Not so long ago a colleague and I wrote on The Huffington Post about the potential health dangers of the thousands of "endocrine-disrupting" chemicals that are pervasive in our environment. Our hope was that we could nudge, in some small way, the forthcoming decision from the FDA on whether to ban BPAs in food and beverage containers.
Unfortunately the FDA didn't see the research in the same way we did. They chose to ignore what seems plain to us, that these chemicals are transforming our bodies and minds, and that we should err on the side of caution in exposing ourselves to them. As we wrote:
There is a long scientific history showing a link between exposure to endocrine disruptors and reproductive disorders such as infertility and early puberty. Furthermore, the evidence is growing that the damage is much more widespread. In studies of animals, both in the lab and in the wild, these chemicals have been shown to increase the risk of various cancers, to contribute to obesity, and to influence the activity of neurotransmitters in the brain. In fact, there are even hints that exposure to the chemicals may have something to do with the dramatic rise in autism and mental disorders over the past few decades.
This week another colleague and I published the results of a study that shows, for the first time, how an individual's ancestor's in utero chemical exposure, coupled with stress in that individual's own life -- generations later -- can combine to alter behavior even more dramatically than either kind of exposure does on its own. The paper appears in this week's issue of the Proceedings of the National Academy of Science.
It is a model, in other words, of how this is likely to be working in the real world, where it's not one exposure to one chemical that's likely to be determinative of a disease or a condition or a behavioral tendency. Life rather is a complex series of exposures -- to different chemicals, better or worse nutrition, varying degrees of stress, etc. -- that cumulatively change the patterns in how our genes are expressed. And those "epigenetic" changes alter our predispositions to different health and behavioral outcomes.
Our experiment was a proof of principle study. We subjected rats to a "two-hit" scenario. There was an in utero exposure to vinclozolin, which is a common fungicide used on fruits and vegetables. Then we let the rats reproduce and looked at how their great-grandchildren responded to stress during adolescence -- the second hit -- when they became adults. This was in comparison to a control group of rats whose ancestors weren't exposed to the fungicide or to the stress.
What we found was striking. Even before they were stressed, vinclozolin-imprinted and control mice performed significantly differently on a number of standard tests that measure anxiety, emotionality, and social responsiveness (they were also overweight, though that's a story for another time). But if they were also stressed as adolescents, those differences were in some cases exacerbated later in adulthood.
On one test, for instance, the stressed-out, vinclozolin-imprinted males were significantly more interested in spending their time with other rats than their control counterparts, who were more willing to split their time between socializing and exploring. It was as if, after the double whammy of ancestral exposure and the stress in their own adolescence, the affected males became more needy.
It's not difficult, nor is it inappropriate, to make the connection between results like these and one of the big questions that's been haunting our society for the past few decades: Why are so many mental health disorders on the rise?
We haven't proved that chemical exposure is at the root of increases in autism, bipolar disorder, anxiety and depression, and similar conditions. My guess is that we'll eventually discover a significant connection with at least some of these conditions, but we don't know yet.
What we do know with increasing confidence, however, is that chemical exposure is changing our brains, and that those changes are being passed on to our descendants. Not all of those changes are likely to be beneficial.
Maybe next time around, the FDA will take note.
This post has been updated since its original publication.
David Wallinga, M.D.: Food, Toxics and ADHD: Old Fears, Ever Stronger Science
Bill Chameides: The Chemical Exposure That Keeps Going and Going and Going
While your findings are academically interesting, the rate at which you tested this chemical is completely non-contextual for the broad implications you are making. A dose of 100 mg/kg is thousands of times beyond the exposure that anyone would ever have gotten from vinclozolin residues back when it was used in the US (it is no longer used which you fail to mention). I looked at all the detections in the USDA, PDP database from 1995-2008. In the very worst case of one lot of strawberries from 1998, a 100 lb woman would need to eat 1,923 pounds in a single sitting to get the dose you gave the mice. For most residues ever detected, that woman would have to eat 100,000 to 1,000,000 pounds. "The dose makes the poison" certainly applies to epigenetic effects as it does with all other toxicological issues. What you are claiming to have "demonstrated" is actually quite irresponsible. Demonstrate the effect at 1/100th the dose before you start claiming that the sky is falling
Steve Savage, Ph.D. Applied Mythology Blog
http://baby.healthguru.com/video/top-ten-vaccines?mode=cycle
Also check this out:
Human race being terminated by 'scientific suicide'
http://www.naturalnews.com/035790_scientific_suicide_humans.html
That's one view, but to argue that exposure to miniscule amounts of various chemicals is okay because no single variant is proven harmless, that's nuts. We all contain many industrial molecules, and they do affect us in many ways. Modern life is a huge uncontrolled petrochemical experiment without a control group, we're all in, all the way.
It's hardly clear that this is really the case and it is very hard to pinpoint causality in this case. The leading driver in the US suicide statistic was the prohibition. Suicide rates almost doubled within a decade and then plummeted within a decade once the prohibition was repealed. Does that make alcohol a good antidepressant?
While I completely agree that we should remove these substances from our environment as quickly as possible, I don't think that the correlation between mental health and environmental factors is an effective argument for this cause. It hasn't worked in the past and it won't work in the future. What we need is a general consensus that all NEW substances that we want to introduce into the environment have to go through a very similar process as is needed for drug approval by the FDA. This requires controlled experiments BEFORE they are approved, rather than hard to control "phase IV" trials on the whole population!
So, in effect, your research would be great as an animal study before approval... but once these things are out there (and the economic and political interest is lined up to keep them out there), it will be next to impossible to recall them through the same mechanism.
So what this is saying, to me, is we need to approach our scientific and medical evaluations and recommendations taking into consideration that these are adaptive ecosystems working by a different set of rules than our medical science has been using as its framework which was singular linear direct cause and effect.
He's not saying he wants them recalled, as I understand it he's saying we need to find other solutions, but we first have to change our approaches.
Fortunately for us, the world does run on cause and effect. Without it, it would be a very messy place. Toxicology is all about cause and effect. The problem is simply that toxicology is a wonderful method of controlling consequences BEFORE people get hurt, but it makes for a lousy one after the fact. Again, that's a matter of human behavior, not one of science.
I can't quite see your point, but I am pretty sure that you completely missed mine.
It seems a no-brainer to a lot of people but obviously not to the FDA. I wonder if its because their brains have been affected by all of the above or is it their pocketbooks?
re the 7.5g.....I assume you made calculations for a 150 lb adult?
A 15 lb baby is affected by a ten times less dose of 7.5g = .75gram
What are the massively bigger effects on human embryo? A one ounce embryo?
Our next generation is affected by decisions we make today. Do we wait, until damage is obvious?
Sanitation did more to save lives than all the doctors in the world put together. It wasn't obvious damage in history, to ancients living in cities without sewer systems. Raw sewage running in the streets.
Additionally, there is not one substance that causes harm but potentially hundreds of thousands. Are we going to remove all of them from the environment? What if part of the damage was done by the large amount of radiation our parents and grandparents were subjected to by atmospheric nuclear tests? We can't undo those... yet, they may be large part of the problem.
So, in essence, this is a very complex problem, which will always give either side plenty of speculative arguments for their particular view.
off-gassing inhalants have a lower threshold trigger to affect the brain.
Treating something as a poison at 7.5grams, is different than something affecting the complex delicate balance of hormones & behavioral changes.
For example, we require 100 mcg of many micro-nutrients to make a huge change in our behavior & health. That's 80 times smaller than 7.5 grams.
Then there's micro-hormones, perhaps 1 mcg, such as eicosonoids. Microhormones can get easily overwhelmed, by 100mcg of a hormonal disruptor.
"Silent Spring"? My cousin was one of Rachel Carson's assistant. They're all dead now. :-) I saw a bee just this morning. It's just a lot of hype. People get upset to keep themselves entertained.