesity and attention-deficit dsiorder.

Babies and children are thought to be at greatest risk from the exposure. During the first few years of life, when babies' cells continue to undergo "programming," exposure to certain toxic chemicals can disrupt this delicate process. In fact, the NTP report cautions that "a higher level of concern than those expressed by the scientific panel for possible effects of BPA on prostate gland, mammary gland and early onset of puberty in exposed fetuses, infants and children."

The biggest problem with the report is the decision to limit the review to 'oral-dose studies', primarily the industry-sponsored studies, and not 'injection studies', the Natural Resources Defense Council said. "This means they failed to include evidentiary science of the full range of risks to unborn fetuses, who receive BPA through the contaminated blood circulation, irrespective of the pregnant mothers route of exposure," the group stated. There's enough evidence from animal studies to warrant concern, especially for women who are pregnant or attempting to conceive, they say. "The definitive study may not be possible," says Hugh Taylor, chief of the division of reproductive endocrinology and infertility at Yale University School of Medicine. "Why not protect ourselves and the next generation from this threat?"

For people who want to minimize their exposure to the controversial chemical, experts have some tips: Avoid storing food or beverages in polycarbonate plastic, which is often used to make baby bottles and "sippy" cups, 5-gallon water cooler jugs, and hard, transparent water bottles. Use glass containers instead. Cover microwavable dishes with a paper towel rather than plastic wrap. And avoid canned goods, since the linings of metal cans often contain bisphenol A. For people who continue to use polycarbonate food and drink containers, avoid heating them to reduce exposure, says Frederick vom Saal of the University of Missouri, who is a vocal critic of bisphenol A. The acidity of a container's contents and the age and condition of the polycarbonate can also affect how much of the chemical leaches into food or drink, he adds.

Alternatives to polycarbonate include polyethylene and polypropylene plastics, as well as glass. Both alternative plastics are usually identifiable by recycling code, a number that should appear inside a triangular symbol on each plastic container. The number 2 marks polyethylene and the number 5, polypropylene. Polycarbonate doesn't have a unique recycling code, but it tends to be assigned the code 7, a category for miscellaneous plastics.

Metal cans containing liquidy products can be a significant source of human exposure to bisphenol A and finding alternatives isn't simple. According to vom Saal, "The breakdown of the plastic lining of cans, or any [bisphenol A]-based product, is greatly accelerated by acidic substances or alcohol." For many canned products, there are fresh or frozen alternatives, as well as products that come packaged in glass.

Despite hundreds of published studies by goverment scientists and university laboratories that substantiate these health concerns, the FDA has deemed these plastics safe largely on two small studies funded by the American Plastics Council, an industry trade group representing manufacturers that produce 7 billion pounds of BPA annually. "Tobacco figured this out, and essentially it's the same model," said Daivd Michaels, a former regulator in the Clinton administration. "If you fight the science, you're able to postpone regulation and victim compensation, as well. Eventaully the science becomes overwhelming."

Some manufacturers, like BornFree, Medela and Adiri, have begun to offer plastic bottles and training cups that are BPA free. And Valspar, one of the largest makers of plastic coatings, has been developing bisphenol A-free coatings for cans. Eden Foods, a Clinton, Mich.-based natural-foods company, sells beans and tomato products in bisphenol A-free cans. The company switched in 1999 when its officers first learned of concerns about bisphenol A, according to spokeswoman Tonya Martin. The catch: That material costs 14% more and can't be used with the tomato products, which are acidic enough to corrode the lining and limit shelf life. As a result, Eden's canned tomatoes still contain trace amounts of bisphenol A, Martin says.

Toys 'R' Us announced Monday that it will phase out bottles and other "baby feeding products" containing BPA by the end of the year. Wal-Mart last week said that it will stop selling baby bottles made with BPA by early next year.

SEPTEMBER 2007

A number of researchers contend that an individual's battles with middle-age spread, hypertension, and diabetes, can be traced back to their mother's diet during pregnancy. This month, Kaiser Permanente researchers report in the journal Diabetes Care that children who consumed an excessive amount of sugar in the womb—because their mothers' mild diabetes caused high blood glucose levels—were nearly twice as likely to become obese by elementary school as those whose moms had been successfully treated for severe diabetes. Another study found that women who followed a high-protein Atkins-style diet had children who much later were unusually sensitive to stress, which is associated with heart disease and diabetes. The implications of this are enormous.

Scientists now believe that after the initial construction of DNA at conception, a baby's genes are programmed a certain way --switched off or on, depending on the conditions in utero. For example, cells may be wired to sock away fat if they're bathed in too many or too few nutrients -- or to release it readily for fuel if given just the right amount. Underweight newborns appear to have systems unable to cope effectively with glucose, which makes them more prone to obesity once they're happily enjoying a fast-food lifestyle. "We first found in the 1980s that people who were born at low birth weights to poor malnourished mothers tended to have high rates of heart disease, stroke, and diabetes," says David Barker, a professor of medicine at Oregon Health and Science University in Portland, who was the first to suggest that fetal programming can lead to chronic disease.

Women who are overweight when they become pregnant risk developing the abnormally high blood glucose levels associated with gestational diabetes. As this sugar-rich blood passes through the placenta, the baby adapts, even becomes "addicted", to this uber-sweet plasma. The baby might be programmed to crank out too much of a "hunger" hormone, leptin, for example, and his/her overfed cells may be less sensitive than they should be to insulin, which normally enables cells to use glucose for energy. Both types of hormonal programming may leave the child with a tendency to overeat that is difficult to reverse. The Kaiser Permanente study found that even women whose blood sugar levels fell into the upper range of normal, 122 to 140 milligrams per deciliter, might benefit by lowering those levels further. Their children were almost 30% more apt to be fat by age 7 than those born to women with lower blood sugar levels. A St. Louis University study found that when compared with those who gained 15 pounds, overweight women who gained 25 pounds or more had more than twice the likelihood of giving birth to large babies, who are at increased risk of becoming obese and diabetic adults.

Too much protein can have adverse consequences, too. In MAR2007, Scottish researchers released the findings from a study of 70 adult offspring of a group of women from Motherwell, Scotland who were told in the 1960s to eat a pound of red meat a day during pregnancy to prevent high blood pressure. When asked to perform such challenging tasks as public speaking and mental arithmetic, these adults produced excessive amounts of the stress hormone cortisol. High cortisol producers tend to develop hypertension and carry fat around the abdomen, which increases the likelihood of heart disease and diabetes.