Bile Acid Malabsorption: How an RDN can help

Suffering from diarrhea is no fun, especially if it is chronic. 

One often under-recognized and under-diagnosed cause of chronic diarrhea is a gastrointestinal condition called bile acid malabsorption (BAM). BAM may occur in 32% of individuals with IBS-D symptoms according to the authors of a 2022 review in the Journal of Neurogastroenterology and Motility and up to 50% of individuals with functional diarrhea according to the Mayo Clinic.

Individuals with BAM tend to have unexplained diarrhea or IBS-D and a higher BMI, according to experts in a 2020 American Journal of Gastroenterology review article and the Cleveland Clinic, and also could experience the following symptoms: 

• Diarrhea that can be watery or fatty
• Abdominal pain or cramps
• Frequent, urgent bowel movements and occasional incontinence
• Bloating, gas, and gas pain
• Indigestion
• Fatigue
• Brain fog
• Dehydration
• Nausea
• Headaches
• Dizziness
• Weight loss or gain

Bile is synthesized in the liver, stored in the gallbladder, released into the small intestine, reabsorbed in the ileum, and modified by the gut microbiota; therefore, problems with any of these may cause BAM. 

According to a 2020 article in Practical Gastroenterology, a 2020 review in the American Journal of Gastroenterology, and the Cleveland Clinic there are several BAM types, categorized by their causes:

• Type 1 happens when the ileum is removed or damaged, interfering with bile acid reabsorption. Crohn’s disease, surgical resections, or radiation can cause type 1 BAM.
• Type 2 is considered idiopathic, and functional diarrhea or IBS-D are often in this category. Type 2 might involve bile overproduction. 
• Type 3 is caused by another disease interfering with the bile acid cycle, or intestinal motility or contents. Celiac disease, gallbladder removal, vagotomy, pancreatic disease, radiation enteritis, or small intestinal bacterial overgrowth can cause type 3. 
• Type 4 is due to excessive production and reduced reabsorption of bile acids as a medication side effect of Metformin. 

The right BAM treatment depends on the underlying cause, so it is very important to speak with a physician if you experience BAM symptoms. Treatment could include both medication and diet modifications. Although more research is needed to conclude the best BAM nutrition interventions according to a 2022 Journal of Human Nutrition and Dietetics review, a GI dietitian remains an important resource for individuals with BAM. 

6 Ways an RDN can help with Bile Acid Malabsorption 

1. Address underlying conditions with nutrition. For example, someone with BAM who has celiac disease requires a gluten-free diet. 
2. Personalized fat recommendations. A low-fat diet may be helpful for symptom management in certain BAM cases, although more studies are needed. Beyond limiting concentrated fats found in deep-fried foods and high-fat processed meats, individuals with BAM considering a low-fat diet should consult an RDN to optimize their fat sources and doses for their unique case.
3. Identify and treat nutrient deficiencies. Ileum damage or removal can cause vitamin malabsorption in addition to BAM. Moreover, vitamins D, E, A, and K and essential fatty acids could be affected by BAM and the immune system, skin, brain, and more depend on them. An RDN can do a nutrition-focused physical exam, recommend lab work, and provide recommendations for food and supplements for vitamin and mineral replenishment. 
4. Strategic meal planning advice. Small, frequent meals that evenly divide fat into smaller doses throughout the day might be better tolerated than a few large meals.
5. Hydration tips and tricks. Chronic diarrhea increases the risk of dehydration. 
6. Personalized supplement guidance. There is no generally applicable supplement regimen for BAM. Micronutrients, probiotics, fiber, enzymes, essential fatty acids, or other dietary supplements might be useful depending on the individual case and comorbidities. 

1. _{Min, Y. W., Rezaie, A., & Pimentel, M. (2022). Bile Acid and Gut Microbiota in Irritable Bowel Syndrome. Journal of neurogastroenterology and motility, 28(4), 549–561.}
2. _{Mayo Foundation for Medical Education and Research. (n.d.). Digestive diseases. Mayo Clinic. Retrieved January 18, 2023.}
3. _{Camilleri, M., & Vijayvargiya, P. (2020). The Role of Bile Acids in Chronic Diarrhea. The American journal of gastroenterology, 115(10), 1596–1603.}
4. _{Cleveland Clinic (2022, October 19). Bile Acid Malabsorption. Retrieved December 31, 2022.}
5. _{Dibaise, J. K. (2020). Does your patient have bile acid malabsorption? Practical Gastroenterology, 44(5), 10-24.}
6. _{McKenzie, Y. A., Sremanakova, J., Todd, C., & Burden, S. (2022). Effectiveness of diet, psychological, and exercise therapies for the management of bile acid diarrhoea in adults: A systematic review. Journal of human nutrition and dietetics : the official journal of the British Dietetic Association, 35(6), 1087–1104.}