"Imagine three of the top scientific agencies in the U.S. working with the one of the nation’s top research laboratories try to find out how much BPA you are exposed to when you eat a lot of canned food over 24-hours. Imagine they continuously measure blood and urine to create a picture of human metabolism, a “Where’s Waldo” of chemical absorption and diffusion. Imagine they find that BPA rises in the urine after a meal of canned food as the chemical is rapidly metabolized and excreted and – even more surprising – they effectively fail to find any active BPA in human blood (it’s below the level of detection using the most advanced techniques for detection).
Imagine, also, that one of the world’s top endocrinologists, who specializes in looking at the potential risks of tiny amounts of chemicals to humans, calls the study “majestic,” for the way it was carried out, and says its conclusion effectively rules out the possibility that rodent experiments, where the chemical caused adverse effects, have any relevance for humans.
Well, such a study exists – but it might as well be a dream or a work of fiction, because the mainstream media just couldn’t be bothered to report it, despite publishing hundreds upon hundreds of stories about the alleged dangers of BPA in the past six years.
But what makes this particular omission particularly ironic, is that lo, a letter cometh out of Harvard and the Journal of the American Medical Association in which the best and the brightest students were fed canned soup, and behold, they haveth BPA in their urine. Cut to journo-evangelist, Anahad O’Connor, in the New York Times.““The new study is the first to measure the amounts that are ingested when people eat food that comes directly out of a can, in this case soup.”
Well, um, no. The aforementioned study by the Centers for Disease Control, Food and Drug Administration, and Battelle researchers at the Pacific Northwest National Laboratory (Teeguarden et al.), which was funded by the Environmental Protection Agency, fed humans a diet almost entirely composed of canned food, which included chicken noodle soup and clam chowder. Perhaps Professor Michels and the New York Times weren’t aware of this?“The spike in BPA levels that the researchers recorded is one of the highest seen in any study. ‘We cannot say from our research what the consequences are,” said Karin Michels, an associate professor of epidemiology at Harvard Medical School and an author of the study. “But the very high levels that we found are very surprising. We would have never expected a thousand-percent increase in their levels of BPA.’”
Actually, it’s not surprising at all. Why? Because the FDA has studied the concentrations of BPA in canned food and it published the results last July in the Journal of Agricultural Food Chemistry. BPA levels varied widely in canned food (note this point, because we’ll come back to why it is highly significant later) and in terms of soup, levels of BPA were up to 100 parts per billion (ppb) or nanograms per gram.
So, work out the dose for a 70 kilo person ingesting 12oz of soup at the highest level, and you end up with 0.5 ug/kg bw – which is ten times higher than the mean daily intake of BPA for the general population as calculated from the NHANES database (Lakind and Naiman, Journal of Exposure Science and Environmental Epidemiology, 2010). This comports with the levels found by Michels.
And wait – remember the Teeguarden study that no one in the media thought was worth reporting? Yes – that too shows similar levels of BPA in urine to Michels (and in some cases higher) after certain meals, with the added bonus that it demonstrated the levels did not translate into active BPA in the blood, which is the only thing we should be concerned about when it comes to this chemical.
But here’s where the New York Times allows Professor Michels to spin the most:“Dr. Michels said that the increases in BPA were most likely temporary and would go down after hours or days. ‘We don’t know what health effects these transient increases in BPA may have,’ she added.”
We know exactly the metabolic profile of BPA, and not just from Teeguarden et al. There is almost 100 percent elimination in 24 hours. Active BPA is below the level of detection. Inactive BPA cannot, by virtue of basic chemistry, mimic estrogen.“But she also pointed out that the findings were probably applicable to other canned goods, including soda and juices. ‘The sodas are concerning, because some people have a habit of consuming a lot of them throughout the day,’ she said. ‘My guess is that with other canned foods, you would see similar increases in bisphenol-A. But we only tested soups, so we wouldn’t be able to predict the absolute size of the increase.” (emphasis added)
Why bother with guessing when we have extensive knowledge of BPA levels in canned goods thanks to the FDA? We know there is such wide variance that we cannot make any assumption that the level of BPA in one product is “probably” the same in another. More to the point, Health Canada, has done extensive testing on canned soda and other drinks, and the results are nowhere close to Professor Michel’s soup cans. (By the way, this takes very little specialist knowledge to work this out: Google “BPA migration soda can” and you can find the Health Canada data).
But then Professor Michel’s study was in part funded by the National Institute of Environmental Health Sciences, which has a truly remarkable track record of funding almost all the scare studies on BPA – and then later (sotto voce, of course) admitting that many of them can’t really tell us anything about human risk, and should have really be conducted in a manner similar to studies funded by the FDA and EPA – and their overseas equivalents.
Unfortunately, if journalists don’t bother to wrestle with the regulatory science, they’ll never know whether they are being spun or whether, in this case, Professor Michels is not as familiar with the research literature on BPA as a professor with two Ph.Ds should be."
Friday, November 25, 2011
BPA Is Not A Danger
See Harvard Prof Spins Scary Soup Study: Media Swallow by Trevor Butterworth of Forbes.
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