Causes and symptoms of irritable bowel syndrome

Published At: 16 December 2019 , 03:48 PM

Irritable bowel syndrome (IBS) affects between 6–18% of people worldwide.

This disease involves changes in frequency or form of bowel shifts and lower intestinal pain (1).

Diet, poor sleep, stress, and differences in gut bacteria may all trigger symptoms.

However, triggers are different for every person, creating it challenging to name particular foods or stressors that everyone with the disease should avoid.

This article will explain the most common symptoms of IBS and causes.


The specific cause of IBS isn't known. Factors that seem to play a role include:

Nervous system. Irregularities in the nerves in your digestive system may cause you to feel higher than average discomfort when your stomach stretches from gas or stool. Poorly coordinated signals within the brain and the organs can cause your body to exaggerate to changes that usually occur in the digestive process, resulting in diarrhea, pain, or constipation.

Muscle contractions in the intestine. The walls of the tubes are lined with layers of tissue that contract as they push food through your digestive region. Contractions that are stronger and last longer than average can cause bloating, gas, and diarrhea. Weak intestinal contractions can slow food entrance and lead to severe, dry stools.

Inflammation in the intestines. Some people with IBS have an extended number of immune-system holes in their organs. This immune-system response correlated with pain and diarrhea.

Changes of bacteria in the gut (microflora). Microflora are the "good" bacteria that live in the intestines and perform a key role in health. Study shows that microflora in people with IBS might differ from microflora in healthy people.

Severe infection. IBS can improve after a severe bout of diarrhea (gastroenteritis) produced by bacteria or a virus. IBS might also correlate with a surplus of bacteria in the organs (bacterial overgrowth).

Symptoms of irritable bowel syndrome


Diarrhea-predominant IBS is one of the three main kinds of disorders. It afflicts approximately one-third of patients with IBS.

A research of 200 adults discovered that those with diarrhea-predominant IBS had, on average, 12 bowel movements weekly — more than twice the amount of adults without IBS.

Stimulated bowel transit in IBS can also occur in a sudden, quick urge to have a bowel movement. Some patients explain this as a vital source of stress, even avoiding some social situations for fear of the immediate onset of diarrhea.

Additionally, stool in the diarrhea-predominant type favors to be loose and wet and may carry mucus.

Gas and Bloating

Altered digestion in IBS begins to more gas generation in the gut. This can cause bloating, which is uncomfortable.

Many with IBS classify bloating as one of the most persistent and nagging signs of the disorder.

In a research of 337 IBS patients, 83% described bloating and fastening. Both symptoms were more evident in women and constipation-predominant IBS or mixed types of IBS.

Avoiding lactose and other FODMAPs can help decrease bloating.


Although it looks counterintuitive, IBS can produce constipation as well as diarrhea.

Constipation-predominant IBS is the most typical type, hitting nearly 50% of people with IBS.

Altered interaction between the brain and bowel may speed up or slow down the standard transit time of stool. When transit time slows, the intestine absorbs more water from stool, and it becomes more challenging to pass.

Constipation is defined as having fewer than three bowel movements per week.

"Functional" constipation describes chronic constipation, not defined by another infection. It is not associated with IBS and is very common. Functional constipation varies from IBS in that it is usually not painful.

In contrast, constipation in IBS involves abdominal pain that helps with bowel movements.

Constipation in IBS also often produces a feeling of an incomplete bowel movement. This points to unnecessary straining.

Along with the conventional treatments for IBS, exercise, eating soluble fiber, drinking more water, taking probiotics, and the limited usage of laxatives may help.