IBS and its causes

Irritable bowel syndrome (IBS) is a common digestive condition that affects the large intestine, causing symptoms such as abdominal pain, bloating, and changes in bowel habits. Although IBS is a chronic condition, it can often be managed with lifestyle adjustments, dietary changes and medical treatment. Understanding the potential causes of IBS helps to better manage symptoms and improve overall quality of life.

What is IBS?

IBS is a functional gastrointestinal disorder, meaning that it impacts how the bowel works rather than causing physical changes in bowel structure. Symptoms can vary widely among individuals and often include:

• Abdominal cramping or pain, usually relieved after a bowel movement
• Bloating and gas
• Diarrhoea, constipation - or alternating bouts of both
• Mucus in the stool

Symptoms can range from mild to severe, affecting daily life in many cases. The causes of IBS remain unclear, but several contributing factors have been identified.

What causes IBS?

The exact cause of IBS is unknown, but research suggests it may result from a combination of factors:

1. Gut-brain connection

The connection between the brain and the gut (often referred to as the "gut-brain axis") plays a significant role in IBS. Nerves in the gut communicate with the brain, and disruptions in this communication can lead to changes in gut function and sensitivity. This can result in symptoms like pain, bloating and changes in bowel habits, with stress or anxiety often exacerbating these symptoms.

2. Muscle contractions in the intestine

The muscles in the intestines contract to move food through the digestive tract. Abnormal or poorly coordinated contractions, often seen in IBS patients, can lead to symptoms such as gas, bloating, diarrhoea and constipation. Stronger, longer-lasting contractions can cause diarrhoea, while weaker contractions can lead to constipation.

3. Inflammation in the intestines

Some people with IBS may have low-grade inflammation in their intestines, which may contribute to the severity of symptoms. Although the inflammation seen in IBS isn’t as severe as in inflammatory bowel diseases (IBD), it can still lead to pain, cramping, and irregular bowel movements.

4. Gut microbiome imbalance

The gut microbiome, which consists of trillions of bacteria living in the intestines, plays a crucial role in digestion and overall health. An imbalance in gut bacteria, known as dysbiosis, has been linked to IBS. Certain bacterial strains are more common in people with IBS, and the microbiome may contribute to symptoms like gas, bloating, and irregular bowel habits.

5. Infections and previous illnesses

Some people develop IBS after a severe bout of gastroenteritis or food poisoning, a condition known as post-infectious IBS. Additionally, certain bacterial overgrowths, such as small intestinal bacterial overgrowth (SIBO), have been associated with IBS-like symptoms.

6. Food intolerances

While specific foods don't cause IBS, certain foods can trigger symptoms in people with the condition. Foods that commonly worsen IBS symptoms include:

• Dairy products
• Caffeine
• Spicy foods
• Fried foods
• Artificial sweeteners

These foods may increase bloating, gas, or discomfort in some people with IBS. In addition, the FODMAPs diet, which limits certain types of carbohydrates that are poorly absorbed in the intestines, has shown to help alleviate symptoms for many IBS patients.

How is IBS managed?

Since IBS varies from person to person, management strategies are often tailored to individual needs. These might include:

• Dietary changes, such as following a low-FODMAP diet
• Medications to alleviate symptoms like diarrhoea or constipation
• Stress management techniques, such as mindfulness or cognitive behavioural therapy (CBT)
• Probiotics, which may help rebalance gut bacteria

IBS is complex, and has multiple potential causes. Factors like the gut-brain connection, muscle function in the intestines, inflammation, and gut microbiome imbalances all contribute to its development. While the exact cause remains unknown, understanding the possible triggers and using a personalised management approach can help improve symptoms and quality of life for those living with IBS.