Bile Acid Malabsorption: Malabsorption Explained

Bile Acid Malabsorption (BAM) is a condition that occurs when your intestines can't absorb bile acids properly. This results in excess bile acids in your intestines, which can lead to diarrhea and abdominal pain. BAM is also known as Bile Acid Diarrhea (BAD). Although it's not as well known as other conditions that can cause these symptoms, it's estimated that up to 1 in 100 people could have BAM.

BAM can be a difficult condition to live with. The symptoms can be uncomfortable, and they can also be unpredictable. They can affect your ability to carry out everyday activities, and they can also affect your self-confidence and your emotional wellbeing. But with the right treatment and care, it's possible to manage the symptoms and to live a healthy, active life.

Understanding Bile Acids

Bile acids are a type of steroid acid found predominantly in the bile of mammals. Bile acids serve two critical functions in the body: they aid in the digestion of dietary fats and oils, and they help eliminate excess cholesterol from the body. When functioning correctly, bile acids are reabsorbed in the ileum, the final section of the small intestine, and recycled by the liver.

However, in people with BAM, this process doesn't work as it should. Instead of being reabsorbed, the bile acids remain in the intestines. This can irritate the lining of the intestines, leading to symptoms such as diarrhea and abdominal pain.

Types of Bile Acids

There are two primary types of bile acids: primary and secondary. Primary bile acids are produced by the liver and include cholic acid and chenodeoxycholic acid. Secondary bile acids result from bacterial actions in the colon and include deoxycholic acid and lithocholic acid.

Both primary and secondary bile acids play a crucial role in digestion and the regulation of cholesterol. However, when these acids are not properly absorbed, they can lead to the symptoms associated with BAM.

Causes of Bile Acid Malabsorption

BAM can be caused by several different factors. In some cases, it's due to a problem with the ileum. This could be because of damage to the ileum, such as from surgery or disease, or because the ileum is overloaded with bile acids. In other cases, BAM is caused by an overproduction of bile acids by the liver.

There are three types of BAM, known as Type 1, Type 2, and Type 3. Type 1 is associated with ileal dysfunction due to diseases such as Crohn's disease or following ileal resection. Type 2, also known as idiopathic BAM, is not associated with any other underlying condition and its cause is unknown. Type 3 BAM is associated with various conditions that can secondarily affect the enterohepatic circulation, such as cholecystectomy (gallbladder removal) and coeliac disease.

Role of the Ileum

The ileum plays a crucial role in the absorption of bile acids. It contains cells that are specifically designed to absorb these acids and return them to the liver. However, when the ileum is damaged or removed, this process can't occur as it should, leading to BAM.

Conditions such as Crohn's disease, which can cause inflammation and damage to the ileum, can therefore lead to BAM. Similarly, surgical removal of the ileum, which may be necessary in some cases of severe intestinal disease, can also result in BAM.

Overproduction of Bile Acids

In some cases, BAM is caused by an overproduction of bile acids by the liver. This can occur for several reasons, including liver disease and certain genetic conditions. When the liver produces too many bile acids, the ileum can become overloaded and unable to absorb them all, leading to BAM.

It's also possible for BAM to occur without an obvious cause. This is known as idiopathic BAM, and it's thought to be the most common type of BAM. It's not clear why this happens, but it's possible that it's due to a problem with the way the bile acids are transported in the intestines.

Symptoms of Bile Acid Malabsorption

The primary symptom of BAM is diarrhea. This can range from mild to severe, and it can be chronic (long-term) or intermittent. Other symptoms can include abdominal pain, bloating, and an urgent need to go to the toilet. Some people with BAM may also experience weight loss and fatigue.

These symptoms can have a significant impact on a person's quality of life. They can make it difficult to carry out everyday activities, and they can also lead to feelings of embarrassment or anxiety. However, with the right treatment, it's possible to manage these symptoms and reduce their impact.

Diarrhea

Diarrhea is the most common symptom of BAM. This is because the excess bile acids in the intestines can irritate the lining of the intestines, causing water and electrolytes to be secreted into the intestines. This results in loose, watery stools.

The diarrhea caused by BAM can be severe, and it can also be unpredictable. Some people with BAM may have episodes of diarrhea several times a day, while others may have episodes less frequently. The unpredictability of the diarrhea can make it difficult to manage, and it can also lead to feelings of anxiety and embarrassment.

Abdominal Pain and Bloating

Many people with BAM also experience abdominal pain and bloating. The pain is usually located in the lower right part of the abdomen, but it can also be felt throughout the abdomen. The pain can range from mild to severe, and it can be constant or intermittent.

The bloating associated with BAM is due to the excess bile acids in the intestines. These acids can cause gas to be produced, leading to bloating and discomfort. The bloating can be worse after eating, especially after meals that are high in fat.

Diagnosis of Bile Acid Malabsorption

Diagnosing BAM can be challenging, as its symptoms are similar to those of other conditions, such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). However, there are several tests that can be used to diagnose BAM, including the SeHCAT test, the C4 test, and the FGF19 test.

These tests all work in different ways, but they all aim to measure the amount of bile acids in the body. If the tests show that there are too many bile acids, this can indicate that BAM is the cause of the symptoms.

SeHCAT Test

The SeHCAT (Selenium Homocholic Acid Taurine) test is considered the gold standard for diagnosing BAM. This test involves swallowing a capsule that contains a small amount of a radioactive substance. This substance is similar to a bile acid, and it's absorbed in the same way as bile acids. After a week, a scan is done to see how much of the substance is left in the body. If a lot of the substance has been lost, this can indicate that BAM is the cause of the symptoms.

While the SeHCAT test is highly accurate, it's not widely available. It's also relatively expensive, and it involves exposure to a small amount of radiation. Because of these factors, other tests are often used instead.

C4 Test

The C4 (7 alpha-hydroxy-4-cholesten-3-one) test is a blood test that can be used to diagnose BAM. This test measures the level of a substance called C4 in the blood. C4 is a precursor to bile acids, and its level in the blood can indicate how much bile acid is being produced by the liver.

If the level of C4 in the blood is high, this can indicate that the liver is producing too much bile acid. This can suggest that BAM is the cause of the symptoms. The C4 test is less accurate than the SeHCAT test, but it's more widely available and it doesn't involve exposure to radiation.

Treatment of Bile Acid Malabsorption

The treatment for BAM usually involves medication to reduce the amount of bile acids in the intestines. This can help to reduce the symptoms of BAM, such as diarrhea and abdominal pain. The most commonly used medication for BAM is a type of drug called a bile acid sequestrant.

In addition to medication, some people with BAM may find it helpful to make changes to their diet. This can include reducing the amount of fat in the diet, as fat can increase the amount of bile acids in the intestines. However, it's important to ensure that the diet still provides all the necessary nutrients, so dietary changes should be made under the guidance of a dietitian or other healthcare professional.

Bile Acid Sequestrants

Bile acid sequestrants are a type of medication that can be used to treat BAM. These drugs work by binding to bile acids in the intestines, preventing them from being reabsorbed. This reduces the amount of bile acids in the intestines, which can help to reduce the symptoms of BAM.

There are several different types of bile acid sequestrants, including cholestyramine, colestipol, and colesevelam. These drugs are usually taken as a powder that is mixed with water or food. They can cause side effects such as bloating and constipation, but these are usually mild and can be managed with adjustments to the dose or the timing of the medication.

Dietary Changes

Some people with BAM may find it helpful to make changes to their diet. This can include reducing the amount of fat in the diet, as fat can increase the amount of bile acids in the intestines. However, it's important to ensure that the diet still provides all the necessary nutrients, so dietary changes should be made under the guidance of a dietitian or other healthcare professional.

It may also be helpful to eat smaller, more frequent meals, rather than three large meals a day. This can help to reduce the amount of bile acids in the intestines at any one time, which can help to reduce the symptoms of BAM. Drinking plenty of fluids can also help to prevent dehydration, which can be a risk with chronic diarrhea.

Living with Bile Acid Malabsorption

Living with BAM can be challenging, but with the right treatment and care, it's possible to manage the symptoms and to live a healthy, active life. This can involve taking medication, making changes to the diet, and getting regular check-ups with a healthcare professional.

It's also important to take care of mental health when living with BAM. The symptoms can be uncomfortable and unpredictable, and they can also affect self-confidence and emotional wellbeing. Support from family, friends, and support groups can be very helpful, as can talking to a healthcare professional about any concerns or worries.

Managing Symptoms

Managing the symptoms of BAM can involve a combination of medication, dietary changes, and lifestyle adjustments. The goal is to reduce the amount of bile acids in the intestines, which can help to reduce the symptoms of BAM. This can involve taking medication, making changes to the diet, and getting regular check-ups with a healthcare professional.

It's also important to manage stress, as stress can worsen the symptoms of BAM. This can involve techniques such as relaxation exercises, mindfulness, and cognitive behavioral therapy. Regular exercise can also help to reduce stress and improve overall wellbeing.

Emotional Support

Living with BAM can be emotionally challenging. The symptoms can be uncomfortable and unpredictable, and they can also affect self-confidence and emotional wellbeing. It's important to seek support if you're finding it difficult to cope with the emotional impact of BAM.

Support can come from many different sources, including family, friends, support groups, and healthcare professionals. Talking to others who are going through the same experiences can be very helpful, as can talking to a healthcare professional about any concerns or worries. There are also many resources available online, including forums and websites, that can provide information and support.