November 01, 2020

Could a bile acid problem be causing my on-going, hard to treat diarrhea?

Q: My doctor recently said that a problem with my bile acid could explain my chronic diarrhea. What is bile acid diarrhea, and what does treatment look like?

A: About one-quarter to one-third of people with unexplained, chronic diarrhea have bile acid diarrhea (BAD). It can sometimes be overlooked as a diagnosis, and recognizing it can markedly reduce your need for health care visits and expense — in addition to discomfort and inconvenience — that occur when dealing with chronic diarrhea.

Bile acids, which are produced in your liver, help digest fat. These acids are stored in your gallbladder and are released into the small intestine after eating a meal. Most of these bile acids are eventually reabsorbed by the last portion of the small intestine, returned to the liver and used again.

However, if there is a problem with reabsorption — or if the liver produces too much bile acid — the acids spill into the colon and can cause urgent, watery stools. Conditions such as Crohn's disease and celiac disease, as well as removal of the gallbladder, can result in BAD. Sometimes the cause is unknown.

In the U.S., the best way to diagnose BAD is a fecal bile acid test, which requires you to eat a high-fat diet for four days and collect your stool for 48 hours. However, a recent study by Mayo Clinic researchers validated a fasting blood sample and a single stool sample — used in combination — as a way to screen for BAD.

BAD is usually treated with drugs known as bile acid sequestrants, such as cholestyramine (Prevalite), colestipol (Colestid) and colesevelam (Welchol). Unfortunately, these can cause bothersome side effects such as bloating, constipation and flatulence —...