To understand the common causes of constipation, it helps to know how the colon (large intestine) works. As food moves through it, the colon absorbs water while forming waste products, or faeces. Muscle contractions in the colon push the stool toward the rectum. By the time stool reaches the rectum, it is solid because most of the water has been absorbed. The hard and dry stools of constipation occur when the colon absorbs too much water. This happens because the colon’s muscle contractions are slow or sluggish, causing the stool to move through the colon too slowly.
The most common cause of constipation is a diet low in fibre found in vegetables, fruits, and whole grains and high in fats found in cheese, eggs, and meats. People who eat plenty of high-fibre foods are less likely to become constipated. Fibre – soluble and insoluble – is the part of fruits, vegetables, and grains that the body cannot digest. Soluble fibre dissolves easily in water and takes on a soft, gel-like texture in the intestines. Insoluble fibre passes almost unchanged through the intestines. The bulk and soft texture of fibre help prevent hard, dry stools that are difficult to pass. A low-fibre diet also plays a key role in constipation among older adults. They often lack interest in eating and may choose fast foods low in fibre. In addition, loss of teeth may force older people to eat soft foods that are processed and low in fibre.
Liquids like water, preferably filtered or bottled 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, have a dehydrating effect and should be avoided.
Lack of exercise can lead to constipation. For example, constipation often occurs after an accident or during an illness when one must stay in bed and cannot exercise.
Pain medications, antacids that contain aluminium, antispasmodics, anti-depressants, iron supplements, diuretics, and anticonvulsants for epilepsy can slow passage of bowel movements.
Some people with IBS have spasms in the colon that affect bowel movements. Constipation and diarrhoea often alternate, and abdominal cramping, flatulence and bloating are other common complaints. Although IBS can produce lifelong symptoms, it is not a life-threatening condition. It often worsens with stress.
During pregnancy women may be constipated because of hormonal changes or because the heavy uterus compresses the intestine. Ageing may also affect bowel regularity because a slower metabolism results in less intestinal activity and muscle tone. In addition, people often become constipated when travelling because of their normal diet and daily routines are disrupted.
Longterm use of laxatives is not usually 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.
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.
Bibliography: Murray M, Pizzorno P Encylopedia of Natural Medicine. Prima Health 2nd Edition 1998 Balch J Balch P Prescription for Nutritional Healing. Avery 2nd Edition 1997 Golan R. Optimal Wellness. Ballantine Books 1995