Chris
Masterjohn and Dr Datis Kharrazian have been talking about importance
of Vitamin A for “immune tolerance” for years, particularly regarding
immune tolerance,
preventing autoimmunity, and
managing allergies !!
Masterjohn has focused on the synergistic relationship between Vitamin A and Vitamin D, 
he argues they work together to prevent Autoimmunity.

Deficiencies in Vitamins A and D can lead to post-infectious autoimmunity 
by failing to properly regulate the immune system's response !
Masterjohn notes that Vitamin A deficiency is a significant, 
often overlooked cause of allergies and can lead to increased reactivity (e.g., in the gut or eyes).

Vitamin A helps suppress overactive Th17 cells while boosting immunity against infections.
He advises caution with high-dose supplementation, often recommending
testing blood retinol levels (aiming for 600-700 µg/L) and
using liver (within safe, 
moderate amounts) as a primary source.
( The Weston A. Price Foundation )
Dr Kharrazian says Vitamin A is a key
modulator required to boost anti-inflammatory regulatory T cells (T-reg cells).

He uses Vitamin A help the immune system stop reacting to food proteins and environmental triggers (improving "oral tolerance").

He has argued that addressing micronutrient deficiencies like Vitamin A is crucial, especially when dealing with
chemical sensitivities and
intestinal barrier issues.
Using Vitamin A as a modulator, not just an immune booster, to restore balance.
Preventing the loss of tolerance that leads to autoimmune diseases.

Evidence supports the role of Vitamin A in strengthening the gastrointestinal (GI) barrier and regulating immune responses, 
although the ability to specifically "stop" reactions to salicylates and tannins is not yet a direct clinical claim.

Effect on GI Permeability
Vitamin A (and its metabolite, retinoic acid) is essential for maintaining the physical barrier of the gut.
Tight Junctions
VItamin
A directly improves the expression of "gatekeeper" proteins like
occludin, claudin-1, and ZO-1, which seal the gaps between intestinal
cells.
VItamin A It promotes the secretion of mucin !! (
MUC2),
the protective gel layer that prevents pathogens and irritating
chemicals like tannins from reaching the sensitive gut lining !!
Repair:
Supplementation
has been shown to reduce markers of "leaky gut" (such as serum zonulin
and diamine oxidase) following infection-induced damage.
Interaction with Salicylates and Tannins

While Vitamin A doesn't neutralize these chemicals directly, it addresses the consequences of sensitivity:
Tannins can irritate the gut lining

Vitamin A helps by reinforcing the mucus layer that acts as a buffer against these astringent compounds.

Salicylates Intolerance often involves mast cell overactivity and a 
lack of immune tolerance.

Vitamin A is crucial for inducing Regulatory T cells (Tregs), which are the primary cells responsible
for teaching the immune system 
not to overreact to food proteins and chemicals.
Reducing Antibodies and Food Reactivity
There
is no clinical evidence that taking Vitamin A will immediately "delete"
existin antibodies, but it modulates the environment where they act !!
Immune Tolerance:
By
promoting Treg production, Vitamin A helps the body transition from an
"attack" mode (autoimmunity/reactivity) to a "tolerance" mode.
It
has been shown to reduce pro-inflammatory cytokines (like IL-6 and
TNF-α) which are often elevated when food sensitivities trigger joint
pain or systemic flares.

Anti-Inflammatory Effect


In post-infection states, Vitamin A can reduce the recruitment of inflammatory cells to the gut, potentially 
calming the "false alarms" that occur when your friend eats reactive foods.


Note
on Safety: Vitamin A is fat-soluble and can be toxic in high doses. It
is critical to consult a professional to check blood levels before
starting high-dose supplementation, especially if already dealing with a
stressed liver or metabolic system post-infection.
Vitamin A and vitamin D regulate the microbial complexity, barrier function and the mucosal
While
Vitamin A is not a direct antidote for salicylate or tannin reactions,
it plays a critical role in supporting the systems that prevent these
symptoms


How Vitamin A Addresses Respiratory "Air Hunger"
Vitamin A (retinoic acid) is essential for maintaining the integrity of the respiratory epithelium—the lining of the airways.

Reduces Airway Hyperresponsiveness: Vitamin A deficiency is linked to "twitchy" airways that overreact to triggers.
Supplementation
may help stabilize these tissues, making them less likely to spasm or
feel "tight" when your friend is exposed to salicylates.
Alveolar
Support: Vitamin A is vital for the formation and maintenance of lung
alveoli, the tiny sacs where oxygen exchange happens.


Strengthening these can theoretically improve the efficiency of breathing 
Stopping GI Permeability (The "Root" of the Reaction)


 Vitamin A is a primary regulator of intestinal tight junctions.
By repairing the "leaky gut", Vitamin A can reduce the amount of undigested salicylates and tannins that enter the bloodstream.

It promotes T-regulatory (Treg) cells, which signal the immune system to stop attacking harmless food chemicals. 
This can help lower the circulating antibodies and reduce the systemic "alarm" that leads to joint pain and air hunger. 
Why Salicylates Cause Air Hunger

In
people with this intolerance, salicylates interfere with the COX enzyme
pathway, leading to an overproduction of leukotrienes. 

Leukotrienes are powerful chemicals that cause bronchoconstriction (narrowing of airways) and 
mucus buildup, which directly causes the sensation of air hunger.

Salicylates can also act as a direct respiratory stimulant in the brain's medulla, 

which can trick the body into hyperventilating even when oxygen levels are normal.
Important Precautions

Dosage is Critical: While Vitamin A helps, 
excessive amounts can actually worsen asthma-like symptoms and cause toxicity.