Here at Ignite Nutrition, many of our patients describe feeling held back by their digestive symptoms. Some of the most frustrating symptoms for our patients are urgency and diarrhea, as they feel they can’t leave the house or participate in social events due to unpredictable bowel habits.
Nutrition for Bile Acid Diarrhea
Chronic diarrhea can occur for a variety of reasons, one being something called bile acid diarrhea (often called bile acid malabsorption) or ‘BAD’ for short. Although you may not have heard of this before, BAD is a common cause of diarrhea. However, with symptoms so similar to conditions like IBS or IBD, it can often be tricky to diagnose.
Today we will be reviewing the details of bile acid diarrhea – what it is, how it’s diagnosed, and what you should know about managing this condition long-term. Let’s get started!
What is Bile Acid Diarrhea?
BAD is diarrhea that results from poor absorption of bile acids, which are important molecules that help to digest and absorb fat and nutrients from our food.
Every human body is designed to release bile acids when we eat. These bile acids aid in absorbing fat and fat soluble vitamins like vitamins A, E, D, & K (to name a few). This process occurs in the small intestine, which is the primary site of digestion and absorption.
From there, about 97% of the bile acids we produce get reabsorbed in the terminal ileum (the very end of the small intestine). The body recycles these bile acids so that they can be used again and again. Isn’t the human body SO efficient? Bile acid diarrhea occurs when bile acids do not get reabsorbed at the terminal ileum and instead continue on to the colon, causing irritation and excess water secretions that lead to loose stool. This can happen for a variety of reasons.
Primary Bile Acid Diarrhea
For some patients with BAD, they actually produce too much bile for their body to absorb all at once, meaning excess bile acids slip through to the colon, causing BAD.
Secondary Bile Acid Diarrhea
For others, absorption of bile at the terminal ileum is not efficient. This is often secondary to another condition that has caused previous damage to the small intestine such as inflammatory bowel disease, previous bowel surgeries, celiac disease, or small intestinal bacterial overgrowth (SIBO). However, for certain patients, BAD can also occur without a known cause – this is called ‘idiopathic bile acid diarrhea’.
Symptoms of Bile Acid Diarrhea
Unsurprisingly, the most common symptom of bile acid diarrhea is well, diarrhea. It IS right there in the title. However, there is generally more to it than that.
Key characteristics of BAD include:
- Watery, loose diarrhea – often stool is pale in colour, greasy, malodorous and/or difficult to flush
- Bowel urgency & frequent bowel movements
- Fecal incontinence
- Excess gas
- Abdominal pain (typically in the lower abdomen)
Bile Acid Diarrhea vs. Irritable Bowel Syndrome
Both BAD and diarrhea-dominant IBS (IBS-D) have very similar and overlapping symptoms, making it difficult to diagnose the cause of diarrhea in many patients. It is also thought that many IBS-D patients may actually have both diagnoses. In fact, some studies report up to half of individuals with IBS-D or functional diarrhea have bile acid diarrhea!
At Ignite Nutrition, we work with a lot of patients who have been diagnosed with IBS-D. In doing so, we sometimes see patients who also show signs of BAD that may have been overlooked during the diagnostic process. There is no doubt that these two conditions can be VERY difficult to separate during screening – so how is BAD diagnosed?
Diagnosing Bile Acid Diarrhea
When an individual presents with chronic diarrhea and urgency, their family doctor will refer them to a gastroenterologist who will perform a series of tests to rule out specific gut disorders. If there are risk factors and as appropriate, a gastroenterologist will conduct a colonoscopy to identify whether that person has inflammatory bowel disease, celiac disease, or colon cancer – however, many times conditions can be ruled out with blood work and assessment.
If the results of your test come back clear, but you’re experiencing diarrhea and abdominal pain, the most common diagnosis is irritable bowel syndrome – which makes sense given the symptoms, and can be managed with nutrition intervention. But what happens when nutrition interventions, like the low FODMAP diet, don’t work?
We often see patients diagnosed with IBS-D that work with us on nutrition management of IBS, and STILL have significant diarrhea, even despite being disciplined with the low FODMAP diet and managing their stress. As we work through their food and symptom journals, we can see a correlative pattern with high fat foods, and worsening of diarrhea. This is a common sign that there may be more going on!
To scientifically diagnose bile acid diarrhea, a fecal sample can be taken and analyzed to measure the amount of bile acids in a person’s stool. However, this procedure often isn’t available outside of research facilities. Instead, BAD is most often therapeutically diagnosed by administering a bile acid sequestrant drug and monitoring how an individual responds to the therapy. If a patient’s symptoms improve with the pharmacological therapy, we can observationally say that they have bile acid diarrhea.
Management of Bile Acid Diarrhea
As mentioned above, the most reliable therapy for BAD is a type of medication called bile acid sequestrant drugs. The most common of these in Canada is called cholestyramine, which is a powder medication that binds to unabsorbed bile acids in the colon. By doing so, it makes them osmotically inactive, meaning they can no longer pull excess water into the bowels and cause diarrhea. As a plus, cholestyramine may also help to lower cholesterol in the blood through the same mechanisms – binding fat and cholesterol molecules that usually get re-absorbed and recycled!
It is important to work closely with your medical team to determine the proper dose of cholestyramine for you, as the amount needed can vary depending on the person, the severity of your symptoms, and even what you eat.
Can Diet Impact Bile Acid Diarrhea?
Bile acid sequestrant drugs are the main treatment for BAD, but diet and lifestyle changes can also greatly reduce incidence of bile acid diarrhea. At the end of the day, the best management strategies for BAD include a combination of BOTH medical therapy and nutrition therapy!
Dietary considerations for managing BAD include:
Consuming high soluble fibre foods and/or soluble fibre supplements such as psyllium husk – Fibre supplements act as a natural bile acid binder, helping to reduce the amount of water being pulled into the bowel.
Consuming a diet low in poorly absorbed and highly fermentable carbohydrates – Many of our patients do have IBS-D overlapping with their BAD, and see great success following a low FODMAP or modified low FODMAP diet to reduce excess gas and fluid in the gut. This likely has to do with some FODMAP’s speeding up digestion, giving bile acids less of a chance to absorb, leading to worsening symptoms.
Reducing fat in the diet – When we consume less fat, we don’t release as many bile acids to absorb and breakdown that fat. In turn, the result is fewer symptoms associated with poor bile acid reabsorption.
Eating small, frequent meals as opposed to large meals – Smaller portions also require fewer bile acids and therefore cause less episodes of diarrhea.
If you have recurrent diarrhea and urgency, discuss it with your family physician and ensure you get properly screened for gut disorders that may be contributing to your symptoms. If you have not worked with a gastroenterologist, consider talking with your family doctor about being referred.
Additionally, talk to a dietitian about how you can start to improve your chronic diarrhea through dietary strategies. A trained gut health dietitian can also help to identify signs of bile acid diarrhea if you feel this could be part of your story. Work with one of our Calgary-based registered dietitians today.