Most believe that passing stool or having a bowel movement is simply the body's way of removing waste while allowing you to catch up on some reading. However, the quantity and quality of stool produced can be quite informative as it is a potent indicator of your overall health. The gastrointestinal (GI) tract is a processing unit that metabolizes all of the nutrients you take in and eliminates all of the body's waste," explains Dr. Amy Foxx-Orenstein, former president of the American College of Gastroenterology in an article by MSN Health. "What comes through is reflective of how well or how ill the body is." In particular, the color of stool may serve as an obvious gauge of health. Although changes in color can be commonplace and generally insignificant, persistent color change may suggest an underlying health issue.
Normal Stool Color
The color of stool may vary between individuals, but it is typically a shade of brown due to its bilirubin content. Bilirubin is a by-product of hemoglobin degradation in the liver and is secreted into bile. As the bile travels through the intestine, bilirubin undergoes a series of chemical modifications that result in stool that is light to dark brown. The color of stool may be affected by diet or medications, however, these changes are usually not consistent between bowel movements. Chronic changes in the color of stool may indicate medical problems.
Changes in Stool Color
Certain stool colors can signify health problems. These include:
Red or maroon stool: referred to as hematochezia and may indicate gastrointestinal bleeding that originates from the colon. Red colored stool may also be a result of ingesting certain foods such as beets, rhubarb, radishes and turnips. Red food dyes and food coloring may also cause your stool to become red.
Black stool: may indicate bleeding in the stomach or the upper part of the small intestine. Black stool that results from a gastrointestinal bleeding is often associated with a tarry texture and foul odor. Iron pills or certain medications, like Pepto Bismol, may also cause black stool.
Chalky, white or clay-colored stool: may indicate the absence of bile from the stool as a result of an obstruction of bile flow to the intestine. Obstruction of the bile duct may occur as a result of a medical condition called biliary obstruction or a tumor. This stool may look like a pale yellow, or off white.
Pale and yellow stool: may indicate the presence of undigested fat in the stool. Such conditions as pancreatitis (inflammation of the pancreas) or pancreatic cancer can prohibit the absorption of fats by the body, resulting in fat-laden and pale stool. This type of stool often has a greasy texture and foul smell.
Green stool: may indicate that food is traveling through the long intestine too quickly and therefore not allowing bile to break down completely. Vegetables such as spinach or lettuce, or green dyes (found in both food and drinks) may also turn your stool green.
Symptoms Associated with Changes in Stool Color
Changes in stool color maybe asymptomatic or produce an array of symptoms, which usually correspond to the underlying medical cause.
Red, maroon or black, tarry stools that are caused by bleeding from the gastrointestinal tract (esophagus, stomach, small intestine, large intestine) may have the accompanying symptoms:
- Abdominal pain
- Nausea or vomiting of blood
- Diarrhea and cramping
- Weakness, lightheadedness, and dizziness
Persistent white or clay-colored stool is often caused by an obstruction of bile flow. Obstruction caused by gallstones may cause pain on the right side of the abdomen. However, an obstruction caused by cancer of the bile duct or cancer of the head of pancreas does not present any overt symptoms unless the tumor is large.
The most common symptoms associated with yellow stool is abdominal pain caused by chronic pancreatitis, tumor of the pancreas, or obstruction of the pancreatic duct.
To discern the underlying medical condition causing the change in stool color, a doctor will initially perform a thorough physical exam and medical history. Additionally a doctor may order the following blood tests:
- Complete blood count (CBC)
- Comprehensive metabolic panel
- Blood clotting
- Pancreatic enzymes
These tests can show the presence of anemia, liver disease, gallbladder disease, or other underlying conditions that may be responsible for the changes in stool color.
Doctors may also utilize the following endoscopic methods to evaluated the underlying cause for the change in stool color:
- Esophagogastroduodenoscopy: a procedure that visualizes the upper part of the gastrointestinal tract.
- Colonoscopy: a procedure that visualizes the colon and the distal part of the small bowel.
- Endoscopic Retrograde Cholangiopancreatography: a procedure that combines endoscopic and fluoroscopic methods to diagnose problems of the biliary or pancreatic ductal systems. The endoscope is utilized to visualize the stomach and duodenum, while a dye is injected into the duct in the biliary tree and pancreas so they can be seen on x-rays.
Treatments may vary depending upon your particular stool color and other symptoms. Consult your physician if you have any questions or concerns about a recent, abnormal change in stool color.