Causes of Constipation


Cause details for Constipation:


The most common cause of constipation is a diet low in fiber found in vegetables, fruits, and whole grains and high in fats found in cheese, eggs, and meats. People who eat plenty of high-fiber foods are less likely to become constipated.

Fiber--soluble and insoluble--is the part of fruits, vegetables, and grains that the body cannot digest. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Insoluble fiber passes almost unchanged through the intestines. The bulk and soft texture of fiber help prevent hard, dry stools that are difficult to pass.

On average, Americans eat about 5 to 20 grams of fiber daily, short of the 20 to 35 grams recommended by the American Dietetic Association. Both children and adults eat too many refined and processed foods in which the natural fiber is removed.

A low-fiber diet also plays a key role in constipation among older adults. They often lack interest in eating and may choose fast foods low in fiber. In addition, loss of teeth may force older people to eat soft foods that are processed and low in fiber.

Not Enough Liquids

Liquids like water and juice add fluid to the colon and bulk to stools, making bowel movements softer and easier to pass. People who have problems with constipation should drink enough of these liquids every day, about eight 8-ounce glasses. Other liquids, like coffee and soft drinks, that contain caffeine seem to have a dehydrating effect.

Lack of Exercise

Lack of exercise can lead to constipation, although doctors do not know precisely why. For example, constipation often occurs after an accident or during an illness when one must stay in bed and cannot exercise.


Pain medications (especially narcotics), antacids that contain aluminum, antispasmodics, antidepressants, iron supplements, diuretics, and anticonvulsants for epilepsy can slow passage of bowel movements.

Irritable Bowel Syndrome (IBS)

Some people with IBS, also known as spastic colon, have spasms in the colon that affect bowel movements. Constipation and diarrhea often alternate, and abdominal cramping, gassiness, and bloating are other common complaints. Although IBS can produce lifelong symptoms, it is not a life-threatening condition. It often worsens with stress, but there is no specific cause or anything unusual that the doctor can see in the colon.

Changes in Life or Routine

During pregnancy, women may be constipated because of hormonal changes or because the heavy uterus compresses the intestine. Aging may also affect bowel regularity because a slower metabolism results in less intestinal activity and muscle tone. In addition, people often become constipated when traveling because their normal diet and daily routines are disrupted.

Abuse of Laxatives

Myths about constipation have led to a serious abuse of laxatives. This is common among older adults who are preoccupied with having a daily bowel movement.

Laxatives usually are not necessary and can be habit-forming. The colon begins to rely on laxatives to bring on bowel movements. Over time, laxatives can damage nerve cells in the colon and interfere with the colon's natural ability to contract. For the same reason, regular use of enemas can also lead to a loss of normal bowel function.

Ignoring the Urge to Have a Bowel Movement

People who ignore the urge to have a bowel movement may eventually stop feeling the urge, which can lead to constipation. Some people delay having a bowel movement because they do not want to use toilets outside the home. Others ignore the urge because of emotional stress or because they are too busy. Children may postpone having a bowel movement because of stressful toilet training or because they do not want to interrupt their play.

Specific Diseases

Diseases that cause constipation include neurological disorders, metabolic and endocrine disorders, and systemic conditions that affect organ systems. These disorders can slow the movement of stool through the colon, rectum, or anus. Figure 3 lists the diseases that cause constipation.

Figure 3

Diseases That Cause Constipation

Neurological disorders that may cause constipation include:
  • Multiple sclerosis
  • Parkinson's disease
  • Chronic idiopathic intestinal pseudo-obstruction
  • Stroke
  • Spinal cord injuries.
Metabolic and endocrine conditions include:
  • Diabetes
  • Underactive or overactive thyroid gland
  • Uremia.
Systemic disorders include:
  • Amyloidosis
  • Lupus
  • Scleroderma.

Problems with the Colon and Rectum

Intestinal obstruction, scar tissue (adhesions), diverticulosis, tumors, colorectal stricture, Hirschsprung's disease, or cancer can compress, squeeze, or narrow the intestine and rectum and cause constipation.

Problems with Intestinal Function (Chronic Idiopathic Constipation)

Also known as functional constipation, chronic idiopathic (of unknown origin) constipation is rare. However, some people are chronically constipated and do not respond to standard treatment. This chronic constipation may be related to multiple problems with hormonal control or with nerves and muscles in the colon, rectum, or anus. Functional constipation occurs in both children and adults and is most common in women.

Colonic inertia and delayed transit are two types of functional constipation caused by decreased muscle activity in the colon. These syndromes may affect the entire colon or may be confined to the left or lower (sigmoid) colon.

Functional constipation that stems from abnormalities in the structure of the anus and rectum is known as anorectal dysfunction, or anismus. These abnormalities result in an inability to relax the rectal and anal muscles that allow stool to exit. 1

People may become constipation if they start eating fewer vegetables, fruits, and whole grains. These foods are all high in fiber, and, according to some studies, high fiber diets can help prevent constipation. Eating more high fat meats, dairy products, and eggs can be another cause of constipation. So can eating more rich desserts and other sweets high in refined sugars.

People who live alone may lose interest in cooking and eating. As a result they start using a lot of convenience foods. These tend to be low in fiber, so they may help cause constipation. In addition, bad teeth may cause older people to choose soft, processed foods that contain little, if any, fiber. 2

Lack of exercise or lengthy bedrest, such as after an accident or illness, may cause constipation. For people who stay in bed and who suffer from chronic constipation, medications may be the best solution. But simply being more active, when possible, is best.

If people ignore the natural urge to have a bowel movement, they may become constipated. Some people prefer to have their bowel movements only at home, but holding a bowel movement can cause ill effects if the delay is too long. 2

Underlying condition causes of Constipation: The list of possible underlying conditions (see also Misdiagnosis of underlying causes of Constipation) mentioned in various sources as possible causes of Constipation includes:

Constipation as a complication: Other conditions that might have Constipation as a complication might be potential underlying causes of Constipation. The list of conditions listing Constipation as a complication in our database includes:

Constipation as a symptom: Conditions listing Constipation as a symptom may also be potential underlying causes of Constipation. The list of conditions listing Constipation as a symptom in our database includes:

Causes of Constipation: medical news summaries: The following medical news items are relevant to causes of Constipation:

Related information for causes of Constipation: Further relevant information on causes of Constipation may be found in the risk factors for Constipation and underlying causes of Constipation.

1. excerpt from Constipation: NIDDK
2. excerpt from Constipation - Age Page - Health Information: NIA

Last revision: Nov 10, 2003

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