Can Diarrhea Be A Symptom Of Type 2 Diabetes?

Diarrhea — passing loose, watery stools — is an unpleasant condition that can affect people of all ages. Most people get acute diarrhea (three bouts of diarrhea within 24 hours) multiple times in their lifetime. Adults in the US get acute diarrhea once per year on average.

But could your diarrhea be a symptom of a more serious health condition like type 2 diabetes? Is there a link between type 2 diabetes and gastrointestinal problems like diarrhea? Read on to find out.

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What is type 2 diabetes?

Type 2 diabetes is a lifestyle-related condition that develops over time.

Your cells need sugar to function properly, and you mostly obtain it from the food you eat. However, with type 2 diabetes, your cells may not be able to use this sugar effectively, so it stays in your blood. This could be because your body doesn’t make enough insulin or makes enough but doesn’t use it efficiently.

Insulin is a hormone that regulates blood sugar and “unlocks” your cells to obtain sugar. If you don’t have enough insulin, or your body doesn’t properly respond to insulin, this causes sugar to build up in your blood, damaging parts of your body.

Who is at risk of type 2 diabetes?

Some people have a higher risk of developing type 2 diabetes than others.

Here are some of the risk factors for type 2 diabetes:

Symptoms of type 2 diabetes

Speak to your doctor if you develop any of the following symptoms:

  • Tiredness

  • Increased hunger or thirst

  • Urinating more often, especially at night

  • Blurred vision

  • Tingling or numbness in your feet or hands

  • Unexplained weight loss

  • Thrush or itching in your genital area

  • Cuts, wounds, or sores that are slow to heal or don’t heal

Not everyone experiences symptoms of type 2 diabetes. The condition can develop very slowly over time. Some people are only diagnosed with type 2 diabetes when they develop complications.

Can type 2 diabetes cause diarrhea?

Most people experience diarrhea at some point during their lives. You may have diarrhea if your stools are loose or watery more than three times in 24 hours. It can be very unpleasant but usually clears up after a day or two.

Diarrhea is considered chronic if it lasts four weeks or longer. In this case, your diarrhea may be a symptom of chronic disease.

But can type 2 diabetes cause diarrhea?

Yes, it can. Most people with type 2 diabetes experience gastrointestinal symptoms, including diarrhea. This is known as “diabetic diarrhea.” Diabetic diarrhea could occur due to your medication for type 2 diabetes, the foods you eat, or complications.

Diabetes-related diarrhea may last several weeks to months, and you may also experience fecal incontinence.

What causes diabetic diarrhea?

Experts are not sure what causes diabetic diarrhea exactly but believe it could be nerve damage — specifically, autonomic neuropathy.

Here are the potential causes of diabetic diarrhea:

Autonomic neuropathy

Diarrhea is a symptom of autonomic neuropathy, a complication of type 2 diabetes where the nerves that control your internal organs are damaged due to high blood sugar levels.

Autonomic neuropathy can affect your heart, blood pressure, sex organs, bladder, eyes, sweat glands, and digestive system. Diarrhea, especially at night, is just one of the signs autonomic neuropathy is affecting your digestive system, but you may also experience:

  • Constipation, or constipation alternating with diarrhea

  • Fecal incontinence

  • Nausea and vomiting

  • Feeling bloated and full

  • Trouble swallowing

Exocrine pancreatic insufficiency (EPI)

Exocrine pancreatic insufficiency is known to affect people with type 1 and type 2 diabetes. The condition causes a deficiency in exocrine pancreatic enzymes, making it difficult to properly digest foods.

EPI symptoms are usually mild to moderate for people with diabetes. They include diarrhea, abdominal pain, and excessive flatulence. In more serious cases, EPI can cause weight loss and steatorrhea (excess fat in stools).

Talk to your doctor about your symptoms. Treatment options for EPI include vitamin supplementation and pancreatic enzyme replacement therapy.


Your doctor may prescribe metformin (Glucophage, Glumetza, Fortamet, Riomet, and others) to help treat your diabetes and regulate your blood sugar levels.

Metformin works in two ways:

  1. Helping your body respond to insulin more efficiently

  2. Preventing your liver from releasing as much glucose into your body

According to the Federal Drug Administration (FDA), 53.2% of 141 patients¹ in a placebo-controlled clinical study of Glucophage monotherapy experienced diarrhea as a side effect. It’s one of the most common side effects of metformin.

Speak to your doctor about your side effects. They may recommend taking metformin towards the end of your meal or after eating to lessen your discomfort. Taking an extended-release form of metformin may also help.

Bacterial overgrowth

An overgrowth of bacteria in the small intestine is a gastric complication of diabetes. This can cause diarrhea and other symptoms, including bloating, abdominal pain, gas, and nutritional deficiencies.

Artificial sweeteners

Sugar alcohols like sorbitol are often used in sugar-free foods, such as sugar-free gum or foods labeled as suitable for people with diabetes. People with diabetes may choose these products as they have low sugar content.

Sorbitol and other sugar alcohols can cause diarrhea, gas, and stomach cramps. Although diarrhea is unrelated to diabetes in this case, it may affect people with diabetes who consume sugar and alcohol.

Other causes of diarrhea

Your diarrhea may not be related to your type 2 diabetes. Don’t assume diarrhea is a symptom of type 2 diabetes if you haven’t been diagnosed.

Everyone experiences diarrhea from time to time. Numerous other things can cause it. It’s also possible to have type 2 diabetes and another condition that causes diarrhea.

The following things may cause diarrhea:

  • Viral infections: Your diarrhea could be caused by a virus, such as viral gastroenteritis or norovirus.

  • Bacterial infections: Bacteria like Salmonella or Escherichia coli can enter your digestive tract through contaminated food or water and cause diarrhea.

  • Parasitic infections: Your diarrhea could be caused by a parasitic infection, such as Cryptosporidium enteritis or Entamoeba histolytica.

  • Medications: Some medications can cause diarrhea as a side effect. Taking some medications long-term can cause chronic diarrhea, such as antibiotics.

  • Food allergies or intolerances: Foods containing lactose, fructose, soy, egg, seafood, and cereal grains can cause chronic diarrhea in some people.

  • Other health conditions: Some conditions related to digestive health cause diarrhea, including Crohn’s disease, celiac disease, and ulcerative colitis.

  • Abdominal surgery (surgery to your stomach, intestines, appendix, liver, spleen, or gallbladder): You may develop chronic diarrhea after having abdominal surgery.

How is diarrhea diagnosed?

Most cases of diarrhea do not require diagnosis or treatment since they typically get better within four days.

However, chronic diarrhea (diarrhea that lasts longer than four weeks) could suggest you have an underlying health condition. In this case, your doctor may look at your medical history and ask you questions about your symptoms. They may also organize some diagnostic tests, such as:

  • Stool test: This involves testing a stool sample to determine the presence of blood, bacterial infections, parasites, and inflammatory markers.

  • Breath test: This can help determine if you have a lactose or fructose intolerance.

  • Blood tests: Testing your blood can rule out medical reasons for diarrhea, such as thyroid disease, celiac disease, or pancreatic disease.

  • Endoscopy: This involves examining your upper and lower gastrointestinal tracts to help determine what is causing your diarrhea.

How is type 2 diabetes diagnosed?

If your doctor suspects type 2 diabetes, they will conduct a series of tests to determine how well your body regulates blood sugar.

These tests include:

  • A1C test: This is a blood test that looks at your average blood sugar levels over the past three months.

  • Fasting plasma glucose test: You will be asked to fast for eight hours before this test, meaning most tests are taken in the morning. This test determines your blood sugar levels at a single point in time. More than one reading is usually needed to confirm your results.

  • Random plasma glucose test: This test, taken at any time, can help diagnose diabetes. It is not as effective as other tests at diagnosing diabetes in people whose blood sugar levels are only slightly elevated, but it can help people with very high blood sugar levels get urgent treatment.

  • Oral glucose challenge test: You will be asked to fast for at least eight hours before this test. First, a blood sample will be taken to measure your blood sugar level after fasting. Then you will be asked to drink a high-sugar drink. You will have another blood sample taken two hours later to check your blood sugar level. A high reading may suggest you have diabetes.

Treating diarrhea

You can take over-the-counter medications to ease diarrhea symptoms, including loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol or Kaopectate). However, see your doctor if you have worsening diarrhea that lasts longer than two days.

Don’t take over-the-counter medications if you have blood in your stool or fever.

Here are some general non-medicinal tips for coping with diarrhea:

  • Stay hydrated: Diarrhea causes your body to lose a lot of water, so be sure to drink plenty.

  • Follow the BRAT diet: The BRAT diet consists of bananas, white rice, applesauce, and toast. It’s gentle on your stomach. Avoid fatty, fried, or greasy foods until you feel better.

  • Drink less caffeine: Foods and drinks with caffeine can aggravate your diarrhea with their laxative effects. Avoid or limit caffeine consumption until you feel better.

  • Avoid foods that cause gas: Some foods cause gas, which could worsen your symptoms. These include high-bran foods, beans, brown rice, and vegetables like Brussels sprouts, cabbage, cauliflower, leeks, and parsnips.

Diarrhea caused by an infection may require medication, like antibiotics. Persistent or chronic diarrhea caused by an underlying health condition will also require treatment. This may involve lifestyle changes or medication.

Remember to consult your doctor if your diarrhea lasts longer than two days and worsens.

Treating diarrhea caused by diabetes

Treatment for diabetes-related diarrhea depends on the cause.

Your doctor may prescribe antibiotics if you have bacterial overgrowth.

For EPI, your doctor may recommend vitamin supplementation and pancreatic enzyme replacement therapy.

If autonomic neuropathy is causing your diarrhea, your doctor may decide to adjust your treatment to help stabilize your blood sugar levels.

You’ll need to discuss the options available if you have metformin-related diarrhea. They may change your dose or medication.

Can I prevent diarrhea?

For people with type 2 diabetes, managing the condition is essential for preventing complications like diarrhea.

You’ll need to work closely with your medical team to find a treatment plan that works well for you and keeps your blood sugar levels under control. Your doctor may recommend lifestyle adjustments, such as healthy eating, exercising, and quitting smoking (if you smoke). They may also prescribe medication, such as supplemental insulin.

Sticking to your recommended treatment plan can help keep your digestive system healthy and avoid nerve damage caused by continuously high blood sugar levels.

Here are some general tips for avoiding diarrhea:

  • Drink filtered, boiled, or bottled water: This is particularly important if you’re traveling to a high-risk area to avoid water-borne bacteria, viruses, and parasites that cause diarrhea.

  • Practice safe food hygiene: Always cook food thoroughly and store it correctly. Don’t eat food past its use-by date.

  • Wash your hands regularly: Thorough and regular handwashing with soap and warm water can help prevent diarrhea. This is particularly important before and after preparing food, before eating, and after using the toilet and touching surfaces.

  • Clean your toilet: If you or someone in your household have diarrhea, be sure to clean the toilet after each bout of diarrhea.

When should I see a doctor?

Make an appointment to see your doctor if:

  • You develop any of the symptoms of type 2 diabetes listed above

  • You have worsening diarrhea that lasts for more than two days

  • There is blood in your stool

  • You are dehydrated

Your doctor will examine your medical history, conduct a physical exam, and ask you questions. Be prepared to tell your doctor:

  • When your diarrhea started

  • What symptoms do you have

  • How regular your bowel movements are

  • What your stool looks like (including color and consistency)

  • If there is blood in your stool

  • What medications you are taking

  • If you have any diagnosed health conditions

  • If you have recently had contact with someone who is sick

  • If you have recently traveled to a high-risk country

The lowdown

Type 2 diabetes does not cause symptoms in everyone who has it, but diarrhea can be one such symptom. It may suggest you have nerve damage in your digestive system or a bacteria overgrowth in your small intestine.

Some people with type 2 diabetes develop a condition called exocrine pancreatic insufficiency, which can cause diarrhea. Alternatively, diarrhea can be caused by metformin, a type of diabetes medication, or by sugar alcohols like sorbitol.

Speak to your doctor if you have worsening diarrhea that lasts more than two days or if you develop other symptoms of type 2 diabetes.

  1. Glucophage® (metformin hydrochloride) tablets | Access Data

Other sources:

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