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BLOG: December 2008
Bisphenol A in humans: evidence of harm?
Can bisphenol A harm your health at exposures far below the FDA's official safe limit? Evidence from large number of studies, nearly all on animals, suggests the answer is "yes". But the industry and the FDA - entrenched together against concerned consumers and (independent) scientists - maintain that all the new evidence is inconclusive, and that the current official safe limits for bisphenol A are, indeed, safe.
The focus of concerns, thus far, was possible adverse effect of bisphenol A on fetal development, on infants and small children, as reported in more details in July's bisphenol A article. However, a new recent study - this time on humans - establishes statistical link between bisphenol A levels and incidence of heart disease, diabetes (Type II) and abnormal liver function; and the subjects are not babies - they are full grown adults (Association of Urinary Bisphenol A Concentration With Medical Disorders and Laboratory Abnormalities in Adults, Lang et al., JAMA, 09/16/2008).
The study used urine samples data for 1455 adults, age 18 to 74, participating in the 2003-2004 National Health and Nutrition Examination Survey (NHANES). Among 25% of the participants with the highest bisphenol A readings, incidence of cardiovascular disease was 3 times greater, and incidence of diabetes 2.4 times greater than among 25% of study participants with the lowest readings.
While the researchers readily admit study limitations, with the association being only statistical, and not necessarily causative, the magnitude of it, combined with the results of many animal studies, does raise legitimate concerns with respect to bisphenol A safety. More so considering that, as one of the researchers (Melzer) points out, the increased incidence levels occurred at levels of daily exposure
50 to 100 times lower than the official safe exposure level.
More specifically, researchers estimate that those with no diabetes or cardiovascular disease were exposed to an average 20μg of bisphenol A daily, while those with the diseases were in the 28-35μg range. According to the FDA, the safe exposure limit for bisphenol A is 3,200μg (3.2mg) a day.
Industry representatives, as expected, reacted as if the study results, well, at this point mean nothing to them. Not in the sense that they would even consider reduction in bisphenol A use or, God forbid, look for alternatives. One American Chemical Council expert stated that the inner can coating, containing bisphenol A (BPA), is necessary to protect from corrosion, and that finding safer BPA-free substitute "wouldn't be easy".
What could be easy enough is to determine what canned products really need the inner epoxy resin coating. Eden Foods, for instance, only uses it for canned tomatoes. Evidently, if there was any good will at the side of the industry, bisphenol A use could be significantly reduced without even looking for BPA-free alternatives.
Likewise, there are already existing, viable alternatives to BPA-containing plastics. Not a few companies have already taken that path. While the switch for the majority still using bisphenol A would incur certain expense, that shouldn't be more important than possible - and probable - harm to the general public.
Unfortunately, the one who gets to decide here - the FDA - shows no intention to change anything. Seems that as far as the agency is concerned, all and any of warnings about bisphenol A toxicity - the environmentalists, consumer agencies, the research scientists and their results - account for no more than a noise not worth paying any attention to.
Does the FDA has a solid factual basis to discount new findings?
Not at all. FDA's own safe limit for bisphenol A is based mainly on two old studies funded by the industry. It chooses to rely on very limited in sample size and duration studies of the industry on human volunteers showing that it is rapidly excreted by the body - some 95% of the daily intake in a 24-hour period.
Of course, it is by far insufficient data to be regarded as a general average. And even if it would be the legitimate population average, it would still leave ample room for significant variation in individual rates of bisphenol A elimination, i.e. accumulation within the body.
No one ever conducted a large, controlled study on the long-term effect of continued bisphenol A exposure in humans. In other words,
no one - including FDA - has reliable evidence
supporting that it is indeed safe at the present official levels.
How, then, to explain FDA's stubborn stance against any changes that would not only accommodate public concerns, but also pay due attention to the mounting scientific data confirming bisphenol A toxicity, as detailed in a recent lengthy article by two researchers (Bisphenol A and Risk of Metabolic Disorders, Saal, Myers, JAMA, 09/16/2008)?
Why would the government agency be so unreasonable, and rather biased? Maybe the fact that bisphenol A, with the production of over 7 billion pounds a year worldwide, is a part of the billion-dollar industry has something to do with it? And this is still only the
tip of the iceberg.
Should the FDA allow bisphenol A to be disgraced and discarded, it would be very likely followed by other toxic industrial chemicals - and there's plenty of them. That could actually put strain on the economy, and no government will easily take that chance.
In addition, the government is pretty much an accomplice in relying on the industry for establishing the safe levels of exposure.
So, it is slowing things down, as much as it can. What can you do? Stay well informed, so that you can take good care of yourself, and of those that may need your help.