Multiple chemical sensitivity (MCS) is a chronic condition in which an individual is highly sensitive to chemicals that are normally tolerated by other people. MCS is also known as environmental illness, sick building syndrome, chemical intolerance, toxin-induced loss of tolerance, reactive airway dysfunction and even Persian Gulf War Syndrome.

There is a wide variety of symptoms in MCS. These include:

· Fatigue
· Headache
· Insomnia
· Irritability
· Depression
· Memory loss
· Nausea

The precise cause of MCS is not known, though a few theories are being investigated. There is a controversy surrounding these theories however. Some believe that MCS is a purely psychological illness. Some like to call MCS sufferers hypochondriacs. They do this because of the many symptoms and chemical triggers of the illness. The truth is, MCS is difficult to study. But some researchers are making headway. The biological mechanisms underlying multiple chemical sensitivity are slowly being uncovered and are disproving the idea that MCS is a mental illness. These theories include:

· Oxidative stress
· Imbalanced immunity
· Central sensitivity
· Inflammation
· Limbic system dysfunction

Oxidative stress can explain both the initial triggering of MCS as well as the chronic persistence of the illness. A particular oxidative stress cycle in the body, known as the nitrous oxide/peroxynitrite cycle, is activated by a wide variety of chemicals. Each chemical activation worsens the cycle which then becomes difficult to stop. A chemical trigger or triggers initiates the cycle, and subsequent chemical contact, even at very low exposure, perpetrates the cycle, promoting the chronic nature of the illness.

Interestingly, this nitrous oxide/peroxynitrite cycle is also found in illnesses including chronic fatigue syndrome, fibromyalgia, and post traumatic stress disorder.

Nerve inflammation is another finding in people with MCS. This is thought to occur by the irritation of nerve endings in the upper airways from inhaled chemicals. This inflammation can manifest in other areas of the body causing the wide array of symptoms seen in MCS, specifically headache, myalgia (aches), arthritis and airway symptoms.

One theory of MCS states that inhaled chemicals enter the nostrils and affect the limbic system of the brain. The limbic system regulates mood and emotions, formation of new memories, fear, rage, aggression, pleasure, and reproductive cycles – all related to the symptoms of MCS.

The hypersensitivity seen in MCS could be due to some underlying factors. These factors are also found in other health conditions that are similar to MCS such as chronic fatigue syndrome and fibromyalgia. These underlying health conditions, when not treated, can contribute to the worsening of MCS. These factors include:

· Dysbiosis
· Candida overgrowth
· Leaky gut
· Food allergies and sensitivity
· Liver dysfunction

Dysbiosis is an imbalance in the ration of good to bad bacteria, or microbes, in the gut. Fungal dysbiosis can also occur, which usually involves an overgrowth of Candida. This increase in pathogenic bacteria and/or Candida results in the production of toxins and inflammation which causes the small intestine to become permeable, or leaky - a condition called leaky gut.

A leaky gut allows toxins to enter into the body. These toxins travel throughout the bloodstream and provoke an inflammatory response in various areas of the body. This can influence the symptoms that are experienced in MCS.

Toxic load is another term that is used in reference to MCS. Toxic load is the amount of toxins that the body can effectively handle and detoxify. This amount is different for everyone. In people with MCS, toxic load is very low. The body simply cannot tolerate toxins of any sort. Liver dysfunction may cause a slower detoxification process, also known as sluggish liver, resulting in an overburden of toxins. Leaky gut contributes to this overburden by sending toxins to the liver that would otherwise remain in the intestines and pass with bowel movements.

Standard Medical Treatment

There are varying treatments for MCS. All agree on one thing – avoidance of chemical triggers is important. From there, treatment varies. Some conventional doctors will dismiss the illness saying that it is “all in your head”. Antidepressant medications, usually selective serotonin reuptake inhibitors (SSRIs), are often prescribed by these doctors.

Treatment Alternatives

People with multiple chemical sensitivity need to be careful to take things slowly while healing. The first step is to regulate bowel elimination. Two to three bowel movements a day need to be occurring before detox and cleansing begins. This ensures that the body is able to regularly release toxins with the bowel movement. Then, a mild Total Body Cleanse, taken at half strength, followed by daily support of the liver with a liver supporting supplement, is recommended.

[Brenda Watson, C.N.C., is a New York Times bestselling author, PBS health educator and digestive care expert, and is considered one of the foremost authorities today on natural digestive health and the gut connection to total-body health. ]