Thursday, November 8, 2012

BPA: 15th Century Science Keeps Hormone Mimic in Food Supply

Sierra Magazine recently asked me to do an update on the status of the hormone disruptor, BPA, a chemical that is used in the linings of almost all food and beverage cans. Space was short and I could not explain the science behind what otherwise is a “he said, they said” back and forth controversy that leaves you wondering whether there really is a danger.
Instead, here's what you need to understand: The FDA and chemical manufacturers insist that these chemicals are safe in the low amounts which we ingest because tests on animals of VERY LARGE amounts do not result in the breast cancers, changes in mammary glands, lowered sperm counts, obesity, and behavior changes, found when VERY LOW doses of the chemicals are tested. Read on to learn more.
If you eat or drink enough of anything, even water,  eventually it will kill you. That’s the idea behind the adage,  “The dose makes the poison,”  a principle that still, in fact, governs safety decisions about human exposure to radiation, chemicals and contaminants of all kinds.
But what if that paradigm were turned on its head? What if tiny, indeed minutely small doses of a chemical could cause cancer and other health problems that would not occur at larger doses?
This is what scientists have told me is the case with hormone-disrupting chemicals including  Bisphenol A (BPA), pthalates, atrazine and other similar chemicals. Now gone from plastic baby and water bottles because of public pressure on manufacturers, BPA is still used in the lining of almost all food and beverage cans. Analyses have found that traces of BPA migrate from the linings into the food we eat.
However, the U.S. Food and Drug Administration has declined to ban  the substance. Its reason: “standardized toxicity tests” find that the chemical is safe.
But standardized toxicity tests are based on the-dose-makes-the-poison principle. And that is exactly the problem because hormones are very different from other substances.
 “At millions of times lower than what toxicologists study, then you see the harm that is not predicted by just looking at what happens at a high dose,” said reproductive biologist Dr. Frederick Vom Saal, a professor at the University of Missouri, Columbia, who has studied BPA extensively. . 
“Massive scientific evidence, “  Vom Saal told me in a phone interview, “shows that hormones operate at staggeringly low doses." In fact, he says, medical students in their first two weeks learning endocrinology learn that our cells are specially programmed to let in the miniscule amounts of hormones, like estrogen,  that naturally circulate in our bodies, but block larger amounts. "The concept that higher doses are always worse than low doses comes from an idea from the 1500s," says Vom Saal. "The old-line toxicologists will not accept that they’ve been ignorant of the last century of endocrinology.”
As an example of how hormones operate, Vom Saal cited Tamoxifen, a hormone treatment for hormone-sensitive breast cancer. “Tamoxifen at high doses inhibits breast cancer growth, but if you let the dose get too low, it will stimulate breast cancer,” said Vom Saal. “This is indicated on every bottle of tamoxifen. That is a signature of how hormones operate.” Tamoxifen is a hormone mimic. (
I asked John Rost, chairman of the North American Metal Packaging Alliance and a Ph.D. in organic chemistry, about Vom Saal’s statements.
“His perspective is shared by a vast minority of endocrinologists,” he insisted. “I do believe there is a big controversy about this low-dose hypothesis, what effect chemicals can have at low doses. But as a regulated industry, it is important for us to look to the regulators and see what conclusions they come to about this. That has happened at the FDA, (and their conclusion) is that current levels of exposure are safe.”
The linings inside cans prevent the food and the metal from interacting. Rost explained that many foods are corrosive to metal, creating pinholes through which microbes can enter food. Tin was originally used to coat metal cans; then oleoresin came into use. About 35 years ago, said Rost, epoxy became the “gold standard” of can coatings. BPA is a key ingredient in the epoxy.
“Since the move to epoxy, there has not been a food-borne illness case arising from the failure of metal packaging,” he concluded.
However, the effects of hormone mimics like BPA are totally different from, for example, botulism, whose contamination of canned food is the telltale swollen can.
Endocrinologists have documented feminizing effects in fish, amphibians, and reptiles exposed to tiny doses of Atrazine, a very widely used weed-killer, that also mimics estrogen and has been shown to turn male frogs into females.  Even the FDA said  it had “some concern”about the effects of BPA “on the brains, behavior and prostate glands” of fetuses, infants and young children.
The hormone mimic pthalates, a so-called plasticizer, has been found to cause reduced sperm counts, testicular atrophy and structural abnormalities in the reproductive systems of male test animals, reports the Environmental Working Group.
Food is a major route of human exposure to pthalates, according to Sarah Janssen, senior scientist in the public health program at the Natural Resources Defense Council (NRDC), but how it gets there is something of a mystery. “We all have pthalates in our bodies, but it is not directly added to foods," said Janssen in an interview. "But it is a contaminant in food processing. It could be from the plastic wrap, or where it’s stored, or from the tubing” used in milking machines.
It was the NRDC that petitioned the FDA to ban BPA in food packaging.  
The record shows that when it comes to these chemicals, the FDA is following rather than leading regulatory changes. After  manufacturers eliminated BPA from baby bottles and sippy cups  in response to public alarm, the FDA followed by codifying their action, banning the chemical’s use in those products.
Some manufacturers are acting ahead of the FDA in regard to BPA in food can linings as well.  Campbells announced its intention to phase out BPA in the linings of soup cans, an action that followed a big drop in sales, according to Bloomberg News. Consumers avoided the soup after the Breast Cancer Fund tested food products popular with children, including Campbell soup, and found traces of the chemical.  A Campbell’s company spokesperson, Anthony Sanzio, told me there was no specific timeline set for the change.
Last June, the FDA said it also intended  to ban BPA from infant formula cans but no regulations have yet been issued.
Eden Foods switched away from BPAlinings in 1999, putting its organic beans in cans lined with an oleoresinous c-enamel, a mixture of oil and resin extracted from plants like pine and balsam fir.  Recently it began putting its tomato products in amber glass jars when it could find no suitable can lining replacement.
The NRDC’s Janssen said finding safe replacements is not simple. “Many replacements have not been adequately tested,” she said.
The big losers if the use of BPA is curtailed would be some of the world’s largest chemical companies. Dow, Bayer, and Saudi Basic Industries, owned by the Saudi government are the biggest players in a market estimated at $2 billion in annual sales.
Vom Saal sees this potential financial loss as the motive for the lack of action by the FDA. “It’s very political,” he says. “They (the FDA) are protecting the corporations at the expense of public health.”

What you can do:  Eat fresh or frozen fruits and vegetables, avoid the canned varieties.
Fruits and vegetables tend to be acidic, and acid increases the amount of BPA that leaches from the can lining into the food. Buy tomato products and juices in glass jars or tetrapacks to avoid potential BPA contamination. Many soups are now also available in paper/aluminum packages known as  tetrapacks.