Bisphosphenol A and Health Risk: “Drinker Beware”

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September 25, 2008 - 12:00 pm email to a friend printer friendly view / write comments

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Dr Bufi

As far back as the 1930s, it has been suspected of being hazardous to humans. However, the use of Bisphenol A in consumer products never really hit the headlines until recently, when several governments began questioning its safety.

Bisphenol A products have been in commerce for more than 50 years, and its uses are numerous. Along with shatter-proof plastic, it is used to make polyesters (remember Disco?), epoxy resins (coatings on the inside of almost all food and beverage cans), PVC industrial plastics, baby bottles, water bottles (Nalgene), sports equipment, medical devices, CDs, various household electronics, and even flame retardants. In the United States, BPA is manufactured by General Electric, Dow Chemical Company, Bayer Material Science, Sunoco Chemicals, and Hexion Specialty Chemicals.

Bisphenol A has become controversial because it mimics estrogen and thus could induce hormonal responses. Laboratory animal experiments in the 1930s showed the first evidence of the estrogen activity from Bisphenol A. However, it was not until 1997 that adverse effects of even low-dose exposure were first reported. Since then more than 100 studies have been published with health concerns about Bisphenol A.

Various BPA animal studies have stated the following:

-Bisphenol A can disrupt the endocrine system affecting the way in which glands and hormones interact. Even low doses of Bisphenol A can mimic the body’s own hormones and possibly cause negative health effects. Long term low dose exposure may create chronic toxicity in humans. Bisphenol A has been known to leach from the plastic lining of canned foods and plastics that contain acidic or high-temperature liquids. While most exposure is through diet, exposure can also occur through air and through skin.

-Studies have demonstrated carcinogenic effects and possible neurotoxicity at low doses ,as well as a possible linked to obesity by triggering fat-cell activity.

-The U.S. Environmental Protection Agency and the International Agency for Research on Cancer have yet to evaluate Bisphenol A for carcinogenic activity.

Of course some toxicologists and some regulatory agencies have criticized low-dose toxicity studies, especially when Bisphenol A is injected directly into animals since human exposure is mainly through ingestion. Some studies (funded by the chemical industry) have found no evidence of adverse effects from low dose exposure. And a recent 2008 study concluded that blood levels of Bisphenol A in neonatal mice (cute little baby mouse) are the same whether it is injected or ingested.

The first study of the BPA effects on humans was published in September 2008 by Iain Lang and colleagues in the Journal of the American Medical Association (article link here). The study of about 1,500 people assessed exposure by looking at BPA levels in urine. The authors found that high Bisphenol A levels were markedly associated with diabetes, heart disease, and abnormally high levels of some liver enzymes. An editorial in the same JAMA issue (here) states that while this preliminary study needs confirmation and cannot show cause, there is a model here for equivalent effects in animal studies. This adds a great deal of biological probability to the results reported by Lang and colleagues.

Despite a soil half-life of only 1 to 10 days, it is an ever-present pollutant. According to Environment Canada, an initial assessment shows that over time even low levels of BPA can harm fish and organisms. Studies also indicate that it can currently be found in some municipal wastewater.

There are seven classes of plastics used in packaging applications. Type 7 plastics (sometimes identified with the letters “PC” near the recycling symbol) are made from Bisphenol A. Some type 3 plastics with BPA are PVC piping that is popular for household plumbing. When these plastics are exposed to hot liquids, Bisphenol A leaches out rapidly. The Types 1 (PET), 2 (HDPE), 4 (LDPE), 5 (polypropylene), and 6 (polystyrene) plastic products do not contain Bisphenol A so leaching into food or beverages is not a worry.

Some type 7 and type 3 plastics may leach BPA and will have their three arrow triangle with the number 7 or 3 inside the triangle. This symbol is located somewhere on the plastic, usually the bottom of the container.

There are some main points to help decrease BPA concerns:

1. Discard clear plastic baby bottles. Research that says there are problems point to the effect of the estrogen-like BPA on children as the most significant.
2. Tin cans are often lined in plastic BPA and sit around a long time, so discard older cans especially tomatoes and other acidic fruits.
3. Do not plastic bottles for hot drinks.
4. Replace your BPA bottle with a BPA free one, particularly if pregnant or pre-pubescent.
6. Use only BPA free water jugs.
7. Get a filter and use city tap water in lieu of drinking bottled water.

Don’t worry about polycarbonates in non-food related products like CDs and DVDs but do keep them out of the mouths of babes.

This issue remains controversial, however. The plastics industry and the maker of Nalgene bottles say there are no ill health effects with BPA. According to Chemistry World, the FDA maintains that there is no reason to ban or restrict the use of BPA in food or drink containers because human exposure levels to the chemical from these sources is too low to have any adverse effects. There is concern that the Food and Drug Administration’s policies on BPA are entirely dependent on two studies’ that were both funded by a subsidiary of the American Chemistry Council, and they represents plastic resins manufacturers.

So…debate continues on what is the safe limit of this BPA compound. Within the United States, an exposure of up to 50 µg/kg/day (50 parts per billion (ppb)/day) is considered safe by the Environmental Protection Agency. The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymer products that can be molded or extruded into objects or films or fibers. The Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, is recognized as the leading United States agency for protecting the public health and safety of people.

For the most part, we know the animal studies raise concerns and the human studies show exposure but no true effects…yet?

The jury is still out in some circles and has long gone home in others. I’m switching back to glass.

Be good to yourself,
Dr. Bufi

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