Multiple Sclerosis (MS) & Constipation: Lab Testing

chronic fatigue syndrome testing, MS, lab testing

Do you suffer from MS and constipation? Do you know how to test and identify the root cause of your constipation? If you are struggling with these issues, then read on for the details!  

In this blog on constipation, you will learn:

  • How constipation and digestive issues are quite common with Multiple Sclerosis (MS)
  • How to identify the root cause of constipation, whether or not you have MS
  • What specific tests you and your functional medicine practitioner should consider running to find the root causes of constipation 

Constipation can be due to many factors. Issues related to Multiple Sclerosis (MS) may be the cause of your constipation. But if you don’t have MS, there may be other underlying root causes for constipation. This blog on how to test for and identify the root causes of constipation applies to people with MS and to people who don’t have MS. We will review the various tests that will identify the things that can contribute to, or directly cause, constipation. 

In future blogs, we will cover how we can treat constipation. Please stay with us for this series of blogs on MS & constipation.

What is Multiple Sclerosis (MS)?

  • In the US, 1 million people are living with MS (National MS Society, 2023).
  • MS is the most common non-traumatic cause of disability in young adults today (Preziosi G, 2018). 
  • MS is unpredictable and affects different people in different ways. 

Multiple Sclerosis is a chronic disease affecting the central nervous system, including the brain and spinal cord. It is an autoimmune condition in which the body attacks itself by mistake. 

In MS, the immune system attacks nerve fibers and the myelin sheath in the brain and spinal cord. The myelin sheath is the fatty tissue that surrounds and protects nerve fibers. The autoimmune attack damages the myelin sheath which normally protects nerves. In addition to myelin, nerve fibers and neurons in the central nervous system (i.e., the brain and spinal cord) are damaged. Myelin gets destroyed in many areas and there is chronic inflammation from the autoimmune damage to myelin and nerve cells.

Once the myelin protection is damaged, the nerves become damaged leading to communication problems between the brain and the rest of the body. Normally, nerves transmit electrical signals to help with sensory perception and movement. But damaged nerves cannot transmit electrical messages to and from the brain as they are meant to. This affects nerve signaling and how different parts of the body function, including the digestive tract. This type of damage to myelin, neurons and neurological pathways eventually leads to neurodegeneration and neurological symptoms. 

What is Constipation?

Constipation is not having a regular bowel movement or being unable to completely empty the bowel. It is generally defined as having fewer than three bowel movements a week. Constipation can cause stools to be hard and lumpy, or unusually large or small. Constipation is a very common issue with MS and often becomes chronic.

MS Can Cause Constipation

  • MS interrupts messages that the nerves send to and from the brain. Among other important information for bodily functions, these messages signal that it’s time for a bowel movement.
  • MS can affect pelvic floor and anal sphincter muscles, which are part of the process of a bowel movement.
  • Motility, or the movement of food through the intestinal tract, may be slowed with MS.
  • Insufficient fluid intake contributes to constipation. MS patients with difficulty being mobile may simply not be able to get to the toilet often or easily, so they may intentionally drink less water.
  • Too little exercise is a factor in constipation. Again, people with MS and mobility issues may not be able to exercise very much, or at all.
  • Some medications used for MS can cause constipation.

Why is Lab Testing Useful?

‘Test Don’t Guess’ is our motto in Functional Medicine. It is important to identify root cause(s) of any condition. Once we know the root cause, we can target treatment and resolve the issue. To identify the root cause of constipation, we run lab tests. 

Various gut issues can cause constipation in anyone. For example, SIBO (Small Intestinal Bacterial Overgrowth) can cause either constipation or diarrhea. Dysbiosis, other gut infections, and pathogens can be responsible for constipation or other digestive symptoms. There are some standard tests that we can do to identify the different gut infections that may contribute to constipation.

Laboratory testing is not always perfect for infections and toxins, but they are still worth doing to identify possible root causes for constipation. 

We run tests at the Medicine with Heart clinic to drill down to the precise root cause(s). With the information from the tests, we can target the right treatment and not waste time with treatments that are not relevant. 

The Lab Tests to Identify the Root Cause of Constipation

The SIBO Test

SIBO is a sign of gut dysbiosis and is common in IBS (Takakura W, 2020). Due to gut dysbiosis, people with IBS may have increased intestinal permeability, dysmotility, chronic inflammation, autoimmunity, decreased absorption of bile salts, and even altered central neuronal activity (Takakura W, 2020). SIBO and IBS share symptoms including abdominal pain, gas, constipation or diarrhea, and bloating (Takakura W, 2020). In fact, SIBO can be a major cause of IBS.

Various things can cause SIBO. It can happen when there is a motility issue with the Migrating Motor Complex or MMC. The MMC is meant to move bacteria from the small intestine into the large intestine between meals and during the night. But if MMC function is impaired, bacteria do not get cleared from the small intestine correctly, and SIBO can develop. Other causes of SIBO include low stomach acid. Stress, for example, lowers stomach acid. Food poisoning is a frequent cause of damage to the MMC. 

There is not a lot of research on the SIBO – MS link. One study indicates that people with Multiple Sclerosis may have a high prevalence of SIBO (Zhang Y, 2016). We know that IBS is more common in people with MS: IBS affects 20% of people with MS (Levinthal DJ, 2013). IBS was once thought to be a psychological issue. But we now know that a key reason for IBS is gut dysbiosis, and is often SIBO. Up to 78% of patients with IBS have SIBO (Ghoshal UC, 2017). 

To test for SIBO, we use a noninvasive test. It involves breathing into a device that measures the amount of hydrogen or methane in the breath after drinking a mixture of glucose and water. A rapid rise in exhaled hydrogen or methane may indicate bacterial overgrowth in the small intestine. For example, constipated people can have very different gut bacteria composition than non-constipated healthy people, with higher levels of methane producing bacteria in their intestines, which slows intestinal transit time. In our clinic, we run this test in order to identify or rule out SIBO as a root cause of constipation or other digestive symptoms.

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The Stool Test

We also run the GI Map Stool Test on many of our patients. The GI Map provides insight into gut health. It is a comprehensive stool test that shows a variety of bacteria, both harmful and normal, as well as fungi, parasites and viruses. It might identify dysbiosis, parasites, harmful bacteria, H pylori, fungi or other microorganisms that can be the cause of constipation. 

For example, constipation can result from intestinal dysbiosis, involving an imbalance of gut bacteria (Zhao Y, 2016). The gut bacteria help to control motility, the rate at which food moves through the digestive tract. When gut motility is too slow, constipation occurs. The bad bacteria literally secrete toxins into the gut which slow down the motility, so that they can stay in the body longer.

Running the GI Map Stool Test allows us to see the potential issues in a patient’s gut and target treatment to the particular microorganisms causing the constipation. This saves time in the treatment process so someone can feel better quickly.

Food Sensitivities or Intolerances Testing

Food sensitivities or intolerances are often not a root cause in themselves. They are typically caused by another gut issue such as infection and leaky gut that may result from the infection. We can perform testing to look at food issues but these often just show us a person has leaky gut. It can be helpful in the case of gluten issues. 

The most effective way to check for food intolerances or sensitivities is to do an elimination diet. This involves removing typical allergenic foods like gluten, dairy, nuts or others from the diet for a period of 6 weeks. After the elimination phase, we add back one food at a time for 3 days. If no reaction occurs, then we can add back the next food. In our clinic, we can explain in great detail how to do an elimination and re-introduction diet for the best results.

The other option is to do a food sensitivity panel lab test to identify food triggers. Then we can remove those foods from the diet. But this lab test is not perfectly accurate. If a person has leaky gut, then results will show many food sensitivities. It really is much better and more accurate to do the elimination and re-introduction diet. 

Although food triggers make symptoms like constipation worse, they are usually not the root cause. We need to find and resolve the underlying root cause. Once this is done, it is not necessary to avoid a particular food forever.

Micronutrient Imbalances Testing

It is useful to check both macronutrient and micronutrient content of a person’s diet. It is important to get enough protein, fats, fiber, vitamins, minerals and other nutrients. Many symptoms can result from simple macro or micronutrient deficiencies. Fatigue, for example, is a common symptom. It is also possible to get too much of a particular micronutrient. For example, excessive vitamin A can be harmful to the liver. For these reasons, it is important to occasionally check macro and micronutrient levels to check for excessive or inadequate amounts.

One quick and easy way to check nutrients is to use a diet tracking app like Cronometer. With Cronometer, you can check your macronutrients – carbs, protein and fats. It will also track grams of sugar and grams of fiber which are useful. We want to minimize sugar. Fiber should be around 25 grams per day. Inadequate fiber can contribute to or be the cause of constipation. 

While Cronometer can be helpful as a guide, it is not a completely accurate way to measure micronutrient imbalances or deficiencies. Other types of tests can be much more accurate, depending on what we are trying to measure and assess. For things like vitamin D, B12, iron, zinc etc., a blood test is the best thing to do. 

For a fully comprehensive nutrient test, we can use either the NutrEval test from Genova Diagnostics Lab or the Organic Acids Test from Great Plains.

The NutrEval Test

The Nutri Eval is a combined blood and urine test that looks at over 125 biomarkers. It assesses the body’s need for 40 different antioxidants, vitamins, minerals, essential fatty acids, amino acids, digestive support and other specific nutrients. It will give information about how well the body is managing with methylation, toxic exposure, mitochondrial dysfunction, fatty acid imbalances and oxidative stress. 

Based on the lab report findings, we can provide personalized recommendations for rebalancing micronutrients. This may include recommendations for antioxidants, B complex vitamins, minerals, essential fatty acids, GI support and/ or amino acids support.


The Organic Acids Test

This test is also helpful for identifying nutrient deficiencies. It tests 76 metabolite markers in urine that provide a comprehensive snapshot of a patient’s overall health. 

It tests for issues in the gut like intestinal dysbiosis or bacterial overgrowth, levels of various nutritional markers and markers related to detoxification function.

The Organic Acids Test is very useful if we are looking for additional information related to underlying gut bacterial and fungal toxins, and/or mitochondrial function. It is recommended for anyone dealing with a complicated and chronic health problem.


  • MS is a chronic disease and an autoimmune condition. It affects the central nervous system. The autoimmune attack leads to damaged nerves and impaired nerve signaling. This affects how different parts of the body function, including the digestive tract. 
  • The precise cause of MS is not known but we know that gut health is part of the picture.
  • Constipation is not having a regular bowel movement or being unable to completely empty the bowel. Constipation is the most common gastrointestinal problem in the US (NIH, 2018).
  • Constipation and MS are linked because the gut is linked to the brain via the gut-brain axis.
  • The causes of constipation can be complex. There are many underlying root causes of constipation, such as gut dysbiosis, gut infections & pathogens, low stomach acid, IBS or SIBO, food sensitivities or intolerances, a low fiber or low-fat diet, micronutrient imbalances or deficiencies or other reasons. 
  • There are a number of tests that we can recommend in our Functional Medicine clinic. These include tests for assess for SIBO, overall gut health, food sensitivities or intolerances, micronutrient deficiencies and other issues.
  • We recommend working with an experienced Functional Medicine practitioner in order to pinpoint and identify the root cause(s) of your constipation. The root causes of constipation are treatable.
  • You can follow a targeted treatment plan to resolve your particular constipation-causing issues. Repairing gut health can resolve digestive issues like constipation.

** Please stay tuned for our next Blog on Treatment Ideas for Constipation!  **

As always, please get in touch with us. If you or someone you know is struggling with MS and/ or constipation or other digestive symptoms, contact our clinic today. 

We can work on any issue(s) and improve your health. Book a free health evaluation call with us today to see how we can help you with your concerns. We can answer your questions and help you book an initial consult with one of the functional medicine doctors in our clinic. 

Are You Suffering From A Chronic Illness?

Does your current health situation look like this…

  • Do you feel that you have tried many things and either nothing works, or the treatment does not hold?
  • Have you been told that there is nothing that can be done to reverse your illness and you just need to manage symptoms?
  • Does your illness impact your work, your family, your happiness and your social life?

We specialize in finding answers and solutions for complicated chronic illness when people feel like they have tried everything. If this sounds like you, book a free call with us to see if we are the right fit for your health goals. 

Dr. Miles has spoken for the following organizations:

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