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When we have a healthy gut, our small intestine has a strong lining, called the intestinal barrier that handles nutrient absorption very well.
The intestinal barrier covers a surface area of around 400 m² and requires about 40%of the body’s energy expenditure.
The Importance of a Healthy Gut
The intestinal barrier plays an essential role in health and disease. It allows nutrients to be absorbed from food and protects harmful substances from entering the body, such as allergens, bacteria, fungi, and parasites.
Its role is a gatekeeper means that it contains holes that are the perfect size to allow only the necessary nutrients into the body, and to prevent anything else from entering.
However, when intestinal permeability weakens, these holes begin to allow harmful substances into the body, causing problems.
They trigger inflammation and create changes in the microbiome, which can lead to more serious health conditions.
When this occurs, it is called “leaky gut.”
The Symptoms of Leaky Gut
Leaky gut can lead to many different symptoms, which can be very uncomfortable.
This includes digestive issues, such as diarrhea, constipation or bloating, fatigue and frequent food sensitivities.
If you’re experiencing any of these symptoms, it is worth visiting a healthcare professional to determine whether these are related to leaky gut, or another health condition.
The Causes of Leaky Gut
Scientists aren’t entirely sure what causes leaky gut to occur. Some people likely have a genetic predisposition to be more sensitive to changes in the digestive system.
However, there may also be other factors at play, such as the contribution of heavy alcohol use and stress.
The Link Between Leaky Gut and Disease
Gut permeability is already known to play a role in several gastrointestinal conditions, such as celiac disease, Crohn’s disease, and irritable bowel syndrome.
At present, it is not clear whether leaky gut may cause issues in other parts of the body.
Some research has suggested that there might be a link between leaky gut and autoimmune conditions, such as lupus, type 1 diabetes, and multiple sclerosis, but there is currently no cause and effect evidence (1, 2).
Other studies have also highlighted a potential link between leaky gut and mental health conditions but more research is needed to clarify this relationship (3).
Diet and Leaky Gut
Several dietary strategies have been proposed to help leaky gut but none have strong scientific evidence for their effectiveness.
It is worth removing foods that you know you are allergic too, whilst trying to maintain a diet that is balanced and contains a wide range of different foods.
Eliminating foods from your diet is generally ill-advised unless it’s medically necessary (for example in celiac disease) and done following the advice of a healthcare professional because it can lead to nutrient deficiencies.
6 Most Helpful Supplements for Leaky Gut
Alongside eating a varied diet, several supplements can help with a leaky gut. These can help to reduce uncomfortable symptoms as well as protect the gut against future problems.
Here are the best supplements for leaky gut:
Zinc is a trace element found in cells throughout the body and is necessary for many metabolic processes.
It helps the immune system to fight off invading bacteria and viruses and it is used by the body to make proteins and DNA.
Zinc also helps wounds to heal and is important for maintaining the senses of taste and smell.
It is found in a lot of different foods but is particularly high in beans, chickpeas, lentils, tofu, walnuts, cashew nuts, chia seeds, flaxseeds, hemp seeds, pumpkin seeds, and quinoa.
Leavening bread can help to boost zinc absorption, which can also be achieved by sprouting beans, lentils and chickpeas.
How does zinc help leaky gut?
Research has found that zinc can modify the tight junctions of the intestinal lining, helping to limit gut permeability.
Taking 110mg of zinc sulfate three times per day for 8 weeks was shown to improve intestinal permeability (4).
The majority of participants continued to have normal intestinal permeability when they were followed up 1 year later. However, after one year two had reverted to having increased intestinal permeability again, highlighting the benefits of taking zinc on an ongoing basis.
How do I take zinc?
Different forms of zinc contain varying amounts of elemental zinc, which refers to the weight of the zinc molecule by itself. There are four main types of zinc: citrate, sulfate, gluconate, and monomethionine.
Achieving a dose of 25 mg zinc per day is recommended to obtain the benefits for leaky gut. This is equivalent to 73 mg of zinc citrate, 193mg of zinc gluconate, 110mg zinc sulfate 119 mg of zinc monomethionine.
Although some studies have demonstrated that zinc can be safely taken in large amounts (called superloading), taking up to 100 mg zinc per day for between 2 and 4 months, this is significantly higher than the 40 mg tolerable upper limit, and thus is not recommended.
Zinc can be taken at any time of the day, ideally with food.
Glutamine is one of the 20 naturally occurring amino acids within the dietary protein. It is considered to be a conditionally essential amino acid because the body can usually meet its needs but during periods of disease or physical trauma, glutamine needs can be elevated.
It can be purchased alone or alongside other amino acids. It is found predominantly in animal products, such as meat and eggs. It is in particularly high amounts in whey and casein protein.
Glutamine can provide benefits for both the intestinal and immune system health compounds because cells use glutamine as a preferred fuel source rather than glucose.
How does L-glutamine help leaky gut?
A review of research found has shown that glutamine can improve the growth and survival of enterocytes, or intestinal cells. It can also help to regulate the function of the intestinal barrier during stress (5).
Studies have also shown benefits for gut permeability during exercise.
A placebo-controlled study compared three different doses of glutamine (0.25, 0.5 and 0.9 g kg−1 of fat-free mass) with placebo taken two hours before exercise. It was found that even the lowest dose, glutamine was able to attenuate gut permeability relative to placebo.
How do I take l-glutamine?
To obtain the benefits of l-glutamine for leaky gut, it is recommended to consume 5 g per day.
Extremely high doses are not recommended due to the potential for excessive ammonia to be created in serum. The lowest dose found to increase ammonia in serum has been 0.75 g/kg.
Glutamine can be taken at any time of the day, and either with or without food.
Probiotics are living microorganisms that help to improve the microbiome of the gut, and are important for maintaining a strong digestive system, as well as the health of other areas of the body.
They are usually bacteria although certain types of yeast can also function as probiotics.
There are many different groups of probiotics. Each of these contains different species, and each species has multiple strains.
Supplements sometimes combine different species in the same product, which are referred to as broad-spectrum probiotics or multi-probiotics.
Probiotics can also be found in foods, such as yogurt, sauerkraut, tempeh, and kimchi.
How do probiotics help leaky gut?
A randomized, double-blinded, placebo-controlled trial found that a multi-species probiotic (1010 CFU) taken daily for 14 weeks was able to improve gut permeability compared to a placebo (6).
The probiotic supplement also significantly reduced markers of inflammation.
A randomized, double-blind, placebo-controlled crossover study found that UCC118 (a specific strain of probiotic) taken daily for 4 weeks was able to significantly reduce exercise-induced intestinal hyperpermeability compared to placebo (7).
How do I take probiotics?
It is unclear which strains of probiotic bacteria are most beneficial for leaky gut so it is recommended to take a broad-spectrum probiotic to obtain multiple strains.
This should be at a strength of at least 1010 CFU.
It should be taken daily, 15-30 minutes before food. They should not be consumed with a hot drink as this will destroy the bacteria.
Fiber consists of non-digestible carbohydrates that pass through the intestines to be excreted out of the body or are fermented by intestinal microbes.
They can have mechanical properties, such as being gel-forming, and/or they can serve as a substrate for the production of short-chain fatty acids via fermentation within the microbiome.
There are two main types of fiber: soluble and insoluble.
Soluble fiber dissolves in water and can be metabolized by the friendly bacteria in the gut.
Insoluble fiber does not dissolve in water.
However, there is a crossover between these two types. Some insoluble fibers can be digested by the bacteria in the intestine, and most foods contain a mixture of both.
A more useful distinction is to categorize fiber as fermentable or non-fermentable, which refers to whether friendly gut bacteria can use it.
How does fiber help leaky gut?
The friendly bacteria produce nutrients for the body, including short-chain fatty acids such as acetate, propionate, and butyrate.
Butyrate appears to be the most important. Research has shown that butyrate plays an important role in gut permeability (10). It is even used as an indicator of gut permeability when measured in fecal concentrations.
Studies have also shown that fiber can stimulate mucus production and improve tight junctions in the lining of the gastrointestinal tract (11).
How do I take fiber?
It is important to be gentle when adding in high-fiber foods or supplementation as increasing your intake too quickly can cause digestive issues.
Supplements come in several different forms, including capsules, powders and chewable tablets.
It is recommended to start with supplementing between 3 and 5 g of fiber per day, increasing gradually if needed.
It is also important to drink plenty of water alongside supplementation to prevent bloating, cramping or gas.
Fiber can be taken at any time of the day.
Licorice is the common name for plants in the Glycyrrhiza family. It has a long history of use in traditional Chinese medicine for digestion and other aspects of health.
The licorice root contains almost 75 bioactive compounds. These can be categorized into four main types: flavonoids, coumarins, triterpenoids, and stilbenoids.
One of the most important compounds in Licorice is glycyrrhizin, which is the sugar-bound form of Glycyrrhetic Acid.
This is found in high amounts in licorice root and is easily absorbed by the body. However, it can cause side effects in some individuals, which are related to its ability to increase cortisol and reduce testosterone levels (12).
To avoid this, licorice can be taken in the form of deglycyrrhizinated licorice, which does not contain glycyrrhizin.
Licorice root with low glycyrrhizin content is also available.
How does licorice help leaky gut?
Research has shown that licorice may be particularly beneficial for digestive issues when taken alongside probiotics and digestive enzymes (13).
This study also demonstrated that licorice has several benefits for digestion, including reducing inflammation and increased mucus production, all of which can help leaky gut.
How do I take licorice?
To avoid the potential for side effects from the glycyrrhizin content of licorice root, it is best to take a supplement with a low glycyrrhizin content.
150 mg has been demonstrated not to affect cortisol or testosterone. If taking a low glycyrrhizin content supplement, it is recommended to take 500 mg per day.
Alternatively, deglycyrrhizinated licorice can be consumed.
If taking the supplement in this form, it is recommended to take 380-400 mg of licorice per day.
Whichever supplement form is chosen, it should be consumed around 20 to 30 minutes before a meal, ideally at breakfast or lunch rather than dinner.
Curcumin is the main bioactive substance in turmeric and gives its yellow color. It’s a polyphenol which has anti-inflammatory properties and can increase the number of antioxidants that the body produces.
Curcumin and the other curcuminoids found in turmeric can be extracted to produce supplements that have a much higher potency than turmeric.
Because curcumin is poorly absorbed during digestion, there are many different formulations available to improve its bioavailability.
When it is absorbed, it tends to concentrate in the digestive tract, which is why it is particularly beneficial for leaky gut (14).
How does curcumin help leaky gut?
A review demonstrated that curcumin has antimicrobial and immunomodulatory properties, which act to improve intestinal barrier function (15).
This research also found that curcumin can regulate gut bacteria, which means it can help maintain digestive health and prevent future problems.
A study also found that curcumin can improve intestinal permeability and reduce inflammatory markers in the gut (16).
This occurs as a result of curcumin being taken up by the intestinal epithelial cells where it modulates several signaling pathways, which prevents disruption to intestinal barrier function (17).
How do I take curcumin?
As curcumin has poor bioavailability, it is best to combine it with other ingredients to enhance absorption. The most commonly used ingredients are piperine (black pepper extract) and lipids, such as CM-95, or Meriva.
If taking curcumin with piperine, it is best to supplement 1500 mg of curcumin and 60 mg of piperine per day, split into three separate doses.
If taking BCM-95, a patented combination of curcumin and essential oils, it is recommended to take 1,000 mg split into two separate doses.
If taking Meriva, a patented combination of curcumin and soy lecithin, it is best to take 400 mg per day, split into two separate doses.
Curcumin can be taken at any time of the day but should be consumed alongside food.
Leaky gut can be associated with uncomfortable symptoms and can cause a wide range of problems in the body. Fortunately, the intestinal hyperpermeability that characterizes leaky gut syndrome can be successfully addressed with diet and lifestyle changes.
This includes eating a wide variety of foods, moderating alcohol intake and reducing sources of stress.
Several supplements can also help to restore intestinal permeability and promote healthy gut bacteria, protecting the body against future gut-related issues.
Keep Reading: The 13 Most Helpful Supplements for High Blood Pressure
ⓘ Any specific supplement products & brands featured on this website are not necessarily endorsed by Emma.
Stock Photos from SewCream / gritsalak karalak / Shutterstock
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About the Author
Emma Green has a PhD, MSc and BSc in Psychology and is a certified personal trainer. She currently works as a freelance writer, producing on content on science, health and fitness for a number of online platforms. She also coaches clients online on a one-to-one basis to help them achieve their health and fitness goals. Contact Emma.