After digestion and absorption are complete, waste products make their way through the large intestine to be excreted from the body. Fluid continues to be absorbed from this waste matter through the length of the organ. When too much fluid is reabsorbed, the stools become hard and dry. This causes difficult bowel movements, known as constipation. When too much fluid remains in the stools, the output is more frequent and watery, referred to as diarrhea.
Food and Fluid Intake
Ingesting adequate fiber and water keeps bowel movements regular. A low intake of fiber or water can lead to constipation with hard, dry stools that are difficult to evacuate. Conversely, a high fiber intake may cause diarrhea, especially until a person adjusts to the change in diet. Sorbitol is an artificial sweetener found in some sugar-free candies and has a laxative effect. Milk contains a unique sugar called lactose. People who have lactose intolerance experience diarrhea after ingesting dairy products.
Exercise and Activity Level
According to the National Digestive Diseases Information Clearinghouse, lack of exercise can lead to constipation, especially in older people. Patients who are immobilized or require bed rest may also experience constipation.
Medications
Laxatives work to increase water content of the stools, making passage easier and more comfortable for the person who is constipated. People who abuse laxatives can become dependent on them and end up with chronic constipation. Some medications have a side effect of making stools loose, leading to diarrhea. Others, like pain medications, can slow the contractions along the intestine, increasing water absorption and leading to dry stools. Antibiotics can alter the natural flora of the intestine and result in diarrhea. Sorbitol is present in some liquid medications and can act as a laxative.
Infectious Diarrhea
The North Dakota Department of Health notes that infectious bacteria can be transmitted through contaminated food, contaminated water or unwashed hands. The Mayo Clinic lists salmonella, shigella, campylobacter and Escherichia coli as the more common bacterial causes of diarrhea, and names rotavirus as the most common culprit of acute diarrhea in childhood. Giardia, a parasite found in contaminated water sources, is another cause of diarrhea. Traveler's diarrhea is caused by the E. coli bacteria. It occurs most often in countries without a sanitary water supply.
Chronic Diseases
According to Harvard Health Publications, about 24 million Americans suffer from irritable bowel syndrome, described as recurring bouts of constipation, diarrhea or both. Symptoms can worsen with stress. Jackson Siegelbaum Gastroenterology, a practice in Camp Hill, Pennsylvania, attributes other cases of diarrhea to chronic diseases such as ulcerative colitis, Crohn's disease and diverticulosis.
References
- National Digestive Diseases Information Clearinghouse: What I need to know about Diarrhea
- Mayo Clinic: Diarrhea: Causes
- National Digestive Diseases Information Clearinghouse: Constipation
- North Dakota Department of Health, Division of Disease Control: Diarrhea: What Do I Need to Know?
- Jackson Siegelbaum Gastroenterology: Diarrhea
