What causes diarrhoea?

The digestive system breaks down everything you eat and drink to absorb nutrients and make the energy your body needs. Whatever solids can’t be broken down and used get excreted as poop.

Poop comes in many shapes, sizes, colors and consistencies.

Doctors like me who treat people with digestive issues use what’s called the Bristol stool scale to grade poop texture. It goes from Type 1 – separate hard lumps – to Type 7 – liquid with no solid pieces. The texture of the best poops, Type 4, resembles a mushy banana.

When your poop is loose and watery and comes out that way at least three times a day, you have diarrhoea. It can be uncomfortable and inconvenient, because diarrhoea tends to come out quickly and with little warning.

Beware of bad germs

By the time food passes out of the stomach, it’s a liquid that travels through the small intestine, where nutrients are absorbed. The leftovers flow into the large intestine, where water is absorbed and poop forms.

When the small intestine or the large intestine can’t do its job, poop will be liquid.

Diarrhoea usually occurs because of infections caused by many different viruses, bacteria and parasites.

That’s why there are rules about keeping drinking water clean and food safe. It’s also why you should wash your hands before eating.

These germs cause diarrhoea a few different ways. Often, they irritate the intestines, interfering with water absorption. Some germs cause diarrhoea by releasing chemicals that make the intestines release fluid, making poop even more watery. When these germs come from food, symptoms can include vomiting, belly pain and diarrhoea.

To be sure, not all microbes are bad.

In fact, your digestive system is filled with billions of bacteria and other germs that help you digest food and protect you from bad germs. Taking antibiotics for an infection can cause diarrhoea by killing off these good bacteria along with the ones that originally made you sick. But people usually get better once they finish prescribed antibiotics and the good bacteria have a chance to recover.

People with diarrhoea need to consume lots of liquids to stay hydrated. Water is best. Avoid juice and soda, which can worsen diarrhoea. Also refrain from foods that can make your digestive system work harder, like dairy products.

Eating sweet potatoes, oats, beets and other high-fiber foods may help firm up loose poops. Never take a medication, even if doesn’t require a prescription, for diarrhoea without asking a doctor first.

Many other causes

There are many other causes of diarrhoea.

Some people are born with or develop conditions over the course of their lives that can cause diarrhoea.

A common example is lactose intolerance. Lactose is a sugar that is in milk that requires a special enzyme, called lactase, to digest it in the small intestine. There are people who have little, or even none, of this enzyme in their small intestine. As a result, lactose travels into their large intestine without being broken down and absorbed – leaving poop very runny.

Celiac disease can also trigger diarrhoea. People with it have trouble digesting gluten, a protein found in wheat and additional grains. For people with celiac disease, eating gluten can damage the small intestine by activating their own immune system. This damage is reversible through a gluten-free diet, but diarrhoea may continue until the small intestine heals and can do its job.

Others have digestive system allergies. They need to avoid eating specific foods to prevent diarrhoea and other symptoms.

Some medications make you poop more often.

There are also medical conditions, like inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis, in which the small intestine, large intestine or both become inflamed over a period of time.

Even your brain can play a role: Experiencing anxiety or getting stressed out can bring about loose poops. Some conditions, like irritable bowel syndrome, where the brain and the intestines do not communicate well with each other, can lead to belly pain and diarrhoea, particularly amid stress.

Certain cancers and some tumors can cause diarrhoea too.

Finally, for some people, eating spicy or fatty food or consuming artificial sweeteners or large amounts of caffeine can result in diarrhoea.

Even if you find it icky, I recommend you pay attention to your poop. If you’re having diarrhoea all the time, rather than occasionally, you may need to see a doctor.

This article is republished from The Conversation under a Creative Commons license.