I am surprised by how many people receive a diagnosis of IBS-D (diarrhea type) without ever getting dietary counseling about elimination diets or avoidance of dairy products. People with IBS-D are often prescribed antidiarrheals like Immodium. When people with IBS come to see me, I ask them questions about their diet and the age of onset of their symptoms as well as any known triggers.

I have had two cases of long-term undiagnosed Giardia infections that caused intermittent diarrhea but the vast majority of the patients I see for IBS have great improvements with diet changes or digestive support.

The Food Related Causes of Diarrhea

There are a few ways that foods can affect digestion in a way that causes diarrhea:

  • Lactose intolerance: Many people have decreased lactase activity as they get older. Lactase is the enzyme that breaks down lactose, the sugar in milk, so if lactase activity is decreased, lactose does not get broken down and causes fluid to come into the intestines and produce diarrhea. Estimates range from 50-70% of the adult population are affected by low lactase activity.
  • Diarrhea, Dr. Gwenn Rosenberg, Third Stone Integrative HealthOsmotic diarrhea: this means that more fluid enters the intestines due to a substance (usually a carbohydrate) that is not effectively broken down or absorbed. Diarrhea caused by lactose intolerance is one example of osmotic diarrhea. I have also seen many people who experience diarrhea as well as gas and bloating from sugar alcohols (erythritol, lactitol, maltitol, sorbitol, xylitol, isomalt, and mannitol) because these sugars do not fully break down. Often people will notice that they begin to have diarrhea, gas and bloating soon after starting to consume sugar alcohols.
  • Lack of digestive enzymes: diarrhea can also be caused by a lack of digestive enzymes which means that foods are not adequately broken down. People with lack of digestive enzymes (also known as pancreatic deficiency) or low stomach acid (hypochlorhydria) will often feel excessively full for a prolonged period after meals and may notice undigested food in their stool. People often experience this type of diarrhea after a gallbladder removal surgery. We treat this type of diarrhea with digestive enzymes and/or digestive supportive herbs and nutrients.
  • Malabsorption: when carbohydrates are not adequately absorbed in the intestines, they cause osmotic diarrhea. Sometimes this presents with symptoms of vitamin deficiency like specific rashes or dry, scaly skin. In this case, we often address the breakdown of foods as well as the health of the lining of the gastrointestinal tract.
  • Food Intolerance/Allergy: my last blog addressed adult-onset food allergies. Intestinal permeability (also known as “leaky gut”) can allow proteins to pass through the lining of the intestines where the immune system can mistakenly identify them as bacteria or viruses and produce an immune reaction. Some food intolerances cause diarrhea while others cause constipation. We use elimination diets as well as food intolerance testing to identify food intolerances. As soon as the foods that are causing the immune response are removed, diarrhea or constipation often resolves. Often people will notice other improvements like increased energy, reduced body pain and reduced congestion or headaches as well.

Other Causes of Diarrhea

  • Stress: Stress can cause a “hypersecretory diarrhea” which means that the liver and intestines produce too much stomach acid and bring extra water into the intestines. If the diarrhea is associated with acute stress, we often help to balance the stress response and use things like psyllium husk and flax seeds as needed to soak up the excess fluid.
  • Inflammatory Bowel Disease (Crohn’s or Ulcerative Colitis): This type of diarrhea is often accompanied by abdominal cramping and blood in the stool and can be life-threatening if untreated. If you experience either of these symptoms, I would suggest a referral to a gastroenterologist to rule out Inflammatory Bowel Disease.
  • Celiac Disease: celiac disease is different from gluten intolerance because it involves a severe immune reaction to gluten which damages the intestinal lining. People with celiac disease often have persistent diarrhea and abdominal pain. They may also have chronically low iron levels (or anemia), joint pain and frequent rashes.

Treating the Root Cause of Diarrhea

As with all conditions, we focus on treating the root cause instead of just managing the symptoms of diarrhea. When we treat IBS-D with diet changes, people often are often pleasantly surprised by how much better they feel in general.

If you’re experiencing diarrhea, please contact our office for a consultation so we can work together to treat the root cause.