Leaky gut

Leaky gut’ is gaining more attention by the day. This is because various diseases are increasingly associated with the state of our gut. Increased intestinal permeability, also known as ‘leaky gut’, can trigger autoimmune diseases, chronic fatigue syndrome, allergies and even depression. In this post, you will learn more about the intestinal barrier, factors that disrupt it, and ways in which you can heal a leaky gut.

CONTENTS [HIDE]

• Introduction to Intestinal Barrier
• What Is Leaky Gut
• Leaky Gut Signs and Symptoms
• Testing for Intestinal Permeability
  • The Lactulose-Mannitol Test
  • Zonulin Blood Test
  • Food Sensitivity or Antibodies Against Foods
• Causes of Leaky Gut
  • 1) Poor Diet
  • 2) Lectins
  • 3) Chronic Stress
  • 4) Injury
  • 5) Strenuous Exercise
  • 6) Alcohol
  • 7) Bacterial Imbalance – Dysbiosis
  • 8) Infections
  • 9) Inflammation
  • 10) Drugs, including NSAIDs and PPIs
  • 11) Zinc Deficiency
  • 12) Vitamin Deficiency
  • 13) Vitamin C
  • 14) Iron
  • 15) Circadian Rhythm Disturbances
  • 16) Radiation
  • 17) Chemotherapy
  • 18) Birth and Infancy
  • 19) Formula Vs. Breast-Feeding
  • 20) Aging
• Diseases Linked to Leaky Gut
  • 1) Autoimmune Diseases
  • 2) IBD
  • 3) IBS
  • 4) Chronic Fatigue Syndrome
  • 5) Diseases of the Nervous System
  • 6) Depression
  • 7) Autism
  • 8) Allergies
  • 9) Asthma
  • 10) Eczema, Psoriasis, and Acne
  • 11) Obesity
  • 12) Diabetes
  • 13) Liver Disease
  • 14) Obstructive Sleep Apnea
  • 15) Cancer
• How to Heal a Leaky Gut
  • 1) Lectin Avoidance Diet
  • 2) Beneficial Foods
    • Unsaturated Fat (Omega-3)
    • Fermented Dairy and Vegetables
    • Broccoli Sprouts
  • 3) Stress Management
  • 4) A Healthy Circadian Rhythm
  • 5) Avoid Alcohol
  • 6) Moderate Exercise
  • 7) Avoid Medications That Cause Leaky Gut
  • 8) Vitamins and Minerals
    • Vitamin A
    • Vitamin D
    • Vitamin B
    • Zinc
  • 9) Supplements
    • Glutamine
    • Quercetin
    • Melatonin
    • Lipoic Acid
    • Ginkgo
    • Curcumin
  • 10) Probiotics
  • 11) Prebiotics
  • 12) Butyrate
  • 13) Drugs
  • 14) Reduce Inflammation
  • 15) Address chronic infections
• Genetic Factors that Influence Intestinal Permeability
  • HLA-DQ2.5 and HLA-DQ8.1
  • MYO9B
  • NOD2/CARD15
  • JAK2
  • MAGI2, MAGI3, and PARD3
  • AHR

Introduction to Intestinal Barrier

Source: http://www.nature.com/ctg/journal/v7/n10/fig_tab/ctg201654f1.html#figure-title

The main function of the gut is to absorb nutrients from the food. However, the gut also has another important function – to keep harmful things such as bacteria (good as well as harmful), toxins, and food antigens (inflammatory agents) out and away from the rest of the body [R].

This barrier basically separates the gut content from the body. It is made of a single layer of cells (epithelial cells, sensing cells, and cells that produce enzymes and neurotransmitters).

These cells are linked by tight junction (TJ) proteins [R].

The intestinal/gut barrier covers a surface of about 400 m2. It uses approximately 40% of the body’s energy expenditure and it is renewed approximately every 5 days [R].

Many other factors help support this barrier [R]:

• Mucus
• Beneficial gut bacteria
• Antimicrobial molecules
• Immunoglobulins (especially IgA)
• Cytokines

Gut bacteria, in particular, have many beneficial roles in maintaining the intestinal barrier [R]:

• They help the digestion and absorption of nutrients
• Prevent colonization by harmful bacteria
• Stimulate immunity
• Improve our mood

What Is Leaky Gut

When there are abnormalities in the intestinal barrier, the intestinal permeability increases. This means more of the gut content can pass/leak through, which is referred to as “leaky gut” [R].

When the gut is ‘leaky’, gut bacteria and their products can escape the gut, which can produce inflammation and cause tissue damage [R].

Also, food-derived antigens (proteins or partially digested proteins) can pass through the gut and promote both local or whole-body immune responses [R].

Zonulin is a protein that causes tight junctions to open. When tight junction open, intestinal permeability increases. Bacteria and gluten are examples of agents that can cause ‘leaky gut’ by increasing zonulin [R, R]. Zonulin levels may be a measure of paracellular (between cell) gut permeability.

Leaky Gut Signs and Symptoms

How do you know if you suffer from ‘leaky gut’? You will likely experience one or more of the signs and symptoms listed below:

• Bloating
• Gas
• Cramps
• Food sensitivity
• Pain
• IBD
• IBS
• Autoimmune disease
• Thyroid problems
• Skin conditions (inflammatory, acne)

Testing for Intestinal Permeability

The Lactulose-Mannitol Test

This test has been used the longest in both human and animal studies [R].

Lactulose and mannitol are sugars that aren’t broken down in the digestive tract. Mannitol is smaller and gets absorbed through the gut. Lactulose is larger and is only absorbed if there is increased intestinal permeability [R].

Levels of lactulose vs. mannitol can then be measured in the urine [R].

Note that decreased gut flow and kidney dysfunction can affect the results. The test is also unsuitable in patients on blood transfusion since mannitol is used in the storage solution of banked blood [R].

Zonulin Blood Test

Zonulin is a protein that causes tight junctions to open. More zonulin means higher intestinal permeability.

It is a good marker for leaky gut and autoimmune diseases that are caused by the zonulin pathway [R, R]. Blood tests for zonulin are now available.

Food Sensitivity or Antibodies Against Foods

With an intact gut, the immune system should not be exposed to the gut content. Therefore there shouldn’t be a lot of antibodies against foods. By inference, if you have a lot of antibodies against various foods, you likely have some intestinal permeability.

Read more