It seems as though, now, everyone has heard of leaky gut. Studies, like this one and that one, shine a light on intestinal permeability, barrier dysfunction and its relationship with conditions like autoimmunity. However, even with three decades of acknowledgement and research, leaky gut or intestinal permeability is not well understood or commonly discussed. Let's fix that.
What is leaky gut?
Leaky gut is a condition in which the lining of the intestine becomes damaged and leads to a development of small gaps between the cells that line the intestinal wall. These gaps allow substances, like undigested food and bacteria, to escape into the bloodstream.
In a normal, healthy functioning small intestine, the intestinal cells sit closely together and form a barrier, keeping the undigested contents in the small intestine and out of the bloodstream.
Chris Kresser does a fantastic job at describing the barrier function of the gut:
The gut is a hollow tube that passes from the mouth to the anus. Anything that goes in the mouth and isn't digested will pass right out the other end. This is, in fact, one of the most important functions of the gut: to prevent foreign substances from entering the body. (Kresser, Beyond Paleo)
When these larger undigested protein molecules enter the bloodstream, the body produces an immune response and attack to these foreign proteins. Our immune system activates cytokines (immune system messengers; regulate the body’s response to infection) which can produce irritation, inflammation, and even autoimmunity.
A recent study was published showing the link between leaky gut and autoimmunity:
There is growing evidence that increased intestinal permeability plays a pathogenic role in various autoimmune diseases including [celiac disease] and [type 1 diabetes]. Therefore, we hypothesize that besides genetic and environmental factors, loss of intestinal barrier function is necessary to develop autoimmunity. (PubMed, 2009)
What causes leaky gut?
- Chronic stress -- Suppresses immune system, suppresses gut flora
- Antibiotics, NSAIDS, birth control pills -- Destroys beneficial gut bacteria, irritates and damages brush border
- Gluten and gliadin -- Stimulates zonulin and intestinal permeability
- Inflammatory foods: processed foods, sugars, flours, food additives, caffeine, alcohol -- Irritates gut lining, overburdens liver and immune system
Let’s take a closer look at the trifecta that is gluten, gliadin and zonulin:
Gluten is a type of lectin found in wheat, barley and rye. Gliadin is a protein component of gluten which plays a central role in the plant’s development. Gliadin stimulates the release of zonulin, a protein that has been found to loosen the tight junctions between the cells that line the small intestine.
As discussed previously, the intestinal permeability allows protein molecules to enter the bloodstream and activate cytokines and antibodies against the foreign proteins. The unabsorbed food and nutrients can lead to nutrient deficiencies, autoimmunity and inflammation.
How do you know if consumption of gluten is causing a leaky gut?
Here are some of the possible symptoms of intestinal permeability:
- Digestive distress: gas, bloating, diarrhea, IBS
- Food allergies, sensitivities
- Hormonal imbalance: PMS, PCOS
- Autoimmune disease (multiple sclerosis, rheumatoid arthritis, Celiac, Hashimoto’s)
- Chronic fatigue, fibromyalgia, headaches
- Mood issues: anxiety, ADD, ADHD, depression
- Skin issues: acne, rosacea, eczema
- Allergies, asthma
You have symptoms, and you suspect you have leaky gut. Now what?
Heal with the 4-R protocol
1. Remove inflammatory foods
- Sugar (artificial and natural)
- Processed foods
- Non-gluten grains (including corn, soy)
- NSAIDS, antibiotics
- Other consideration: eggs, nuts and seeds, caffeine, legumes, nightshades
An elimination protocol is an excellent method to determine if gluten, or other gut irritants like sugar and artificial sugar are disrupting the intestinal membrane. Remove it for 30 days, then reintroduce it and see how you feel.
Those with gluten intolerance can cross-react with other foods that have a similar molecular structure to that of gluten. Cross-reactant foods include dairy, alcohol, caffeine, eggs, legumes, nuts and seeds, and non-gluten containing grains like corn and soy. Again, an elimination protocol is the best method to determine if these foods are irritating your gut.
After removing reactant foods, NSAIDS, medications and stress, it’s time to replace them with nutrient-dense, reparative foods to help rebuild a strong gut.
2. Replace for proper digestion
- Anti-inflammatory foods
- Meats, vegetables, fruits, healthy fats, fermented foods
- Try digestive enzymes
- Amylase, protease, lipase with every meal
- Mineral-rich bone broth
- Rich in amino acids glutamine and glycine to repair gut-lining
3. Repair gut lining
- L-glutamine – repairs gut lining – 5-10 mg./day
Glutamine is the most abundant amino acid in the bloodstream and supports intestinal mucosal growth. Glutamine is in grass-fed beef, bison, chicken, eggs and bone broth. L-glutamine can also be supplemented twice per day in between meals at 2-5 grams.
- Zinc – supports healing of the gut – 30-60 mg./day
Zinc is necessary for maintaining a strong intestinal wall. Zinc also supports a healthy immune system and is a critical part of the antioxidant cycle. A deficiency in zinc can weaken the integrity of the intestinal wall, creating a more permeable barrier. However, a study recently showed supplementing with zinc improves intestinal lining integrity.
Excellent sources of zinc include oysters, beef, lamb, turkey, sesame seeds and pumpkin seeds.
- Vitamin B5 (pantothenic acid) – soothes gut lining – 250-500 mg./2-3 times per day
Like zinc, Vitamin B5 is necessary for maintaining a strong intestinal wall. Vitamin B5 strengthens the integrity of the intestinal wall and creates a less permeable barrier.
Excellent sources of Vitamin B5 include shiitake mushrooms, avocados, sweet potatoes, chicken and turkey.
- Marshmallow root is a demulcent herb; it helps relieve inflammation and irritation due to its cooling, soothing and slippery nature. Marshmallow root and other demulcent herbs are not meant to treat leaky gut or an irritation of the gut, but instead help to ease short-term digestive distress.
- Slippery Elm, like marshmallow root, is a demulcent herb and provides a soothing film over a potentially inflamed mucous membrane. Demulcent herbs are helpful for conditions like IBS, colitis and heartburn.
4. Reinoculate with healthy bacteria
- Non-dairy fermented foods, like raw sauerkraut, kimchi
- Probiotic to restore gut ecology and function; 50+ billion IU, 10+ strains OR soil-based probiotic, L. acidophilus or B. bifidum
Sure, general awareness of leaky gut may take time (maybe because the term leaky gut sounds a bit cartoonish?).
Meanwhile, if suffering from digestive distress or an autoimmune condition, it may be helpful to try an elimination protocol for 30 days, then replace, repair and reinoculate the gut.
Bauman, E., Friedlander, J. Lecture Slides from Unit 106 (Vitamins and Minerals). Penngrove, CA: Bauman College, 2015.REFERENCES
Beyond Paleo. Chris Kresser. Retrieved from https://chriskresser.com/beyond-paleo-6.
Effect of Lactobacilli on Paracellular Permeability in the Gut. 2011 January. Retrieved from http://www.drperlmutter.com/study/effect-lactobacilli-paracellular-permeability-gut/.
Leaky Gut Syndrome in Plain English – and How to Fix It. SCD Lifestyle. Retrieved from http://scdlifestyle.com/2010/03/the-scd-diet-and-leaky-gut-syndrome/.
Molecular Mechanisms Contributing to Glutamine-Mediated Intestinal Cell Survival. PudMed. 2008 Dec. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2432018/.
Tight junctions, intestinal permeability, and autoimmunity: celiac disease and type 1 diabetes paradigms. PudMed. 2009 May. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19538307.
Zinc supplementation tightens "leaky gut" in Crohn's disease. PudMed. 2001 May. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11383597.