Does Leaky Gut Exist?

what is leaky gutWhen a gastroenterologist or other health professional claims that “leaky gut does not exist”, I cringe. I believe that they are really stating that, in their opinion, leaky gut has no scientific basis. I personally feel that such bold claims are a discriminatory technique used against alternative providers such as Naturopathic doctors, Chiropractors and Nutritionists who are increasingly seeing clients for problems once restricted to medical care. In a sense, I agree that “leaky gut” is not a medical problem. This is because Leaky gut is a FUNCTIONAL problem, that may lead to medical conditions like Crohn’s disease, depression, or other autoimmune disorders down the road. The claim that leaky gut exists or does not exist is a bias rooted in a health professional’s philosophy, not necessarily science.

  • You can believe that leaky gut is not a medical concern.
  • You can believe that it is over-diagnosed.
  • You can also believe that the evidence for a role of leaky gut in health and disease is not strong enough.

But lets weigh existence vs. non-existence with a discussion rooted in science. I believe that it is time to replace static thinking of how the gut works, with new recognition of the dynamic roles of the gut in both health and disease.

What is Leaky Gut?

“Leaky gut” refers to a clinical condition of varying severity in which the intestines absorb large, undigested molecules that are normally blocked. The intestines act somewhat like a sieve, keeping most molecules out, and regulating which small molecules are let in. In “leaky gut”, the intestines become hyperpermeable to substances that otherwise have no business being absorbed. Once “leaky gut” or “hyperpermeability” is established, the more important question is to ask “Why?”.

What Causes Leaky Gut?

Leaky gut is thought to be caused by exposure to “toxic” substances or clinical conditions that directly or indirectly damage the integrity of the gut (Bralley, J. 2005). Whether you call it “leaky gut” or “hyperpermeability”, leaky gut is a functional process by which the intestines fail to regulate what molecules are absorbed into and what molecules are kept out of the bloodstream. This altered control can lead to hypersensitivity responses to food and byproducts of gut bacteria. For instance low-grade “endotoxemia” from bacterial overgrowth may lead to autoimmune disorders (12; 3), and the link has been supported with recent review in February 2012 (4). Leaky gut is being implicated in a wide range of chronic disease processes & the hypothesis continues to grow support.

Normal Gut Physiology

In between gut cells are “tight junctions” which are largely responsible for maintaining the functional barrier between the “external” environment and the “internal” environment. Tight junctions are modulated by a host of physiological & pharmacological factors & their role is much more dynamic than previously recognized  (5). The tight junctions of the gut barrier are naturally imperfect. Normally, 1-2% of large proteins to pass into the bloodstream & the immune system is able to protect us against foreign and potentially harmful molecules that pass the gut barrier. In fact, up to 70% of the entire immune system is present in the gut in the form of gut-associated lymphoid tissue or GALT. Maintaining the integrity of this mucosal immune barrier is increasingly recognized as crucial for health.

Abnormal Gut Physiology

When normal physiology is impaired by exposure to toxic substances, the intestine becomes hyperpermeable to foreign & poorly digested materials. The absorption of these molecules & foreign antigens is capable of initiating an overzealous immune reaction that may reverberate across many body systems.

Common causes of  intestinal hyperpermeability:

  • Alcohol (6). A small study of 36 alcoholic patients without liver cirrhosis, malabsorption or malnutrition suggested that small bowel hyperpermeability following alcohol consumption may last at least 4 days and as long as 2 weeks following cessation of drinking (7)
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as aspirin or ibuprofen
  • Viral, bacterial, parasitic, and fungal infections (89101112).
  • High levels of free radicals from bile, food, and drugs (13)
  • Inflammatory cell messengers from other disease processes (1415)
  • Celiac disease, Crohn’s disease, trauma, & burns (16)
  • Vaccines (17)
  • Food antigens, particularly Gluten and Milk (17)
  • Exposure to stress is also well-accepted to disrupt gastrointestinal function (18)
  • High Fructose Corn Syrup: The Chairman of the Institute for Functional Medicine, Dr. Mark Hyman, MD remarks in his latest book The Blood Sugar Solution (affiliatenon-affiliate):”High doses of fructose have been proven to literally punch holes in the intestinal lining, allowing nasty by-products of toxic gut bacteria and partially digested food proteins to enter your bloodstream and trigger inflammation. Naturally occurring fructose in fruit is part of a complex web of nutrients and fiber and doesn’t exhibit the same biological effects as the high fructose found in corn sugar.

Implications of Leaky Gut:

Gastrointestinal function has been increasingly recognized to play an essential role in brain function (19). Numerous clinicians and researchers now refer to the links as the “gut-brain axis“. It has been suggested that “leakiness” occurs in the blood-brain-barrier (BBB), and that causes of intestinal hyperpermability may also be associated with hyperpermeability of the BBB.

  • For instance, focusing just on serotonin and cortisol imbalance is not sufficient to explain depression. It has been hypothesized that inflammatory and neurodegenerative processes including leaky gut may also predispose an individual to depression (20).
  • A possible mechanism is that pro-inflammatory cytokines and lipopolysacharide from small bowel overgrowth of gram negative bacteria may “leak” or “translocate” into the bloodstream and induce depressive symptoms (2122).
  • Recent review in February 2012 from the University of Maryland School of Medicine suggests leaky gut may be associated with autoimmune diseases due to the importance of the intestinal barrier in tolerance and immunity to foreign compounds (4).
    • As early as 1997, “leaky gut” has been suggested to play a role in Crohn’s disease – an autoimmune disease of the intestine in response to gluten from wheat, barley & rye. Substances that increase intestinal permeability have shown to worsen Crohn’s disease, and removal of those substances may put the disease in remission (23)
    • There is evidence that leaky gut has an effect on other pediatric problems such as systemic inflammatory response syndrome (SIRS)inflammatory bowel diseasetype 1 diabetesallergiesasthma, in addition to autism (24)
    • The complex interplay between intestinal bacteria, gut permeability, and mucosal immunity, may create a “perfect storm” for type 1 diabetes (27), an autoimmune disease of the pancreas, and may also play a role in the development of type 2 diabetes (28)
  • Problems with intestinal permeability are commonly associated with Autistic children, and there are theories in which gastrointestinal function may influence brain function (17).
  • Leaky gut and related oxidative stress may also be a key mechanism involved in Chronic Fatigue Syndrome (25) and there are calls for the development of new drugs aimed at addressing these novel pathways (26).
  • Some studies suggest that gastrointestinal health, particularly permeability, may be crucial for heart function and disruptions in the intestinal barrier may stimulate inflammatory reactivity implicated in chronic heart failure patients (2930).

Testing for Leaky Gut

There are number of tests that can suggest or are commonly associated with “leaky gut”. Testing is not always necessary, and specific choice of testing depends on individual symptoms and health history. In my practice, I am less concerned with identifying a specific “diagnosis”, and more concerned with assessing physiological patterns of function and dysfunction.

  1. Presence of bacterial, fungal, viral, & parasitic infections. ex./A microbial ecology stool test can identify certain infections.
  2. Adrenal Salivary Index: Acute and chronic stress may suppress immunity and increase susceptibility to mucosal antibody reactions in the gut. Unknown infections or allergic reactions can also drive hidden stress responses and influence the release of other hormones.
  3. Secretory IgA (sIgA): Both high and low levels of sIgA (serum, saliva, or fecal testing) can screen for disruptions in mucosal immunity.
  4. Antibody testing for ZonulinOccludin and Actomyosin which are proteins involved in regulating intestinal permeability. Positive antibodies may suggest intestinal hyperpermeability.
  5. Food antibody testing: Common reactive foods are wheat, milk, soy, & corn. Eating foods that you are sensitive to may cause leaky gut, and likewise, the presence of leaky gut may cause you to be sensitive to certain foods.
  6. Lactulose/Mannitol Intestinal Permeability Challenge Test
  • Mannitol and Lactulose are sugars that are not metabolized by the human body, and should be excreted in the urine within 6 hours.
    • Lactulose is a naturally large protein only absorbed 1% of the time
    • Mannitol absorption is normally 14%
    • The test looks at the ratio of lactulose/mannitol recovered in the urine. In healthy individuals, the ratio should be <0.03
  • The test is preformed by swallowing a solution of 5g mannitol and 5g lactulose, collecting urine over 6 hours, assess lactulose and mannitol.
    • If Mannitol is less than 14% absorbed, malabsorption is suspected.
    • If Lactulose absorption was greater than 1%, hyperpermeability or “leaky gut” is suspected.

Natural Approaches for Leaky Gut:

Appropriately address hidden infections and stress imbalance. 4R Program for Gastrointestinal Wellness: Remove offending substances (alcohol, offending foods). Replace digestive enzymes Reinoculate with healthy pre-biotics and probiotics Repair the GI tract with supportive nutrition. It is important to note that each stage of the 4R program may take 30 days or longer. Additionally these stages have overlaps with one another and serve simply as a guide to promoting gastrointestinal health. After completion of the repair phase, individuals are encouraged to continue abstaining from offending substances, waiting a period of 6-9+ months before reintroducing on regular basis. One may also consider rotating mildly reactive foods on a 4-day rotation diet. It is important to work with a health professional as gastrointestinal health issues can reflect problems in other areas of your health, and so that food allergies are not confused with food sensitivities or intolerances. Supplements: There are many herbs and supplements that may offer gastrointestinal health benefits. Here is a taste of what appears in the literature…

  • Small study suggested that zinc supplementation over two months may improve intestinal permeability in Crohn’s patients (31)
  • Glutamine is a favored fuel of colonocytes and certain immune cells and is associated with a protective effect on gastrointestinal integrity.
  • Glutamine as well as curcumin from turmeric may modulate the inflammation and oxidative stress associated with hyperpermeability (32)
  • Vitamin D levels may have a synergistic role with healthy bacteria in the gut to promote integrity (33)
A variety of herbs and supplements may be useful at any stage of the 4R program and specific choices can be personalized to the client with respect to their full health profile.

Reference: Bralley, J. (2005). Laboratory evaluations in molecular medicine: Nutrients, toxicants, and cell regulators. (pp. 223-264). Norcross, GA: Institute for Advances in Molecular Medicine (AffiliateNon-Affiliate)


  1. Allergies, Sensitivities and Intolerances | Prepare Wellness Allergies, Sensitivities and Intolerances | for self ~ for surroundings February 7, 2013 at 9:42 pm - Reply

    […] chemotherapy, birth control pills, antibiotics, steroids or even chemical based vitamins. There is controversy as to whether this leaves holes where opportunistic infections – bacterial, viral, parasitic or […]

  2. Fannie May 1, 2013 at 4:17 pm - Reply

    I place Chia seeds in my oatmeal! Gives it some bulk.

  3. Observer November 25, 2013 at 8:08 pm - Reply

    “High Fructose Corn Syrup…”

    This raises a question.

    Within my limited knowledge, I understand that table sugar is about half fructose and half glucose. HFCS is a corn syrup containing fructose and glucose in somewhat variable ratio, usually about half of each.

    So, what’s so special about HFCS, other than it makes for a good scare story? Excessive sugar intake is almost universally considered to be a bad thing. Should we care if it’s table sugar, corn sugar or a slightly different version of corn sugar?

    • Alexander Rinehart, DC, MS, CCN, CNS November 25, 2013 at 8:39 pm - Reply

      There’s some truth to the notion that any added sugars are going to be harmful to you, so I’m not going to split hairs on that as the general rule stays the same – stop eating processed food.

      But I will offer some comments…

      High fructose corn syrup is typically added to foods that are generally terrible for you. By just choosing HFCS as the source of sweetness, the company is purposely trying to be cheap, shelf-stable, and unnaturally sweet for mainstream appeal and addictive sweetness- which means the foods are going to be that much more refined and processed – which means you should stay that much more away from them.

      On a more technical level, humans actually have a tough time digesting any source of fructose and fructose intolerance is actually more common than you might think and contributes to leaky gut and general GI dysfunction.

      HFCS is more likely to be contaminated with things like mercury than your regular table sugar.

      Sucrose is 50-50 fructose to glucose, while HFCS is about 55-45 (10% higher). The bonds are different too where the fructose from HFCS is unbound and free able to go directly to the liver and contribute more directly to non-alcoholic fatty liver disease, while sucrose still requires an enzymatic step to break the fructose free from the glucose. This slight biochemical difference can mean a lot to the body already dealing with blood sugar challenges and compensated systems for dealing with processed food.

      HFCS is cheap and therefore easy to load up in things like sugar without increasing manufacturer costs…so you consume 20+ oz of soda in a sitting, so the sources of HFCS tend to be more sugar-laden than their more “natural” counterparts – increasing flavor, shelf-stability, and sales, without hurting margins.

      On a socioeconomic level, there is an enormous lobbying interest to keep HFCS seen as a safe and viable ingredient suitable for grocery store shelves and to help corporations keep solid margins and profits- there is a lot of industry funded campaigns with these ingredients from the corn industry to the food and beverage industries – which generally gives me distrust.

      Lastly on an economic level, HFCS is cheap mainly because of things like corn subsidies which make the “true” cost of cheap sweet food greater than what appears on the surface. Environmentally, this has effects on agricultural practices, land use, etc.

      Needless to say, I still don’t promote outright bans and promote personal choice – but if you eat non-processed food without any added sugars of any kind like we should – then it really doesn’t become an issue either way.

  4. john January 21, 2014 at 4:59 pm - Reply

    Hi. Interesting page. I think I have leaky gut but I can’t find who can diagnose it and treat it here in New Jersey. Do you know of any doctor in nj that treats it

  5. Andrea May 11, 2014 at 5:15 am - Reply

    Thank you for a wonderful article. It is comprehensive and all the information that I need, in one place. I plan to take this to my homeopathic dr in order to help me get on the right tract.

  6. Laura Moore September 14, 2014 at 4:30 pm - Reply

    I know I have leaky gut and have been treating myself with quite a bit of success. I had muscle and joint pain, allergies, asthma, heartburn (GERD) and I was overweight. I had a chronic cough that has lasted for years. Docs just gave me allergy pills, nasal sprays, muscle relaxants, anti inflammatories, pain killers and puffers. I finally got fed up and told I am tired of covering up the symptoms and taking all these medications. I stopped taking them all and started listening to my body. The first thing I did was I removed all grains from my diet and follow a paleo diet. I researched online and read books on the paleo diet and leaky gut. I stoppped drinking alcohol and started taking some supplements. I take vit D, a probiotic, magnesium, glutamine, DGL (licorice), a B complex, omega 3, MSM and melatonin. It seems like a lot but I split them up over the course of the day. (I take my probiotic, magnesium and melatonin at bedtime.) It takes time to reverse and heal a leaky gut. The first few weeks were tough. I had a lot heartburn and lots of foods bothered me. I chewed on the DGL tablets like they were candy! I would eliminate foods that seems to bother me and reintroduce a couple weeks later, giving my body time to heal. I drink ginger tea every day and drink freshly juiced lemon juice in a glass of water every morning. I don’t take pain killers or any over the counter meds. Instead I use ice packs for pain, hot epsom salt baths or lay down for a rest. You can heal yourself and you can feel better. It’s been 12 weeks and I almost never have heartburn. I sleep better and my muscle and joint pain has improved oh and the best part….I lost 33 pounds! I know it is going to be a long road ahead. I also know I can’t go back to eating the way I did, drinking alcohol and taking pain killers if I want to continue to heal. Good luck to everyone suffering and trying to heal. 🙂

    • Alexander J. Rinehart, DC, MS, CCN, CNS September 17, 2014 at 3:06 pm - Reply

      Wow that’s a great story of self-discovery and self-healing. It’s nice to know that you were willing to take the plunge to test alternatives out, but also to have the patience to play around with it until you discovered what works. I am humbled by functional medicine because it does take some “educated trial and error”, but when push comes to shove it’s about asking the right questions, when you ask the right questions, the answers come much faster. Thanks again for the positive story 🙂

  7. Rebecca April 8, 2015 at 10:22 pm - Reply

    It’s hard to take what you have written seriously, when you use wrong terms together. Crohn’s disease is an inflammatory bowel disease for example, which is not functional (unlike irritable bowel syndrome). Then you say neurodegenerative processes, like “leaky gut” – umm? WHAT. Throwing big words together (whether they be physiological, medical etc.) When it is clear you don’t have an understanding of the terms used, is just dangerous to the uninformed.

    I don’t know what kind of “doctor” you claim to be, but clearly not medical, or a PHD in physiology.

    • Thanks for your comment Rebecca, I’m happy to clarify your “ad hominem” remarks with 3rd party resources listed below (while you may not personally view DC/CNS as qualified, the resources listed below are PhD and peer-reviewed). Functional medicine is a “lens” that de-emphasizes the need for a “diagnosis”. As with any lens, it has its advantages/disadvantages.

      Autoimmune diseases like Crohn’s happen on a spectrum of severity…just as there is the spectrum of non-Celiac gluten sensitivity vs. outright full-blown Celiac disease. Also leaky gut is quite established in the literature, it is commonly referenced as “malabsorption”, leaky-gut is easier to understand by the public.

      Also, in just the last 2-3 years, we have learned how to measure early antibodies to tissues that can predict autoimmune disease later in life, so it is on a functional spectrum before a “diagnosis” is ever given.

      You may not have been aware of this new work, but it has clearly put autoimmunity on a functional scale. Ultimately a predisposition still needs to be “triggered” by environment, diet and lifestyle, but this new information can help an individual modulate their future risk as well as more effectively manage current full-blown autoimmunity. It’s predictive, not reactive.

      In the case of Celiac disease, there are extra-intestinal symptoms which include neuroinflammatory disorders and even other autoimmune presentations. For instance, gluten has been shown to be able to cause MS-like lesions in the spinal cord. How many people are diagnosed with MS- but are actually gluten intolerant and may never know? – just one example of how functional processes can underlie full-blown autoimmune presentations.

      Ultimately diagnoses are just labels we put on clinical presentations, there is still an underlying functional process, so you and I may just understand “functional” to mean different things.

      From a functional medicine perspective autoimmune disorders are a functional immune disorder with various causes that are different person to person (unidentified food sensitivities/allergies, chronic underlying infections/dysbiosis/and chronically high LPS, as well as issues pertaining to heavy metal/pesticide exposure, and chronic adrenal stress – and all the overlaps in between)

      I’ve also included resources to clarify the links between leaky gut and neuroinflammation (“leaky brain”). (Recent Advances in Characterizing the Gastrointestinal microbiome in Crohn’s Disease: A Systematic Review (Antibodies as Predictors of Complex Autoimmune Diseases) (Citrullination and autoimmunity) (Chronic functional bowel syndrome enhances gut-brain axis dysfunction, neuroinflammation, cognitive impairement, and vulnerability to dementia) (Non-Celiac Gluten Sensitivity Triggers Gut Dysbiosis, neuroinflammation, Gut-Brain Axis Dysfunction, and Vulnerability for Dementia) (Extra intestinal manifestations and complications in inflammatory bowel disease) (Extraintestinal manifestations of inflammatory bowel disease)

    • Alexander Rinehart, DC, MS, CNS September 7, 2016 at 12:14 pm - Reply

      You still do not have to trust me as a source, but kindly consider this peer-reviewed article published in a medical journal:

  8. Sarah July 27, 2015 at 8:46 am - Reply

    Thank you for this well written, informative article. I have recently been diagnosed with leaky gut syndrome and feel overwhelmed with the number of food allergies/sensitivities (51 things that I eat on a regular basis plus about a hundred more in the “equivocal” range.) It’s hard to trust in alternative medicine when the medical establishment calls functional medicine quackery. But my medical doctors have nothing to offer me. It is good to see that there is scientific evidence that my condition exists. This gives me motivation to follow my DC’s advice instead of sticking my head in the sand and continuing with the status quo.

  9. Margo klein February 21, 2016 at 8:43 pm - Reply

    I was dying from leaky gut. One morning I woke up with nausea and almost 4 years later I still suffer with it. I went to 5 specialists and 6 MDs. Test after test showed nothing. Only one gastroenterologist mentioned it could be related to celiac disease so I went gluten free for 6 months with no relief. I went to a naturopathic practioner and we both agreed I had leaky gut. Nausea was only the start of the sickest I’ve ever been in my life. It was like being poisoned from head to toe. I could barely walk, and was many days bedridden. For women I think it’s harder to get help. I would go in their office hardly able to keep my head up and since all my tests came back normal, I would get looks from the Drs as if they thought I was a hypochondriac. Which, by the way, is due to the many awful symptoms that accompany this disease. I was a part time hospice nurse for two years and never saw anyone suffer the way I did because I couldn’t get any help. Thankfully,my husband by chance,was talking to a Dr. who told him about a clinic in Grand Rapids Michigan that cured leaky gut. They saved my life. I was dying and I knew it. So did my acupuncturist. The medicall establishment denied my sickness even existed while I was obviously in a critical condition. I couldn’t tolerate most any food. My weight plummeted to 113 lbs. I am 5 foot 6 and was “skin and bones”. One day I went to my Drs and he stated there was nothing else he could do. That’s the day I knew I was on my own or I wasn’t long for this world because every time I ate something I got deathly ill. I would lie in bed and prayed to die. The chronic nausea is caused by damage to the nerves in my gut. This is called neuropathy. My. Gastro said it will be a long time if ever I heal. All because western medicine mostly denies it exists. I feel Drs deny this disease because they don’t have a clue how to treat it. So it accellerated to this damage that could have been prevented if I could have gotten help sooner. It took 3 years to find someone who believed I had it. I’ve really lost faith in allopathic Drs. If it doesn’t fit their cookie cutter mold it doesn’t exist. I want to warn anyone who will listen, to eat healthy, control stress levels, avoid antibiotics as much as possible, stay away from antacids, and avoid NSAIDS as much as possible. By the way, if you stick to a healthy diet most people won’t suffer from heartburn). I’d hate to have anybody suffer as much as I have. I’m praying the nerves in my gut will regenerate. In the meantime I’m doing everything I can do to get healthy again. There are so many symptoms to this disease. If you are having digestive problems don’t wait to find help. Also leaky gut plays havoc on your emotions , brain function, and physical energy. I hope this helps someone. After caring for so many people I couldn’t get help myself. Drs need to open some new books! AND their minds.

  10. Anne April 18, 2016 at 9:12 am - Reply

    I recently went to a homeopath. When I told her I believe I have leaky gut she laughed and said it does not exist. She said that if the gut were really leaky I would die. What evidence or reports can I give her to convince her that does exist? There is so much on the internet, but I am sure she would need something weighty. Can you advise? Please? I am very disheartened. But I have already paid her a lot o f money to start treatment with her; if I go elsewhere I will have to fork out another hefty consultation fee, which I cannot afford as I am on benefits. Thanks in advance if anyone replies

  11. May 28, 2016 at 9:41 am - Reply

    can you find one in delhi,india? i am sure i have leaky gut all ssymptoms match but can’t find one in india plz help

  12. […] the inside world of your body. When the integrity of your gut lining is challenged and becomes “leaky”, such as with a gluten-sensitivity or infection with a nasty pathogen, the immune system mounts […]

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