[soundcloud url=”https://api.soundcloud.com/tracks/166861524″ params=”color=ff5500&auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false” width=”100%” height=”166″ iframe=”true” /]
For many people, the word “toxin” usually creates a mental image of a colorful frog, or maybe venom from a reptile, or possibly some industrial chemical with hazard symbols on the bottle. Images that certainly don’t come to mind, at least for many, are brand-name soaps, lotions, deodorants, toothpastes, store receipts, and coffee cups. Government officials wouldn’t allow name brands to mass-produce consumer products with toxins in them, would they? Well, it turns out, the answer is yes, and here is why.
There are new toxins on the block called endocrine-disrupting chemicals which are defined by the US Environmental Protection Agency (EPA) as “an exogenous chemical substance or mixture that alters the structure or function(s) of the endocrine system and causes adverse effects at the level of the organism…based on scientific principles.
The toxins found in consumer products interfere with our hormones—either by increasing or decreasing their synthesis—and affect their transport, metabolism, and breakdown.
Many of these compounds bind to the same receptor-docking stations used by our own hormones.
The prevailing paradigm in toxicology has been that “dose makes the poison.” The venom from a black widow spider bite would almost certainly kill a small dog, but a 250-pound man might fair pretty well.
The venom of poisonous insects and exposure to industrial materials follow linear pharmacokinetics. The higher the dose, the more disruption the compound will have on the body.
In contrast, the endocrine-disrupting compounds—the toxins present in many consumer products and plastics—don’t adhere to this simple “linear” pharmacokinetic model.
Instead, these compounds have what scientists call nonlinear or biphasic disease responses. This means that both very low and very high exposure can negatively affect our biology.
Moreover, many of these endocrine-disrupting compounds are known to have synergistic effects, meaning that exposure to more than one of these compounds in combination (as present in many cosmetics and cleaning products) amplifies the impact these compounds have in our body.
Manufacturers of these compounds study their toxicity in isolation, not in combination. In such safety evaluation studies, scientists also look at signs of overt pathology and disease in animals exposed to these endocrine-disrupting chemicals.
Scientists in favor of re-evaluating the safety of these chemicals argue that absence of disease doesn’t mean “safe from disease”; these compounds still pivot hormones out of the optimal healthy ranges.
But that is just the tip of the iceberg.
Our hormones have natural buffers called binding globulins. You can think of binding globulins like the stoplights present on the on-ramps of freeways during rush-hour commutes. (If everyone leaving work merged onto the interstates at the same time, traffic would come to a halt.)
Proteins in the blood, like albumin and sex hormone-binding globulins, are the stoplights of the body’s hormone system; only a few hormone molecules can be “free” at any given time.
In contrast, just low levels of endocrine-disrupting chemicals (EDCs), found in numerous commercial products, are able to exist in the bloodstream, free and unbound. Just a few picograms of EDCs can raise blood levels enough to activate hormonal receptors and change your internal biochemistry in a negative way.
To add insult to injury, the intensity of our hormone signaling does change over the course of our lifespan and can have a permanent impact on our biology. Boys are boys because testosterone latches onto the androgen receptor, causing the development of male sex organs.
This is an example of how a hormone can create a permanent change in human biology (i.e., the development of male genitals).
Similarly, the natural rise in estrogen in prepubescent girls matures secondary sex characteristics.
Well, it turns out that the hormone-like compounds found in consumer products can affect the metabolism of these critical hormones, leading to permanent changes in our physiologies.
As an aside, maternal cord blood and breast milk from otherwise healthy mothers contain trace levels of endocrine-disrupting chemicals.
Unfortunately, the EPA doesn’t require manufacturers to demonstrate the safety of endocrine-disrupting chemicals throughout various time points in a human lifespan. Nope, most studies are conducted in adult mice, rats, and monkeys.
Here is the real problem: chemical manufactures don’t account for these variables to validate the safety of these chemicals. They still use the obsolete (linear) dose-response models to prove to the EPA that compound X (fill in the blank) is safe in your deodorant and child’s shampoo.
Thankfully, scientists throughout the globe are speaking out on our behalf and encouraging policy makers to wake up to the 21st century understanding of pharmacology.
Key Compounds to Avoid
Endocrine-disrupting compounds found in low concentration in plastics and personal-care products. Even low doses of these compounds have deleterious effects on our hormonal systems.
Minimizing exposure is key.
Filtered water and showers: water is a rich source of endocrine-disrupting compounds (EDCs). It’s best to filter shower water and drinking water.
Drink coffee in mugs or stainless steel containers.
Exercise daily – increase high-intensity exercise.
Try to minimize exposure to plastic toys – children are exposed to chemicals through toys.
1) Vandenberg et al . Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses. Endocrine Reviews March 14, 2012 er.2011-1050
2) Marla, C. Low doses, big effects: Scientists seek ‘fundamental changes’ in testing, regulation of hormone-like chemicals. Environmental Health News. March 15, 2012