Leaky gut is becoming a hot topic, and many people are asking questions about what it is and how they can fix it if they have it. In this article, I will go over exactly what leaky gut is, and what evidence-based natural treatments we can use to help resolve it.
Leaky gut is more popular now than ever. This is due, primarily, to the interplay of overuse of antibiotics, a poor diet, food sensitivities, and sometimes even too much exercise(41)!
To put it simply, leaky gut is a disruption of the tight-junction barrier in the intestines.(1) Tight junctions regulate how macromolecules (large molecules) can travel between cells and enter into the body. They are supposed to be very selective in what they let through. When these tight junctions become disrupted, large food molecules like gliadin (from gluten) and bacteria(2) may be able to pass through.
When big molecules get passed the gut barrier that shouldn’t, big problems can occur. One response that can occur is called “molecular mimicry”.(3) Molecular mimicry happens when an antigen is able to get into the bloodstream that shouldn’t have, and it happens to have a similar “structure” as a self-antigen. When the body’s antibodies (or, many times, T-cells) have to attack the antigen to clear it from the blood, those same cells can start attacking the body’s own structures or organs, such as the thyroid(4), joints(5,6), nervous tissue(7), or intestinal cells(8). These reactions can contribute to autoimmune diseases such as thyroiditis, rheumatoid arthritis, multiple sclerosis, and celiac disease, among others.
While it would not be accurate to say that every autoimmune disease is originally caused by a leaky gut and molecular mimicry, we do have enough information to say that for many patients, increased intestinal permeability contributes to the whole body and specific inflammation in autoimmune diseases for many patients. Furthermore, some autoimmune conditions may benefit from diets that limit specific dietary antigens. One study has already shown that a gluten-free diet can benefit many patients with rheumatoid arthritis(6).
While there has also been evidence that having a gluten-free diet does not benefit all autoimmune patients, the most prudent approach is to test to see if the patient does have any food allergies or sensitivities with a blood test, and then see if removing those foods improves symptoms for that patient.
A “leaky gut” or increased intestinal permeability can easily be tested with a mannitol/lactulose test by a functional medicine practitioner or anyone else who is skilled in testing for gut-related issues. This test uses the two different compounds to see how much is getting through a transcellular route (through the cells themselves) and through a paracellular route (between the intestinal cells).
Besides removing any food allergies/sensitivities, giving the patient-specific supplements to help their gut barrier “tighten up” will automatically decrease the number of antigens that can get through the gut lining and cause problems. Additionally, this can lead to a reduction in whole-body inflammation.(9)
The following are some key nutrients that can help to decrease intestinal permeability:
- MSM (methylsulfonylmethane, the popular joint supplement)
- This one needs more formal research. Yet, the decrease in allergy symptoms and gut issues tend to support the idea that the sulfur of MSM is being used to increase collagen production in the gut. MSM is part of my protocol for most people with allergy symptoms and increased gut permeability.
- Niacin(10,11) and Niacinamide
- While we have evidence that niacin is important for tight junction function, niacinamide does seem to be able to decrease allergy symptoms.(12) Still, niacin would probably be the better choice here, as it also has other anti-inflammatory properties that make it very beneficial for autoimmune diseases such as multiple sclerosis.(13)
- In my opinion, niacin is highly underutilized as a weapon against gut-related issues.
- Glycine increases tight junction function.(14) Glycine can be taken as a stand-alone supplement, or you can take gelatin, hydrolyzed collagen, or make/buy bone broth (all have a high amount of glycine as well as some other beneficial amino acids such as proline).
- Glutamine protects the integrity of intestinal tight junctions.(15)
- Vitamin D supplementation helped to maintain intestinal permeability in those with Crohn’s disease while the placebo group deteriorated.(31)
- Zinc is important for tight junction formation, and supplementation can enhance intestinal barrier integrity.(16)
- Usually 15-30mg of zinc picolinate is enough for most people. It is always beneficial to test your mineral levels before supplementing though, as zinc competes with copper and iron for absorption.
- Flaxseed and its oil(17)
- Ground flaxseed can be irritating to some people with IBS or related conditions, so flaxseed oil would be more prudent in that case.
- Fish oil / Cod liver oil(18,19)
- The omega 3’s from fish oil (EPA and DHA), as well as the omega 3 from flaxseed oil (ALA), can all be tested by a functional medicine doctor with a blood test to see if you need to supplement. This test will also look at the omega-3/omega-6 ratio, which can help you know if you need to lower your omega-6 intake (from vegetable oils). Omega-6 fats can worsen leaky gut in high amounts.(20,21)
- Be careful where you buy your fish oil from. Many fish oils are already rancid by the time you consume them, which greatly diminishes the ability for them to help you. Also, many fish oils can have high levels of persistent organic pollutants which are not good to consume over time. You can use Labdoor to help you decide on a fish oil supplement.
- Curcumin can enhance the gut barrier function, as well as decrease intestinal inflammation and circulating endotoxins.
- Probiotics and help synthesis new tight junction proteins, help repair the intestinal mucosa, and protect the gut barrier from damage.(28)
- Probiotics can be in the form of a pill, yogurt, kombucha, and/or other fermented foods
- One of my favorite probiotics is apple cider vinegar with the “mother” still in it. These bacteria naturally live in a very acidic environment (i.e. vinegar), so it is more likely that they will survive digestion through the stomach acid make it to the large intestine.
- Apple cider vinegar also has other beneficial properties such as helping to fight off candida and pathogenic bacteria(29) and has anti-inflammatory properties(30)
While there are some others such as n-acetylglucosamine and intestinal alkaline phosphatase that can help to decrease permeability, I believe that the list above should be focused on as far as supplementation goes. (There is also some preliminary research that n-acetylglucosamine may be able to enhance the survival of candida, which would not be good for individuals who are suffering gut issues due to candida overgrowth.)
As far as diet goes, there are many things that you can do that can help to increase tight junction function.
Foods to add:
- Virgin Unrefined Coconut Oil.
- While there haven’t been any studies specifically done on coconut oil to test its ability to decrease intestinal permeability, there are many reasons why it would be a good addition for someone with a leaky gut.
- One of the ways that a leaky gut can be caused is by candida, a fungus that is usually present in low amounts in the colon. When it is allowed to grow out of control (by taking antibiotics, for example, because these can kill the beneficial bacteria, especially lactobacilli, that usually competes with candida and keeps it in check via hydrogen peroxide production), candida can invade the intestinal mucosa, cause disruption and inflammation of the gut barrier, and even increase the possibilities to develop food allergies/sensitivities (common with leaky gut).(22,23)
- Candida can be tested for via a stool test by a functional medicine practitioner to either rule it in or out. This will help you focus on the right strategies to heal your individual leaky gut, because treatments specifically for candida overgrowth are different than treatments for a leaky gut due to a low omega-3/omega-6 ratio or reduced levels of niacin, for example.
- While detailing a treatment protocol for candida overgrowth is beyond the scope of this article, virgin unrefined coconut is one of the effective treatments to help get rid of candida over time via the capric and lauric acid that is in coconut oil.(24)
- Candida is becoming more of an issue in recent years due to the increase in consumption of refined carbohydrates and lower levels of polyphenols in the diet. Unrefined carbohydrates are loaded with polyphenols, which inhibit the growth of pathogenic bacteria and candida, while refined carbohydrates can easily feed candida.(25)
- Virgin Unrefined Coconut oil also has many anti-inflammatory properties as a great side effect (due to the abundance of polyphenols present in the unrefined version)!(27)
- Cooked vegetables / natural fiber
- While vegetables are beneficial for health in general, some people with impaired intestinal permeability cannot handle raw vegetables very well. For this reason, lightly steamed vegetables are the best way to go for digestive health.
- Many vegetables also provide a great mix of fiber and polyphenols to the colon. This mixture helps to feed the good bacteria while inhibiting the growth of pathogenic bacteria and fungi. The fiber will get eaten by the good bacteria and produce short-chain fatty acids such as butyrate as a byproduct. These short-chain fatty acids and also help improve the intestinal barrier.(32)
- It is important to remember that fiber from whole foods like vegetables comes with an abundance of polyphenols. These polyphenols help to modulate the gut microbiome, which will make the fiber even more beneficial. Taking fiber as a stand-alone supplement is devoid of these polyphenols, which means that potentially any type of bacteria, good or not, can eat that fiber and grow. While there definitely are differences between types of fiber, this general principle holds.
- Spices and herbs
- We’ve already stressed the importance of polyphenols, but here is where you take out the big guns.
- Spices / herbs are some of the foods that have the highest polyphenol count. These food ingredients interact with the gut microbiome to promote homeostasis and a reduction in inflammation.(33,34)
- Try to include foods like garlic, turmeric, marshmallow root, onions, dandelion, ginger, cinnamon, etc. into your diet on a regular basis. You can add these to foods, cook with them, or take them as supplements.
- Be careful with very spicy herbs such as cayenne, paprika, and sometimes even ginger. While the spicy polyphenols like capsaicin can increase mucous production over time (which is beneficial in the GI tract), starting with large doses can cause trouble for some people. If you choose to try these, start low and go slow so your body has time to adapt.
Foods to avoid:
This section is the trickiest to give recommendations for because everyone’s body is so different and different people react to different foods. Your best bet for knowing which foods to remove from your diet is to seek out a knowledgeable functional medicine doctor who does up-to-date food allergy and sensitivity testing. (I say “up-to-date” because there are some practitioners who utilize outdated food allergy tests that can have many false-positives due to cross-contamination or be interpreted poorly. For example, IgG4 testing is widely utilized, yet for many people, high IgG4 antibodies to a particular food may just mean that you have been eating a lot of it. IgG4 antibodies can go up as clinical allergy symptoms go down.)
Being hypersensitive to a particular food or multiple foods is correlated with an increase in intestinal permeability.(35) This goes both ways: eating a food that you are hypersensitive to can increase the permeability of the gut even more, and having a leaky gut can promote food hypersensitivities.(3)
Thus, I cannot tell you which foods you may be sensitive to that you should avoid in this article. What I can do is give you some general recommendations that have scientific support for a variety of issues similar to irritable bowel syndrome such as Crohn’s or ulcerative colitis.
- Reducing calories or losing weight if you are overweight
- “In summary, a 4-week caloric restriction resulted in significant weight loss, improved gut barrier integrity and reduced systemic inflammation in obese women.”(36)
- Try the low-FODMAP diet
- The low-FODMAP diet is a particular type of elimination diet that has been shown to be useful for managing the symptoms of a variety of intestinal issues such as IBS, Crohn’s, and ulcerative colitis.
- To learn more about the low-FODMAP diet, click here (article in progress)
- Avoid foods that you are sensitive to via an allergy/sensitivity blood test, or try an elimination diet and slowly add foods back in one by one to determine which are giving you symptoms. (Note: It can take up to a week for symptoms to appear from some foods, so add back foods slowly.)
- Avoid bad fats, particularly omega-6 fatty acids (37)
- Check nutrition labels for soybean oil, corn oil, sunflower oil, safflower oil, or cottonseed oil. Avoid fried foods as well, as these are likely cooked in omega-6 fats.
- Avoid consuming too many saturated fats, as these can increase the ability of lipopolysaccharide (a part of the outer membrane of gram-negative bacteria, also called “endotoxin”) to get from the gut to the bloodstream, which can increase inflammation throughout the body. (40)
- Avoid refined sugars and carbs
- Refined sugars and carbs are devoid of beneficial nutrients like fiber and polyphenols. Without these nutrients that help to modulate the gut microbiome, these carbs are able to have free reign to feed whatever in your gut.
- Sugars from natural sources like fruit will not present such an issue most of the time, as they come with fiber and polyphenols. (38, 39)
- Remember, this is for whole fruits or fruits that have been completely blending, leaving everything in them. Fruit “juice” has a much higher ratio of sugar to fiber/polyphenols.
- Some fruits may still be bothersome to some individuals due to the FODMAPs they contain. Read more about FODMAPs here (article in progress).
- Also, in some conditions, like those who have systemic candida infections, it would be better to reduce sugar to as little as possible. This does not apply to someone with just increased permeability, though.
While there are many other treatment options available for irritable bowel syndrome, ulcerative colitis, Crohn’s, other autoimmune conditions, etc., fixing your leaky gut is definitely a foundational step that will help to keep your health in check. Furthermore, following the guidelines of this article will also help to improve your intestinal microbiome, which also has a wide-ranging impact on overall health!
Please leave a comment, questions, or any experiences you have had with this condition below! I would love to hear from you!
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