The scientists in the new review said neither of those applies to hormone-like chemicals.
"Accepting these phenomena should lead to paradigm shifts in toxicological studies, and will likely also have lasting effects on regulatory science," they wrote.
In the report, the scientists were concerned that government has determined "safe" levels for "a significant number of endocrine-disrupting compounds" that have never been tested at low levels. They urged "greatly expanded and generalized safety testing."
"We suggest setting the lowest dose in the experiment below the range of human exposures, if such a dose is known," they wrote.
Vandenberg said that there may be no effect or a totally different effect at a high dose of a hormonal substance, while a lower dose may trigger a disease.
The breast cancer drug tamoxifen "provides an excellent example for how high-dose testing cannot be used to predict the effects of low doses," according to the report. At low doses, it stimulates breast cancer growth. At higher ones, it inhibits it.
"Imagine taking 100 individuals that are representative of the American population and lining them up in order of exposure to an EDC [endocrine-disrupting compound] so that the person on the far left has the least exposure and the person on the far right has the most. For many toxic chemicals, individuals with the highest levels of exposure, at the right end of the line, have the highest incidence of disease. But for some EDCs, studies suggest that people in the middle of the line have the highest risk," Vandenberg said.
She compared hormones, which bind to receptors in the body to trigger functions such as growth of the brain or reproductive organs, to keys in a lock.
"The more keys that are in the locks, the more of an effect that is seen. But at some point, the locks are overwhelmed and stop responding to the keys. Thus, in the lower range, more keys equals more of an effect, but in the higher range, more keys equals less of an effect," she said.
Vandenberg predicted the report "will start conversations among academic, regulatory and industry scientists about how risk assessments for EDCs can be improved."
"The question is no longer whether these phenomena exist, but how to move forward and deal with them."
This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.
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18 Comments
Add CommentHow long will it take for this study to be buried?
Reply | Report Abuse | Link to thisAll manufacturers of human health disrupting compounds will weigh the cost of replacement or displacement of the offending chemicals vs the projected cost of losses generated by lawsuits. That simple equation will ensure the continued sacrifice of our health to monetary wealth.
Congratulations SciAm, you finally produced an article worth reading. Why can't all your articles be as good as this one? I actually felt like I learned something this time. This was actually an excellent article and I didn't feel like I had to attack the republicans. Good job.
Reply | Report Abuse | Link to thisAny change is subject to the rule of unintended consequence. While I welcome this article and the change in direction of what criteria is suitable for determining health risks, I am reminded of what happened with the chemical used to make children's clothing flame retardant.
Reply | Report Abuse | Link to thisAfter wide spread mandatory use in the U.S., there were subsequent indications that the health effects of children's exposure was not adequately tested; or ever established. The chemical used was replaced by a far more vicious concoction. This, in turn, was replaced with an even worse chemical. As far as I know, this is where we stand today. Arguing if treating children's clothing with a nasty toxic conglomeration will expose them to risk, and if that risk is greater than the risk of burns from clothing catching on fire. Most mothers know that children will sometimes suck and even chew on their clothing. It is not limited to exposure by contact with a child's skin.
There are those in the U.S. who can't even acknowledge the advantages of the European model of requiring such chemicals to be proved safe before they are permitted to be used and enter the environment. The U.S. model says companies must be allowed to profit first, then if a problem arises, they can do their own testing to minimize or confound the effects, and continue to reap profits until the ensuing law suits become too distracting or potentially damaging. Then those companies are not held libel or accountable as they are in other developed nations. They keep the money, and see nothing wrong with what they did or the US model of exposing the public first and then waiting to see if those who cry, keep on crying, or eventually shut up.
So hormone mimicking chemicals were on the same path. I can only hope that research, publication, and peer review can change the direction of how we asses health risks. But I think we will need stronger laws, and more stringent regulations to protect public health and lower per capita costs, regardless of how the story of synthetic hormone-like chemicals goes. I would hope we error on the side of caution, and not on the side of profit where illness, disease, and human suffering are concerned.
Situations like this is why the "free markets fix everything" model doesn't really work. The problem is the markets aren't really free, partly because information flow is restricted.
Reply | Report Abuse | Link to thisIf all consumers had all the information when they went to purchase a product, then they simply wouldn't buy products with ingredients that would hurt them or their families, but since either the information is unavailable, or hidden, or is too complicated for the average consumer (not all of us are trained chemists), people are constantly buying with woefully incomplete information, thus throwing a wrench in the "free market" self correcting mechanism.
And of course big business has a lot of incentive to keep information hidden or to confuse the issue as much as possible. After all, their job is to make money, not protect public health.
This is why Government's role is to regulate, and why it is so silly that so many Americans today scream about too much regulation, when really in many cases there is too little regulation (look at the mess Wall Street is still in... a situation crying for serious regulations). Sure some regulations are outdated and silly, and some can hurt legitimate business interests... so focus on cleaning those up, but don't focus on being against all government regulations.
We can't have smaller and smaller government in a world where corporations are larger and larger, and the economies are global, and other governments work to subsidize and promote their own industries... magically going back to the US government of the 1950's (or the 1850s!), simply wouldn't be able to protect it's citizens from corporate abuses or on the global stage. All this hooplah about seriously shrinking the federal government is wishing Pandora's box of globalization and big business was never opened... but it was, deal with it.
Not necessarily. Public outcry over studies, some accurate though cursory, others flawed, have gotten many substances removed from the food supply. The second the outcry starts, so do the lawsuits. The presumption that public outcry will not reach that level is flawed!
Reply | Report Abuse | Link to thisWith the european 'REACH' program, industries must ensure that any chemicals they market are safe.
Reply | Report Abuse | Link to thisI agree! As I read this article I was thinking there was finally something written that didn't sound like propaganda supporting the industrial point of view over human well being.
Reply | Report Abuse | Link to thisIf I understand this correctly, if the food comes in a box, can or bag or was grown using chemical pesticides, there is a fair chance that it may sicken or kill people over time. I guess that is one way to limit population growth.
Reply | Report Abuse | Link to thisThis article simply recounts the opinion of doctrinaire scientists that unidentified studies support their conclusion.
Reply | Report Abuse | Link to thisThey state without explanation that low doses of some substances are worse than high doses. Naturally, this means that studies that test the effect of whatever amount of administered substance that find no harm can be ignored because a lower dose is the real problem.
Interesting article. Something to think about. But science it is not.
Alongside this issue is birth control pills. I used the pill for 15 years until now. My emotions got the best of me more and more thoughout the years and I was never able to hold a relationship because of how much I lost control of myself from all the crying and fits of anger. I asked doctors to look at everything, not knowing what could have been my problem. My thyroid, wondered if I was bipolar, depressed, anxious, mentally insane, or all of the above... After a thyroid blood test indicated that my levels there were fine and noted on the side that all my symptoms (depression, anxiety, headaches, cold hands and feet, weight gain, sinus problems, foggy memory/thinking...) were indicating a hormone problem. Without consulting any time wasteful doctors, I quit taking my birth control and have been the happiest woman of my entire life since I can remember. All those lost years because of a hormone I was taking. I finally have my life in control... my emotions in check and am smiling every day.
Reply | Report Abuse | Link to this@northernguy. Have you bothered to read the paper? It's 78 pages long, cites 845 references to the scientific literature and provides a very detailed account of how low doses are not always predictable in terms of high doses.
Reply | Report Abuse | Link to thisNo wonder why autoimmune illness is becoming rampant in our society. We are poisoning ourselves.
Reply | Report Abuse | Link to thisI have a special concern over the herbicide Atrazine. I have been monitoring water quality in a central Kentucky lake (Rough River Lake) which is a Corps of Engineers flood control lake. Each spring I take water samples for the state and the water lab at Western Kentucky University does the testing.
Reply | Report Abuse | Link to thisI started three years ago. The atrazine level in the part of the lake I use was 1.8 ppb. I had noticed, over time, that the frogs had disappeared. Nobody seemed to notice. I then learned that 1 ppb interfered with the endocrine systems of male amphibians, resulting in sterilization, hence no frogs.
Two years ago the level of atrazine had climbed to >7.4 ppb.
Last spring the atrazine level was 13.4 ppb. Last summer was what I call a warm water summer, with water temperatures up to 90f. When this happens the green algae is everywhere and all over. Normally I scrape the algae off my boat at least three times during the summer. I didn't have to scrape the algae off my hull at all, because there was none. Only a fraction of the algae that is normally there in the lake was present.
I spend a lot of time in that water observing "nature", swimming for exercise, etc.. Is there anybody out there that is aware of other effects of atrazine? What might be next to die off? Is there a negative impact on humans? Atrazine seems to have a long half life and it is concentrating in the lake. I can't believe that this is the only lake with this problem.
A few years ago, Canada banned plastics containing Bisphenol A from any products used with infants and children: soothers, baby feeding bottles, children's toys, etc. based on early reports appearing at the time.
Reply | Report Abuse | Link to thisI think UK did the same as well.
A move I firmly applauded at the time, even though this Canadian gov't is scientifically illiterate, downright stupid and fascist in other matters.
You Sir show a woefully inadequate understanding of "free markets". In a real free market a corporation that knowingly causes harm (without suitable warnings) will be sued out of existence.
Reply | Report Abuse | Link to thisA corporation that knowingly causes harm while following government regulations is legally protected from legal consequences. All too often regulations protect the corporations, not the consumer, or perhaps even more often they give an advantage to the large corporation over the small company, frequently at the expense of the consumer's health and/or financial well being. Yes we need regulations, that is in fact a responsibility outlined in the Constitution, but we should never lose sight of the principle belief that was held by the founders, "That government is best which governs least."
It may just be a difference in perspective though. I was raised in an era where there were only 9 cabinet (regulatory) positions instead of the current 15 (and the additional 6 "unofficial" cabinet "status" departments).
It's truly amazing that any of us survived those horrible times before an avalanche of regulations was enacted to protect us poor, stupid, helpless, consumers.
I am so glad that someone is TALKING about this! I think its fundamentally unacceptable that one of the most commonly used forms of medication in the world has side effects that without shame or apology include: mood changes,headaches and nausea and vomiting, and the ones not on the box insert but socially accepted as "normal" and "expected" for the pill include depression, loss of concentration, difficulty remembering and severe anxiety related problems. And these are not uncommon side effects. Its becoming clear that we don't properly understand the functioning of the endocrine system, and developments take time I grant you, but is the Pill really the best that medical science has to offer?
Reply | Report Abuse | Link to thisIt's fantastic to watch such an informed and interesting debate on the free market, as more often than not when the term comes up in regular conversation, its simply a name drop to further the speakers argument that generally doesnt relate to the free market at all and displays a lack of engagement with reality in general, let alone economics.
Reply | Report Abuse | Link to thisI wonder though, if you and Tharriss arent more on the same page than is first appearant.
You both acknowledge that the current state of affairs both nationally and globally do not by any means represent and true free market, and you both acknowledge the conflict of interest that arises between the consumer and the corporation.
I must say that *I* have a woefully inadequate understanding of the Free Market, but to the layman nothing much seems wrong with Tharriss's "Failure due to Lack of Perfect Information Analysis". And I applaud Tharriss's point that calling for massive de-regulation will not fis the problem of unscrupulous Corporations. Thats like saying the recent global economic recession happened because Capitalism is a bad system.
But then, the point that more regulations may end up *shielding* corps rather than protecting the consumer cannot be ignored either. It seems that both of you are calling for BETTER regulations rather than more or less.
What constitutues a better regulation?
Do these chemical studies include phytoestrogens, the plant-derived estrogens in soy, for example or is that subject off-limits?
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