How to Manage Diarrhea


By Tara Whyand

There may be several reasons why you may suffer with diarrhea. Steatorrhea (fatty stools) is also a form of diarrhea and both of these problems can result in weight loss and malnutrition. Some people will have more than one cause of diarrhea and it is important to see a dietician, especially if you are losing weight (See Approaches to Healthy Weight Gain).

Carcinoid tumors

Patients with NETs, previously known as carcinoid tumors, tend to get diarrhea due to the tumors release of serotonin. This is part of carcinoid syndrome. Some foods can trigger the process of carcinoid syndrome and you should make your own food and symptom diary, linking back to any of the common carcinoid triggers (See Food and Beverage Triggers of Carcinoid Syndrome) so they can be avoided.


VIPomas are pancreatic tumors that produce the hormone vasoactive intestinal polypeptide (VIP). This can lead to profuse watery diarrhea which results in low potassium, phosphate and bicarbonate levels in the blood. Although diet cannot stop the tumor from secreting hormones, diet is important in controlling side effects:

  • If you experience muscle aches, weakness, numbness, or cramps try supplementing potassium, or eating potatoes and bananas and drinking pure fruit juice.

  • If you experience dehydration (including thirst, dry skin, a dry mouth, tiredness, headaches, and dizziness) try drinking 10-12 cups of non-alcoholic, non-caffeinated fluid per day.

Insufficient PERT

Patients requiring pancreatic enzyme replacement therapy (PERT) due to somatostatin analogs prescription or pancreatic surgery will need to take enough enzymes to absorb nutrients and stop steatorrhea.

Bile acid malabsorption

Patients who no longer have a terminal ileum (very end of small bowel) or gallbladder may start to have problems with bile acid malabsorption. This is reflected in watery or fatty stools (steatorrhea). It can be tested for with a type of body scan. If positive, a bile acid binding drug can be prescribed. Seeing a dietician for a low fat diet, and the use of medium chain triglycerides (MCT oil) may also be useful.

Small intestinal bacterial overgrowth (SIBO)

When you have had any form of surgery to the digestive system, have poorly controlled diabetes, or take acid-lowering drugs, you are at increased risk from something called small intestinal bacterial overgrowth (SIBO). The small bowel is supposed to have small numbers of protective bacteria living inside it, but sometimes a few strains of bacteria can grow out of control in areas that they should not, or move upwards from the colon and multiply into high numbers, causing digestion problems. Some people do not notice they have it, but others have a change in bowel habits, becoming constipated, having flatulence or diarrhea fatty stools/steatorrhea. A hydrogen and methane breath test will be booked for you if your doctor suspects this problem. If the test is positive you may be prescribed an antibiotic and you may need to see a dietician to alter your diet or treat any vitamin deficiencies it has caused.