Environmental Endocrine Disruptors and Bisphenol A

I am often asked about environmental toxins at my work here at ZRT and in my private practice. People find the topic confusing for multiple reasons - how is it that chemicals which are in everything and everywhere could be dangerous? Why would the FDA and EPA allow them to be there? And what happens if you get exposed to these levels?

I find environmental endocrine disrupters (EEDs) biochemically fascinating; personally, I find them terrifying. In a very short time frame of human history, we have created chemicals which can latch on to our own hormone receptors and create DNA and genetic changes. We then have put them in multiple places so that we are exposed to them all the time. We have no idea how to get rid of them, neither from our own bodies nor from our environment. Industry and society are wedded to EEDs which means safety issues maybe secondary to financial implications. Our government's politicians receive monies from chemical industries at the same time complaining about the monies spent on healthcare of individuals who may be ill secondary to exposures. In addition, the US government's general perspective is that most chemicals are safe until proven dangerous. Altogether, the whole thing is a truly mind-bending mess. But since this blog isn't about how to become active in government and public policy, I'll just share what I know and am concerned about with these endocrine disrupters.

One of the first things to understand about these disruptors is that we can't continue to think of them as poisons. Human history is filled with people using poisons for healthcare and beauty. Anyone for lead makeup to create pale youthful skin? Perhaps with some nice belladonna eye drops to dilate your pupils to mimic sexual interest? What we do to be beautiful. Poisons are generally safe at small dosages with mild symptoms, that get worse as you increase the dosages, until eventually you die. Classic poisons like arsenic, medications, and certain mushrooms all work on this principle. In science this is referred to as a monotonal curve -

However with environmental endocrine disruptors (EEDs) the curve does not appear to work this way. Rather, EEDs show a pattern logically called a non-monotonal curve. It is thought to look like this… In this diagram, symptoms are present at both low and high dosages rather than increasing with the dosage. EEDs are also tricky, showing us certain symptoms at low levels and then completely different and occasionally opposite symptoms at high levels. As if that were not hard enough to research, because they are hormones, the duration of exposure, and your age at the time of the exposure to these chemicals, also can change your symptoms and their toxicity. GREAT! (read sarcastically). Sandra Steingraber PhD names this beautifully as the "window of vulnerability." In summary - the amount of the EED, the dose of the EED, how long you were exposed to the EED, and the your age at the exposure may all influence your symptoms and the consequences of your exposure. This is why research on these chemicals is so difficult.

But wait, it gets even more fun. NOW think IN-UTERO & MULTIGENERATIONALLY! Ok, here's where things get even crazier. Now we have the dose/exposure/timing etc, but we now have to also think of your age as the age of your DNA when that DNA was being exposed to these EEDs. So, now we have you as a baby inside your mother and to get even crazier, now we have you as an egg inside your mother when she was a baby inside your grandmother! Yikes, don't you want off of this train? Women are born with all the eggs that they will ever have, so when a woman is pregnant with a girl, that girl is also forming her eggs - or in other words, the grandmother is pregnant with the eggs of her grandchildren, and their DNA may be influenced by the EEDs. Therefore, the exposure isn't just you being exposed, it's also your mom being exposed and possibly even your grandmother being exposed to EEDs (thankfully, that seems to be where we stop with the generations). With EEDs however, it means that the exposure may have different effects on each generation. Since research always tries to be as straightforward as possible, you can see the trouble. This also makes things more difficult because ongoing research suggests that you may react differently if you are exposed to an EED in adulthood, that you were already exposed to in-utero.

This past week one of the most concerning EEDs is once again making news - Bisphenol A (BPA). Bisphenol A is a chemical that was created approximately 120 years ago. In the 1930s it was being looked at as a synthetic estrogen replacement, but upon the discovery of DES (Di-ethyl-stilbestrol) it was abandoned. (DES has its own traumatic history as well). Meanwhile BPA was found to have properties that were helpful in making plastics flexible and clear. With BPA containing products we were able to line cans so that the metal taste didn't contaminate the food, as well as make polycarbonate plastics. The realization that BPA in plastics could be an issue occurred when a doctor who was doing breast cancer research found that cells that were supposedly estrogen-free were growing as if exposed to estrogens. This led to the realization that our plastics are not inert as we had thought. Unfortunately, the safety standards for BPA were established when we did not yet recognize the non-monotonal curve. This has led to a number of the arguments in industry and scientific journals about the safety levels maintained by the EPA for BPA. At this time, it is thought that the safety dosages set by the EPA for BPA is approximately 25 times higher than the dose shown to produce harm. It is thought that almost everyone has exposure to BPA at concentration levels shown to cause problems in rats.

Well, you might ask, why is everyone not sick if this BPA is such a big deal? The answer to this lies in what symptoms have been linked to BPA, and all the other things we know about EEDs - timing of exposure, dosage etc. However, the truth today is that in general, we are not very healthy. BPA has been linked to cardiovascular disease, brain changes, low testosterone and testicular size in males, sperm deficiency, and cancer risks. BPA is thought to show beautifully in some studies this non-monotonal curve, for example contributing to obesity at low concentrations and weight loss at high concentrations - 2 different symptoms for different dosages. Research has also suggested that exposure to BPA in-utero means that you only have to be exposed to a lower dosage during the adult years to trigger cancer. Exposure to very low levels on a daily basis for many years may create different symptoms than the higher bolus dosages. The research for BPA is vast - search bisphenol-a at pubmed.gov for 5,000+ articles. The website Ourstolenfuture.org is an environmental website based on the book by the same name, their site has a ton of research and explanations about BPA. The Environmental Health Perspectives is a peer reviewed journal looking at environmental health concerns including bisphenol-a. Or check out the 2000 report from the World Wildlife Fund for a European analysis of BPA. The National Toxicology program and the Environmental Working Group also have more information about bisphenol-a. To read the plastic industries response to this research click here.

So what things do you find BPA in? Lots! If you want to err on the safe side, think 2, 4, and 5 as your "safe plastics" since they don't contain BPA. Avoid polycarbonate plastics (the hard and glass-like plastics) found in plastic drinking bottles (non-disposables), baby bottles, and bowls. If you have the option, choose glass which does not leach any chemicals. When eating canned foods, choose canned products that do not use a BPA liner (Eden foods is one example) or better yet, choose frozen or fresh. Many companies are making the switch to BPA free since some countries are banning its use. If you do have to use a BPA container - don't heat it, especially in the microwave, and try to avoid putting acidic foods like tomato paste in contact with the plastics. For more information as to products containing BPA see thedailygreen.com.

So how big is the challenge of BPA? Think 6 billion tons per year. Knowing that we make this much, use this much and in all the products that BPA is in and you start to see the enormity of the research and industry challenge. This month, the FDA is reviewing again the research into BPA. Research suggesting the potential problems of BPA has been available since the 80's but the US government is being put in the difficult situation of reviewing the status while other countries including Canada are banning the chemical. We only have to think of the lawsuits to understand why. Follow the FDA's debate in the next couple of months here.

Really, it's enough to make you want to crawl into your glass bubble (definitely not plastic) to hide.

Alison McAllister, ND