What is "Leaky Gut" and Could it be the Cause of Your Child's Symptoms?

Leaky gut, also known as increased intestinal permeability, is a digestive disorder that develops when tight junctions loosen or become damaged and allow undigested food, bacteria, or toxins to leak through the wall of the intestine ^[1]. Tight junctions are small gaps in the intestinal lining that promote the transfer of nutrients, while preventing undesirable compounds from passing through the intestinal tract into the bloodstream.

Unfortunately, when tight junctions loosen, harmful substances begin to accumulate in the bloodstream and this may cause various types of inflammatory issues ^[2]. In addition to inflammation, symptoms such as food sensitivities, bloating, gas, cramps, and additional digestive problems may develop as a result of leaky gut.

Although some healthcare providers do not consider leaky gut as an actual medical diagnosis, mounting scientific evidence indicates that this a true condition that affects many people and may be associated with the onset of numerous health problem such as allergies, asthma, skin disorders, and chronic fatigue syndrome (CFS), among other issues ^[1-4]. Furthermore, many children with attention deficit hyperactivity disorder (ADHD), autism, and other forms of developmental delays tend to suffer from digestive issues including leaky gut. ^{[5, 6]}

One of the main reasons that mental health is linked to digestive health is because in addition to playing a role in the transfer of essential nutrients to the brain, the lining of the intestinal tract is comprised of numerous nerves and beneficial gut bacteria that also support optimal cognitive function ^{[5, 7]}. However, in order to promote proper nutrient transport to the brain, the intestinal environment must be healthy.

Leaky gut causes harmful substances to damage the intestinal lining and this disrupts normal digestive function. Similarly, if nerves in the gut become inflamed or damaged due to leaky gut, then the transfer of nerve signals that influence mental performance will also be negatively impacted. Therefore, leaky gut can worsen the symptoms of ADHD and autism ^{[5, 7]}.

The development of leaky gut is associated with a number of factors that include: bacterial or candida (yeast) overgrowth in the gut, taking certain medications, and eating inflammatory or gut-irritating foods. However, two of the main triggers are bacterial overgrowth and gluten intake because they enhance the production of a protein called zonulin. As zonulin levels increase, tight junctions gradually begin to loosen and this causes harmful substances to pass into the bloodstream, the immune system becomes overactive, and it causes children to experience intestinal discomfort ^{[8, 9]}. 

There are several strategies that help target leaky gut symptoms in children with ADHD or autism. The first strategy involves eliminating food that irritates the gut or causes inflammation. These include: 

• Gluten-based food, as this protein is hard to digest and it is a common allergen  
• Dairy products, as some children are intolerant to casein (milk protein)  
• Corn, soy, and eggs, as these are also common allergens

Eliminating these foods from the diet helps promote natural healing of the intestinal tract and this is especially beneficial for children with autism or ADHD.

Micronutrient and probiotic supplementation also foster a healthier intestinal environment and research shows that this type of supplementation helps improve behavior in children with developmental delays ^{[10, 11]}.

Micronutrient supplementation addresses nutritional deficiencies that may be contributing to cognitive impairments and probiotics improve digestive function by targeting harmful bacteria that cause intestinal inflammation, enhancing nutrient absorption, and releasing enzymes that heighten the digestion of food ^{[6, 10]}. The combination of these types of strategies target leaky gut by supporting the restoration of proper tight junction function. This can improve intestinal and cognitive health for children with autism and ADHD.

References

1. Maes M, Leunis JC. Normalization of leaky gut in chronic fatigue syndrome (CFS) is accompanied by a clinical improvement: effects of age, duration of illness and the translocation of LPS from gram-negative bacteria. Neuro Endocrinol Lett. 2008;29(6):902-10.
2. Odenwald MA, Turner JR. Intestinal permeability defects: is it time to treat? Clin Gastroenterol Hepatol. 2013;11(9):1075-1083. 
3. Farshchi MK, Azad FJ, Salari R, et al. A Viewpoint on the Leaky Gut Syndrome to Treat Allergic Asthma: A Novel Opinion. J Evid Based Complementary Altern Med. 2017;22(3):378-380. 
4. Simeonova D, Ivanovska M, Murdjeva M, et al. Recognizing the leaky gut as a trans-diagnostic target for neuro-immune disorders using clinical chemistry and molecular immunology assays. Curr Top Med Chem. 2018, in press.
5. Molloy CA, Manning-Courtney P: Prevalence of chronic gastrointestinal symptoms in children with autism and autistic spectrum disorders. Autism. 2003;7(2):165-171.
6. Ming X, Chen N, et al. A Gut Feeling: A Hypothesis of the Role of the Microbiome in Attention-Deficit/Hyperactivity Disorders. Child Neurol Open. 2018;5:2329048X18786799. 
7. Verlaet AA, Noriega DB, Hermans N, Savelkoul HF. Nutrition, immunological mechanisms and dietary immunomodulation in ADHD. Eur Child Adolesc Psychiatry. 2014;23(7):519-29. 
8. Fasano A. Intestinal permeability and its regulation by zonulin: diagnostic and therapeutic implications. Clin Gastroenterol Hepatol. 2012;10(10):1096-100.
9. Fasano A. Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011; 91(1):151-75.
10. Rucklidge JJ, Eggleston MJF, Johnstone JM, Darling K, Frampton CM. Vitamin-mineral treatment improves aggression and emotional regulation in children with ADHD: a fully blinded, randomized, placebo-controlled trial. J Child Psychol Psychiatry. 2018;59(3):232-246. 
11. Sheridan PO, Bindels LB, et al. Can prebiotics and probiotics improve therapeutic outcomes for undernourished individuals? Gut Microbes. 2014; 5(1):74-82.