Our Bodies’ Chemical Burden: Little Doses Matter a Lot

Here’s sobering news: any one of us, anywhere on the planet, lugs hundreds of industrial chemicals around in our bodies – and they are up to no good.

If you want to know what industrial chemical compounds Michael Lerner or his wife Sharyle Patton carry around in their bodies, just go to this Environmental Working Group website. Lerner and Patton are both active in environmental health, the field that studies how the chemical byproducts of industry and commerce impact the human body.

Lerner, it seems, lugs around relatively high levels of methylmercury, inorganic arsenic, and polycholorinated biphenols (better-known as PCBs). These are but a few of the 102 industrial chemicals (of the 214 assayed by measuring metabolites) in his blood and urine.

Patton’s body, in addition to these, also has relatively high levels of chlorinated dioxins and organochlorine pesticide residues, plus a generous helping of others that did not show up in her husband’s tests.

Medical databases link (at various levels of certainty), each of these compounds with a distinct set of illnesses. Environmental Working Group has done several body burden studies of its own and shown that babies come into the world contaminated with a complex mixture of chemicals, many of them known to be toxins or carcinogens.

For instance, inorganic arsenic is a known carcinogen. BPA, found in plastics, dental sealants and the linings of tin cans, is a chemical suspected in certain birth defects and developmental delays in children, some cancers, and disturbances in endocrine and hormone function.

Both chlorinated dioxins and PCBs come to us mainly in fatty meats, dairy products and fish. Like BPA, they may link to defects and delays in children and to cancers, as well as to malfunctions of the nervous and immune systems.

The pesticide residues enter our bodies via the foods they are used on, as well as in drinking water; they are associated with a similar roll call of disorders.

Stepping back and looking at the entire list of 214 industrial chemicals this assay finds in our bodies creates the creepy feeling that nothing is safe: toxins waft our way in house dust or thin air, in water and soil, or off-gas from a long litany of objects — from paint and carpeting to computer consoles and furniture.

The body is an ecosystem of sorts, an exquisitely coordinated mass of disparate units functioning within a whole. And like any ecosystem, the body can be invaded by foreign substances that muck up the works. Quantifying how many such invaders our bodies harbor has been the quest of studies on bio-accumulation such as the one Lerner and Patton participated in to assay this biological build-up over a lifetime.

Bio-accumulation has become its own corner of medical science, with studies suggesting that virtually everyone alive on this planet harbors a stew of toxic substances. This shift from measuring pollutants in our water, air or soil to studying what has melded into our biology has led to related shifts in thinking about medical etiology and chemical risk.

One medical model for these chemical invasions holds that ill effects can emerge slowly, over decades, from cumulative chemical exposures at doses so low they are measured in parts per million. For instance, an emerging consensus in oncology holds that a person’s lifetime exposure to many tiny amounts of cancer-causing agents can be just as toxic as a few big doses of carcinogens.

This model of causation rejects seeking a single smoking gun – some substance that in itself fosters cancer – but rather looks to a person’s lifetime, cumulative exposure to a wide range of chemicals that trigger cell mutation. This continual barrage of mutagens can finally overwhelm the immune system’s ability to kill off mutant cells, and so resist cancer.  Our risk of cancer, in this view, reflects the sum total of day-to-day doses of carcinogenic molecules shed into our air, food and water.

Dr. Martha Herbert, a pediatric neurologist at Harvard Medical School, points to the tens of thousands of manufactured compounds that now pepper the nature world in some three billion potential combinations, and the fact that no one knows all the ways these chemical concoctions might impact us. One of the greatest human dangers from this slew of molecules, Dr. Herbert reasons, comes when a child’s fast-growing organs, budding central nervous system and hummingbird-like rapid metabolism gets exposed to – and voraciously incorporates — small amounts of foreign molecules, doing biological damage that may not surface for years.

The brain has a special vulnerability to interference from invading chemicals because of all organs, it utilizes the widest variety of molecules to transmit the chemical messages that coordinate our mental life and biological functions. This very design means there are that many more ways molecules from outside the body can disrupt these processes if they happen to interact with any of countless chemical reactions in the brain.

That’s why little doses can matter a lot.

Adapted from Ecological Intelligence: The Hidden Impacts of What We Buy. Originally posted at ewg.org

One thought on “Our Bodies’ Chemical Burden: Little Doses Matter a Lot

  1. …and I wonder if there is a relationship between these chemical overloads and such illnesses as Chronic Fatigue Syndrome. I had this for many years, and was found to be reactive to so many common chemicals and substance it wasn’t funny. Just think of what is belching into the atmosphere from manufacturing, what is carried by the wind, and the chemicals used in food production. How much do these contribute to a ‘sick’ population?

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