Mucosal barrier

Question 1

Mucosal barrier

Answer 1

Mucosal barrier = mucus covering the entire GIT provides a thick barrier between the immune-stimulating contents of the outer world and the multitude of immune cells in the gut wall (1 st line of defence). * Mucus contains water (96–98%), glycoproteins called mucins, IgA and anti-microbial peptides such as α and β defensins.

• In ulcerative colitis, it has been observed that the inner mucosal lining becomes permeable = large amount of bacteria in close contact with host tissues = inflammation.
• Mucus provides an adhesion site / nutrient source for commensals.
• A disturbed mucosal barrier can lead to bacterial translocation and the leakage of LPS → metabolic endotoxaemia

Question 2

Supporting the mucosal barrier

Answer 2

• Optimise dietary fibre (because if you don’t feed the bacteria, they can eat your mucins!).
• A diet rich in polyphenols — feeds commensal bacteria (including the important ‘keystone’ bacteria Akkermansia spp.) and protects the mucin lining; reduces inflammation.

‒ Green tea, blueberries, cranberry, blackcurrants, pomegranates.

• Mucopolysaccharides such as slippery elm, marshmallow root, liquorice and flaxseeds.
• Fucoidans, which are polysaccharides, in seaweeds and algaes.

Question 3

Intestinal tight junction permeability

Answer 3

• Intestinal tight junction disassembly contributes to ↑ LPS load and excessive immune reactions.
• Support the intestinal epithelial barrier with:

‒ Glutamine — supplemented or from food, e.g., cabbage juice, spirulina, asparagus.
‒ Zinc carnosine, vitamin A and N-acetyl glucosamine. ‒ Bone broth (rich in glycine).

• Testing: Zonulin (stool). ‘Cyrex Labs Array 2’ (serum antibodies).

Question 4

Bone broth recipe

Answer 4

Bone broth recipe:

• 1 chicken carcass
• 1 stalk celery
• 1 carrot
• 1 onion
• Small bunch of herbs:

(e.g ,bay, thyme)

• 5 peppercorns
• 2 tbsp apple cider vinegar Cover with plenty of water, bring to boil and simmer for 12–24 hours.

Question 5

Secretory IgA

Answer 5

Secretory IgA = resides in the mucosal lining and protects the intestinal epithelium from toxins and pathogenic microbes through a process called ‘immune exclusion’ (promoting the clearance of antigens by blocking their access to epithelial receptors).

• SIgA plays a role in immune tolerance by ‘tagging’ microbes.
• Low SIgA: Increases the risk of GI infections including SIBO.
• Low SIgA can be caused by: Ongoing emotional / physical stress, NSAIDs and antibiotics

Question 6

How to increase SIgA

Answer 6

• Address stress.
• Saccharomyces boulardii (a non-pathogenic yeast).
• Mushrooms (esp. medicinal varieties due to the ↑ beta-glucans).
• Vitamin A (needed for the transport of SIgA over the mucosal lining).
• Vitamin D3 (upregulates SIgA expression).
• Polyphenols (e.g., green tea, cocoa, pomegranate).
• Chlorella.
• Probiotics and prebiotics.
• Echinacea spp