Leaky Gut Test: Understanding “Increased Intestinal Permeability”

It doesn't sound good: increased intestinal permeability. See the symptoms below, and if they sound familiar, your next step is a "leaky gut" test.

leaky gut test

"Increased intestinal permeability" is as it sounds; symptoms will lead you to a "leaky gut" test.

© Marek Uliasz | Dreamstime

Bloated, always tired and constantly craving sugar? You may be suffering from leaky gut. There’s a test for that! So what is the leaky gut test, and do you need one?

Increased intestinal permeability, also known as leaky gut, occurs when the barrier between the gut and the bloodstream (mucosal membrane) fails to prevent potentially harmful molecules from entering the bloodstream. These molecules include large fat particles, toxins, and bacteria, which may cause bowel dysfunction and a generalized inflammation in the body, which in turn contributes to chronic health problems such as heart disease, cancer, and dementia. Leaky gut is a syndrome or group of symptoms, not a disease.

The Leaky Gut Test

Testing for leaky gut is relatively new. The “lactulose mannitol ratio” test or challenge is also known as the Intestinal Permeability Assessment and is used to uncover disorders characterized by changes in gut permeability.

During the test, you will be asked to drink a solution containing two sugars, lactulose and mannitol. Urine is collected over a period, up to 24 hours, and then tested in a lab. Lactulose is a large molecule that is normally unable to cross the gut-blood barrier, so if your gut is healthy, there should be little or no lactulose in your urine. But if your gut is leaky, levels will he high.

Mannitol, on the other hand, is a small molecule that is normally able to cross the barrier. Low levels in the urine suggest a problem with absorption of small molecules. In the lab, technicians will look at both urine levels and calculate their ratio.

Your doctor will interpret the results and may recommend further testing. As the test is new, it is still being perfected. Some centers use rhamnose rather than mannitol and others give a dose of aspirin before the test.

Other Tests for Leaky Gut and Bowel Dysfunction

Your doctor will interpret the results and discuss the need for other tests. The lactulose mannitol ratio only assesses gut permeability; it does not help diagnose the cause. Your doctor may recommend other investigations including:

  • Blood tests
  • Stool examination
  • Bowel imaging with a plain x-ray, ultrasound, computed tomography scan (CT), CT enterography or magnetic resonance (MR) or magnetic resonance imaging.

Endoscopy is essential for diagnosing more severe conditions such as Crohn’s or ulcerative colitis. Here a fiberoptic scope or tube is introduced into the gut, so that it can be examined visually and biopsies taken. Your doctor may refer you for a colonoscopy to look at the colon and ileum, and/or a gastroscopy to look at the stomach and duodenum.

Symptoms of Leaky Gut: Who Needs the Leaky Gut Test?

Most people are unaware that they have a leaky gut, because symptoms are often vague and progress slowly. Symptoms include:

  • Change in bowel habit, including diarrhea, constipation, bloating, or flatulence.
  • Fatigue for no reason.
  • Headaches, poor concentration, brain fog, and memory decline.
  • Rashes such as acne, rosacea, and eczema.
  • Weak immune system. You may notice that you catch every cold or tummy bug that is doing the rounds.
  • Craving sugar and carbohydrates.
  • Aches and pains in muscles and joints.
  • Depression, anxiety, and ADHD.
  • Nutritional deficiencies. These may be detected on a routine blood test.
  • Autoimmune diseases like rheumatoid arthritis, Ankylosing spondylitis, and thyroid disease.

Risk Factors for Leaky Gut

Leaky gut can affect almost anyone, but experts say there are some factors that increase the risk:

  • Alchohol abuse
  • Bowel infections: Food poisoning, parasites, bacterial overgrowth
  • Gut conditions, including gastritis, colitis, and Crohn’s disease
  • Eating disorders, notably anorexia.
  • Medical shock, trauma, burns, or surgery
  • Cancer and cancer treatment
  • Chronic hepatitis and chronic pancreatitis
  • Medications including NSAIDS
  • Rheumatoid arthritis
  • Environmental toxins: Heavy metals, organic pollutants, solvents, endocrine disruptors
  • Psychological distress: This is a major one as stress is such a huge problem today.

Healing Leaky Gut

Treatment of leaky gut begins with diagnosis. More serious conditions such as Crohn’s and ulcerative colitis require medical supervision. If your leaky gut is due to irritable bowel syndrome or allergies you may want to check out the “4R Program.”

The 4R Program was developed by at the Functional Medicine Institute by Jeffrey Bland, Ph.D. and his associates. It involves exploring:

  1. Remove stress, allergenic foods, toxins from food and bowel pathogens including bacterial, yeast, viruses, fungi, and parasites, as well as and other toxic substances are common contributors to gut-related symptoms.
  2. Replace stomach acid and digestive enzymes, if you are lacking.
  3. Reinoculate with good bacteria using fermented foods, prebiotics, and probiotics.
  4. Repair with good nutrition, using a healthy diet and perhaps supplements.

For more information, see our post “Tired All the Time? Try Healing Leaky Gut Syndrome for Fatigue Relief.”

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Leonaura Rhodes, MD

Dr. Leonaura Rhodes is a physician turned author, coach, and freelance medical writer and editor. She has worked for Belvoir Media since 2017 and has authored hundreds of articles on … Read More

View all posts by Leonaura Rhodes, MD

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