The conditions of IBS and IBD, while only differentiated by a single letter, are two very different creatures, even when the existence of shared symptoms is taken into consideration. As it’s April, which is IBS Awareness Month, it feels like a good time to look at how these two gut conditions are similar, and the significant ways they are different. In spite of their shared symptoms, they are very different conditions with distinct and separate causes, diagnostic methods and criteria, prognoses and treatment/management options.

In spite of their shared symptoms, they are very different conditions.

Most people with IBD will, at some point, inevitably be on the receiving end of the statement “I have IBS too”! While Good Gut Feelings was created for, and is predominantly aimed at, those with IBD, knowledge of IBS is also important, for a couple of different reasons, namely: (1) because of how often the names of the two conditions are (incorrectly) used interchangeably, (2) because, if suffering with gut distress, it’s crucial to determine which of the two you may have, and (3) because it is possible for someone with IBD to also suffer with IBS.

Most people with IBD will, at some point, inevitably be on the receiving end of the statement “I have IBS too”!

There is unquestionably a number of shared symptoms between the two letter combinations of IBS and IBD, and it is possible for them to coexist, but they are not interchangeable, and their being used as such, in addition to being medically inaccurate, is also a source of frequent frustration to IBD-sufferers in particular.

All the essential info on IBD is covered in The ABC of IBD, but I will touch on the key points again here, for the purposes of comparison with IBS.

DEFINITIONS – WHAT’S IN A LETTER?

IBD:

IBD stands for Inflammatory Bowel Disease, and includes the conditions of Crohn’s Disease and Ulcerative Colitis. These are chronic gut conditions that cause inflammation and ulceration in the lining of the digestive tract, causing damage, and are characterised by periods of active illness, followed by periods of remission. Symptoms vary in intensity, severity and duration, and can affect several parts of the body (see ‘Symptoms’ section below).

IBD is an autoimmune disease, which involves the immune system mistakenly attacking the body’s own healthy tissue, causing inflammation. While the precise cause of autoimmunity is unknown, it appears to be multifactorial, and most likely a combination of an underlying genetic predisposition and environmental/lifestyle factors. This genetic component means that IBD can often affect multiple people within the same family. Finally, there is an elevated risk of colon cancer with IBD, which makes regular surveillance labs and endoscopy necessary.

IBD is an autoimmune disease, which involves the immune system mistakenly attacking the body’s own healthy tissue, causing inflammation.

IBS:

IBS, on the other hand, stands for Irritable Bowel Syndrome, and is a functional gut disorder (as opposed to inflammatory, like IBD). Classified as a syndrome, it describes a group of symptoms that occur together, including: abdominal pain, cramps, bloating, and changes in bowel movements. These can come and go, varying in intensity, and can be quite disruptive to a person’s daily life. IBS can be further categorised as either IBS-D, IBS-C, IBS-M or IBS-U (see ‘Diagnosis’ section below).

IBS is a functional gut disorder.

IBS is usually a chronic condition, affecting around 1 in 10 people, and is 2.5 times more common in women than men. It is thought to be caused by a number of factors, including disruptions to the gut’s microbiome, and/or the gut-brain axis, which controls how the brain and gut communicate and interact.

SYMPTOMS

The main reason for IBD and IBS often being mixed up and/or used interchangeably is that, both conditions affect the gut, and they tend to have several overlapping symptoms. Indeed, symptoms common in both conditions include:

Abdominal pain
Cramping
Abnormal bowel movements (usually diarrhoea)
Mucus in stool
Bloating
Excess wind
Urgency
Stress/anxiety

But this is where the similarity ends. While IBS can also include constipation (depending on the subtype in question), with IBD, there can be many additional symptoms, both in the intestine but also affecting many other parts of the body (called extra-intestinal symptoms), including:

With IBD, there can be many additional symptoms, both in the intestine but also affecting many other parts of the body.

DIAGNOSIS

IBD:

The ‘gold standard’ for diagnosing IBD is a colonoscopy, where a thin, flexible tube is inserted into the rectum, and a small camera is passed through. This enables the doctor to to capture images of the intestinal lining, and take biopsies (tissue samples) for further testing. Other imaging tests may also be used, such as an MRI or CT scan. Analysis of scans and biopsies will determine the presence of IBD, and whether it is Ulcerative Colitis or Crohn’s Disease. Blood tests are also used to determine and monitor the extent of systemic inflammation in the body as well.

The ‘gold standard’ for diagnosing IBD is a colonoscopy.

The key distinctions between the two forms of IBD are the part of the digestive tract affected, and the ‘depth’ of inflammation in the tissue. Ulcerative colitis only affects the colon (large intestine), and involves surface inflammation of the intestinal wall, usually spanning large, continuous areas. Crohn’s disease on the other hand, can affect any area of the gastrointestinal tract, most commonly the end of the small intestine (the ileum) and the colon, and the inflammation of the gut wall can span the entire thickness of the tissue, well beyond superficial surface damage, but tends to be more localised to specific spots of the GI tract.

IBS is more a diagnosis of exclusion.

IBS:

When it comes to diagnosing IBS, on the other hand, it is more a diagnosis of exclusion, resorted to when all other diagnostic tests and methods (such as imaging and/or colonoscopy) have come back clear - as IBS does not cause physical damage to the intestine, which would be evident upon testing.

A set of criteria, known as the Rome IV Criteria (C1), usually needs to be satisfied for a diagnosis of IBS. This requires that there has been recurrent abdominal pain on average at least one day per week in the last three months, associated with at least two of the following: defecation; a change in frequency of stool; or a change in form/appearance of stool.

Once this diagnostic ‘baseline’ is established, IBS can then be further categorised into subtypes: IBS-D, IBS-C, IBS-M or IBS-U, depending on the specific symptoms. Now, this is where things start to feel a bit mathematical, with various percentages being thrown about. As anyone with any kind of health issue well knows, symptoms don’t necessarily always follow black and white rules, or satisfy criteria perfectly! So, while the below criteria are certainly useful, and very much applied when it comes to diagnosis, keep in mind that the information is most useful as a guide for patients, and a specific diagnosis should be reached by a qualified medical practitioner in possession of all the patient’s relevant medical history and test results. Self-diagnosis, while seemingly achievable, is not advisable.

IBS can be categorised into subtypes: IBS-D, IBS-C, IBS-M or IBS-U, depending on the specific symptoms.

IBS-D is the most common form of IBS and is where, on days with at least one abnormal bowel movement (ABM), the predominant symptom is diarrhoea, causing loose and watery bowel movements. There may be more frequent bowel movements and feelings of urgency as well, and also a tendency to suffer with more gas. For an IBS-D diagnosis, at least 25% of the stool should be loose, and less than 25% should be hard on ABM days (I told you it gets ‘mathematical’!).

IBS-C, conversely, is IBS with constipation, and the numbers are reversed here, so that at least 25% of the stool is hard/lumpy, and less than 25% is loose on ABM days. Here, there is likely to be less frequent bowel movements, more difficulty/straining passing the stool, and even a feeling of pressure in the rectum, or of not being quite ‘finished’ after a BM. Bloating also tends to be common in this type of IBS.

IBS-M refers to IBS with mixed bowel habits (also sometimes referred to as IBS with alternating bowel habits, or IBS-A). In this instance, symptoms tend to alternate between diarrhoea and constipation, even within the same day, and sometimes even within the same BM. For those who prefer a numerical representation: to be classified as IBS-M, stool should be loose more than 25% of the time, and hard/lumpy more than 25% of the time on ABM days.

IBS-U is Unclassified IBS, which essentially means that the diagnostic criteria for IBS are satisfied, (ie standard IBS symptoms are present), but do not fall neatly into one of the three IBS categories above. In such a case, symptoms are likely to be somewhat more mixed and changeable.

It’s important to also mention here, at least briefly, two other types of IBS, which are more specific:

Post-infectious IBS (PI-IBS) is, as the name suggests, the occurrence of IBS symptoms following a gastrointestinal infection (gastroenteritis). Such infections can cause inflammation, disruption of the balance of bacteria in the digestive system and increased intestinal permeability (‘leaky gut’), allowing PI-IBS to occur. The most common symptoms for this type of IBS are diarrhoea, abdominal pain, and sometimes vomiting. Up to one-third of those who experience a GI infection may develop IBS, of which about half completely recover over time, though it can take a while (up to even six years), and may require targeted treatment of the underlying inflammation that is causing the IBS.

Post-Diverticulitis IBS refers to a possible complication of diverticulitis (when small pouches or pockets, called diverticula, form in the lower part of the large intestine and become infected or inflamed). Indeed, there is an increased risk of developing IBS symptoms following a diverticulitis episode. The symptoms of this type of IBS are similar to PI-IBS, and occur as a result of the intestinal inflammation and microbiome disruption caused by the diverticulitis.

TREATMENT/MANAGEMENT

Both IBD and IBS are classified as chronic conditions, and so neither is technically ‘curable’. However, a variety of treatment options do exist, and so symptom management, to the point of substantial reduction, is certainly achievable.

Treatment and management options generally fall into one of three categories: medication, diet and lifestyle. Both diet and lifestyle changes are very helpful when it comes to managing both IBD and IBS. The main difference in treatment options for the two conditions relates to medication. While an IBD patient may at times benefit from some medications that are given to help ease IBS symptoms (eg anti-spasmodics), IBD medications would certainly not be administered to IBS patients.

When it comes to lifestyle factors, both IBD and IBS can be affected by diet and stress. While neither factor is causative or curative, both conditions can be aggravated by poor diet and an increase in stress levels. On the more positive flip side, the symptoms of both can also be managed by dietary adjustments and stress-management and/or relaxation techniques.

Treatment and management options generally fall into one of three categories: medication, diet and lifestyle.

IBD:

Although there is no outright ‘cure’ for IBD, the goal of treatment is to achieve remission (when the disease becomes inactive, and the patient no longer has IBD symptoms). Even without full remission though, symptoms can be managed to varying degrees.

Standard medical treatment for IBD will depend on where the inflammation is located in the digestive tract, and on the severity of symptoms, but generally involves medication (anti-inflammatories, immunosuppressants, antibody-based treatments etc), and sometimes surgery.

Some meds work ‘symptomatically’ to reduce the inflammation in the GI tract, and others suppress the immune system to stop it attacking the body’s own healthy tissue (the hallmark of autoimmunity). If medication and dietary/lifestyle adjustments are not successful, surgery may be necessary to remove the affected part of the intestine or colon. Surgery may also be required, particularly in Crohn’s Disease, to deal with disease complications such as abscesses or strictures.

Although there is no outright ‘cure’ for IBD, the goal of treatment is to achieve remission.

Unfortunately, however, while these medications help reduce IBD symptoms, they can come with a number of side-effects, and as a result often cannot be used for long periods of time without consequence. Side-effects can include pancreas and kidney problems, insomnia, high blood pressure, diabetes, osteoporosis, eye problems, increased risk of infection, and more.

Lifestyle changes, including diet (see next section), stress management techniques and exercise can also help ease symptoms, as well as improve the overall health of IBD patients

There are various ways to help manage IBS symptoms.

IBS:

For IBS, although there is no specific established treatment, there are various ways to help manage symptoms.

Both over-the-counter and prescription medications are often used to help with abdominal pain and cramping, and to either increase or reduce intestinal motility, to help with constipation or diarrhea, depending on the subtype of IBS in question. Medication can include:

Antispasmodics
Laxatives
Anti-diarrheal meds
Meds to increase gut motility
Antibiotics
Anti-depressants (which can help with both gut motility, and with anxiety/depression that can be caused by IBS).
Specific supplementation may also be recommended by medical practitioners, including probiotics or fibre supplements, and also herbal remedies such as peppermint oil or Iberogast.

Dietary changes (see next section) for IBS can be very helpful, as can several lifestyle and psychological approaches, including relaxation and stress-reduction techniques (such as meditation or breathwork), hypnotherapy and Cognitive Behavioural Therapy (CBT). Incorporating regular gentle physical activity, such as yoga or walking can also help.

Dietary changes for IBS can be very helpful, as can several lifestyle and psychological approaches, including relaxation and stress-reduction techniques.

It should be noted that there are situations where the development of IBS can be linked to other underlying issues or conditions. In such a case, determining and seeking treatment for those conditions can help improve the symptoms of IBS. Specifically, IBS has been linked with the following:

GI infections (see above)
Diverticulitis (see above)
GERD (Gastroesophageal Reflux Disorder) - about 63% of people with IBS have GERD symptoms too
SIBO (Small Intestinal Bacterial Overgrowth) - up to 78% of people with IBS have SIBO
Food intolerances/sensitivities
Stress, anxiety and/or depression
And, of course, IBD

Working with a qualified medical practitioner to determine whether any of these are present, and addressing them, can help alleviate IBS and its symptoms.

THE ROLE OF DIET in IBD & IBS

Both IBS and IBD can benefit from dietary adjustments. While a change of diet cannot cure either condition, it can certainly help manage and reduce symptoms, often to a substantial degree.

For both IBD and IBS, knowing which foods aggravate symptoms is very useful for any patient to be aware of. But, in addition to removing problematic foods, it’s important to also pay attention to what is being included: the focus should be on ‘real food’, eating as much variety as can comfortably be managed (to ensure a wide variety of nutrients), and finding ways to make food interesting and tasty so that it can be enjoyed, without feelings of deprivation.

While a change of diet cannot cure either condition, it can certainly help manage and reduce symptoms, often to a substantial degree.

IBD:

For IBD, it has only been in more recent years that the impact of diet on the development, progression and management of the disease has really been acknowledged. Several dietary protocols have emerged with the aim of healing the gut including: the GAPS Diet, the Specific Carbohydrate Diet, the Autoimmune Protocol (AIP), the Paleo Diet, and more. These generally suggest the elimination of processed and fried foods, along with other foods (or food categories) that can be challenging for the gut (standard among these are gluten and at least some forms of dairy), and focus on including real, unprocessed, anti-inflammatory and nutrient-dense foods that can be more easily digested.

The question of what to eat or what diet to follow for IBD is ultimately a highly individual matter. A great deal will depend on the individual patient and the severity of symptoms at any given time. Moreover, there is absolutely no one-size-fits-all dietary approach - no single diet is beneficial to all IBD patients and at all disease stages.

For IBD, it has only been in more recent years that the impact of diet on the development, progression and management of the disease has really been acknowledged.

IBS:

For IBS, diet can play a significant role for many people, and adjusting one’s diet can be very helpful when it comes to reducing symptoms. Such adjustments generally focus on the removal of specific foods that have a tendency to trigger IBS symptoms. The low-FODMAP diet is often recommended for this, and in fact was specifically created by Monash University for the purpose of reducing IBS symptoms. FODMAPs are specific short-chain carbohydrates (ie sugars) found in certain foods, that are not absorbed properly in the gut, and so tend to aggravate IBS symptoms. The low-FODMAP diet essentially involves the removal of these foods (for some recipe ideas, click here).

Additionally, it can be helpful to determine if food intolerances or sensitivities are also contributing to symptoms, either through specific testing or by keeping an eye on your symptoms using a Food Diary and/or trying an elimination diet.

The low-FODMAP diet is often recommended for IBS, and in fact was specifically created by Monash University for the purpose of reducing IBS symptoms.

WHEN IBD & IBS COEXIST

It is, annoyingly, possible for someone with IBD to also have IBS at the same time. While there can certainly be a clear overlap of symptoms during an IBD flare, it’s not uncommon for some IBD patients to experience ongoing IBS symptoms even when in remission. This means that, even during phases where there is no active inflammation in the intestine, and blood work, imaging and scopes show that IBD is in remission, a person can still have the functional digestive symptoms of IBS to contend with.

It’s not uncommon for some IBD patients to experience ongoing IBS symptoms even when in remission.

However, it seems there are also cases were IBD patients do not appear have the ‘separate’ condition of IBS, despite having the relevant symptoms, but instead are dealing with something called “occult inflammation”. Meaning that, although in remission, IBD is still causing low level inflammation, which may not be picked up by standard assessment methods. A study demonstrated that a substantial percentage of IBD patients with IBS-symptoms have elevated calprotectin levels, indicating the presence of this occult inflammation, and so it is quite likely that it is this low level inflammation causing the IBS-like symptoms, rather than coexistent IBS.

It seems there are also cases where IBD patients do not appear to have the ‘separate’ condition of IBS…but instead are dealing with something called “occult inflammation”.

The distinction seems to therefore centre on calprotectin levels: if elevated, then the symptoms are most likely attributed to IBD occult inflammation and not IBS and, if calprotectin is normal, then it could be concluded that it is a case of coexistent IBS.

It’s also important to note that, while a number of patients may first be diagnosed with IBS, only to later be diagnosed with IBD, IBS does not cause, nor does it become IBD. Rather, in such situations, it’s simply a case of IBD originally presenting in a form mild enough to be mistaken for IBS, but, over time and without appropriate treatment/management, it progresses and becomes evident with specific testing.

IBS does not cause, nor does it become IBD.

In Summary: THE KEY DIFFERENCES BETWEEN IBD & IBS

So, while IBD and IBS certainly share a number of unwelcome gut-based symptoms, it’s clear that they are not the same thing, and the terms should not be used interchangeably. They are very different, from diagnosis to treatment, prognosis and long-term monitoring needs.

It’s clear that they are not the same thing, and the terms should not be used interchangeably.

To summarise, these are the important ways they are different:

IBD is a chronic inflammatory (autoimmune) condition - IBS is a functional disorder of the gut.
IBD is classified as a disease - IBS is classified as a syndrome (a set of symptoms).
IBD has a genetic component - IBS does not.
IBD affects men and women equally - IBS is two times more common in women.
IBD can be specifically diagnosed - IBS is a diagnosis of elimination, resorted to when all other diagnostic tests and methods have come back negative.
IBD can be seen on medical imaging like MRI and CT scan - IBS does not show up on medical imaging.
IBD involves physical changes to the colon that can be observed with colonoscopy - IBS has no abnormal findings on colonoscopy.
IBD can show up in lab tests, elevating levels of calprotectin, lactoferrin CRP etc - IBS does not show up in lab tests.
IBD’s inflammation in the intestinal tissue causes actual physical damage and deterioration (often permanent) - IBS does not cause physical damage to the intestinal tissue.
IBD has bleeding as a symptom - IBS does not (unless relating to fissures and/or hemorrhoids, possibly caused by IBS-C).
IBD has extra-intestinal manifestations that can affect multiple body systems (eyes, joints, skin, liver etc) - IBS does not have extra-intestinal manifestations.
IBD can be life-threatening due to the potential complications - IBS does not cause life-threatening complications.
IBD requires long-term surveillance with labs, imaging and endoscopy - IBS does not require labs, imaging or endoscopy for surveillance.
IBD elevates the risk of colon cancer - IBS does not elevate the risk of colon cancer.

In a nutshell then, IBD and IBS are a letter, and a world, apart.

In a nutshell then, IBD and IBS are a letter, and a world, apart.

IBD vs IBS: A Letter & A World Apart

DEFINITIONS – WHAT’S IN A LETTER?

SYMPTOMS

DIAGNOSIS

TREATMENT/MANAGEMENT

THE ROLE OF DIET in IBD & IBS

WHEN IBD & IBS COEXIST

In Summary: THE KEY DIFFERENCES BETWEEN IBD & IBS

Ileoscopy: What It Is, How To Prepare & What To Expect