A diagnosis of constipation is based, in part, on a defecation frequency of fewer than three bowel movements per week. Other symptoms may include the passage of hard stools and excessive straining during defecation. In some cases, a person’s perception of constipation may be due to a mistaken notion of what constitutes “normal” bowel habits, so the person’s expectations about bowel function may need to be addressed. Constipation is particularly prevalent among women and all adults over 70 years of age
Causes of Constipation
The risk of constipation is increased in individuals with a low-fiber diet, low food intake, inadequate fluid intake, or low level of physical activity. All of these factors can extend transit time, leading to increased water reabsorption within the colon and dry, hard stools that are difficult to pass. Medical conditions often associated with constipation include diabetes mellitus and hypothyroidism. Neurological conditions such as Parkinson’s disease, spinal cord lesions, and multiple sclerosis may cause motor problems that lead to constipation. During pregnancy, women often experience constipation because of the enlarged uterus presses against the rectum and colon. Constipation is also a common side effect of several classes of medications and some dietary supplements, including opiate-containing analgesics, tricyclic antidepressants, diuretics, calcium channel blockers, beta-blockers, and iron and calcium supplements.
Treatment of Constipation
In individuals with low fiber intake, the primary treatment for constipation is a gradual increase in fiber intake to at least 25 grams per day. High-fiber diets increase stool weight and fecal water content and promote a more rapid transit of materials through the colon. Foods that increase stool weight the most include wheat bran, fruits, and vegetables.
Bran intake can be increased by adding bran cereals and whole-wheat bread to the diet or by mixing bran powder with beverages or foods. The transition to a high-fiber diet may be difficult for some people because it can increase intestinal gas, so high-fiber foods should be added gradually, as tolerated.
Fiber supplements like methylcellulose (Citrucel), psyllium (Metamucil, Fiberall), and polycarbophil (Fiber-Lax) are also effective; these supplements can be mixed with beverages and taken several times daily. Unlike other fibers, methylcellulose and polycarbophil do not increase intestinal gas.
Several other dietary measures may also help to relieve constipation. Consuming adequate fluid (usually 1.5 to 2 liters daily) can help to increase stool frequency in people who are already consuming a high fiber diet.
An appropriate fluid intake prevents excessive reabsorption of water from the colon, resulting in wetter stools. Adding prunes or prune juice to the diet is often recommended because prunes contain compounds that have a mild laxative effect.