The main symptoms of IBS include, among other things, abdominal pain, cramping, excess gas, bloating, and a change in bowel habits.
Common triggers are hormonal changes, eating, and stress, but IBS affects everyone differently. To some people IBS can be debilitating, while others have only mild or moderate symptoms.
At present, nobody knows what causes IBS. As a result, diagnosis can be challenging, and treatment options are far from satisfactory.
Although there are certain things that are known to increase the risk of developing IBS — such as being a woman, having a family member with IBS, and being under the age of 45 — research is only slowly beginning to lift the fog surrounding IBS.
In this article, we dig into recent research findings and bring you our top five need-to-know facts about IBS.
1. Only half of IBS patients seek medical care
Across the globe, an average of 11.2 percent of people live with IBS, Prof. Paul Enck — who is the head of research at the Department of Psychosomatic Medicine and Psychotherapy at University Hospital Tübingen in Germany — explains in an article in Nature Reviews Disease Primers.
However, this average is skewed because of a lack of data available for many countries in Africa and Asia. In fact, the rate of IBS in individual countries varies hugely; it ranges from as low as 1 percent to as high as 45 percent.
At the upper end of the scale are Mexico with 40 percent, Iceland with 30.9 percent, and Pakistan with 30.5 percent, while Canada sits somewhere in the middle with 15.7 percent.
Despite the millions of people affected, only about half of those with IBS symptoms go to their healthcare provider for help.
"Most of these patients will initially consult primary care physicians for their symptoms, and the factors that drive this consultation are symptom severity, especially pain, the occurrence of alarm symptoms, and concerns that symptoms might indicate an underlying severe disease — for example, cancer."
Prof. Paul Enck
Prof. Philip S. Schoenfeld — the director of the GI Epidemiology Training Program at the University of Michigan School of Medicine Ann Arbor — explains in an article in the journal Gastroenterology & Hepatology that patients often wait for around 4 years before their IBS is diagnosed.
"[...] Treatment remains unsatisfactory for most patients," he adds.
2. IBS is linked to the brain
An estimated 20 percent of those affected by IBS also have symptoms of other gastrointestinal disorders. The list includes functional dyspepsia, heartburn, GERD, diarrhea, incontinence, and constipation, according to Prof. Enck.
It doesn't stop there. Non-gastrointestinal syndromes, such as an overactive bladder, premenstrual syndrome, sexual dysfunction, chronic fatigue syndrome (CFS), migraine, and eating disorders, among others, also go hand-in-hand with IBS.
Prof. Enck further explains that people with IBS also have higher rates of psychiatric conditions, such as anxiety, depression, and neuroticism, than people without IBS.
But why would a gastrointestinal disorder be linked to the brain?
Our brains and guts are intricately linked. The brain influences the movement of food through our gastrointestinal tract, our immune system, and the composition of the gut microbiome. On the flip side, changes in the gut are linked to changes in brain structure.
The big question that remains is which body part is the chicken and which is the egg?
"Although [research] findings have identified disease-relevant brain alterations in patients with IBS, mechanistic and longitudinal studies are required to determine the causality between these factors."
Prof. Paul Enck
3. Gastroenteritis can lead to IBS
Prof. Guy E. Boeckxstaens — from the Translational Research Center for Gastrointestinal Disorders at the University of Leuven in Belgium — explains in a recent article in Scientific Reports that "up to 36 percent of patients with gastroenteritis may go on to develop post-infectious IBS (PI-IBS)."
For their study, Prof. Boeckxstaens and his colleagues looked at the bowels of individuals with PI-IBS, who developed the condition after being exposed to contaminated drinking water.
Based on previous work by other researchers, the team expected to find low levels of inflammation — a remnant of the fight against gastroenteritis and thought to be the cause of pain — in their study subjects.
"To our surprise, we found no evidence for low-grade inflammation in the bowel[s] of these patients."
Prof. Guy E. Boeckxstaens
"However," Prof. Boeckxstaens added, "we did find clear evidence for both neuronal sensitization in PI-IBS patients and a shift in the bowel microenvironment to a pro-nociceptive state."
The team speculates that the ongoing pain experienced by individuals with PI-IBS is due to the sensitization of pain nerves in the gut environment.
Not only does this finding provide an answer to the question of how pain develops, but it also suggests a novel way of treating the condition, Prof. Boeckxstaens concludes. "[...] Histamine receptor blockade may represent a novel analgesic treatment for these patients."
4. Gut microbiome is firmly implicated
As researchers are getting to the bottom of the trillions of microorganisms that live in our guts, we are increasingly beginning to appreciate the role that our microbial passengers play in our health.
Earlier this year, we reported that researchers had transplanted gut bacteria from people with IBS into mice. As a result, the mice developed IBS symptoms. Interestingly, mice that had received microbes from people with IBS and anxiety also displayed anxiety-like behavioral symptoms.
In a separate study, researchers analyzed the composition of microorganisms from the guts of people with CFS, some of whom also had IBS and some who didn't.
They found distinct microbial profiles that allowed them to distinguish these two sets of individuals from control subjects without CFS and IBS.
A greater understanding of how the composition of the microorganisms in the gut contribute to the pathophysiology of IBS will help us to better understand the condition and allow scientists to develop therapies specifically designed to improve gut health.
However, as Prof. Enck points out, "[T]he microbiotic signature (in terms of present species) is very stable." So, making drastic alterations to our microbiome might be challenging, but changes in diet can certainly improve symptoms in some people with IBS.
Yet it seems that some of our assumptions about food and IBS are wrong.
5. Certain foods get the blame unnecessarily
Food is a very common trigger of symptoms of IBS, but the reason for this phenomenon remains a mystery. Researchers speculate that an exaggerated physiological response to food intake by the gut, food compounds that lead to psychological symptoms, or an interaction between food and the gut microbiome is to blame.
Yet IBS manifests differently in each person, and foods on the "no-go" lists tend to vary accordingly. Moreover, the fact that a particular food item has been incriminated does not necessarily mean that it truly causes symptoms.
"Although patients with IBS readily incriminate specific food items as those that are especially likely to precipitate symptoms, only 11–27 percent of those are correctly identified when confirmed in formal, blinded food challenge studies."
Prof. Paul Enck
This really muddies the waters for those affected by IBS. But there is hope; more research means a better understanding of which foods to avoid.
"The limitations of dietary surveys and the poor reproducibility of reported food intolerances notwithstanding, some food items are reported as being more problematic: wheat, fruit, and vegetables," Prof. Enck explains.
Living with IBS can certainly be challenging, whether you've already received a medical diagnosis or are just starting out on your journey to find what might be causing your IBS-like symptoms.
For more information on how to change your diet and other practical tips for life with IBS, check out our article, "Coping with irritable bowel syndrome."