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IBS vs IBD: Is There a Connection? - Hollywoood Homestead
Irritable Bowel Syndrome and Inflammatory Bowel Disease are completely different conditions which often get confused with one another.  If you are suffering from gut problems, it is very important that you understand the difference between them, and also that they both might be caused by the same underlying problem: a disruption of gut flora.

What is IBS?

With diseases, we have very clear definitions of what they are. For example, strep throat is an infection caused by the streptococcal bacteria. Heart disease is a condition in which the blood vessels are restricted or blocked. Cancer is the uncontrolled division of cells in a part of the body.

Diseases are caused by definitive pathological processes that cause certain symptoms. By contrast, a disorder is simply a “derangement or abnormality of function.”

IBS is not considered a disease. It is a disorder. More specifically, IBS is considered a functional disorder. Functional disorders are conditions in which bodily processes are impaired, but every part of the body looks normal under examination.

Since everything looks normal with IBS, it is diagnosed based on symptoms such as diarrhea, constipation, and abdominal pain. You can read more about IBS symptoms here and how to diagnose IBS here.

What is IBD?

With IBS, there are symptoms but everything looks “normal” under inspection. All bloodwork, scans, and lab tests appear fine. With IBD, things do NOT look normal. Patients with IBD have chronic swelling (i.e. inflammation) in the digestive tract which can be detected through blood tests which look for inflammatory markers, white blood cell counts, endoscopies which allow doctors to look inside your digestive tract, CT scans, stool tests, or any of the numerous other tests which are used to diagnose IBD. (Source)

Depending on where the inflammation occurs, it is considered a different type of IBD:

  • Crohn’s disease: Inflammation can occur anywhere along the digestive tract, including the mouth or anus, but is most usually in the intestines. The damaged tissues can get crater-like sores in them.
  • Ulcerative colitis: This disease involves inflammation to the large intestine and/or rectum. The ulcers aren’t as deep as with Crohn’s disease.
  • Indeterminate colitis: This diagnosis is used in cases where it is difficult to tell whether the inflammation is Crohn’s or ulcerative colitis.

Remember, inflammation is our bodies’ way of protecting itself. There are many reasons why the immune system would trigger an inflammatory response. For example, if you fall and cut your knee, the damaged cells will release chemicals. These chemicals cause the cells to leak out their fluids into the surrounding tissues. The excess fluid is what causes the swelling. In cases of injury, the swelling is useful because it isolates the injured area from the rest of the body so it can’t spread. (Source)

Inflammation chemicals also attract phagocytes to them. Phagocytes are certain types of white blood cells which are capable of “eating” solids – including dead cells, bacteria, and other pathogens. Phagocytes are very important for immune response and healing the body. The pus you see in wounds is actually the accumulation of dead phagocytes. (Source)

In normal situations, the inflammation response is very important to keeping us healthy and heal us after an injury, be it from infection or physical trauma. But, with IBD, the gut is under chronic inflammation. The inflammation eventually causes severe damage to the gut, such as when bleeding ulcers form. IBD is also linked to higher rates of cancer, including colorectal cancer, cervical cancer, and even oral cancer. (Source 1, 2)

When the gut is damaged, it is unable to absorb nutrients from food. People with IBD often suffer from many complications due to nutrient deficiencies. For example, IBD patients may have anemia, night blindness, poor immunity, hair loss, and infertility.

Damage to the gut also affects how it absorbs bile, IBD can lead to gallbladder stones. The increased loss of water in the gut — the large intestine is responsible for reabsorbing almost 5 gallons of water daily —  can dehydrate the body and may lead to kidney stones.

IBD can also cause inflammation outside of the gut, such as skin, joint, and eye inflammation. (Source) A lot of experts were puzzled by this for a long time. But, when you consider how the gut is linked to all parts of the body, it isn’t too surprising that an inflamed gut could inflame other areas too.

By contrast, IBS does not involve an inflammation response. Because there is no chronic inflammation, patients with IBS do not suffer from tissue damage. In this sense, IBS is considered a “less serious” condition than IBD.  IBD patients often need to be hospitalized because of their condition and may require surgery. (Source) I’d like to point out though that, just because you can’t see any physical damage with IBS, it doesn’t mean it isn’t a serious condition.

Symptoms of IBS vs. IBD

Since IBS and IBD are both gut conditions, they have the same main symptoms of diarrhea, constipation, and pain. However, there are some key differences. Doctors even specifically look for these differences when making diagnoses.

Pain is relieved or lessened by bowel movements or passing gas Pain is not relieved or lessened by bowel movements or passing gas
Pain can be anywhere in the gut and often changes location Pain is usually focused in one area
No blood in stools Bloody stools


To understand the differences between these symptoms, you must remember that there is no inflammation or ulcerative bleeding with IBS. The pain is caused by digested food or gas making its way through the gut. Because the nerves are hypersensitive, it can cause severe pain. Once the food or gas is out, the pain goes away. With IBD, the inflammation is causing the pain, so it remains regardless of whether there is food or gas in the GI tract. IBD pain can also be caused by bleeding ulcers, hence the pain focused in one area and the blood in the stools.

Bacteria: The Common Link between IBS and IBD?

Just like with IBS, getting a diagnosis of IBD is really frustrating because it doesn’t tell you anything. Sure, an IBD diagnosis may tell you that you have inflammation, but it doesn’t tell you what is causing the inflammation. More importantly, a diagnosis doesn’t tell you how to cure the inflammation. So, just like with IBS, all IBD treatments have focused on reducing symptoms rather than curing the underlying cause.

Have you noticed how, when doctors can’t explain the cause of a medical condition, they just chalk it up to genetics? Yes, there is ample evidence of a genetic link to IBD  and IBS – but genes alone cannot account for the massive upswing in IBD and IBS cases in recent years.   And the upswing is huge. In the UK, for example, there has been a 3x increase in Crohn’s disease cases in 18-30 year olds in the past decade alone. As for IBS, it was almost unheard of a generation ago. (Source 1, 2, 3)

Now, some smart researchers are finally getting to the bottom of what really causes IBS and IBD: gut bacteria.
More specifically, IBS and IBD are caused by an imbalance in gut bacteria.

Gut Bacteria and IBD

One recent study published in Cell Host & Microbe identified the specific bacteria which are increased or decreased in Crohn’s disease. The study involved over 1,700 samples from patients and found that, in Crohn’s patients, beneficial bacteria were lacking and pathological ones had increased. (Source)

This is just one of many new studies which are shining light on the role of bacteria in IBD. The sad irony is that antibiotics are often given to IBD patients to fight off bad bacteria which could cause infection and worsen symptoms. These new studies are showing that the antibiotics probably just worsen IBD because antibiotics kill off the beneficial bacteria too. As gastroenterologist Séverine Vermeire said, “This study confirms that these drugs don’t do any good to people with Crohn’s disease. We knew antibiotic use increases the risk to develop the disease; now we know they can worsen it, too.” (Source)

Vermeire goes on to say that it was a “missed opportunity” that the researchers didn’t look at the people’s diets. IBD is much more common in the Western world where diets mainly consist of processed food. In one study, for example, researchers found that people eating fast food had a 3.4x higher risk of Crohn’s and a 3.9x higher risk for ulcerative colitis. People who consumed more than 55 grams of sugar per day were also 2.6x more likely to develop Crohn’s.

Another theory is that antibiotic use is causing the upswing in IBD cases. German scientists theorize that IBD could be caused by “a mutated form of normal bacterial flora that became a super germ under constant selection pressure from antibiotics.” (Source 1, 2, 3)

Growing up in Argentina, I can attest to how readily doctors will prescribe antibiotics. I wouldn’t even have to get any bloodwork done. I’d just call my doctor and he’d tell me to go to the pharmacy and get this or that antibiotic. Living in the USA, at least you are required to get a prescription for antibiotics – but doctors pass them out so readily that they might as well be OTC.

It is also worth noting that overuse of antibiotics doesn’t just apply to humans. Antibiotics are now routinely given to meat animals to prevent disease in their terrible factory-farm conditions, and because antibiotics cause animals to gain more weight. This encourages the evolution of antibiotic-resistant bacteria. Now bacteria which used to be treatable by common antibiotics aren’t responding anymore. (Source)

And let’s backtrack for a moment: They give animals antibiotics because it increases weight gain. Antibiotics cause weight gain because they kill off the bacteria which are needed to efficiently metabolize food. When food isn’t getting turned into energy, it is getting stored as fat instead. This is just one of the many beneficial roles of bacteria in our gut.

Gut Bacteria and IBS

One of the most striking statistics I’ve found is that upwards of 84% of IBS patients test positive for SIBO.  SIBO, or Small Intestine Bacterial Overgrowth syndrome, is a condition in which you have too much and/or the wrong type of bacteria in your small intestine.  The bacteria feed off of the carbohydrates you eat and produce gas as a byproduct.  It isn’t just the gas which is worrisome.  New research in the emerging field of neurogastroenterology shows how our gut flora actually controls many bodily functions.  Disturbances in gut flora have been linked to obesity, skin rashes, and a slew of diseases.

It is still unclear as to whether SIBO causes IBS, or whether the conditions in IBS lead to the bacteria overgrowth of SIBO.  However, it is clear that bacteria are at play in IBS. Read more about SIBO here.

What Does This All Mean?

Just because IBS and IBD are both likely caused by disturbances in gut bacteria, it doesn’t mean that they are the same disease.  That would be like saying that an E. Coli and Salmonella infection are the same things.  However, the bacteria link between IBS and IBD does give us clues on how to finally cure these gut conditions.

Basically, it comes down to this: antibiotic use is disrupting our gut flora and causing bad bacteria to thrive while the good guys get killed off. Our bad diets of processed foods and loads of sugar give the bad bacteria plenty of food to eat, so they thrive even more (bacteria love carbs).   All of those chemical preservatives are just the icing on the cake which damage our guts even further.   In this sense, IBS and IBD are very much linked because they have similar underlying causes. The difference is that, with IBS, the bacterial imbalance affects the nerves in the gut and, with IBD, the bacterial imbalance causes inflammation.

If you have IBS or IBD, you need to stop focusing on treating the symptoms and start focusing on treating the underlying cause which means fixing your gut flora.

Do you have IBS? Download our free guide 7 Things You Wish Your Doctor Told You About IBS.

IBS vs IBD: Is There a Connection? - Hollywoood Homestead

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Sylvie McCracken is a former celebrity assistant in Hollywood turned full time entrepreneur currently living in Ashland, Oregon with her husband and 3 kids. She writes about treating and preventing health conditions with real food and natural remedies, as well as anything else she feels like writing about because she's a rebel like that. 😉 She also mentors entrepreneurs on her other site,