Normal bowel movement color can be any shade of brown, ranging from tan and yellowish-brown to darker shades of brown. There can be temporary changes in the stool color after consuming certain foods with strong pigments but it may only last for a day or two at most. When there is an abnormality in the stool color, especially if it persists or is accompanied by other symptoms like diarrhea or abdominal pain, then it needs to be investigated further.
In order to understand why stool may appear pale to gray or even white in color, it is important to first understand why stool has a characteristic brown color. This is mainly due to a substance known as bilirubin. It is a substances that is constantly produced in the liver as a result of the breakdown of red blood cells. It is an ongoing cycle as red blood cells are constantly being removed from circulation and replaced by new red blood cells.
This bilirubin is then passed out of the liver with bile. It is stored in the gallbladder and eventually released into the gut at the point of the duodenum (the first part of the small intestine). The bilirubin is converted into a substance known as stercobilin within the gut by the normal intestinal flora (“good bowel bacteria”). It is this stercobilin that is responsible for the brown color of stool.
Causes of White Bowel Movement
When less than normal or no bile is excreted from the liver into the bowel (cholestasis), excreted stool will be pale, clay, gray, or white. Someone can describe it as a light color, but this is not bright yellow bowel movement, and also not mucus in the bowel movement that is jelly-like and translucent. Main causes of white bowel movement are:
- Obstruction of the biliary duct (due to gallstones, inflammation, fibrosis, cancer, pressure from outside (pancreatic cancer or cyst, abdominal tumor like fibroma) may cause cramping pain in the right upper abdomen.
- Obstruction of the outflow of the bile from the liver due to a liver disease (viral hepatitis, fatty liver, alcohol liver disease, cirrhosis, hemochromatosis or, rarely, tuberculosis, spread of cancer into the liver (liver metastases) may cause fullness or pain in the upper right abdomen, jaundice, nausea, or vomiting.
It is important to note that when bile outflow is hampered (cholestasis) then the bilirubin builds up in the bloodstream. The bilirubin is then deposited in various tissues and is most noticeable in the skin, whites or the eyes and inner lining of the mouth, all of which are stained a yellow color. This is known as jaundice and this type of jaundice is known as cholestatic or obstructive jaundice.
Another common symptoms that also arises with the pale to white stools in these cases is dark urine. It arises due to the excess bilirubin in the bloodstream, which cannot be passed out with bile. Similar to the bilirubin that is converted to stercobilin in the bowels, bilirubin is converted to urobilin in the kidneys. This urobilin in large quantities can cause the urine to become darker in color.
Above reasons (obstruction of the bile flow), or lack of pancreatic enzyme lipase that digests fats prevents fat absorption in the small intestine. Unabsorbed fats will reach the colon and irritate it, causing diarrhea. Loose, white, sticky, greasy, foamy, floating, smelly stool appearing several hours after a fatty meal is called steatorrhea. Main causes of white diarrhea are:
- Acute or chronic pancreatitis (low appetite, pain in the middle or left upper abdomen, nausea)
- Pancreatic cancer (low appetite, weight loss).
- Liver or biliary duct disease
- Infections of the bowel such as cholera which causes a characteristic white ‘rice water’ stool.
- Severe inflammation of small intestine (Crohn’s disease, celiac disease, tuberculosis, severe food poisoning).
- Candida overgrowth in the large intestine (in persons with lowered immunity, like in AIDS or after a chemotherapy).
Magnesium-containing medication, like antacids, can also have a laxative effect and cause diarrhea. Magnesium hydroxide is used in many antacids and is also the main component of a widely used compound known as milk of magnesia. It may sometimes lead to white diarrhea when overused, particularly if used in combination with large quantities of calcium.
Other Causes of White Stool
White stool may appear after:
- Barium enema, a diagnostic procedure where a fluid is used to make the bowel more visible on x-ray.
- Antacids, especially overuse of antacids containing calcium.
- Supplementation with excessively high doses, particularly of calcium.
White Specks in the Stool
White specs in the stool may represent:
- Undigested food, like rice or seeds.
- Unabsorbed drugs or supplements.
- Parasite eggs in very large quantities (uncommon).
- Clumps of fungi (Candida albicans) when extreme overgrowth occurs in disease like AIDS, or in immunosuppression from chemotherapy or radiation therapy.
Stool analysis involves collecting a stool sample and sending it to a laboratory for further testing. One of the important findings that needs to be noted is the presence of fats in the stool. Since there is little to no bile to emulsify the fats to allow the digestive enzymes to break it down further, the undigested fat will be found in the stool. This may also cause steatorrhea where the stool is greasy.
- White blood cells are elevated in pancreatitis, bowel inflammation
- Pancreatic enzymes (lipase) in the blood may be elevated in pancreatic disease
- Liver enzymes in the blood may be elevated in liver, biliary duct disease
- Bilirubin levels in the blood may be elevated since this bilirubin is not being passed out with bile.
Ultrasound of the abdomen may reveal gallstones in gallbladder, or rarely in biliary duct, swollen pancreas (in pancreatitis, pancreatic cancer or cyst), or abdominal tumor.
Pale to white bowel movement is only a symptom of an underlying condition. Treatment has to be directed at the causative condition in order for the stool color to return to normal. The choice of treatment is therefore dependent on the final diagnosis. This may involve a combination of medication, surgery and dietary changes such as a low fat diet. Always consult with a medical professional about the treatment and management of pale bowel movement or white diarrhea.