It started in 2008 with plastic bottles. After a report suggested that bisphenol A – used as a sealant in food and beverage containers – might be toxic to humans, some bottle manufacturers cut the chemical out of their products. Since then, the body of research on BPA has grown rapidly but a consensus has not, as evidence has supposedly “proven” both its relative safety and its potential risk.
This week, however, the Food and Drug Administration (FDA) asserted its opinion that BPA in food packaging does not pose a health hazard by turning down an environmental action group’s petition to ban the substance.
And at a news conference Thursday hosted by the industry-supported nonprofit International Food Information Council (IFIC), leading independent and government scientific experts reiterated their conclusion that BPA is safe at the levels typical Americans are exposed to today.
The root of the BPA question, said Dr. Justin Teeguarden, Senior Scientist at the Pacific Northwest National Laboratory in Richland, WA, lies in exposure. If humans are exposed to a chemical at a level that can cause harm, then the substance is dangerous.
But calling a chemical “toxic” or “not toxic,” he says muddies the issue, because “everything is toxic” at a certain level.
And the low level of BPA that people consume from food or beverage packaging is not one that’s harmful, said Teeguarden.
“In the end,” he said, “the concentrations in the blood that we calculate are 1,000 to 1 million times lower than the levels that would be required to bind the various estrogen receptors that are believed to cause BPA toxicity and endocrine disruption.”
Teeguarden and a team of researchers conducted a study on 20 people in which subjects were fed canned and bottled foods (which contain the highest levels of BPA from packaging) three times a day. Their urine and and blood were then measured for BPA.
The study – funded by the Environmental Protection Agency and released last summer – found that after eating these foods, the individuals displayed higher levels of BPA exposure than subjects in any other BPA studies. But it also found that these people rapidly absorbed, detoxified and eliminated all of the chemical. No bioactive BPA – the kind that is not processed by the body and can therefore be dangerous – was detected in any of the 320 blood samples the researchers collected.
What’s more, he says, this study used tests that were 10 to 45 times more sensitive to the substance than some previous studies.
So what about other research that has found that BPA exposure even at low levels is in fact harmful?
One recent study in which pregnant rats were given BPA found that the animals still displayed effects of the exposure 3 generations later.
This, says Teeguarden, is where one has to look at the amount of BPA given to the rats.
“That particular study exposed those rats to 250,000 times more BPA than even highly exposed humans get.”
Another commonly documented problem with BPA studies is contamination of samples. In other words, blood samples picking up trace levels of BPA after they’ve been collected.
A blood sample comes into contact with many materials that can contain BPA, Teeguarden explained, such as the plastic tubes used to store blood, plastic tubing used by hospitals when drawing blood, solvents used to clean a sample, water in labs, and columns that blood samples are run through for cleaning, which have been shown to leak BPA into liquids.
“[BPA] is virtually everywhere in the laboratory and in the field and if you don’t protect against contamination and monitor against it at every step along the pathway…the chances of you seeing contamination are huge.”
How is this contamination identified?
By detecting levels of bioactive BPA (the dangerous kind) over 1 percent in the bloodstream, since research has found that .01 is the maximum amount that can be present in the body. Any more than this and the sample has likely picked up more BPA from another source.
Several studies have found significantly higher concentrations of this free bisphenol A, suggesting sample contamination.
“If it’s much more than 1 percent you know the bisphenol A came from contamination,” explained Teeguarden.
What about the possibility that BPA accumulates in the body over time?
“It doesn’t bioaccumulate in the fat tissues, and it washes out very quickly from our bodies so there’s no risk of accumulating this material over time,” said Teeguarden. “The stuff is 99.9 percent metabolized when you ingest it. It’s washed out of your body within 5-8 hours.”
Instead of being a risk to health, BPA actually promotes food safety, said Marianne Smith Edge, IFIC’s Senior Vice President of Nutrition and Food Safety.
“It’s used to prevent the corrosion of cans,” she noted during the news conference. “It’s used to prevent contamination of foods…BPA packaging does serve as an important food safety vehicle in protecting foods from pathogens and contaminates.”
Some argue that FDA should regulate BPA because other governments, including those in Belgium, Canada, France, Japan and the European Union, have banned the substance.
Dr. Mitchell Cheeseman, a 20-year veteran of FDA’s Office of Food Additive Safety, said the science in support of BPA’s safety is overwhelming, and that those decisions were made by legislative bodies against the advice of scientists, including the European Food Safety Authority.
“Risk managers in each of those countries have chosen to take action against BPA without consideration of the risk assessments they’ve received from their own scientists,” he said during Thursday’s press call.
Echoed Teeguarden, “The France ban has been blocked by objections from 6 European countries.”
FDA made its decision to allow BPA in packaging by taking a large body of scientific evidence into account, says Cheeseman.
“The agency has consumed upwards of 10 staff years or more on the review of this substance. The federal government overall has probably spent 40 million dollars or more on research to address the uncertainty with regard to the safety of BPA.”
Studies on BPA safety amount to “probably the largest body of evidence on safety of food contact material available,” he said.
Adds Teeguarden, “The data set that exists for BPA right now is one of the best for any chemical out there.”
FDA has yet to issue its final assessment on BPA, although its recent ruling on the petition of the environmental group indicates that it’s not likely to restrict the substance.
FDA will presumably continue to update its review in preparation for that final assessment which will eventually follow,” said Cheeseman.