We may not give the color of our stool much thought until it becomes an unusual hue but normal human stool varies between a light to dark brown color. Sometimes there may be tinges of black, blue and even green but this usually not abnormal and often related to a heavily colored food that we ate earlier. However, when stool is overtly one color and persists for more than one or two bowel movements then it needs to be medically assessed. Yellow bowel movement is such an instance.
Yellow Color of Stool
Sometimes stool has a slight yellow tinge but it is more towards a brown color. A yellowish color of stool may occur for a number of different reasons – some are acute and quickly pass on its own while other conditions can cause persistent yellow stool. Usually a yellowish tinge is due to the presence of certain byproducts of red blood cell breakdown. This yellowish pigment known as stercobilin is broken down by bacteria in the gut so that by the time stool is passed out it appears brown.
Causes of Yellow Bowel Movement
There are several diseases where yellow bowel movement may be a symptom. Some are minor acute illnesses that quickly resolve on its own. However, there are certain diseases that cause yellow stool which are very serious and can be life-threatening. The yellow stool is only a symptom and not a disease on its own. It often occurs along with other symptoms. It is therefore important that the exact cause of the yellowing of the stool is identified through diagnostic investigations.
Any causes of diarrhea can hamper the normal bowel bacteria from breaking down the bile products that are yellow in color. In diarrhea the food and other intestinal contents move rapidly through the gut. This reduces the exposure time for bowel bacteria to act on the bilirubin secreted with bile. As a result the yellow color of bilirubin is largely unaffected and stains the stool yellow. People suffering with irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), celiac disease and other conditions where diarrhea is a common symptom may therefore suffer with yellow bowel movements more often.
Cholestasis is the medical term for an obstruction to bile flow. The liver produces bile which contains water, bilirubin, cholesterol, metabolic byproducts and wastes. The bile is then passed out into the gut where it is eventually expelled with stool. It also helps with emulsifying fats in food. With cholestasis the body cannot expel bile. As a result bilirubin builds up in the body.
This is seen as a yellowing of the skin, whites of the eyes and even the inside of the mouth and is known as jaundice. The bilirubin deposition in the skin causes itching. The urine becomes dark and stool becomes lighter in color – a pale to clay-colored hue. The cause of cholestasis can originate from the liver, the bile ducts or gallbladder or from the pancreas.
1. Neonatal Jaundice
Jaundice is a common occurrence in newborns. Once the baby is born, his/her liver has to take over the removal of bilirubin in the blood. This can take a period of time to start functioning optimally. It usually lasts for a few days to about 2 weeks. However, some babies have jaundice for longer due to breastfeeding. This is not considered abnormal provided that the bilirubin levels in the blood remain within a certain range.
There are some less common instances where the body breaks down red blood cells too rapidly, bile cannot be expelled or the liver is not able to function as it should and jaundice persists. Apart from jaundice the baby’s stool may also be pale to clay-colored. It is important to remember that babies may have a slightly yellower stool for a short period of time after birth even when there are no problems.
2. Liver Disease
Among its many functions, the liver filters the blood and breaks down some toxic products into harmless substances as well as removing other toxins. If this filtering is disrupted the bilirubin may accumulate in the body. Yellow stool due to liver disease may occur with:
- Hepatitis (alcoholic or viral)
- Hepatocellular carcinoma (liver cancer)
There may be other diseases like tuberculosis and sarcoidosis which can also affect the liver and need to be considered.
3. Gallbladder Disease
The bile from the liver is passed into the gallbladder where it is stored until the time comes for it to be released into the gut. The bile ducts funnel bile between the liver, gallbladder and duodenum (first part of the small intestine). Gallbadder diseases which may result in yellow stool includes:
- Cholecystitis (gallbladder inflammation) or cholangitis (bile duct inflammation) usually from an infection.
- Gallbladder or bile duct cancer
Among adults, gallbladder disease and particularly gallstones is one of the more common causes.
4. Pancreatic Disease
The pancreas shares the common bile duct with the gallbladder.Although the pancreas does not play any direct role in bile formation and expulsion its location means that certain pancreatic conditions can affect the bile duct by pressing on it and occluding the duct. As a result bile outflow is impeded. It may occur with:
- Pancreatic pseudocyst
5. Bile Duct Compression
The abdominal organs lie very close together in an enclosed space (the abdominal cavity). A number of different diseases particularly where there is organ enlargement or a growth can cause compression of the bile duct. This includes absesses, cysts, tumors (particularly large benign masses) and so on.
Foods and Drinks
It is not common for colorants in foods and drinks to reach all the way to the colon unaffected and then color the stool. However, it can happen especially when there is rapid gastrointestinal transit time. This means that the intestinal contents move too quickly through the digestive tract, as is seen with diarrhea. Therefore the colorants may be unaffected by the digestive process and retain its original color. As a result the stool may be tinged with any yellow colorant depending on the food and drink consumed.