Is bile acid diarrhoea the missing piece in your IBS-D?

Could bile acids be behind your diarrhoea?

If you live with irritable bowel syndrome with diarrhoea (IBS-D), frequent loose stools, urgency and unpredictable bowel movements can be frustrating, particularly when you’ve tried changing lots of different things without getting the answers you’re looking for.

But what if your diarrhoea isn’t just “IBS”?

Bile acid diarrhoea (BAD) sometimes referred to as bile acid malabsorption (BAM), is an under-recognised cause of chronic diarrhoea that can look very similar to IBS-D. Around 25–30% of people diagnosed with IBS-D may have evidence of bile acid diarrhoea (1,2).

For some people, understanding the role of bile acids in digestion can provide an important clue as to why their symptoms are occurring, and what may be worth investigating next.

In this article, I’ll explain what bile acid diarrhoea is, how it differs from IBS-D, how it can be investigated and what dietary and lifestyle approaches I use in my naturopathic practice to support people living with BAD.

How is bile acid diarrhoea different from IBS-D?

BAD is a disorder of bile acid metabolism in which too many bile acids reach the colon. This can occur because bile acids aren’t adequately reabsorbed in the small intestine or because too many are being produced.

Differentiating symptoms

Certain symptoms and medical history may increase suspicion of BAD, although symptoms alone can’t confirm a diagnosis. Your doctor may consider BAD particularly when diarrhoea occurs alongside factors such as:

• Other primary relative with a diagnosis of BAD or bile acid malabsorption
• Stool leakage – faecal incontinence when passing gas
• Waking at night to pass a bowel motion
• Symptoms that are noticeably worse after high-fat meals
• Symptoms began after gastroenteritis
• Cholecystectomy (Gallbladder removal)
• Right sided hemicolectomy
• Bariatric surgery
• Diagnosis of Crohn’s disease
• Liver disease
• Obesity
• History of radiation/radiotherapy in the pelvic area
• Use of metformin, which may influence bile acid metabolism and contribute to diarrhoea in some people

What causes BAD?

Bile acids are produced by the liver, stored in the gallbladder and play an important role in digesting and absorbing dietary fats. In a healthy person most bile acids (95-97.5%) are reabsorbed at the end of the small intestine (terminal ileum) and recycled for future use.  When too many reach the large intestine, they can draw excess water into the bowel and overstimulate intestinal motility resulting in urgency and watery diarrhoea. (3)

 BAD can be caused by:

 An overproduction/higher release of bile acids

• Meals or dietary patterns with a higher fat content stimulate higher bile release. This excess can exceed the ability of the small intestine to reabsorb them.
• Gallbladder removal means bile production from the liver is not sequestered in the gallbladder but continually drips into the small intestine
• Metabolic factors, including obesity and altered lipid/cholesterol metabolism, may influence bile acid production and regulation.

Reduced absorption of bile acids in the small intestine

• Inflammatory conditions like coeliac disease and Crohn’s disease may impact reabsorption of bile acids in the small intestine
• Surgery or radiation therapy in the small intestine can also change absorption capacity.
• Mutations in the SLC10A2 gene affect the expression of a protein needed to reabsorb bile acids.
• Metformin can cause diarrhoea and may also influence bile acid metabolism.

Consequences of BAD

Aside from the discomfort of the cramping and bowel urgency BAD may contribute to:

Nutritional status

Persistent diarrhoea can affect dietary intake and nutritional status in some people. Nutrient deficiencies are more likely to be relevant when there are additional conditions affecting digestion or absorption. If there are clinical concerns, your healthcare practitioner can assess whether nutritional testing is appropriate.

Changes in the gut microbiome

Bile acids and the gut microbiome influence each other, and research suggests that bile acid composition and microbial balance can differ in people with BAD. However, the clinical significance of these changes is still being investigated (4).

Mood impacts and social isolation

Worrying about urgency of bowel motions and faecal incontinence may contribute to anxiety and ability to socialise/travel.

Testing for BAD

Diagnosing bile acid diarrhoea can be challenging because the tests used to identify it aren’t widely available in all countries or healthcare settings.

Tests that may be used include SeHCAT testing, fasting serum 7α-hydroxy-4-cholesten-3-one (C4), and measurement of faecal bile acids. Availability varies by location (5).

Where specific testing isn’t available, a doctor may sometimes use a therapeutic trial of a bile acid sequestrant. However, response to these medicines isn’t a definitive diagnostic test, as they can improve diarrhoea for reasons other than confirmed BAD.

For this reason, your doctor may also investigate other potential causes of chronic diarrhoea depending on your symptoms, history and test results.

Medical management

Medical management of BAD can include bile acid sequestrants, which bind bile acids in the digestive tract and reduce the amount reaching the colon. Other medicines that slow bowel motility may also be used in some circumstances to help manage diarrhoea (6).

Your doctor or gastroenterologist can advise whether medication is appropriate based on your diagnosis, symptoms and individual circumstances.

If you are taking medication for BAD, don’t change or stop your treatment without discussing this with your healthcare provider.

🌿 A naturopathic approach to BAD 🌿

My role as a naturopath is to provide additional support around nutrition, dietary patterns, symptom management and relevant lifestyle factors which complement any medical treatment you are having for BAD.

In my clinical experience, a personalised approach is important because the factors contributing to diarrhoea can vary considerably between individuals. Education is also central to my approach. I find that understanding what’s happening in the digestive system can help people make more informed decisions about their diet and day-to-day management.

Starting point

Crucial first steps include a detailed health history in the first 60-minute consult to determine individual drivers and susceptibility.

Alongside this is a low tech but very clinically insightful tracking of 7-day diet, symptom and stool diary. This step alone often yields valuable information that directs the most appropriate treatment.

Diet modification

 Adjust fat intake

Given that eating fat stimulates bile release, reducing the amount of dietary fat can be a useful starting point for some people with BAD. I generally work with patients to find an amount that reduces symptoms while still providing adequate dietary fat and overall nutrition. Rather than eliminating fat completely, I focus on the amount, type and distribution of fat across the day. Some dietary fat is essential for vitamin metabolism, brain, nerve, cell and hormone health.

Saturated fat from meats and dairy tends to trigger a larger bile response so I encourage patients to switch to lean cuts of meat and include unsaturated fats from extra virgin olive oil, nuts, seeds and avocados.

Because ketogenic and carnivore diets can be relatively high in fat and low in fibre, they may be difficult to tolerate for some people with BAD.

Caution with coffee

Coffee stimulates a digestive hormone, cholecystokinin that stimulates the liver to make bile and the gallbladder to release bile (7). If coffee seems to worsen your symptoms, experimenting with the amount and timing is worthwhile.

Make fibre your friend

Fibre may be helpful for some people with BAD because certain fibres can increase stool bulk and may bind some bile acids. However, the type and amount of fibre matters, particularly if you are prone to bloating.

Psyllium is one option I sometimes use clinically to help improve stool consistency.

Animal studies have shown psyllium husk forms viscous semi soluble gel that binds bile acids in the small intestine and improves faecal excretion (4). Evidence specifically for BAD is still limited, so I use it primarily as a symptom-management strategy rather than as a treatment for the underlying condition.

Limit refined sugar and low sugar alternative

Independently of bile acids, refined sugar increases intestinal transit time. High consumption of low sugar alternatives such as the sugar alcohol xylitol are poorly absorbed in the small intestine and draw more water into the colon which could exacerbate watery diarrhoea.

Herbal medicines

Herbal medicines may be considered as part of an individualised naturopathic treatment plan. While there are many herbs that have traditionally been used to manage diarrhoea evidence specifically for their use in BAD is limited (8).

Because some herbs can affect gastrointestinal motility, bile flow or interact with medicines, I don’t recommend self-prescribing herbal medicines for BAD. If you’re considering herbal treatment, discuss this with an appropriately qualified practitioner who can take your medical history and medications into account.

Herbs to avoid with BAD

Some herbs have strong actions on bile production or gallbladder contractions and these could exacerbate symptoms. These include Dandelion, Globe artichoke, Turmeric/Curcumin and Milk Thistle/St Mary’s thistle. This is particularly relevant because these herbs after often ingredients in generic “gut health” products available in the retail environment.

Supporting a healthy microbiome

Research suggests that bile acids and the gut microbiome interact in complex ways. Whether probiotics improve outcomes specifically in people with BAD remains uncertain. I therefore consider probiotics on an individual basis rather than recommending them routinely for BAD

Monitoring for and addressing nutrient deficiencies

Supplements should be used where there is a clear clinical reason rather than routinely because of a BAD diagnosis. Depending on your symptoms, diet and medical history, your practitioner may consider testing nutrients such as the fat-soluble vitamins (A,E,D,K), Vitamin B12, folate and the minerals iron, zinc and selenium.

Supporting any underlying conditions

Where BAD occurs alongside another health condition, addressing relevant underlying factors may form part of a holistic management plan. This is particularly important when conditions affecting digestion, absorption or metabolism are contributing to symptoms.

Timelines and treatment expectations

How quickly symptoms improve varies considerably between individuals. Some people notice changes in urgency or stool frequency relatively quickly after identifying and addressing their triggers, while others require a longer period of investigation and management.

For some people, BAD requires ongoing symptom management. Where an underlying contributor is identified and can be addressed, managing that contributor may also form part of the longer-term treatment plan in supporting healthy digestive function.

📚 Related resources & further reading

If you’d like to learn more about gut health treatment approaches these articles may help

These articles reflect the clinical framework I use when supporting digestive conditions in practice.

Frequently asked bile acid diarrhoea questions

References

1. Mottacki N, Simrén M, Bajor A. Review article: bile acid diarrhoea – pathogenesis, diagnosis and management. Aliment Pharmacol Ther. 2016;43(8):884–98. doi:10.1111/apt.13570
2. Polishchuk S, Neverovskyi A, Shypulin V. Alterations of bile acid metabolism in patients with functional bowel disorders: a case-control study. Gastroenterol Rev Gastroenterol. 2023;18(4):442–8. doi:10.5114/pg.2023.133062
3. Farrugia A, Arasaradnam R. Bile acid diarrhoea: pathophysiology, diagnosis and management. Frontline Gastroenterol. 2021 Nov 1;12(6):500–7. doi:10.1136/flgastro-2020-101436
4. Zöchling A, Séneca J, Pjevac P, Auñon-Lopez A, Zebeli Q, Pignitter M, et al. Comparative analysis of dietary fiber impact on bile acid metabolism and gut microbiota composition in mice. Npj Gut Liver. 2025 Oct 24;2(1):26. doi:10.1038/s44355-025-00041-z
5. Borup C, Vinter-Jensen L, Jørgensen SPG, Wildt S, Graff J, Gregersen T, et al. Prospective comparison of diagnostic tests for bile acid diarrhoea. Aliment Pharmacol Ther. 2024;59(1):39–50. doi:10.1111/apt.17739
6. Kumar A, Galbraith N, Al-Hassi HO, Jain M, Phipps O, Butterworth J, et al. The impact of treatment with bile acid sequestrants on quality of life in patients with bile acid diarrhoea. BMC Gastroenterol. 2022 Jul 2;22(1):325. doi:10.1186/s12876-022-02404-9
7. Iriondo-DeHond A, Uranga JA, del Castillo MD, Abalo R. Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain–Gut Axis. Nutrients. 2021 Jan;13(1):88. doi:10.3390/nu13010088
8. Prempeh E, Akwetey L, Ankamah S, Amofah-Serwaa N, Bekoe E. A systematic review of the efficacy of herbal medicines in the treatment of acute diarrhea. Adv Tradit Med. 2025 Jun 1;25(2):371–84. doi:10.1007/s13596-024-00766-x