Causes of Multiple Chemical Sensitivity: Some You May Not Have Thought About

Multiple Chemical Sensitivity (MCS) is estimated to affect up to 15% of the population in the US and other industrialised nations (1), yet research into why people develop this hypersensitivity to chemicals is sorely lacking. Currently we have mainly animal testing and studies involving small numbers of participants diagnosed with MCS to go on. Once again we have Invisible Illness, remaining invisible to the medical profession and academics alike, no surprises there, sadly for us. However we do have some good data to go on.

One leading theory suggests the development of a hypersensitivity to chemical stimuli in an area of the brain known as the limbic system which controls a variety of functions including emotion, behaviour, long term memory, and olfaction (our sense of smell). Animals studies have shown that both large acute exposures and low-level chronic exposures to certain organic chemicals can result in hypersensitivity of the limbic system to subsequent minute exposures to the same, or similar chemicals (2). Perhaps the most complete theory of the pathophysiology of MCS thus far has been proposed by Martin Pall, Professor Emeritus of Biochemistry and Basic Medical Sciences at Washington State University. Pall believes the symptoms are the result of a trigger (primarily chemical exposures) that results in the body getting locked into a cycle involving elevated levels of nitric oxide, increased free radical production (oxidative stress), chronic inflammation, and again, excessive sensitivity of the brain and central nervous system to "normal" stimuli (mediated by the NMDA receptor).

What all current biomedical research points to is that excessive exposures to chemicals that exceed the body's detoxification capacity, may result in the development of MCS in susceptible individuals. This is true whether the exposure is acute and obvious or is more insidious, occurring at a low-level over a prolonged period of time. The latter, beautifully eluded to in Claudia S. Miller's seminal book: 'Chemical Exposures: Low Levels and High Stakes'. You may have come across Miller as a trailblazer in MCS research and advocacy for patients as an allergist/immunologist. She is best known for her - Toxicant-Induced Loss of Tolerance (TILT) - theory and approach to chemical induced illness.

Learn more about Claudia S. Miller and ongoing TILT research at:
TILT Research Program for Chemical Intolerance (UT Health San Antonio)

For some who develop MCS it is obvious what initially caused their illness. Acute exposure to such things as organophosphate or organochlorine pesticides, formaldehyde, or various powerful industrial solvents, would be obvious examples.

There is much overlap between MCS and Gulf War Syndrome (or 'Gulf War Illness') and this is little surprise, since military personnel were exposed to a highly toxic and stressful environment during Operation Desert Storm in 1991. Unfortunately for many veterans, it was the 'perfect storm' to trigger this invisible illness.

In many cases however, the initial trigger for the development of MCS remains a mystery. For this reason EiR have decided to point out a few sources of chemical exposure you may not have considered, which could potentially trigger MCS:

1. Mold - For people living or working in water damaged buildings, mold could be a prime suspect if MCS subsequently develops. Dr. Lisa Nagy M.D., a leading environmental medicine physician, has attributed her own illness to mold exposure following water damage to her home. Mold and mycotoxins (mold/fungal toxins) in water-damaged buildings and their biological effects have been well studied. They have been found to trigger the production of autoantibodies that attack the brain and central nervous system, cause peripheral neuropathy, and result in various neuropathological effects including altered blood flow and electrical activity in the brain. EiR recommends scientifically proven natural mold removal products for body, home and laundry from Micro Balance Health Products.

2. Carbon Monoxide - Since it is a colourless and odourless gas, exposure to carbon monoxide (CO) can go undetected for long periods of time. For this reason it is important to install CO detectors in your home and have appliances such as gas-fired boilers serviced regularly. Pall suggests CO exposure as a likely trigger for the cascade of pathophysiological changes that can lead to MCS and points out that the symptoms of CO poisoning share many many similarities with those of MCS (3).

3. Candida / Fungal Overgrowth - On the face of it perhaps the least obvious source of toxic chemical exposure that might lead to MCS would be an intestinal overgrowth of the yeast Candida. albicans (causing an imbalance in the gut microbiome). Yet, many MCS sufferers have good reason to believe they also suffer from an imbalance in their gut microflora that has allowed yeast to expand their presence. When we consider the chemical toxins that yeast such as Candida sp. produce as they ferment the carbohydrates in the food we consume, it in fact becomes obvious that when these are absorbed into the systemic circulation from the gut they are able to poison the brain and may ultimately contribute to the development of MCS. These micro-organisms produce ethanol (drinking alcohol), acetaldehyde (a chemical cousin of formaldehyde), and a host of other mycotoxins, which we have already established are neurotoxic.

4. Dental Work - Many MCS sufferers cite dental procedures as the trigger for their illness. Amalgam fillings contain mercury which is a known neurotoxin. When used in fillings it releases gases which are inhaled, plus pieces may chip off and be swallowed while eating. Aside from mercury, people are increasingly complaining of the development of chemical sensitivities after they started using newer techniques for teeth alignment, such as Invisalign (see this blog of a EiR reader's experience: 'Urgent Health Issues Regarding Invisalign Braces'). These are obviously more pleasing on the eye compared to older metal braces (the 'rail tracks', as kids used to tease (bully!) ). They often may even go unnoticed, yet it seems they could be comparably toxic to mercury fillings. This is by no means proven by peer-reviewed medical / dental studies, yet the number of people describing becoming "sick all over" - which as we know is code for invisible illnesses(!) - has become overwhelming. We would not single out Invisalign, as there are many similar orthodontic braces using clear plastics, but this brand does come up often.

There are no doubt many other hidden sources of toxic chemicals that may trigger the development of MCS in those who are susceptible due to genetic characteristics and other factors. After all, our environment in the 21st century is saturated with such chemicals.

If you have any other suggestions, or wish to share your experiences, please let us know using the comment form below. It would also be great to hear what you believe caused your own MCS. All assuming you feel comfortable doing so of course, dear friends of EiR..

References:
1. Caress SM and Steinmann AC (2004) Prevalence of Multiple Chemical Sensitivities: A Population-Based Study in the Southeastern United States American Journal of Public Health 94(5): 746–7
2. Gilbert ME (2001) Does the kindling model of epilepsy contribute to our understanding of multiple chemical sensitivity? Annals of the New York Academy of Sciences 933:68-9
3. Pall ML (2002) NMDA sensitization and stimulation by peroxynitrite, nitric oxide, and organic solvents as the mechanism of chemical sensitivity in multiple chemical sensitivity FASEB Journal 16(11):1407-17