Bile acid diarrhea (BAD), also known as bile acid malabsorption (BAM), is a prevalent cause of chronic diarrhea. This condition arises when bile salts, which normally aid in the digestion of fats, are not effectively reabsorbed in the small intestine for reuse but instead move into the large intestine. Consequently, this leads to a substantial influx of water and salts into the bowel, resulting in watery diarrhea.
Types of Bile Acid Diarrhea Causes
| Type 1 | Examples |
| Terminal ileitis (e.g., Crohn’s disease) | |
| Following resection of terminal ileum (Crohn’s Surgery) | |
| Type 2 | No definable underlying cause or abnormality |
| (this would apply to chronic diarrhea in those that respond to the medication- bile acid sequestrants) | |
| Type 3 | Post gallbladder removal |
| Post vagotomy | |
| Celiac disease |
Bile Acid Malabsorption in IBD
BAD occurs in 40% of cases of Crohn’s disease – this is because the ileum plays an important role in bile acid reabsorption.
When it is resected or inflammation occurs in the ileum, bile acid malabsorption can occur causing diarrhea, fat malabsorption, and floating stool.
Also, 35% of individuals suffering from microscopic colitis may suffer from BAD. Those with ulcerative colitis or overlapping IBS and IBD can also be affected.
Fat malabsorption that occurs in BAD can also complicate the absorption of fat-soluble nutrients like Vitamin A, E, D, and K.
Bile that doesn’t get reabsorbed can also make things complicated with our microbiome and can have a negative impact. On the other hand, dietary adjustments can also help improve the microbiome and in turn, improve bile absorption.
Non-IBD Cases of Bile Acid Malabsorption
- BAD affects approximately 1% of the population
- Is a contributing factor in roughly 25-33% of cases where chronic diarrhea is observed
- Approximately one-third of individuals with IBS with diarrhea (IBS-D) are affected
- Up to 50% of those afflicted with functional diarrhea
What are the Symptoms of Bile Acid Malabsorption?
- Persistent watery diarrhea
- Abdominal bloating, gas, and discomfort
- Fatty stools or stools that float
- Potential long-term risks of dehydration and malnutrition
What to do if you suspect BAM?
While there are tests to measure BAM, they are not widely available but you could ask your GI further about this and get an initial evaluation.
There are medications available such as cholestyramine, however, they do sometimes also come with some uncomfortable side effects.
There are food-based approaches you can try as well to bind malabsorbed bile. Stay tuned for part 2!
Resources: Testing & Treatments for BAM