Irritable Bowel Syndrome (IBS) Symptoms, Causes, & Treatment

What is Irritable Bowel Syndrome (IBS)?

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder characterized by a combination of abdominal pain and altered bowel movements.

The exact causes of IBS are not fully understood, but IBS is thought to be caused by dysfunction in the gut-brain axis. The gut-brain axis is a communication network that connects the central nervous system with the gastrointestinal nervous system, which controls the function of the gastrointestinal (GI) tract.

The gut-brain axis involves neurotransmitters that play roles in both the brain and the gut. For instance, serotonin, which is crucial for mood regulation in the brain, also significantly impacts gut motility and sensation. Imbalances in serotonin levels can affect both mental well-being and gut function, contributing to IBS symptoms.

In IBS, there is often an increased sensitivity in the GI tract. This means that the gut is more sensitive to stimuli than normal. As a result, signals of discomfort or pain may be amplified.

An imbalance in the gut microbiota has been linked to IBS and may interfere with gut-brain communication. This imbalance may be caused by several factors, including antibiotics used to treat an infectious disease or the disease itself, other medications, chronic stress, poor diet, exposure to pollutants or toxins, or aging.

What are the subtypes of IBS?

IBS is categorized into 4 subtypes based on the predominant symptom. These subgroups help tailor treatment approaches to better address the specific symptoms a person is experiencing.

• IBS with diarrhea (IBS-D): Frequent loose or watery stools, often accompanied by abdominal cramping and urgency. People with IBS-D may experience a frequent need to have a bowel movement, sometimes with a feeling of incomplete evacuation.
• IBS with constipation (IBS-C): Predominantly characterized by infrequent bowel movements, hard or lumpy stools, and difficulty passing stools. Abdominal pain or discomfort is also common and may be relieved by bowel movements.
• IBS with mixed symptoms (IBS-M): A combination of both diarrhea and constipation, where symptoms alternate or fluctuate over time.
• IBS unsubtyped (IBS-U): Symptoms do not fit into any of the other 3 subtypes of IBS.

How common is IBS?

IBS is quite common, affecting 13 to 20% of Canadians. For unknown reasons, it affects women more often than men.

IBS can occur at any age and can resolve and recur unexpectedly throughout a person’s life.

According to experts, as many as 60% of people with IBS attribute their symptoms to poor digestion and do not seek medical help.

What are the symptoms of IBS?

The symptoms of IBS can vary from person to person, but commonly include:

• Abdominal pain or discomfort, often relieved by bowel movements
• Changes in bowel movements: diarrhea, constipation, or a combination of both
• Bloating
• Gas
• Mucus in the Stool
• Feeling of incomplete bowel movement
• Fatigue
• Nausea

Symptoms of IBS can vary in intensity and may be triggered or worsened by certain foods, stress, hormonal changes, or other factors.

How is IBS diagnosed?

There is no specific test for IBS so the diagnosis is usually based on a medical history and an evaluation of symptoms.

Laboratory tests, stool tests, imaging studies, or endoscopy may be used to rule out other possible causes of symptoms, such as inflammatory bowel disease (IBD), celiac disease, or colorectal cancer.

Which foods trigger IBS?

Certain foods can trigger symptoms of IBS, although triggers can vary from person to person. Common triggers include:

• High-FODMAP foods, which are short-chain carbohydrates that can be poorly absorbed in the small intestine and fermented by gut bacteria, leading to symptoms like bloating, gas, and abdominal pain. They include certain fruits (e.g., apples, pears, mangoes, watermelon), vegetables (e.g., onions, garlic, cauliflower, asparagus), grains (such as wheat), dairy products, legumes and sweeteners (e.g., high-fructose corn syrup, honey, sorbitol). Various online sources, such as Monash University, have lists of low- and high-FODMAP foods.
• Fatty or spicy foods
• Caffeinated and carbonated beverages
• Alcohol
• Processed foods

Tips for IBS-friendly eating

• Eat small, frequent meals which are easier to digest and may reduce symptoms compared to large meals.
• If lactose is a trigger, try consuming smaller amounts of regular dairy products, ideally with a meal, or opt for lactose-free products or alternatives such as almond, hemp, or coconut milk (fortified with calcium and vitamin D).
• Drink plenty of water, and limit or avoid caffeine and alcohol, which can irritate the gut.

Since IBS triggers vary greatly from person to person, keeping a food and symptom diary can help identify your potential triggers. An elimination or low FODMAP diet, followed by a gradual reintroduction of foods, can help confirm specific triggers and effectively manage symptoms.

It is recommended that you work with a registered dietician or healthcare professional to tailor dietary recommendations to your specific needs and ensure that your diet remains balanced.

How is IBS treated?

Because IBS cannot be cured, its treatment focuses on managing symptoms and improving quality of life through dietary adjustments, stress management, medications and lifestyle changes.

• Avoiding food triggers, such as high-FODMAP foods.
• Taking probiotics that have been shown to be effective in IBS.
• Taking medications such as antispasmodics for abdominal pain, laxatives for constipation, or anti-diarrheal agents for diarrhea. In some cases, medications specifically for IBS, like certain antidepressants or medications targeting IBS symptoms, may be prescribed.
• Since stress can exacerbate symptoms, techniques such as cognitive-behavioural therapy, relaxation exercises, and mindfulness can be beneficial.
• Regular exercise and adequate hydration can also help manage symptoms. 

Can IBS be prevented?

A healthy diet and active lifestyle, stress management, and not smoking all have benefits for the health of the gastrointestinal tract. However, because the exact causes of irritable bowel syndrome are not fully understood and can vary from person to person, there are currently no known preventative measures.

What is the difference between IBS and IBD?

The term “inflammatory bowel disease” (IBD) refers to gastrointestinal diseases characterized by inflammation. The most common types of IBD are Crohn’s disease and ulcerative colitis.

IBD is more severe than IBS. Unlike IBS, IBD causes damage to the intestine that is visible on examination, such as an X-ray or endoscopy. The damage is caused by an inflammatory process whose causes are not fully understood. When the intestines are damaged, they are less effective at absorbing essential nutrients. The inflammation that occurs in IBD can also affect other organs in the body, including the joints, skin, and eyes. Complications can include kidney stones, gallstones and weakened bones. Patients also have an increased risk of developing blood clots.

Your pharmacist is here for you!

IBS symptoms can be debilitating at times, but with proper management, you can relieve them and improve your quality of life. Your pharmacist will work with your healthcare team to make sure you get the best possible care and treatment, and to support your efforts to improve your diet and lifestyle. If you have questions or concerns, do not hesitate to seek their professional advice!