Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a prevalent condition impacting the stomach and intestines, also known as the gastrointestinal tract. Symptoms include cramping, abdominal pain, bloating, gas, and either diarrhea or constipation, or both. IBS is a chronic condition requiring long-term management.

Only a small portion of individuals with IBS experience severe symptoms. Some can manage their symptoms through diet, lifestyle, and stress management. More severe symptoms may require medication and counseling.

IBS does not lead to changes in bowel tissue or increase the risk of colorectal cancer.

Symptoms

IBS symptoms vary but are typically long-lasting. The most common include:

Abdominal pain, cramping, or bloating associated with bowel movements.
Alterations in stool appearance.
Changes in stool frequency.

Other frequently related symptoms include a feeling of incomplete evacuation and increased gas or mucus in the stool.

When to see a doctor

Consult a healthcare professional if you experience a persistent change in bowel habits or other IBS symptoms. They might indicate a more serious condition, such as colon cancer. More serious symptoms include:

Weight loss.
Nighttime diarrhea.
Rectal bleeding.
Iron deficiency anemia.
Unexplained vomiting.
Pain not relieved by passing gas or stool.

Causes

The precise cause of IBS is unknown. Factors that may contribute include:

Muscle contractions in the intestine. The intestinal walls are lined with muscle layers that contract as food moves through the digestive tract. Stronger, longer-lasting contractions can cause gas, bloating, and diarrhea. Weak contractions can slow food passage, leading to hard, dry stools.
Nervous system. Problems with digestive system nerves may cause discomfort when the abdomen stretches from gas or stool. Poorly coordinated signals between the brain and intestines can cause the body to overreact to normal digestive process changes, resulting in pain, diarrhea, or constipation.
Severe infection. IBS can develop after a severe diarrhea episode caused by bacteria or a virus, known as gastroenteritis. IBS might also be linked to bacterial overgrowth in the intestines.
Early-life stress. Individuals exposed to stressful events, particularly in childhood, tend to experience more IBS symptoms.
Changes in gut microbes. This includes changes in bacteria, fungi, and viruses that typically reside in the intestines and are crucial for health. Research suggests that the microbes in people with IBS differ from those without IBS.

Triggers

IBS symptoms can be triggered by:

Food. The role of food allergy or intolerance in IBS isn't fully understood. A true food allergy rarely causes IBS. However, many people experience worsened IBS symptoms after consuming certain foods or beverages, such as wheat, dairy products, citrus fruits, beans, cabbage, milk, and carbonated drinks.
Stress. Most individuals with IBS experience worsened or more frequent symptoms during periods of increased stress. While stress may exacerbate symptoms, it doesn't cause them.

Risk factors

Many people occasionally experience IBS symptoms. However, you are more likely to have the syndrome if you:

Are young. IBS is more common in individuals under 50.
Are female. In the United States, IBS is more prevalent among women. Estrogen therapy before or after menopause is also a risk factor for IBS.
Have a family history of IBS. Genetics may play a role, as might shared environmental factors or a combination of genetics and environment.
Have anxiety, depression, or other mental health issues. A history of sexual, physical, or emotional abuse might also be a risk factor.

Complications

Chronic constipation or diarrhea can lead to hemorrhoids.

Additionally, IBS is associated with:

Poor quality of life. Many individuals with moderate to severe IBS report a diminished quality of life. Research shows that those with IBS miss work three times more often than those without bowel symptoms.
Mood disorders. Experiencing IBS symptoms can lead to depression or anxiety, which can also exacerbate IBS.