Bloating and fatty stool -- stools that are foul-smelling, greasy and usually rather large in volume -- are common digestive symptoms that usually indicate some type of malabsorption. The Merck Manual defines malabsorption as the inadequate absorption of nutrients due to problems with digestion, absorption or transport. While everyone may experience bloating and fatty stools occasionally, some people experience these symptoms as a result of a chronic condition.
Lactose intolerance is a malabsorption disorder characterized by an inability to digest lactose, the primary sugar in milk and milk products. Normally, the small intestine produces an enzyme called lactase that breaks down lactose. In people with lactose intolerance, the ability to produce lactase is decreased or nonexistent. As a result, lactose moves through the digestive system undigested. This results in digestive symptoms such as bloating, fatty stool, nausea, abdominal cramps, gas and diarrhea. Although lactose intolerance can be uncomfortable, it generally does not result in serious health complications.
Celiac disease is a digestive condition characterized by malabsorption as well as intestinal damage. In those with celiac disease, the immune system reacts abnormally to the presence of gluten, a protein found in barley, rye and wheat. When exposed to gluten, the immune system sends out antibodies in an attempt to attack the gluten. These antibodies damage structures in the small intestine called villi. When the villi are damaged, your body cannot absorb nutrients properly. Bloating and fatty stool are common symptoms of celiac disease. Other symptoms include diarrhea, vomiting, constipation, weight loss, fatigue, joint pain, numbness and tingling in the extremities and canker sores. The only way to manage celiac disease is to avoid gluten permanently.
In some cases, bloating and fatty stool can indicate a more serious underlying medical condition, such as cystic fibrosis. In people with cystic fibrosis, defective genes cause the mucus-producing cells to produce thick, sticky mucus, rather than thin, slippery mucus. Instead of lubricating body structures like it was meant to, this mucus causes blockages in the digestive and respiratory systems.
The thick mucus blocks the digestive tubes that carry pancreatic enzymes, which help digest fat, to your small intestine. When these enzymes cannot enter the small intestine, proper digestion cannot take place and nutrients are lost through your stool. This results in fatty, greasy stools, a bloated abdomen and poor growth in children.
Everyone experiences abdominal bloating and may even notice fatty stools at some point in their lives. If these symptoms occur regularly, however, contact your doctor to isolate the underlying cause. Although most conditions that cause bloating and fatty stool are not life-threatening and can be controlled with the proper diet, some conditions may require regular medical care.