Bile Acid Malabsorption’s (BAM) Constipation Connection

Could bile acid malabsorption be an issue after bariatric surgery?

In recent years, the world has seen an alarming rise in obesity and its associated illnesses worldwide. Around 15% of children and adolescents and 65% of adults in the United States are overweight or obese today.

Presently, the most effective and sustainable treatment for obesity and its associated illnesses are metabolic surgeries, specifically Roux-en-Y gastric bypasses and vertical sleeve gastrectomy.

Nonetheless, the surgeries are invasive, which limits their wide application. Additionally, you may encounter digestive issues after weight loss surgery.  And constipation is at the top of the list.

This is where they need to identify the underlying causes of constipation after bariatric surgery. There may be several reasons behind your constipation.  One of which may be an abnormality in bile acid production!

What are Bile Acids?

Bile acids, the major parts of bile, are secreted into the intestine from the liver.  Bile acids are large families of molecules with a steroidal structure.  They are synthesized from cholesterol and are mainly conjugated by the amino acids glycine and taurine.  Bile acids are necessary to digest and absorb fats and fat-soluble vitamins in the small intestine.

Functions of Bile Acids

The most important function of Bile Acids (BAs) is promoting intestinal fat absorption. They also play a role in the absorption of vitamins A, D, E, & K.

Additionally, they are also signaling molecules with numerous endocrine and paracrine functions. Bile acids play a crucial role in the metabolism of lipids and glucose, as well as maintaining the balance of temperatures and energy levels. Moreover, some bile acids are natural laxatives and can influence your colon motor activity.

In fact, all bile acids functions are important.  Especially after bariatric surgery.  This is because Roux-en-Y gastric bypass disrupts the absorption of vitamins and minerals by bypassing absorption pathways.  It could impact fat-soluble vitamins if you throw in the bile acid alterations.

Bile Acids Levels And Absorption

In normal circumstances, the level is between 2 and 5 mg/dL, but levels as high as 20–25 mg/dL and as low as below 2 mg/dL have also been recorded.  In the colon, altered levels of bile acids (BA) may lead to diarrhea or constipation.

Ileal BA transporters absorb 95% of BAs, recycling back to the liver.  Whereas, 5% pass to the colon.  Most are de-conjugated by intestinal bacteria into secondary BAs.  They are reabsorbed by the colon via passive diffusion or lost in feces.

However, the intestines cannot properly absorb bile acids when bile acid malabsorption occurs. Consequently, your intestines produce extra bile acids, causing watery diarrhea.

Over 25% of Western patients with irritable bowel syndrome (IBS) with diarrhea and chronic diarrhea suffer from BA malabsorption (BAM).

As a result, some studies proved that BAs act as laxatives and can affect colon motility by affecting colon secretion or acting as a prokinetic.  These observations explain diarrhea (BAD) with BAM.

BAM constipation connection

Malabsorption of bile acids (BAM) occurs when your intestines are unable to properly absorb.  Consequently, your intestines produce excess bile acids, leading to watery diarrhea. Some studies suggest that bile acids might help chronic constipation sufferers.

2008 Study

According to one study published in the “Scandinavian Journal of gastroenterology” in 2008, patients with IBS-C and functional constipation have marked changes in their bile acid synthesis in relation to colonic transit.

There is evidence that altered bile acid metabolism contributes to constipation pathophysiology.  At no surprise, BAM may also accompany additional digestive symptoms.  Check out this podcast “BAM…bloated again!”  to learn more.

2013 Study 

According to a study published in 2013, BAM can be useful as a proper diagnosis method for chronic bowel dysfunction to guide the most effective treatment course.

2014 Study

In 2014, another study proved that bile acids could treat constipation.  Bile acids, which normally enter the colon via the ileum.  They are transported to the liver via transporters, reducing bile acid concentration and decreasing colonic motility.  The study showed that a medication derived from a bile acid transporter altered colonic motility.

2018 Study 

A 2018 study indicates that patients with Crohn’s disease who have an active Ileal disease or have had terminal ileal resection may experience diarrhea from impaired or absent BA re-uptake in the terminal ileum.  Thus, the study suggested that inhibiting the Ileal Bile Acid Transporter(IBAT) may benefit treating chronic constipation.  This is because blocking IBAT can increase bowel movements.

Recent 2021 Study

A recent study 2021 defined bile as a hormone in its ability to modulate a variety of metabolic effects on lipid metabolism, glucose homeostasis, and gut microbiota alterations after bariatric and metabolic surgery. According to this study, bile acids can help promote weight loss without surgery.

Final words

If increasing fiber and fluids didn’t improve motility.  Increasing bile flow through diet and supplements may be a great strategy to improve your constipation.

If you’d like a deeper insight into this topic, check out my YouTube channel video on this topic!