So, your medical appointment is over. After months or even years of visits and tests, the diagnosis is in – you have IBS.

What now?

You remember bits and pieces of what your doctor told you, but now your mind is reeling with questions you wish you would have asked when you were sitting in your doctor’s office.

Questions like:

  • What is IBS?
  • Why me?
  • How can I get relief?
  • Will my life ever go back to normal?

These were the questions I had when diagnosed with IBS over ten years ago. I had no idea what IBS was, and there was no action plan, let alone advice, for how I would manage my symptoms.

If you’re anything like I was, you want to understand what IBS is, but more importantly, what you can do to control your symptoms so you can get your life back to normal.

That’s the goal of this post. I want to help you make sense of IBS by explaining what it is, the common symptoms, how a diagnosis is made, and the possible risk factors for developing it.

I’ll then share the commonly used non-pharmacological strategies to help manage symptoms. Note that I’ve only included strategies that are shown to be safe and effective.

Let’s get started!

What is IBS?

IBS is a functional disorder of the digestive system (1). This means there’s nothing wrong structurally with the digestive system, but it’s not working as it should.

IBS Symptoms

The main symptoms of IBS are (2):

  • Diarrhea and/or constipation
  • Abdominal pain
  • Bloating
  • Distension
  • Gas

Symptoms can range from mild to severe, and severity can change over time.

How is IBS Diagnosed?

There are no blood tests or imaging techniques that can diagnose IBS. Therefore, diagnosis is made by (3):

  • Comparing symptoms to a formal set of diagnostic criteria (Rome IV criteria)
  • Medical history
  • Physical exam
  • Exclusion of other medical conditions

What Causes IBS?

It’s unclear what causes IBS, but several factors may be involved:

  • Gastrointestinal motility
  • Intestinal hypersensitivity
  • Intestinal inflammation
  • Post-infectious
  • Alteration in intestinal microflora
  • Food allergy and intolerance
  • Genetics
  • Psychological factors

Let’s look at each one more closely.

Gastrointestinal motility (altered movement through the digestive tract)

A primary function of the digestive tract is to move food and water across it to allow for nutrient absorption and waste disposal (4). This movement requires the smooth, coordinated contraction of the muscles of the bowel wall. When these contractions become uncoordinated, symptoms of diarrhea or constipation can occur (5).

Intestinal hypersensitivity

Some people with IBS have heightened sensitivity to movement and gas in the intestines (6). Research shows that when a balloon is inflated in the intestines of people with IBS and healthy controls, people with IBS experience pain at lower balloon volumes than controls (7,8).

Intestinal inflammation

In some people with IBS, symptoms may be due to hyperactivity of the immune system within the intestinal walls. Some studies have shown increased numbers of immune cells within the intestinal tissues (9,10). This hyperactivity and increased immune presence can disrupt the bowel’s normal functioning, leading to motor dysfunction and abdominal pain (10,11).


Some people may develop IBS after a bout of gastroenteritis (12). How this occurs is not fully understood, but research suggests that the interaction between the infection, the immune system and the person’s genetics plays an important role (13).

Alteration in intestinal microbiota

Some people with IBS have markedly altered intestinal microbiota compared with healthy people (14), though it’s unclear why. While our understanding of the intestinal microbiome is evolving, we know that we need a balance between the different bacteria in our gut. When something upsets that balance, it may put people at risk for developing IBS (15).

Food allergy and intolerance

Many people with IBS report digestive symptoms within three hours after eating a meal (16). As such, this could support the hypothesis that there’s a link between food allergy or food intolerance and IBS symptoms (17).

Food allergy:

In individuals with IBS who test negative for classic food allergies, evidence suggests they may have an atypical food allergy (18).

In a recent study, researchers applied a specific food antigen directly to the intestinal mucosa of individuals with IBS and healthy controls (18). They found that about 70% of people with IBS had abnormal changes to the intestinal mucosa in response. These changes included an increase in the number of immune cells and changes in the epithelial cells’ protein content. Taken together, the researchers theorized that these changes led to a dysfunction in the gut’s barrier (18).

When the individuals with IBS excluded the food antigen to which they reacted from their diet, their IBS symptoms showed a dramatic improvement (18).

These findings suggest that specific food allergens may provoke an immune reaction within the intestines and lead to IBS symptoms.

Food intolerance:

Research shows that IBS symptoms may be induced or exacerbated by eating high FODMAP foods. FODMAPs refer to fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols. These are short-chain carbohydrates (sugars) that aren’t digested or absorbed well in the digestive tract of some people. As such, they attract water into the intestinal lumen and are fermented by bacteria in the gut. These actions lead to symptoms of bloating, distension, and altered motility (19).


Studies investigating the heritability of IBS found that:

  • Social learning has an equal or greater influence (20)
  • The genetic contribution may instead be due to the heritability of anxiety and depression (21)

Psychological factors

There’s an important set of connections between the brain and the gut, referred to as the brain-gut axis. It links the brain’s “emotional and cognitive centers with… intestinal functions” (22).

Evidence has shown that psychological stress can alter pathways that act on the brain-gut axis. Specifically, it can affect the “sensitivity, movement, secretion, and permeability of the intestines” (23). As such, this can provoke symptom onset and affect the severity of symptoms in people with IBS (24).

Additionally, research shows that other psychological factors, such as anxiety and depression, are strongly associated with IBS (25) and seem to influence the severity of symptoms (23).


Since IBS is a symptom-based disorder, management focuses on symptom control (2).

For people with mild or occasional symptoms, diet and lifestyle modifications are often enough to control symptoms. However, if the initial management is insufficient or symptoms are moderate to severe, additional support, such as medication, may be needed (26).

The low-fodmap diet

The low-fodmap diet is an elimination diet that helps you understand your tolerance to fodmap subgroups (oligo-, di-, and mono-saccharides and polyols). When carefully applied, it can achieve symptom reduction in 68 – 76% of people (27).

The diet progresses in three phases. You start by removing all fodmaps from your diet for 4 – 6 weeks (28)while monitoring your symptoms. If your symptoms improve, you move to the re-introduction phase, where you add back one fodmap group at a time while continuing to monitor your symptoms. The final phase is personalization, in which you add back to your diet all well-tolerated foods.

Because everyone has a different tolerance to food, the low-fodmap diet is not a “one-size-fits-all” approach. It’s best to do the diet under the supervision of a trained nutritionist or dietician certified in educating about the low-fodmap diet. A nutrition professional can consider your symptom type and severity and tailor the program’s strictness to suit your needs and minimize nutritional restrictions.

Physical activity

Physical activity is recommended as first-line management for symptom control in IBS (2). In a 12-week randomized controlled trial, 75 participants were assigned to either increase their physical activity levels or maintain their current physical activity levels (29).

At the end of the study, the participants who increased their physical activity levels:

  • Reported improvement in the severity of their symptoms (43% vs. 26%)
  • Were significantly less likely to have worsening of their symptoms than the control group (8% vs. 23%)

Gut-directed hypnotherapy

Gut-directed hypnotherapy is a therapeutic technique in which a person is guided into a deep, relaxed state (altered state of consciousness). Once in this state, visualizations and metaphors are used to gain control over and improve IBS symptoms (30).

Cognitive-behavioural therapy (CBT)

As the name implies, CBT is a type of psychotherapy that combines cognitive and behavioural therapy. When applied to IBS, it focuses on modifying behaviours and thinking patterns that can influence mood and physiological symptoms (31).