Abstract
Bile acid diarrhoea (BAD) is a widespread gastrointestinal disease that is often misdiagnosed as irritable bowel syndrome and is estimated to affect 1% of the United Kingdom (UK) population alone. BAD is associated with excessive bile acid synthesis secondary to a gastrointestinal or idiopathic disorder (also known as primary BAD). Current licensed treatment in the UK has undesirable effects and has been the same since BAD was first discovered in the 1960s. Bacteria are essential in transforming primary bile acids into secondary bile acids. The profile of an individual’s bile acid pool is central in bile acid homeostasis as bile acids regulate their own synthesis. Therefore, microbiome dysbiosis incurred through changes in diet, stress levels and the introduction of antibiotics may contribute to or be the cause of primary BAD. This literature review focuses on primary BAD, providing an overview of bile acid metabolism, the role of the human gut microbiome in BAD and the potential options for therapeutic intervention in primary BAD through manipulation of the microbiome.
Highlights
Bile acid diarrhoea (BAD) is a condition that predominantly presents as chronic watery diarrhoea as well as bloating and abdominal pain [1]
Bile acids have a number of functions in the gastrointestinal (GI) tract: conjugated bile acids at the right concentration form micelles, which function as biological detergents through the emulsification and solubilisation of fats in the small intestine [23]; they are essential for the absorption of dietary lipids; they act as a signalling molecules that regulate their own expression; they play a key role in immune homeostasis and the metabolism of glucose [24,25]
Changes in the gut microbiome due to external factors such as stress, antibiotics or diet could be the primary cause of BAD, which would explain why treatment to date by bile sequestrants does not alleviate the underpinning cause of the disease
Summary
Bile acid diarrhoea (BAD) (previously referred to as bile acid malabsorption or bile salt malabsorption) is a condition that predominantly presents as chronic watery diarrhoea as well as bloating and abdominal pain [1]. The authors showed that patients with secondary BAD (type I and III) had lower levels of FGF19 in their blood serum compared with that in healthy subjects [8,9,10]. This excessive bile acid synthesis results in the insufficient absorption of bile acids in the ileum, causing the increased transit of bile acids into the colon. Several studies have reported the importance of bile acids in a number of gut related diseases [11] Despite these observations, the cause of low serum levels of FGF19 and the consequent excess bile acid synthesis remains widely unknown.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
