While there is a general awareness by the public of our increasingly toxic environment adversely influencing our health, the specific relationship of these toxins to our nervous systems warrants further discussion and investigation.  The above quote is an excerpt from a letter by one of our forefathers, Benjamin Franklin, written to his apprentice, in which he alludes to his early discovery as a printer’s apprentice of the toxic influences of directly handling lead on his and his coworkers nervous systems. He describes developing great pain in his hands when handling the warmed lead printing agents, as well as cautioning as to the older guild workers developing ‘feeble hands’ from their more chronic lead exposure.   After the recent loss of a beloved patient of mine from ALS, who had toxic levels of uranium, aluminum, and other industrial toxins, I found myself both heartbroken and angry as to the unconscionable lack of focus by both those in the industry that allowed this to happen, as well as by the medical profession, on the role of environmental toxins damaging the adult and developing nervous systems. I have consequently made it a practice focus to provide my patients with a better awareness of the relevant casual relationships of environmental toxic influences on our nervous systems, including routes of exposure, mechanisms of interaction, tools of assessing one’s neurotoxin burden, and mechanisms of remediation.

Environmental neurotoxins include heavy metals (mercury, lead, aluminum, arsenic, manganese, copper, cadmium, etc.) as well as industrial solvents, hydrocarbons, insecticides, herbicides, fertilizers, fluorides, PCB’s, ionizing radiations, and dietary factors, including ethyl alcohol.   It is well recognized that most disease states are multicausal in their origins, including genetics, nutrition, perinatal trauma, environmental factors, etc. Not as well accepted is that heavy metal neurotoxic exposures have been directly and indirectly linked to such developmental neurological diseases as the Autism Spectrum, behavioral and mood disorders, learning disabilities, mental retardation and Cerebral Palsy, seizure disorders, Spina Bifida, and other maldevelopmental neurologic conditions.  In the adult nervous system, we see heavy metal neurotoxic influences manifesting as brain fog, or focus, attentional, and memory dysfunction, ALS, MS, balance dysfunction, pain syndromes, mood disorders, visual and hearing loss, Alzheimer’s and Parkinson’s Dementias.

A. Mechanisms of Neurotoxicity: most environmental toxins such as heavy metals have a positively charged lipophilic (fat loving) component that is attracted to the negatively charged linings and insulating myelin of the brain, spine, and nerves. The result of this interaction is abnormal brain development in the fetal and juvenile brain, and increased cell death in the adult nervous system. This affinity of heavy metal toxins also applies to other fat bearing organs and tissues of the body, including the thyroid, kidneys, liver, pituitary, and bone marrow, creating similar imbalances and dysregulation.

B. Routes of exposure: inhalation of airborne heavy metals, transdermal absorption, ingestion (mercury leakage from dental amalgams, food or water bearing toxins), nasal seural uptake, transmission from mother to fetus (across the placenta) and to child (breast milk).

C. Tools for assessing toxic burden: assessing environmental exposures is done through history taking, provoked heavy metal laboratory testing, serologic testing, anatomical and functional imaging, and physical examination.

D. Mechanisms of neurotoxin remediation: clearing toxins (chelation), avoidance behaviors (filtering water, air), utilizing organic food sources, and transdermal detoxification.

Although disease and wellness reflect a multicausal nature, the environment represents an increasing source of potentially reversible factors.  In 2008, Neurology journal reported the incidence of ALS in New Zealand to have steadily increased by 3% per year from 1985-2006.  The increasing incidence of autism is even more dramatic. It is incumbent upon us to deeply explore these issues further for possible intervention for patients suffering from these illnesses.