environmental toxins Archives

Evaluating Endocrine Disruptor Research

Published on July 30, 2015

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Every now and again, we see a flurry of press releases flooding social media about new research purporting to prove that endocrine disruptors are safe. Most recently, the press has been focused Bisphenol A or BPA. New FDA proclamations suggest that it has no impact on health. When one reads the actual research upon which these statements are based, it says no such thing. Unless of course, the research is funded by industry, then it is almost always positive. A report in Newsweek found:

In 2013, for example, the American Chemistry Council spent more than $11 million on lobbying expenses, according to the Center for Responsive Politics. Industry groups have also funded, and in some cases written up, research done by governmental scientists. One 2008 investigation, by the Milwaukee Journal Sentinel, found that “a government report claiming that bisphenol-A is safe was written largely by the plastics industry and others with a financial stake in the controversial chemical.”

The report goes on to state that the FDA

…dismissed as irrelevant the vast majority of the BPA safety studies its own scientists reviewed in preparation for that official position statement. According to the FDA, for example, all of the 48 epidemiological studies reviewed had ‘no utility’ for the agency’s risk assessment, the formal process it undertakes to decide if a chemical is safe for human health or not.

With such contradictory claims about safety, who should we believe? How do we evaluate the safety research about endocrine disruptors? Here is a primer.

Industry Sponsored Research Is Biased

In a mini-review of research on bisphenol A (BPA) – the endocrine disruptor in plastics, of the 115 studies published on adverse effects of BPA 81.7% (94) reported significant adverse health effects (2004). However, upon review, it was found that 90% of the government funded, academic research found significant adverse effects while 100% of the industry-sponsored research found no ill-effects of BPA – none. This is a common theme across all industries – pharmaceutical included. When billions of dollars are on the line, industry sponsored studies will show favorable results more often than not. Always check the author’s conflict-of-interest disclosures at the back the article. If none are reported though, don’t assume they do not exist. Not all conflicts of interests are disclosed. You may have to do additional digging to identify conflicts.

FDA or EPA Approved Does not Mean Safe or Risk-Free

Both agencies have long histories of approving and then failing to recall dangerous chemicals, drugs and devices from the market. Their work is particularly incompetent in reproductive (endocrine) and women’s health: thalidomide, DES, Yasmin/Yaz, HRT, Mirena, Prolift to name but a few that have garnered the seal of approval by the FDA. Phthalates, BPA, Glyphosate for the EPA. Remember the EPA doesn’t even study the female reproductive dangers unless research shows that a chemical impacts the male reproductive system.

Research Methods Matter

Perhaps more so than in any other field of science, endocrine research requires serious consideration of all aspects of the study protocol. This means that you cannot rely on a press release about the research to determine the study’s relevance. You must read the original research and evaluate the methods. (Reading original research is a good habit to have for all matters that affect your health and well-being). Once you pull the research, here are some things to consider.

Length of study. Most hormone reactions are longer term and span generations. If the study is short duration, as in the case with the industry sponsored GMO research or doesn’t include third generation effects, as with BPA research – question the results.
Population studied. Whether one is investigating a chemical or a drug in humans or in rodents, the sample population matters. Ascertaining safety of efficacy by testing only healthy young men, when the drug or chemical is meant for the real world where women, children, elderly, healthy and not so healthy individuals reside, is common practice and recipe for disaster. Same is true for rodent research – the strain, sex, age and health of the animal must be considered if the work is to be extrapolated to real humans. I read one study claiming that BPA was safe, but they used a strain of rats that was resistant to environmental estrogens. Of course, BPA’s estrogens would not affect these estrogen-resistant rodents.
Outcomes measured. What does the study measure and how does it evaluate change? More often than not, industry sponsored research will not measure the appropriate endpoints or reproductive dangers. Sometimes this is sleight of hand, other times it is simply ignorance of the endocrine system’s far-reaching regulatory control. In either case, one has to evaluate what the study actually measures before determining its validity. Here, you can use a bit of personal experience – what systems, organs or behaviors are affected by your hormones? If the study didn’t measure any of these variables, then it’s probably not a very solid protocol.
‘Gold-standard’ protocols are not always golden. It takes years, decades even for ‘gold-standards’ to become the accepted methods – often well after their utility has run out and newer, more sophisticated tools have reached the market. This has been the case for endocrine testing and endocrine disruptor evaluation. If a study rests all of its findings using a gold standard, it may not be using the most sensitive testing methods.
Clinical significance is not the same as statistical significance. Clinical significance means the chemical/drug has some meaningful impact on the health or well-being of the individual or animal. Statistical significance is just a math equation. A simple increase in sample size while limiting or ‘restructuring’ outcome variables is all it takes to derive statistical significance in most research. Does that mean the drug or chemical has clinically relevant health effects – not necessarily. The opposite is also true. Want to obfuscate the dangers of a drug/chemical? Do a huge study (preferably by combining dozens of poor quality individual studies into a meta analysis), throw everything but the kitchen sink into the analysis, do simple stats and highlight the lack of statistical significance in the death or injury rates. Only a small fraction of the study population died – but it wasn’t statistically significant, so the drug/chemical is considered safe. If the study does not study distinguish between clinical and statistical significance or downplays the death and injury rates as statistically insignificant, approach cautiously.
Hormone reactions do not conform to linear statistics. Damn it, how dare our complex physiology not conform to the simplicity of linear statistics. A common dose-response curve is highly linear, where a small dose elicits a similarly small response and a larger dose increase the response size. This is not case when dealing with endocrine disruptors. Hormone systems are complex and highly non-linear. Hormone dose-response curves are often in the shape of an inverted U where low doses elicit huge responses, mid-level doses elicit minimal responses and high doses again elicit huge responses. And so, any study measuring hormone effects using simple, linear, dose response calculations is bound to miss the effects entirely.
Hormones have metabolites (as does everything else). Metabolites evoke their own reactions. We know that some of the metabolites from BPA are stronger, 1000X stronger in fact, than BPA itself. Studies that don’t address the full complement of hormone products that circulate in our bodies as a result of exposure to something like BPA will severely underestimate the safety issues.

In a nutshell, we have to do our homework. There is no simple ‘Good Housekeeping Seal of Approval’ for products that impact health and well-being. We wouldn’t trust the marketing put out by car manufacturers or, worse yet, a car salesmen, about the safety, gas efficiency, repair history and comfort of a new/used car; why do we trust the makers of chemicals to give us the straight story. We shouldn’t. We have to become educated consumers of health research in order to protect ourselves.

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This article was published previously in March 2013 and updated and edit for republication in 2015.

BPA Exposure Linked to Egg Maturation Errors and Infertility

by Chandler Marrs, PhD

Published on August 9, 2013

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Bisphenol A (BPA), the polycarbonate, endocrine disrupting plastic is pervasive in the environment. A recent National Health and Nutrition Examination Survey detected BPA in the urine of 95% of the participants. Along with other toxins, BPA has been found in the placenta and follicular fluid of pregnant women. Given its estrogenic actions and its ability to disrupt the normal equilibrium of maternal and placental hormones, scientists have begun to investigate what role BPA might have on infertility, pregnancy complications and fetal development. What they are finding is not good.

In the most recent set of experiments, researchers from Brigham and Women’s in Boston, found that in vitro BPA exposure to human eggs – oocytes, prevented the egg’s ability to mature and disrupted chromosome alignment and organization at the lowest dose possible; a dose lower than levels normally found in women’s ovaries.

The experiment used eggs discarded from patients undergoing IVF/ICSI cycles. The eggs were divided into two groups, those to be exposed to varying doses of BPA and a control group. Sibling pairs, eggs from the same mom, were placed into both the BPA and the control groups equally to reduce the possibility that any maturation errors in egg development might be linked other factors related to maternal infertility, such as age, weight or general health.

The eggs exposed to even the lowest doses of BPA failed to mature appropriately and higher doses were linked to an increased rate of error and maturation failure. Researchers note that this was preliminary study, but that their findings indicate BPA exposure might be linked into infertility at the most basic level – egg health and maturation.

From our perspective, this study suggests that couples contemplating pregnancy should eliminate BPA and other environmental toxicant exposure well before attempting to conceive. For couples having difficulties conceiving, it might be worth testing urinary BPA and other endocrine disruptors such as phthalates and reducing exposure to these chemicals prior to undergoing costly fertility treatments. Here are the four most effective ways you can minimize your exposure to BPA:

Drink filtered tap water. This helps avoid water that has leached BPA from plastic containers.
Use stainless steel water bottles or certified “BPA-free” containers.
Avoid all canned foods, which are often lined with BPA containing resins. Eat fresh, non-processed, organic foods and avoid storing in plastic bags.
Avoid the use of plastic utensils and dishes.

BPA is likely not the only source of endocrine disruptors. All plastics under normal conditions release estrogenic compounds. It may be wise to avoid plastics in general. Additional research on removing BPA and other chemicals from your diet can be found here.

100 Toxic Chemicals Found in Pregnant Women

by Chandler Marrs, PhD

Published on January 14, 2013

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Environmental toxins are everywhere. Not a day goes by that some report doesn’t warn us about this pesticide or that plastic or the host of toxic chemicals floating in the atmosphere. One has to wonder how we survive the toxic soup that has become our environment; but somehow we do – well, mostly. The rate of cancers, immune, endocrine and a myriad of other diseases are on the rise. Though experts argue about direct links between specific chemicals and diseases (correlation does not equal causation), no one can argue that bathing in a chemical cocktail is healthy. Yet that is exactly what we do and when we become pregnant so do our babies.

As part of the National Health and Nutritional Examination Survey (NHANES), 163 toxic chemicals from 12 chemical classes were measured from the blood, urine and serum of a representative group of 268 pregnant women. The results were not good. Researchers found widespread exposure to many toxic chemicals. Exposure to several classes of toxic chemicals were detected in 99–100% of the pregnant women tested including:

Polychlorinated biphenyls (PCBs) – are used as coolants and lubricants in electrical systems. Though no longer produced in the US, PCBs are still present in the environment, mostly in contaminated streams and rivers. Eating contaminated food (fish, meat or dairy) is the primary source of exposure. PCBs are also found in old (>30 years) fluorescent lights, refrigerators and TVs. PCBs are carcinogenic and exposure during pregnancy can cause developmental delays in infants and children.
Organochlorine pesticides – DDT and other pesticides (mosquito control) used in US from 1940-1960s. Many, though not all, are banned in the US. Organochlorines are neurotoxic and cause reproductive failure in animals.
Perfluorinated compounds (PFCs) – are used to create stain and water resistant fabrics such as Stainmaster^TM, Scotchgard^TM, Teflon^TM and represent one of the most pervasively present chemical toxins today. PFCs do not appear to break down in the environment – ever, are linked liver and bladder cancer and cross the placental barrier. PFCs are linked to developmental and reproductive toxicity.
Phenols – are pervasive in the environment, found the resin in plywood, automotive and construction materials, the effluent of oil refineries and in the manufacturing of plastics (bisphenol A – BPA). Phenols are also found in a of medical products such as: mouthwashes, toothache drops, throat lozenges, analgesic rubs, and antiseptic lotions and tobacco. According to the EPA, no human studies have been done to determine the developmental or reproductive affects of phenol exposure, though animal research suggests phenols are weak carcinogens. Research on bisphenol A clearly suggests it is a highly estrogenic endocrine disruptor. Research on a class of phenolic compounds used oil refinery effluent that often leaches into nearby water supplies, reduces thyroid functioning in fish who swim in those streams.
Polybrominated diphenyl ethers (PBDEs) – are flame retardants that appear to be highly environmentally persistent – they don’t degrade – and have bio-accumulative affects that can be toxic to humans and the environment. PDBEs were only recently phased out of use in 2004. Exposure comes through eating foods grown in contaminated soils. The toxins can cross the placental barrier and are passed through breast milk. Though human research is still limited, PDBEs are thyroid toxic in rodents.
Phthalates, are pervasive in our environment from vinyls and plastics, to pesticides and solvents. Phthalates are present in most cosmetics and perfumes, though because of a loophole in the regulations phthalates are not often listed in the ingredients. They are also used in the coatings of many medications. Phthalates are endocrine disruptors and can cause congenital abnormalities in offspring of women who have been exposed.
Polycyclic aromatic hydrocarbons (PAHs) represent a group of over 100 different chemicals emitted when burning coal, oil and gas, garbage, tobacco and even charbroiled meat. Exposure comes from breathing, except in the case of charbroiled meats. Don’t burn the steak the bar-b-que!
Perchlorate or rocket fuel disrupts iodide uptake into the thyroid gland.

Though individually and with high enough exposure any one of these chemicals can have serious reproductive consequences. It is unclear, however, what chronic, lower level exposure to multiple chemicals would do, and yet that is exactly what most women face. How many products from the above list have you been exposed to? Chances are, most of them.