Some Possible Causes of Constipation

Constipation Could Be a Result of Diet, Lifestyle, Disease, or Medication

Abdominal Pain
Constipation is a common problem that can happen to just about anyone. Thankfully, there is plenty you can do to prevent constipation, or treat it when it does happen.. Photo © Ohmega1982

Constipation is a common problem that has many potential causes. For most adults, who may experience constipation a few times a year, the cause may never be known. For people who experience chronic constipation, discovering the cause can lead to some relief from symptoms.

What Causes Constipation?

Constipation can be related to four things:

  • Diet and lifestyle
  • Medications (with constipation as a side effect)
  • Specific stomach/gastrointestinal conditions
  • Other diseases

This article will closely look at all four. Let's start with diet and lifestyle choices that may lead to constipation:

Constipation Related to Diet And Lifestyle

  • Lack of Dietary Fiber. Most adults do not get enough fiber in their diets, especially in Western countries. Fiber helps stool remain soft and easily pass through the intestines and out the rectum during a bowel movement. Without enough fiber, stool does not reach its optimal form, but instead may become hard and difficult to pass, leading to constipation.

    The recommended amount of daily dietary fiber for adults is 25 to 30 grams a day. Most American adults only get about 15 grams a day in their diet. Besides being important for preventing constipation, fiber also helps lower the risk of heart disease, diabetes, and colon cancer. Fiber can be found in fruits, vegetables, legumes, and whole grains.

  • Dehydration. Without enough available water, stool may become hard. Drinking adequate amounts of water throughout the day will help prevent this from occurring. Caffeinated drinks such as coffee and soda pop are not helpful for preventing constipation from this cause, and alcohol may have a dehydrating effect.
  • Lack of Exercise. Regular exercise can help keep abdominal muscles toned and the intestines in good shape and working well. People who are unable to exercise because of illness or injury may need advice from a physician to avoid or treat constipation.
  • Pregnancy. The hormones that are released during pregnancy can also cause the bowel to slow down and lead to constipation.
  • Older Age. Older adults are at risk for constipation for several reasons, including lack of fiber, poor fluid intake, dental problems, lack of exercise, medications, and a focus on having normal bowel movements.
  • Ignoring a Need to Move The Bowels. Some people prefer to have their bowel movements at home or during a particular time of day, and so they put off moving the bowels even when they have an urge. Children may also avoid eliminating while toilet training or if it interferes with their fun activities. Habitually delaying a bowel movement can cause the feelings of fullness that cue a person to defecate to eventually go away. Not knowing when it is time to move the bowels leads to unintentionally delaying bowel movements, which leads to constipation.
  • Travel. Changes in diet and schedule can contribute to constipation while traveling. Ignoring the urge to defecate because of inconvenience may also be a factor in constipation that develops while traveling.

Medications That Can Cause Constipation

Some medications and dietary supplements can have a side effect of constipation.

  • Narcotics. Narcotic pain medications can affect the function of the gastrointestinal tract, and result in a longer transit time for waste traveling through the small and large intestines. This is a very common cause of constipation.
  • Antacids. The calcium and aluminum that are found in some antacids can cause constipation.
  • Anticholinergics. This class of drugs may be used to treat ulcers, nausea, vomiting, motion sickness, Parkinson's disease, and IBS. Anticholinergics may cause a decrease in body secretions (such as saliva and urine) and a slow down of intestinal movement, which could lead to constipation.
  • Anticonvulsants. Medications that are used to treat conditions such as epilepsy, anticonvulsants affect the central nervous system, and may slow down digestion and cause constipation.
  • Antidepressants. Some antidepressants cause the muscles of intestines to slow down and a decrease in the body fluids that help move waste through the digestive tract. These effects can wind up causing constipation.
  • Antihypertensives. These drugs, which are used to control blood pressure and are also called calcium channel blockers, can cause more calcium in the bloodstream and lead to constipation.
  • Calcium Supplements. Calcium may lead to mild constipation, especially in those who are taking other medications or supplements that are also known to cause constipation.
  • Diuretics. The purpose of a diuretic is to cause urination. The loss of fluid from the body in this way can deplete the amount that is available in the intestines, and lead to constipation.
  • Iron Supplements. An excess of iron in the body can send a signal, which similar to an electric charge, to the intestines and cause them to slow down.
  • Parkinson's Disease Drugs. Certain drugs used to treat Parkinson's disease (such as dopamine agonists, anticholinergics, COMT inhibitors, and MAO-B Inhibitors) may contribute to the development of constipation.

Gastrointestinal Conditions That Can Cause Constipation

There are several digestive diseases and conditions that could cause constipation.

  • Adhesions. Adhesions are a type of internal scarring that may happen after surgery. Adhesions can cause the bowel to become blocked or narrowed, and lead to constipation.
  • Bowel Obstructions. A blockage in the intestines that's preventing stool from moving through could be the cause of constipation. Obstructions are more common in Crohn's disease than in ulcerative colitis.
  • Chronic Idiopathic Constipation. A type of constipation with an unknown cause that doesn't always respond to at-home care such as eating more fiber and drinking more water. This type of constipation is more common in women, older people, and those who have IBS.
  • Colon Cancer. Colon cancer could cause constipation through a narrowing of the colon or rectum, or because a tumor is blocking the intestines.
  • Hirschsprung's Disease. A congenital condition, Hirschsprung's disease causes constipation because the bowel is missing some nerves that help to move waste material through.
  • Irritable Bowel Syndrome (IBS). IBS is a chronic condition that can cause diarrhea or constipation, or alternation between diarrhea and constipation. The reasons why IBS may cause constipation are poorly understood.

Diseases That Can Cause Constipation

Certain diseases and conditions can also cause constipation, including systemic diseases and those that affect the metabolic system or the neurological system.

  • Amyloidosis. When too much of the protein amyloid is found in the body, it is called amyloidosis. Constipation could be a result of a build-up of amyloid in the digestive tract.
  • Diabetes. Constipation is a common problem for people who have diabetes, especially those who have nerve damage that is causing a slowdown in the intestines.
  • Hypercalcemia. Hypercalcemia is too much calcium in the blood; this condition is usually a sign of disease such as cancer or primary hyperparathyroidism. Patients with hypercalcemia may be dehydrated, which can contribute to constipation.
  • Intestinal Pseudo-obstruction. In this rare condition, no mechanical obstruction can be found, yet the intestines are unable to move food through at a normal pace.
  • Lupus. An autoimmune disease, lupus could affect any part of the body. If lupus has an effect on the gastrointestinal tract, it could wind up causing constipation or other digestive conditions.
  • Multiple Sclerosis (MS). A common problem for people with MS, an estimated 50 to 75% of people with MS experience constipation. The lesions on the brain that occur with MS, coupled with certain medications and a lack of exercise, could lead to chronic constipation.
  • Parkinson's Disease (PD). Constipation is also a frequent problem for an estimated 20 to 40% of people with PD. PD leads to a lack of dopamine, which, among many other functions, is a chemical that helps stimulate the colon.
  • Scleroderma. Scleroderma is an autoimmune condition that can cause the muscles of the large intestine to weaken or to work less effectively, thereby causing constipation.
  • Spinal Cord Injury. An injury to the spinal cord could lead to the intestines being more sluggish, as well as decreased physical activity, fluid intake, and dietary fiber. Not being aware of when to have a bowel movement as well as certain medications can also contribute to constipation.
  • Stroke. After a stroke, approximately 30 to 60% of patients will experience constipation. The risk factors for constipation in those who have had a stroke include decreased physical activity and a diet that is low in fiber and fluids.
  • Thyroid Disease. People with thyroid disease, especially those with hypothyroidism, may experience constipation. Low levels of thyroid hormones could cause the intestines to move more slowly.
  • Uremia. A toxic condition that may occur when the kidneys are failing, uremia may cause a patient to develop constipation. Poor fluid intake and low levels of physical activity in these patients who are often seriously ill may contribute to bowel problems.


Stanford Hospital & Clinics. "AL (Primary) Amyloidosis." 2011. 27 Sept 2011.

Su Y, Zhang X, Zeng J, et al. "New-Onset Constipation at Acute Stage After First Stroke." Stroke 2009;40:1304-1309. 28 Sept 2011.

Suares NC, Ford AC. "Prevalence of, and Risk Factors for, Chronic Idiopathic Constipation in the Community: Systematic Review and Meta-analysis." Am J Gastroenterol 2011 Sep;106:1582-1591. 03 Sept 2011.

UCSF Medical Center. "Increasing Fiber Intake." The University of California 17 Aug 2011. 27 Sept 2011.

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