Intestinal Permeability and Why You Should Care

Posted On: June 25, 2017

The term “leaky gut” (intestinal permeability) has been thrown around the health blogosphere for quite some time now.  In fact, if you’re into the more natural side of wellness, you likely hear it blamed for most all of our current ailments:  autoimmunity, food allergies/intolerances, gut dysfunction, etc..  In this blog from 2014 I actually go into great length on what leaky gut is, why it matters, how it happens and what to do about it.  However, I stated in there that there is no really good test that doctors can agree on to screen for leaky gut.  Through FDN I have found out that that is not actually the case.   Today I am going to introduce to you the “gold standard” in leaky gut testing: the Genova Intestinal Permeability Test. 


First, let me start by reminding you that having any symptoms of gut dysfunction, compromised immunity, or allergies and autoimmunity are clear signs that health has gone so awry that you are truly having some malfunctions. By doing some extensive testing, functional diagnostic nutrition practitioners seek to identify as many malfunctions as possible, their root causes, and try to then restore normal function to cells and systems.  Excellent health is not just an absence of symptoms, it’s a feeling of being at your optimal self!


The core of the immune system is based in the gut.

The intestinal mucosal barrier and it’s integrity are critical to all aspects of optimal health.  Through the hepatic portal system, the intestinal mucosal barrier facilitates nutrition: digestion and assimilation.  If the mucosal barrier is compromised, then proper digestion and nutrient absorption are negatively impacted.  The “barrier” part is designed to keep offensive particles out of general circulation.  We need a well-functioning gut in order to protect us from antigens, pathogens, and other immuno-complexes that would otherwise lead to illness.

In mounting a response against infections, infestation and/or inflammation, the gut releases an immunoglobulin called secretory IgA.  It is the first line of defense against ingested pathogens.  B-cells are antibodies secreted via IgA to respond to “non-self” antigens/pathogens to neutralize bacteria.  T cells then either direct these out of the body or kill the infected cells.  NK cells ultimately destroy the altered or infected cells.  However, stress (ie, high cortisol and depressed DHEA) will suppress secretory IgA.  If/when the body struggles with production of sufficient secretory IgA to to mount a strong response to offenders the following disease states become more likely:

Yep, all very scary and all very related to intestinal permeability and gut function.


The problems lie in that the gut lining (epithelium) has to cope with an onslaught of daily HIDDEN stressors like poor diet choices, toxic exposures, infections, medications/drugs, emotional stress and even just genetic predisposition.  Malfunctions and imbalances cascade over time into disease states (symptomatology). First, the microvilli or brush border are destroyed by the inflammatory reactions.  This blunts that brush border (tiny little finger-like protrusions along the intestinal lining that allow for optimal nutrition absorption).  Second, the compromised digestion through the microvilli causes malnutrition and poor digestion.  Lastly, villous atrophy leads to “crypt hyperplasia.”  Crypts are the spaces between the villi and these get swollen.

All of that inflammation leads to the zonula (tight junctions between the enterocytes/cells) to be loosed up.  When these tight junctions/zonula are too loose, larger and inflammatory particles can get through into the bloodstream.  This now permeable gut “leaks” antigens and toxins into general circulation and the lymph system.  These offenders then invoke a humoral (bloodstream) immune response- an overall pro-inflammatory disease state.  Essentially, leaky gut leads to a humoral immune response.  A “Humoral” immune response may result in fibromyalgia, sore joints, muscle aches and pains, multiple sclerosis, rheumatoid arthritis, migraines, severe skin issues, and a host of other autoimmune issues.


What is one to do if they think Leaky Gut is at the root of all their ails?

Well, this is where the Genova intestinal permeability test comes in.  This test looks more at the actual physical aspects of a compromised mucosal barrier than the immunological aspects.  As already discussed, molecules pass through the intestinal mucosa through the epithelial cells (via transcellular uptake) or through the space between (zonula) via paracellular uptake.  Small molecules like glucose and mannitol very readily diffuse through the epithelial cells lining the villi.  Larger molecules like lactulose (normally excluded by these cells) also cannot pass through tight junctions between the cells (zonula).

The Genova IP test directly measures the ability of the two non-metabolized sugar molecules (mannitol and lactulose) to permeate the intestinal mucosa.  The mannitol should be readily absorbed via transcellular uptake (through the cell wall) and helps assess the condition of the cells.  The lactulose is only slightly absorbed  and serves as a marker for mucosal barrier integrity between the cells.  If the zonula are loosened and lactulose gets through, it shows that antigens are too easily getting through into the hepatic portal system and thus the humoral system.

Doing the test is actually quite simple, you drink a premeasured amount of lactulose and mannitol in “challenge” drink, collect urine for the next 6 hours, and shoot it off to the lab.  The only contraindication to taking this test is if one has diabetes.  Once results are obtained, your FDN practitioner will be able to tell you how your gut assimilated the sugar molecules your ingested.  If levels of lactulose are high, then you likely have a “leaky” gut.  If, mannitol on the other hand is low, that shows a decreased absorption of essential nutrients- likely due to villous atrophy.  The ratio of lactulose: mannitol indicates disruption of normal absorption of nutrients.

Granted, none of these results really matter if the client doesn’t exhibit symptoms that correlate…  If, however, the symptoms the client orignally complained of do correlate, then it’s important to immediately begin the DRESS for health success program.  D= Diet, here the practitioner may suggest that the client take the Mediator Release Test (more on this in a later blog) to find out which foods might be causing an inflammatory response. At the very least, it would be recommended to drop sugar, excessive caffeine, alcohol, and likely dairy and gluten for at least 90 days.  R= Rest and making sure to get enough sleep, proper self-care, and time off are critical to overall immune health.  E= exercise and moderate amounts of this are very helpful for proper circulation and immunity.  S=Sleep which will help reduce overall stress.

Lastly, the second S= Supplementation.  In this case, the FDN practitioner would likely recommend the following supplementation in order to help heal a leaky gut:

  • digestive enzymes- to help with proper nutrient digestion
  • mucosa barrier healing- these can include amino acids and other herbals to support repair
  • probiotics and prebiotics-to populate healthy gut flora
  • removal of biofilm- supplementation to remove the biofilm formed by gram negative bacteria and pathogens
  • aloe vera- will decrease gut inflammation
  • lower bowel formulas- specially designed to either decrease diarrhea issues or constipation
  • short-term anti-parasites

I was not very specific with the exact supplements, as each client would need individualized recommendations to support their unique issues.


If you, or someone you care about is feeling like leaky gut may be at the root of ailments or health issues, please don’t hesitate to start investigating.  If you are reading this in 2017, I’m not quite done with my training, but you can contact an FDN practitioner near you now to get started on your road to optimal health.

Yours in Health, 





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