IBS-D is a complicated condition

Several factors can affect the digestive system, but the exact cause of IBS-D is unknown. People may have IBS-D for more than 1 reason, and those reasons can be different for every person.

Ask your doctor what might be causing your abdominal pain, diarrhea, gas, or other symptoms of IBS-D. IBS-D could be a result of 1 or more possible causes:

Take a closer look at
the link between gut
microbiota
and IBS-D
symptoms.

Take a closer
look at the link
between gut
microbiota
and
IBS-D symptoms.

Imbalances in the gut microbiota

An imbalance in the usual numbers and proportions of normal healthy bacteria in the digestive system has been found in people with IBS-D. Your digestive system has trillions of bacteria and microorganisms, collectively called the microbiota, that are constantly working to keep your body functioning normally.

Causes of IBS-D: Gut Microbiota

The microbiota help you digest and absorb food and work with your immune system as a barrier against other microorganisms that can cause disease. One study showed that 73% of people with IBS had an imbalance in their gut microbiota, compared with only 16% of healthy people. An imbalance in the microbiota can be related to genetics, infection or disease, anxiety, diet, drug use, and other causes.

Causes of IBS-D: Gut Microbiota

Communication problems between the brain and the digestive system

There is a 2-way communication system between the brain and the digestive system, known as the gut-brain axis.

Normally, signals go back and forth between the brain and the digestive system to help your brain and body know when you have eaten enough, when to start digesting food, and when to have bowel movements.

Changes in these signals can cause problems on either the digestive or brain side, which may lead to stress, anxiety, depression, or symptoms such as pain or diarrhea.

Problems in the immune system

Activation of the immune system can cause inflammation that might result in symptoms of IBS-D.

Your immune system is your body’s defense against disease. But if your immune system takes action in your digestive system—maybe because of an infection or stress—the lining of the digestive tract can become irritated and inflamed, causing pain and diarrhea.

Intestine Graphic: Immune System
Causes of IBS-D: DNA Strand

Family history (genetics and early childhood)

Certain genes associated with the immune system, inflammation, digestion, and psychiatric disease may be linked to IBS. Stress experienced in early childhood could also play a role.

People with family members who have IBS are more than twice as likely to develop IBS themselves.

Anxiety and/or depression

Many people with IBS-D feel depressed or anxious, but it can be difficult to determine if these feelings are a cause or a result of IBS-D.

Some factors associated with IBS-D can cause depression, anxiety, or other mood disorders. While other studies show that stress may cause changes in the gut microbiota and contribute to the symptoms of IBS-D.

Lightning Cloud Graphic: Anxiety
Causes of IBS-D Banner: Quote
“Learning that my IBS-D could be caused by
an imbalance of intestinal bacteria gives me
hope that my symptoms can be helped.
“Learning that my IBS-D could be
caused by an imbalance of intestinal
bacteria gives me hope that my
symptoms can be helped.

Not an actual patient.

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