It is necessary to know how the colon or large intestine works in order to understand the causes of constipation.

The food we eat is digested in the small intestine or ileum. The water content of the food is however absorbed in the next segment of the gastrointestinal tract, the large intestine or colon. Stools, the waste product, are the byproduct of this absorption process.

The peristaltic movements or muscular contractions in the large intestine, about which we mentioned at the beginning of the article, push the stool towards the rectum, the terminal part of the digestive tract that holds the waste before eliminating it though the anus. By the time the stool reaches the rectum it loses most of its water content and is more or less solidified.

Constipation is caused by dry stools

Constipation occurs either if the colon absorbs an excess amount of water or if it has peristaltic contractions or bowel movements that are too slow to move the waste to the rectum. As a result, the hard and dry stool stays in the rectum for a long time, and is expelled only when the rectum cannot hold it any longer.

Why does this happen? One possible reason could be low physical activity on account of a sedentary life-style. Another reason for slow bowel movements could also be ageing.

Causes of constipation

Some of the most common causes of constipation are a low-fiber-high-fat diet and reduced physical activity, especially in old age.

Fiber is the indigestible component of food present primarily in vegetables, fruits, and grains. Meat, eggs and dairy products, which are low in fiber, can cause constipation easily in large numbers of people. However, in quiet a few cases dairy products have also been found to trigger attacks of diarrhea.

Inadequate consumption of liquids

Another cause of constipation is inadequate consumption of liquids.

Some other causes of constipation include changes in routine or life-style, as is the case while traveling and during pregnancy respectively, ageing, irritable bowel syndrome, as well as pathology of the rectum, the large or the small intestines. Pathology is the state of bodily changes that occur during a disease.

Several medicines, such as pain relievers, especially those that have a narcotic base, blood pressure medications, antacids that contain aluminum and calcium, antispasmodics, anti-Parkinson drugs, anti-depressants, iron supplements, diuretics, anticonvulsants, etc. may also cause constipation.

Laxatives may cause problems

While laxatives are usually considered the most used cure for constipation, the laxatives themselves can cause constipation, when used over a long period of time.

This happens because laxatives are basically habit-forming and become ineffective when taken over long periods of time, as the body gets used to their mode of functioning.

Besides, a number of pathological conditions can cause constipation. These include neurological, 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.