How Multiple Chemical Sensitivities May Be Linked to Your Limbic System

Have you ever had someone tell you something is “all in your head”? Or been dismissed as dramatic or even delusional when you try to explain how you’re feeling?

This is the unfortunate reality for many people who struggle with an “invisible illness” known as multiple chemical sensitivities. But as it turns out, telling those with multiple chemical sensitivities that “it’s all in their head” might actually be kind of accurate – just not in the way you might think.

Today, we’re going to explore the complex and fascinating link between multiple chemical sensitivities and a specialized network in your brain known as your limbic system. Let’s dive in.

What Is Multiple Chemical Sensitivity?

A multiple chemical sensitivity or MCS is a subset of a larger diagnosis known as environmental sensitivity. In simplest terms, environmental sensitivity occurs when your body has a negative reaction to low levels of something within your everyday environment that is generally well tolerated by those without a sensitivity. And those with multiple chemical sensitivities tend to experience an adverse reaction in response to exposure to low levels of any number of chemical compounds.¹

Environmental illnesses and multiple chemical sensitivities are complex conditions that are often difficult to pinpoint and diagnose. Their complexity is further muddled by the fact that many conventional healthcare practitioners are not well-versed in these conditions and can mistakenly dismiss these symptoms as being exaggerated or even imagined.

But multiple chemical sensitivities are very real and the symptoms caused by this perplexing illness can have a monumental impact on your life.

What Are the Signs of Chemical Sensitivities?

Symptoms triggered by MCS often involve a large spectrum of different organ systems and symptoms typically disappear when these environmental chemicals are removed. Some of the most common symptoms seen in those with MCS include:^2,3

• Headaches, dizziness, and lightheadedness
• Irregular heartbeat
• Rashes and skin issues
• Nausea, indigestion, and general stomach upset
• Upper respiratory discomfort and/or breathing problems
• Allergy-like symptoms such as runny eyes, sneezing, and/or chest and throat pain
• Arthralgia or unexplained joint pain
• Intense fatigue
• Brain fog, lack of concentration, and memory difficulties
• Feelings of depression and anxiety
• Significant mood disruption and mood swings

What’s even more interesting is that some individuals with MCS report a wide range of other cognitive and psychological disturbances that seem to come on out of nowhere after exposure to certain chemicals. These disturbances include things like:⁴

• Food cravings
• Binges and addictive-type behaviors
• Violence
• Hypersexual activity

So what gives? How can some people be exposed to “normal” levels of these everyday chemicals and feel absolutely fine while others are hit with a barrage of strange, unpleasant, and life-hindering symptoms?

What Causes Multiple Chemical Sensitivities?

MCS can be triggered by an infinite number of possible chemical triggers. You see, in our modern world, just about all of us are exposed to thousands of different chemicals every single day – through the food we eat, the air we breathe, the water we drink, and materials we come into physical contact with as we move through our lives. Exactly why some people respond so negatively to these chemicals while others are entirely unaffected is still a topic of debate, but researchers have speculated that it may be caused by factors like:^5,6

• Allergies and an overzealous immune response: It’s been speculated that exposure to certain chemicals can trigger an overblown immune response – causing your immune system to flag low levels of a wide variety of chemicals as irritants and initiating an allergic type response.
• Impaired detoxification: Others have speculated that perhaps those with MCS have difficulty processing and eliminating toxins – allowing these chemicals to essentially accumulate and overload detoxification pathways. Already overtaxed detoxification pathways then begin overflowing upon exposure to even very low levels of certain chemicals – causing a significant reaction.
• Neurogenic inflammation: Neurogenic inflammation refers to inflammation of the nervous system. When pro-inflammatory mediators and chemicals flood certain areas of your brain, it can alter the way your sensory neurons respond to stimulants like smells and chemical compounds.

While all of these certainly have a potential role in the root cause of MCS, there’s another proposed underlying mechanism that’s gaining traction. Some research is finding that MCS may be, at least in part, triggered via sensitization of what’s known as your limbic system.

What is the Limbic System?

Your limbic system isn’t a singular organ but a specific group of structures housed within your brain. While there’s been some debate regarding exactly which structures technically make up this complex system, the brain regions that constitute the limbic system include:⁷ 

• The limbic cortex
• The hippocampal formation
• The amygdala
• The septal area 
• The hypothalamus

Together, these structures form a complex network that plays a pivotal role in a number of brain functions including:⁷

• Olfaction or the processing of smells
• Appetite and eating behaviors
• Sleep and dreams
• Emotional responses including fear, rage, placidity, and calmness
• Autonomic and endocrine responses to emotions (like the “fight or flight” response)
• Sexual behavior
• Addiction and feelings of motivation
• Memory
• Social cognition or the thought processes involved in understanding and dealing with other people

As you can see, this intricate conglomeration of structures within the brain serves as the central hub for a wide array of different functions. Now let’s look at how this complex, interconnected web of structures that make up the limbic system is speculated to contribute to symptoms of MCS.

The Link Between Multiple Chemical Sensitivities and the Limbic System

It’s speculated that dysfunction of the limbic system may contribute, at least in part, to symptoms seen in MCS in a process that goes something like this:^8,9

• When you encounter smells, especially smells emitted by synthetic chemicals, these odorous molecules travel from your nasal passage and through your nasal epithelium – where they can then cross into the brain.
• As these molecules make their way into your brain, they stimulate electrical activity in the amygdala and hippocampal areas of the limbic system in a process known as kindling.
• Exposure to an acute, high-level dose of chemicals or recurrent low-level, intermittent exposure to chemicals can alter the limbic system response – essentially lowering the limbic system’s threshold and increasing sensitivity to stressors.
• This heightening of your limbic system’s sensitivity is sometimes referred to as toxicant-induced loss of tolerance or TILT. This means your limbic system’s electrical pathways are more easily “kindled” – with low levels of chemical exposure triggering the firing of nerve cells throughout your limbic system.
• Because these electrical signals are primarily concentrated within the limbic system, it can trigger a pronounced and distinct reaction after exposure to low levels of chemicals – leading to the strange constellation of symptoms seen in MCS.

While it’s likely that there are multiple underlying factors that lead to the development and exacerbation of MCS, understanding the intricate role the limbic system plays in this perplexing disorder gives us insight into treatment options.

So, Can You Cure Multiple Chemical Sensitivity?

The answer to this question is – it’s complicated. While there’s not necessarily a “cure” for MCS, there are some steps you can take to manage and drastically reduce your symptoms. Here’s what you can do if you’re struggling with the effects of MCS:

Manage Your Environment: 

Your home and your workplace are likely where you spend the vast majority of your time. And indoor spaces can be a major source of exposure to countless chemicals that can set off a reaction and make you feel downright crummy. While you may not always have a ton of control over your work environment, there are loads of tweaks you can make in your home to make it your safe haven and keep symptoms at bay.

I dive deep into how your home can be a major trigger of symptoms and how you can make your home safer if you have MCS in the following articles:

• Is Your Home Making You Sick? How an Indoor Environmental Professional Can Help
• How To Make Your House Safe When You Have Multiple Chemical Sensitivities

These articles are a great place to start when it comes to managing MCS.

Minimize Your Toxic Burden:

Exposure to chemicals and toxins can have a cumulative effect. Meaning the more frequently you’re exposed to irritating chemicals, the lower your threshold for tolerance can become. So taking steps to minimize your exposure to all toxins – not just those that currently trigger symptoms – can help your body better cope when you encounter those unavoidable exposures. 

To learn more about how to minimize your toxic burden and support your body in detoxing any accumulated toxins, head over and check out the following articles:

• What is Your Total Toxic Burden? How To Reduce It For Better Health
• How to Boost Your Immune System by Reducing Your Toxic Burden
• 4 Detox Methods That Actually Work

Addressing toxin exposure from every angle can go a long way in managing the symptoms of MCS.

Addressing Underlying Trauma and Retraining Your Limbic System

While it can be easy to focus on some of the more obvious physical aspects of addressing MCS – like managing your environment and minimizing your exposure to toxins – there’s another pivotal piece of the puzzle that must be addressed when it comes to environmental sensitivities. You see, your physiological well-being directly communicates with and influences your emotional state – and vice versa. The science behind this intricate connection between your emotions and your physical health is far too robust to dive into in this article, so I recommend checking out the following resources to learn more:

• Mast Cell Activation Syndrome: How It’s Diagnosed and 2 Exciting New Treatments
• Dr. Jill Interviews Beth O’Hara on Mold and MCAS
• Dr. Jill Interviews Dr. Lara Salyer on FLOW states

But the bottom line is, restoring balance to your limbic system is hands down one of the most important aspects of healing. Some powerful ways you can begin retraining and restoring balance to your limbic system include:

• Listening to binaural beats
• Cranial sacral therapy
• Integrative manual physical therapy
• Frequency specific microcurrents
• Neurofeedback
• Breath work (like Buteyko breathing)
• Medical hypnosis
• Neuro linguistic programing

I dive deeper into limbic system retraining and my own experience with healing severe environmental sensitivities in my upcoming book Unexpected: Finding Resilience Through Functional Medicine, Science, and Faith. If you’re grappling with MCS, an environmentally-triggered illness, or any ongoing health condition, this book is a must-read full of practical, scientific recommendations interwoven with my own personal story – to empower you with knowledge, inspire you to overcome, and ensure you know that you are not alone in this journey.

Seek Out Guidance From A Specialist:

Unfortunately, many conventional doctors have a poor or nonexistent understanding of the complexities of multiple chemical sensitivities and other environmental illnesses. So if you’re at all concerned you may be suffering from MCS or if you have unexplained, vague symptoms that seem to pop up out of nowhere, I cannot overemphasize the importance of seeking out the guidance of an experienced Integrative and Functional Medicine Practitioner. 

They can help you identify the root cause of your symptoms while helping you formulate a comprehensive plan to manage your symptoms and create an environment for healing. If you’re new to the functional medicine approach and aren’t sure where to start, I recommend reading my article How to Choose a Good Integrative and Functional Medicine Doctor.

Are You Or A Loved One Grappling With Multiple Chemical Sensitivities?

If you or a loved one are in the trenches and grappling with multiple chemical sensitivities, it can be frustrating, disheartening, and downright disruptive to your life. But the good news is, there is so much hope and so much help available to you. This complex condition is finally beginning to garner the attention and research it deserves – meaning the more we uncover, the more treatment options we have available. 

But regardless of what research unveils, at the end of the day, the power to manage and reverse symptoms of MCS lies within you. The day-to-day choices you make are foundational when it comes to addressing this perplexing condition. 

If you enjoyed this article and are looking for more ways to support a healthy, balanced life with minimal symptoms, I encourage you to check out the countless resources I have available on my blog, my YouTube channel, and in my weekly newsletter. You can sign up by simply entering your name and email address in the form below.

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Has there ever been a time in your life when you’ve felt alone or unsure where to turn for answers?

In Unexpected: Finding Resilience through Functional Medicine, Science, and Faith, Dr. Jill Carnahan shares her story of facing life-altering illness, fighting for her health, and overcoming sickness using both science and faith so that others can learn to live their own transformative stories.

Dr. Jill’s riveting and compassionate exploration of healing through functional medicine demonstrates how to replace darkness and fear with hope and find profound healing, unconditional love, and unexpected miracles in the process.

Resources:

1. Multiple Chemical Sensitivity | Johns Hopkins Medicine
2. Multiple Chemical Sensitivity (nih.gov)
3. Multiple Chemical Sensitivity (MCS): Symptoms, Causes, treatment (webmd.com)
4. Possible Mechanisms for Multiple Chemical Sensitivity: The Limbic System and Others – Multiple Chemical Sensitivities – NCBI Bookshelf (nih.gov)
5. Multiple Chemical Sensitivity Syndrome | AAFP
6. Multiple Chemical Sensitivity – an overview | ScienceDirect Topics
7. The limbic system (nih.gov)
8. Multiple Chemical Sensitivity (nih.gov)
9. Possible Mechanisms for Multiple Chemical Sensitivity: The Limbic System and Others – Multiple Chemical Sensitivities – NCBI Bookshelf (nih.gov)