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Irritable Bowel Syndrome vs. Irritable Bowel Disease

April 13, 2021

What is Irritable Bowel Syndrome (IBS)?

Irritable bowel syndrome is a functional diagnosis that is given to individuals who have chronic gastrointestinal symptoms such as diarrhea and constipation, but no inflammatory diseases are found to be the cause. IBS is a frustrating diagnosis because it is often given by gastroenterologists when there is no known cause of the symptoms. Individuals are often left feeling hopeless because there are no medications for IBS.

IBS is classified as a “functional disorder”, similar to tension headaches and chronic fatigue syndrome (CFS). Another common term is “wastebasket diagnosis”, which means that by exclusion of other problems, this is the default diagnosis. In functional medicine we know that there are physiological causes for these disorders, but this type of classification often leads people to believe that IBS is more psychological which isn’t true.

IBS is very common. In fact, it is the most common reason for individuals to miss work. People with IBS often have normal test results on standard blood panels, which makes it difficult to diagnose. IBS commonly runs in families and it can develop at any age. The Rome criteria for diagnosing IBS is the standard. The criteria include abdominal discomfort and pain lasting at least one day per week for the past three months connected to at least two of the following factors: Defecation causing pain and discomfort, changes in defecation, and stool consistency alterations.

In functional medicine, IBS is known to be caused by intestinal dysbiosis, likely small intestinal bacterial overgrowth (SIBO) or other pathogenic bacterial infections in the gastrointestinal tract. Intestinal dysbiosis may also manifest as a deficiency of healthy bacteria and, not surprisingly, people with IBS list histories of frequent antibiotic consumption.

What is Irritable Bowel Disease (IBD)?

Irritable bowel disease is an umbrella term for many inflammatory gastrointestinal diseases, such as Ulcerative Colitis (UC), Crohn’s, and Microscopic Colitis. A simple trick for identifying inflammatory diseases is to remember that the suffix ‘-itis’ means ‘inflammation’. The most common forms of IBD are Crohn’s and UC, which are also autoimmune diseases. Autoimmunity occurs when the body creates antibodies that attack healthy tissue because it mistakenly identifies its own cells as being foreign pathogens. Not all irritable bowel diseases are autoimmune.

Irritable bowel disease has been on the rise since the turn of the 20th century, especially in developed urban countries. Like other autoimmune and inflammatory conditions, it is believed that increased antibiotics usage and sterilization of our environments have both contributed to this rise. IBD includes chronic inflammatory diseases that occur in different parts of the digestive tract.

Key Distinctions Between IBS & IBD

Though IBS and IBD often have similar gastrointestinal symptoms, they are different. You can actually have both IBS and IBD at the same time. Here are some major differences between IBS and IBD.

Inflammatory Disease
Gastrointestinal symptoms
Other symptoms
Exacerbated by stress
Medications Available
Elevated calprotectin/lactoferrin

Though IBS is not technically an inflammatory condition, you can have another type of autoimmune disease at the same time as having IBS (remember, leaky gut must be present for autoimmunity to start and quite frequently leaky gut exists with IBS). Also, many of the symptoms of IBS are similar to IBD but IBD symptoms also affect other areas of the body, such as the joints (example: Ulcerative Colitis).

Stress can aggravate both IBS and IBD. Anxiety around not being able to have accessibility to a bathroom is commonly associated with IBS. IBD can flare in low-stress or high-stress environments. IBS diarrhea differs from that of IBD in the volume of loose stool; there is often a greater amount of stool for those with IBD.


IBS Symptoms:

  • frequent diarrhea
  • loose stools
  • abdominal pain
  • cramps
  • chronic constipation

IBD symptoms can include the above as well as:

  • occasional constipation
  • fever
  • blood in the stool
  • skin conditions
  • joint pain
  • malnutrition
  • weight loss
  • fistulas
  • urgency of bowel movement
  • extreme fatigue
  • loss of appetite
  • eye inflammation
  • intestinal scarring

If left untreated IBD can lead to:

  • perforations (holes) in the colon
  • colon cancer
  • liver disease
  • osteoporosis
  • anemia

Support Options

Gastroenterologists often depend on prescription medications aimed to help reduce inflammation, but these medications treat symptoms and don’t address the root cause of the inflammation that causes these symptoms in the first place. A more effective method is to get rid of the source of inflammation by thorough functional testing to discover the root cause.

IBS medications are often not effective because they are merely intestinal antispasmodic medications, which are drugs used to reduce muscle spasms. Again, these aren’t getting rid of what is causing your IBS symptoms. Most conventional doctors don’t know that dysbiosis and diet are contributing to IBS.

In functional medicine, we understand that diet and lifestyle can actually ‘turn’ autoimmune-related genes on and off. You may not know that just because someone has a certain gene, doesn’t mean it will actually be expressed. Epigenetics is the study of how the environment affects gene expression. We can alter genetic expression by altering our environment. This is especially true for IBD, but epigenetics also impacts the microbiome in cases of IBS. Dietary and lifestyle changes are the tools we use to optimize our body’s environment. In a functional medicine treatment plan for IBS, diet change and improved digestion can almost completely resolve symptoms because of how we can impact the diversity of the gut microbiome.

IBS Diet

If you think you suffer from IBS or have been diagnosed with IBS, you may find relief from implementing a combination of these dietary changes. To help with your decisions, find out if you classify as constipation-predominant, diarrhea-predominant, or pain-predominant. Testing with a functional medicine practitioner can help you discern this classification. (Contact us using the form below!)

  1. Gluten-free

Going gluten-free is a great option for many individuals with IBS. Gluten has been shown in research to aggravate the intestinal lining and cause holes in the walls of the intestines.

Gluten is a protein found in wheat and other grains like barley, rye, and spelt. Many people with IBS have a gluten sensitivity or intolerance which leads to the symptoms of IBS. Avoiding gluten in the diet can reduce symptoms.

  1. Low-Fiber

Fiber is often recommended for individuals with gastrointestinal issues. Sometimes adding fiber only exacerbates abdominal bloating and pain when trying to eliminate. This is because fiber is bulking. Constipation isn’t a problem of not enough stool, it is a problem with the intestinal cells not having enough energy to contract. So bulking up stool just makes for more painful constipation.

Going on a low-fiber diet or emphasizing mostly soluble fiber from vegetables and fruit is more supportive for most individuals with IBS. To do this, simply go on a paleo-style protocol and avoid grains to reduce insoluble fiber in the diet.

  1. Low-FODMAP

IBS is often a symptom of small intestinal bacterial overgrowth (SIBO), where there is too much bacteria in the small intestines. When this happens, some of the carbohydrates we eat become over fermented in our gut and release gas. Sometimes this gas causes constipation, sometimes it is a different gas that causes diarrhea.

FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are short-chain carbohydrates found in certain foods that will aggravate SIBO and IBS. Avoiding these foods temporarily can help create balance in the microbiome as well as relieve symptoms:

  • dairy products
  • beans/legumes
  • grains
  • sweeteners
  • alcohol
  • certain fruits (peaches, watermelon, pears, mangoes, apples, plums, nectarine)
  • certain vegetables (potatoes, mushrooms, artichoke, onion, garlic)
  • cashews, pistachios

Keep in mind long term FODMAP has not been studied and currently Dr. Autoimmune does not recommend this as a management strategy over 3 months.

  1. Elimination Diet

Each person’s microbiome is like a fingerprint. To discover what your individual triggers are for IBS symptoms you can do an elimination diet. The best elimination diets are the GAPS, Wahl’s or AIP protocols. These are superior because you are eliminating all common food triggers at one time while supporting the reshaping of the microbiome. This allows you to get to a baseline of health before adding in foods. If you take out only one food at a time, you might not be able to see a difference in symptoms.

Here are some common food triggers that you can test:

  • coffee
  • chocolate
  • insoluble fiber
  • nuts
  • dairy
  • gluten
  • eggs
  • nightshades

IBD Diet

Because inflammation is the driving force behind IBD, we have to eat an anti-inflammatory diet. But we also need to do thorough testing to find out what is at the root of the inflammation, often dysbiosis. In autoimmune IBD diseases, a protocol such as the Autoimmune Paleo Protocol or GAPS diet protocol is indicated. However, modifications based on bio-individuality and testing would be necessary. Again, severely restricted diets are not recommended long term. Your microbiome thrives on diversity and fiber so without these elements an elimination diet may cause more harm than good! We strongly encourage you to work with an experienced practitioner to guide you through a customized diet.





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